-------
                      Car 685- Oxygen injection
           O
           c/5
              100
               80
               60
               40
               20
                            23456

                               Oxygen,%
Figure 4-1.  Sulfuric acid emissions  as  a  fraction of oxygen injection

level.  318 Chrysler with air pump  and monolith catalyst.




Source:  U.S. Environmental  Protection Agency (1976b).
                               88

-------
     As mentioned above, reductions of the oxygen level in oxidation catalyst



systems may result in an increase in HC and CO emissions.   Future advances in



oxidation catalyst technology may overcome this problem.  Three-way catalyst



systems, which have an inherently low oxygen level, tend to have low sulfate



emissions without impaired control of HC and CO emissions.







4.2.1.1  Modification of air injection with oxidation catalyst systems—Current



oxidation catalyst-equipped cars make use of an engine-driven pump which intro-



duces air into the exhaust system upstream of the catalyst.   There are several



potential methods by which the function of this pump can be controlled to limit



the oxygen content of the exhaust stream.







4.2.1.1.1  Diverter valve.    Exxon Research and Engineering used a simple



diverter valve to inject air into the catalyst during the warmup part of the



cold start (Bachman et al.  1976).  This system reduced sulfate emissions, but it



also reduced the control of CO emissions.   Loss of CO control was worse with the



monolith catalyst systems tested than with the pelleted catalyst systems, possibly



because there was less surface area and active metal present in the former.







4.2.1.1.2  Air modulation.   Recent EPA work under contract with Southwest



Research Institute indicates that a more sophisticated air modulation device may



make it possible to maintain HC and CO emission control while reducing sulfate



emissions (Ingalls and Springer 1976).   This device uses engine vacuum input to



regulate the air injection system.  Enough oxygen is injected to oxidize the



spikes of HC and CO that occur during a typical driving cycle, but the overall



excess of oxygen is not so high as to cause sulfate production.  Preliminary



results indicate the possibility of attaining mandated emissions levels of HC,
                                   89

-------
CO, and NO  while minimizing sulfate emissions (Ingalls and Springer 1976).   The
          y\


durability of this system is currently being tested.   Another system that may benefit



from the use of a modulated air injection system is the combination of a three-way



catalyst and an oxidation catalyst used by Ford for 1978 in California and being



considered by some other auto manufacturers.  Ford has indicated that this system



is their prime candidate for meeting statutory emission standards of 0.41, 3.4,



and 0.4 g/mile HC, CO, and NOX (U.S. Environmental Protection Agency 1977).   The



current high sulfate emissions from this system (see Table 4-2) are caused by



the high oxygen level associated with full air injection between the three-way



and the oxidation catalysts.  However, the use of modulated air injection on



such systems may reduce high sulfate emissions without loss of HC and CO control.



The auto manufacturers are investigating this possibility.







4.2.1.1.3  Three-way catalyst systems.  The most promising control system for



use in cars designed to meet 1980 emissions standards is the three-way system,



which consists of two major components:  (1) a catalyst which has both oxidation



activity (catalyzes the conversion of CO and HC to CO^ and water) and reduction



activity (NO  to N9) and (2) a continuous fuel/air ratio monitoring and control
            /\     £


device which maintains both adequate oxygen and reductant levels in the exhaust.



Several vehicles manufactured by GM, Ford, Volvo, Saab, and Mercedes now employ



this type of control system (U.S. Environmental Protection Agency 1977).







     Several studies have shown that three-way control systems normally produce



very low emission rates of sulfuric acid (Tables 4-1, 4-3, and 4-4).  Two factors



appear to be responsible for these low rates: low oxygen content of the exhaust



and inherently low sulfate-forming tendencies of the Pt/Rh catalyst compositions



needed for NO  control.
             x
                                   90

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            Table 4-2.   SULFATE EMISSIONS FROM THREE-WAY PLUS
            OXIDATION CATALYST PROTOTYPES WITH AIR INJECTION

System
8D1-302-7P
(3-way and
oxidation catalyst)





8D1-302-1P
(3-way and
oxidation catalyst)





HC,
g/mi
0.14
0.13
0.14
0.13
-
0.13
0.14
0.15
0.16
0.15
0.16
-
0.18
0.18
CO,
g/mi
0.40
0.43
0.29
0.28
-
0.20
0.26
0.16
0.14
0.13
0.17
-
0.14
0. 18
NOx,
g/mi
0.49
0.50
0.49
0.61
-
0.67
0.64
0.60
0.70
0.67
0.55
-
0.55
0.56
H2S04
mg/mi
27.9
33.3
25.8
34.5
37.4
43.0
45.7
40.1
56.2
51.2
61.4
62.3
69.8
53.6
71.4
61.2
aAll data over CUE driving schedule.

Source:   U.S.  Environmental Protection Agency (1977).
                                   91

-------





























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           Table 4-4.   SULFURIC ACID EMISSIONS OF THREE-WAY
                          CATALYST PROTOTYPES
    Car
Control system
Fuel sulfur
 level, %
Exhaust
oxygen    Sulfuric acid,
level, %	mg/ml	
'74 Chevrolet
'74 Chevrolet
'74 Chevrolet
Closed-loop fuel      0.06
  injection, 3-way
  catalyst

Closed-loop fuel      0.06
  injection, 3-way
  catalyst

Closed-loop           0.031
  carburetor,
  3-way catalyst
                0.7
                0.3
                0.7
               0.2
               0.1
               0.2
Source:   U.S.  Environmental Protection Agency (1977).
                               93

-------
     However, a variation on the three-way emission control  system (Section



4.2.1.1.2), currently produced by Ford and considered by other manufacturers,



has been shown to emit high levels of sulfates.   This system combines a three-way



catalyst (TWC) and an oxidation catalyst with air injection together with an



oxygen sensor feedback controlled carburetor.  The added oxidation catalyst is



needed with this system to provide the additional CO control needed to meet the



3.4 g/mile CO standard, according to a Ford spokesman.   However, EPA feels that



there are alternate ways of meeting the 3.4 g/mile CO standard with the three-



way systems without excessively high sulfate emissions.   Substitution of a



closed-loop fuel injection system for the carburetor is  one potential way to



meet the 3.4 g/mile CO standard as evidenced by Volvo and Saab three-way vehicle



devices (Griffith et al.  1978; U.S. Environmental Protection Agency 1977).  A



fuel injection system is superior to a carburetion system in maintaining a



precise stoichiometric control and distribution of air/fuel ratio.  This precise



control leads to better CO control in the TWC and hence eliminates the need for



an added oxidation catalyst.  However, there are substantial price differences



between fuel injection and carburetion.  Another method, and possibly the best,



of potentially attaining the 3.4 g/mile CO standard with low sulfate emissions



with a TWC is to control the air injection with a modulation device similar to



that discussed in Section 4.2.1.1.2.







     Since three-way catalytic control systems are already being adopted because



of NO  control, and since very low sulfuric acid emissions are normal consequences
     )\


of their function, this sulfate control alternative has no incremental cost.  To



put this issue into another context, the sulfuric acid control obtained by three-



way systems costs nothing because the system is already needed for statutory con-



trol of NO .  However, use of a three-way plus oxidation catalyst that is also a
          X
                                   94

-------
low sulfate emitter may require an air injection modulation system, which would



have some costs associated with it.







4.2.2  Catalyst Design







     Several studies have indicated that some degree of sulfuric acid control can



be obtained by modifying catalyst composition/construction details or operating



parameters.  For example, it has been found that both base metal catalysts and



high-rhodium noble metal compositions have lower H^SO. emissions than do more



conventional Pt/Pd mixtures.   However, both types suffer from poor durability



(U.S.  Environmental Protection Agency 1976b).







     Perovskite-like minerals as catalyst supports provide a wider range of metal



dispersion characteristics than are available with more conventionally used alumina



supports.  Chrysler and EPA have studied the possibility of modifying metal dis-



persion and, hence, limiting sulfuric acid formation, but without much success



(Bachman et al.  1976).   Table 4-5 compares sulfate emissions between GM catalysts



and perovskite catalysts.







     Theoretically, reducing the time available for S02 conversion should reduce



the extent of this rate-dependent process.   Therefore, reducing catalyst volume or



increasing exhaust gas velocity, both of which reduce the residence time of exhaust



in the catalyst, should reduce sulfuric acid formation.  Only a limited amount of



research (by Exxon) has gone into the investigation of this possibility, which has



not yet been substantiated or disproven.
                                   95

-------
                   Table  4-5.   COMPARATIVE  SULFATE  EMISSION  RATES OF THE
                       GM  AND  PEROVSKITE CATALYSTS IN  STANDARD AND
                             HIGH-TEMPERATURE  CONFIGURATIONS
          Test
                                        GM  catalyst
Standard configuration
S04=,      Conversion,
mg/km	%	
                                                              High-temperature
                                                                configuration
                   S04=,
                   mg/km
         Conversion,
              %
          FTPa
          SET3
          HET
     64 km/h cruise
 6.7
 5.6
 6.8
 8.4
 4.9
 5.8
 8.0
10.6
4.6
1.8
1.6
1.9
3.4
1.9
1.9
2.5
          Test
                                    Perovskite catalyst
Standard configuration
S04=,      Conversion,
mg/km
                                                              High-temperature
                                                                configuration
                   S04=,
                   mg/km
                                                                      Conversion,
FTP
SET3
HET
64 km/h cruise
6.6
17.2
21.7
17.8
4.8
18.0
25.0
22.4
3.1
7.4
8.5
8.8
2.2
7.6
9.7
12.2
 Average of four tests.

Source:   Bachman et al.  (1976).
                                         96

-------
     Finally, it should be possible to reduce the thermodynamic equilibrium of



hLSO. yield from catalysts by increasing exhaust temperature.   Exxon and EPA have



investigated this possibility by using insulation, ceramic port liners, and reloca-



tion of exhaust elements to minimize heat loss and maximize catalyst temperature.



However, over the narrow temperature range available from these changes, no sub-



stantial reductions in sulfuric acid emissions were found (Griffith et al.  1978).







     In summary, the potential for sulfate control (while regulating HC and CO



emissions) by modifying the catalyst type, preparation, or operating conditions



appears limited.  On the other hand, the three-way system as a control option is



very effective, will be needed for NO  control anyway,  and involves no incremental cost.







4.3  ON-BOARD CONTROL DEVICES







4.3.1  Sulfates







     While most studies of sulfate emissions have dealt with the engine/emission



control system, some research has examined on-board control devices, i.e.,  sulfate



traps.   Sulfate traps can generally be divided into two categories:  particulate



traps and sorbent or chemical traps.







4.3.1.1  Particulate traps—Particulate traps, which use physical  means to  separate



particles from the exhaust stream, have not been considered an effective control



alternative for sulfuric acid emissions.  Sulfate particulates from mobile  sources



are generally considered too small to be effectively removed by such physical



means.   Additionally, in the part of the exhaust system where a particulate trap



would be used, much of the sulfate exists in the vapor phase because of the high



temperatures there.





                                   97

-------
4.3.1.2  Sorbent traps—These traps generally use a chemical  reaction (i.e.,  an



acid-base type of reaction) to remove sulfate from exhaust.   The best candidates



for sorbent trap materials are those which are readily incorporated into a trap-



effective form and which react with sulfate in the vapor or liquid phase.   Exten-



sive work in this area has been done both by Exxon Research and Engineering (under



contract with EPA) and by General  Motors (Bachman et al.  1976;  U.S.  Environmental



Protection Agency 1976b).







     The EPA-funded work at Exxon  Research and Engineering included a literature



search to identify the most promising sorbents, construction of a laboratory reactor



to rapidly evaluate these sorbent  candidates, and operation of  vehicle tests to



demonstrate the actual effectiveness of the materials and designs used.   The lit-



erature search identified calcium  oxide, magnesium oxide, and magnesium and alu-



minum metals as the most likely sorbent candidates.  Many different formulations of



these and other compounds were evaluated in the laboratory reactor.   Results from



these experiments identified the most promising sorbent candidates for later



vehicle evaluation.







     High sulfate collection efficiency ratings were achieved in the vehicle tests.



However, a number of problems were encountered and not satisfactorily resolved.



One of the most significant problems was constructing sorbent pellets that were both



durable and efficient.  These attributes were often in conflict:  thus, a pellet



of proper hardness (i.e., for durability) tended to be less efficient for sulfate



collection than the softer sorbent pellets, which tended to degrade under test



and plug the trap, causing a high  pressure drop.  Another problem was to obtain



pellet materials that maintained a high level of sulfate collection without a



fall in trap pressure, an effect attributed to the geometry of  the pellets used.
                                   98

-------
     GM, relying on the preliminary Exxon literature search and vehicle test



data, tried a large number of supported and bulk sorbents, mostly without



success (U.S. Environmental Protection Agency 1976b, 1977).  The supported



sorbent candidates tested (Table 4-6) had not been thoroughly investigated in



the Exxon study.  These materials were found to be durable, but they showed



very low activity as sulfate traps.  Further investigations by GM involved



testing 40 bulk materials similar to those tested in the Exxon study.   A



schematic of the test cell used is shown in Figure 4-2.   In all this work, GM



found only two potential candidates (both bulk sorbents), CaO and Na^O/AlpO^.



Vehicle testing of these sorbents showed good initial activity followed by a



rapid dropoff in efficiency.







     The results of the GM and Exxon investigations indicate that although it



may be possible to develop a good sulfate trap, an extensive amount of development



work would be necessary before this technology could be ready for production



use.







4.4  FUEL DESULFURIZATION







     Fuel desulfurization is another alternative to control sulfur emissions.



Both sulfur dioxide and sulfate emissions from catalyst-equipped cars and



from diesel passenger cars and trucks correlate directly with the amount of



sulfur in the fuel.   Thus, a 90 percent reduction in fuel sulfur would result



in a 90 percent reduction in sulfur emissions from these vehicles.   Reducing



gasoline sulfur content by 90 percent has been judged prohibitively expensive,



but a 65 percent reduction appears practicable (U.S. Environmental  Protection



Agency 1976a).  For diesel and jet fuels, which have a higher sulfur content
                                   99

-------
                Table 4-6.   SUPPORTED SULFATE SORBENTS

Noble metals
on A1203
Pt (6)a
Pd (4)
Pt-Pd (3)














Metal oxides
on A1203
Ce
Co
Cu (3)
Cr
Fe (3)
Mg (2)
Mn (2)
Nd
Ni
Pb
Th
V
Zn (3)
Zr
Co-Mo
Cu-Cr
Cu-Mn
Alkali /alkaline
earth oxides Mi seel -
on A1203 laneous
Ba Ni/Si02
Ca (3) Cu/Zr02
K (3) Ca/Si02
Li Na/Si02
Na (5) Ca/MgO
Na/MgO
Ca/Zr02
Na/Zr02
Ca/Ti02
A1203
Na/Ti02
A1203







 Number in parentheses indicates number of samples evaluated, with different
support/active material loading combinations.

Source:   U.S.  Environmental Protection Agency (1976b).
                               100

-------
          Engine
  i  i
Exhaust
 gases i
 a
       i    Catalytic

       •    converter     |
                             Cooling water
Sorbent sample tubes

       L,
                                             S02 + SO3
                             Heat exchanger
                                                        Sample pod
            Figure  4-2.   Test cell evaluation of sulfate sorbents.


            Source:   U.S.  Environmental Protection Agency (1976b).
                                101

-------
to begin with, a 90 percent reduction appears economically feasible.   Accord-



ingly, an examination is made of the costs to the United States petroleum-



refining industry for reducing the average sulfur content of gasolines to 100



ppm, diesel fuels to 200 ppm, and jet fuels to 200 ppm.   This report is the



first to examine mobile source fuel desulfurization costs with revised product



demand levels, domestic production estimates, and import estimates consistent



with the National Energy Plan.  Although many parameters have been included,



the forecasted costs hinge on the extent to which the increasing demand for



diesel fuels will reduce the relative demand for gasoline.  Consequently, two



additional scenarios for shifts in the relative demand for gasoline and



diesel fuel are examined.  The data for the present report were taken from a



study by Kittrell and Short (1978) prepared for the U.S. Environmental



Protection Agency.







4.4.1  Gasolines







     Motor gasolines produced in the United States vary widely in sulfur



content.  The Northeast produces gasoline containing roughly twice the sulfur



found normally in that produced in the Pacific Northwest (Table 4-7).  This



regional difference arises from the type of crude oil processed, the processing



configuration, and the grades of gasolines produced.  Unleaded and premium



gasolines contain less sulfur than the regular grade.  Nationwide, the average



of all grades of gasolines currently ranges between 350 and 400 ppm sulfur;



the higher limit occurs during the summer peak production period.  In terms



of the future, as the demand for unleaded fuel increases, so will the produc-



tion of low sulfur-containing gasolines.  However, there will also be increased
                                   102

-------
      Table 4-7.   CURRENT SULFUR CONTENT OF U.S. MOTOR GASOLINES

Sulfur content by grade, ppm
Representative region
Northeast
South Plains
Pacific Northwest
Southern California
U.S. average
Unleaded
315
295
70
310
280
Regular
460
400
225
600
415
Premium
290
320
115
355
275
Source:   Shelton (1977).
                                   103

-------
                                                                          -e
use of crude oils with higher sulfur content.   With these offsetting trends

taken into account, it is estimated that gasolines produced in the future

will have an average sulfur content of about 350 ppm.



     The use of diesel and No. 2 fuel oil will increase considerably through

1990 relative to other refinery products.  At present, the sulfur content of

diesel fuel ranges between less than 200 ppm and 10,000 ppm, with an average

of 2000 ppm (Figure 4-3).  City bus-type vehicles use fuel with a sulfur

content of 1000 ppm, while railroad diesel fuel has a sulfur content of 2500

ppm.  Truck and tractor fuels generally contain about 2000 ppm sulfur, but

some truck-tractor fuels may contain as much as 10,000 ppm.  To meet a 200-

ppm target level, more than 90 percent of the diesel fuels must be hydro-

desulfurized.  Without further sulfur regulations, future sulfur levels will

probably rise above 2000 ppm but not exceed 3000 ppm.



4.4.2  Jet Fuels



     Approximately 30 percent of the jet fuels marketed in the United States

contain less than 200 ppm sulfur, meeting the target specifications of this

study.  At present, in terms of nationwide averages, commercial jet fuel

contains about 600 ppm sulfur, and military jet fuel contains about 420 ppm

sulfur.  However, military fuels are expected to shift to the higher sulfur

content material now used for commercial fuels.  Jet fuels now contain about

30 percent more sulfur than those produced before 1973.  Without further

regulations, this increase will continue, but it should level off at a nation-

wide average of about 1000 ppm sulfur.  Some current jet fuels contain up to

2000 ppm sulfur, and airline specifications allow a maximum of 3000 ppm.


                                   104

-------
Figure 4-3.   Sulfur distribution of U.S. diesel fuels, 1977.



Source:   U.S. DOE Diesel Oil Survey (1977).
                         105

-------
4.4.3  Economic Impacts







     A forecast of the oil needs of the United States through 1990 predicts a peak



gasoline demand between 1980 and 1985, followed by a decline--the first such long-



term decline in the history of the United States (Table 4-8).  According to this



forecast, 43 percent of the crude oil processed would be imported.  Most of the



gasoline processed by crude oil refining [fluid catalytic cracking (FCC) units and



coking units] would require desulfurization to attain a 100-ppm sulfur level.



Over 70 percent of all jet fuels and over 90 percent of all diesel fuels would



require desulfurization to meet the target 200-ppm level.







     Estimated capital investments and operating costs for fuel desulfurization are



noted in Table 4-9.  Because of the lead time needed to install manufacturing



facilities, only 1985 and 1990 costs are reported.  Capital investments are pro-



jected at $6 billion in 1985 and will increase to $6.6 billion by 1990.  Manu-



facturing costs range from $3.3 billion to $3.6 billion for the same dates.



Approximately two-thirds of these costs will arise from gasoline desulfurization.



The 1990 per-gallon costs noted in Figure 4-4 include a 21 percent energy-manufacturing



cost for gasoline and a 12 percent energy contribution for jet and diesel fuels.



On the basis of an earlier study (Bachman et al. 1976), it appears that the consumption



of energy required to produce the total pool of desulfurized gasoline will range



between the equivalent of 42,000 and 175,000 barrels of crude oil per day.







     Because the demand for diesel fuel may increase more rapidly than assumed in



Table 4-8, two additional demand scenarios are considered (see Table 4-9).  Scenario



B extends Table 4-8 to include a 15 percent diesel fuel inroad into the gasoline
                                   106

-------
                       Table 4-8.   BASE CASE SUPPLY DEMAND FORECAST
                                  (million barrels daily)
                                        1976
                1980
                1985
                1990
     Mobile source demand
       Gasoline
       Mobile source diesel  fuel
       Jet fuel
         Total

     Total supply forecast
       Domestic crude oil
       Natural  gas liquids
       Foreign  crude oil
       Product  imports
         Total
 7.02
 0.81
 0.99
 8.82
 8.1
 1.6
 5.3
 2.0
 7.48
 0.97
 1.11
 9.56
 9.0
 1.4
 6.7
 2.6
 7.24
 1.28
 1.27
 9.79
 9.7
 1.4
 7.0
 2.6
17.0
19.7
20.7
 7.00
 1.76
 1.48
10.24
 9.8
 1.4
 7.5
 2.6
FT5
Sources:   Petroleum Industry Research Foundation,  Inc.  (1977).
          Department of Energy data on segregation of diesel  fuels between mobile and
          stationary sources.
                                         107

-------




















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108

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Capital charges
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Gasoline Jet fuel Diesel fuel
           ^Estimated energy consumption (on fuel-oil-
            equivalent basis) directly related to sulfur
            reduction:   gasoline, 175,000 barrels/day;
            jet fuel, 30,000 barrels/day; diesel fuel,
            50,000 barrels/day.   Includes fuel burned and
            electricity and steam consumed, with byproduct
            credits.   For gasoline,  desulfurization will
            improve efficiency of conversion of the FCC
            feedstock,  and additional credits should be
            included.

            Figure 4-4.   Unit manufacturing costs in 1990
            for sulfur reduction in mobile source fuels.
                         109

-------
market, or a daily demand in 1990 of 5.95 million barrels of gasoline and 2.81



million barrels of diesel fuel.  . Scenario C forecasts a 30 percent penetration  by



1990, corresponding to a daily demand of 4.9 million barrels of gasoline and 3.86



million barrels of diesel fuel.   Because desulfurizing diesel fuel entails higher



manufacturing costs (more diesel fuel than gasoline requires desulfurization; see



Figure 4-4), separate gasoline desulfurization facilities and expanded diesel fuel



refineries would inflate the investments noted in Figure 4-5.  In addition, only



the costs of desulfurization, not the additional  marketing or processing costs



associated with an expanded production of diesel  fuels, are noted.







4.4.4  Other Considerations







     As shown in Figure 4-6, the industry-wide average cost for desulfurizing



gasoline to meet a 100-ppm standard by 1990 would be 1.9$/gal.  These costs include



the costs of hydrotreating the feedstock of refinery catalytic cracking units.



However, within the industry, desulfurization costs would vary widely among refiners,



depending upon differences in the sulfur content of the crude oil processed,



refinery capacity, and the availability of hydrogen (used in the desulfurization



process).







     Table 4-10 depicts typical  manufacturing costs for refining three different



crude feedstocks at two refineries differing in production levels--a 100,000



barrel-per-day FCC unit and a 10,000 barrel-per-day unit.  Two variants of hydrogen



availability are also considered:  one case considers the cost of hydrogen available



at fuel prices; another includes costs for construction of plant for hydrogen pro-



duction.
                                   110

-------
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                                                $7.2
                          $6.6
                                     $6.8
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               Diesel fuel
               Gasolines
           25%
           $1.6
36%
$2.5
48%
$3.5
                       Basecase     15% diesel   30% diesel
                       demand      penetration   penetration
                       (Scenario A)   (Scenarios)  (Scenario C)
 Figure 4-5.   Capital investment requirements  by
 1990 for  sulfur reduction  in mobile source
 fuels,* 1977 cost basis.

*Not included:   investments for new processing
 facilities  to expand diesel  fuel volumes  to
 levels of Scenarios B and  C; investment  in
 existing  gasoline production facilities
 which are not needed to  supply lower gasoline
 demand levels of Scenarios B and C.
                            Ill

-------

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112

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     A refinery processing mainly low-sulfur (sweet) crude to meet a 100-ppm sulfur



level would entail no additional processing requirements.   In the worst case con-



sidered in Table 4-10, a small refinery processing high-sulfur (sour) crude and



building a facility for hydrogen production could incur twice the costs shown.







     Higher costs would probably be borne with greater difficulty by small refineries



than large ones.  Thus, the economic advantage and competitive status of larger



refineries could increase.   Among other considerations, differences in the incremental



costs for desulfurization may allow refiners with comparatively low desulfurization



costs to compete in geographic markets now unavailable to them.   That is, the cost



of transporting materials to more distant markets would be overcome by their



relatively lower total production costs.   The impact of this situation could be



profound (see Figure 4-6) in the Rocky Mountain (PADD IV) region, where small



refineries process crudes that would incur relatively high costs for desulfurization.



Analogous trends exist also for diesel and jet fuels.   Also, it should be noted



that refineries do not have complete freedom to select low-sulfur crudes for any



particular refining-processing scheme.  Most refineries cannot segregate products of



one crude from products of another crude.   Another problem not specifically addressed



is that some low-sulfur crudes are highly paraffinic,  creating a pour-point problem



in diesel fuels, and would require additional desulfurization.







     Finally, new refineries take several  years to build—1  or 2 years for design,



permits, and preliminary environmental monitoring and 2 to 3 years for construction



and start-up, assuming no environmental prohibitions on new construction.  Consequently,



sulfur regulations on all three fuels could probably not be implemented until



1985.  In light of these difficulties, refiners might import additional sweet



crudes, even though they are more expensive.
                                   113

-------
    Total U.S.
    East Coast
Upper Midwest
    Gulf Coast
   Rocky Mtn.
   West Coast
   PADD
fUgPADD |||W
^^^^^SSTOMJC^TOTO^^
                  2.0V gal
                  2.0V gal
                  2.0V gal
  IPADDIIll
                                1.8V gal
                  2.0V gal
•SM^^m\\SS\\\\-SSS^MSSs^mSl
                                          I
                       234


                       Manufacturing costs, V gal
       Figure  4-6.   Regional  manufacturing costs*  of
       sulfur  reduction in gasoline,  1977 cost basis.

       *PADD IV is  comprised  primarily of small  refin-
       ers  incurring relatively  high  costs.  The lower
       costs in PADD III reflect the  availability  of
       sweet crude  oil.  It should be noted that
       Alaskan North Shore oil is relatively high  in
       sulfur.
                     114

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4.4.5  Further Action Needed







     To assess more fully the impact of manufacturing low-sulfur,  mobile source fuels,



additional  considerations not possible in this study should be given:







     1.   The relationship between feedstock sulfur content and gasoline sulfur



          content for FCC units and coking units should be refined to  allow more



          accurate projections of gasoline sulfur levels and desulfurization



          requirements.







     2.   Impact estimates of producing low-sulfur jet fuel and diesel  fuel should



          be extended to include effects of economies of scale and availability



          of refinery hydrogen.







     3.   Selected computer model simulations should be initiated  which include the



          parameters investigated in this study, but which further allow additional



          processing and blending interactions to be explored in order  to meet



          target sulfur specifications at minimum costs.







     4.   Certain novel  processing techniques for sulfur reduction in  distillate



          products, which are not yet commercially proven, should  be evaluated to



          determine cost reductions possible through likely technological innovations



          during the next decade.







     5.   The impact of sulfur control of mobile source fuels should be assessed



          more fully for small refiners processing less than 50,000 barrels of
                                   115

-------
          crude oil  per day.   Such studies should include examinations  of the likely



          effect of  regulations on the competitive structure of the  industry.







     6.    Since imposition of sulfur regulations on the mobile source fuels could



          increase the cost of low-sulfur crude oils to U.S.  refiners,  the supply



          and demand for low-sulfur crude oils should be examined,  including



          opportunities for rationalization of crude oil distribution for optimal



          fuel production.







4.5  SHORT-TERM ALLOCATION OF LOW-SULFUR CRUDE OIL







     As noted in the preceding section of this chapter, desulfurization of fuel



is one possible means to reduce sulfate emissions.  Implementation  of this or some



other technological  control alternative, however, could take years.   In the mean-



time, while alternate controls are brought about, sulfate emissions  could be



controlled by refining fuel from crude oils with an inherently low  sulfur content.



Thus, this section,  written by J.  M.  Kawecki and S.  L.  Smith, considers the option



of short-term allocation of low-sulfur crudes--those containing less than 0.5



percent sulfur.







     For purposes of discussion, Bureau of Mines (BOM) District 13  will be considered



in a scenario where  such an allocation might be made.   California,  the major oil



refiner in District  13, currently has the highest vehicular sulfate emissions of



any State.  Not only do the California automotive oxidation catalysts required for



HC and CO control emit higher sulfate levels, but the gasolines themselves, partic-



ularly those refined in southern California, historically contained higher amounts



of sulfur on the average than gasolines refined elsewhere in the United States.



                                   116

-------
Consequently, the implementation of sulfate control  alternatives would be especially



relevant to this area.







     To understand the impact of allocating low-sulfur crudes to California,



several factors should be considered.   First,  California already regulates unleaded-



grade gasoline sulfur levels to 400 ppm.   In addition, a 300-ppm limit goes into



effect in 1980.  Recently, the California Air Resources Board was petitioned to



rescind this 1980 regulation.







     Second, California supplemented its  domestic crude stocks with foreign imports.



From 1970 to the summer of 1977, foreign  imports rose from 23 to 54 percent of



the total crudes processed in BOM District 13.   A slight decline in foreign imports



occurred in the second half of 1977, reflecting the  entry of Alaskan North Slope



oil.   Roughly half of these imports were  from Indonesia, a source of relatively



low-sulfur crude oil.   Projections indicate that by  1985, increasing supplies



of Alaskan oil into District 13 may reduce foreign oil imports.   Most of the Alaskan



crude is sour, having an average sulfur content of 0.9 percent.   Thus, over the



next decade, there may be a marked increase in the processing of high-sulfur crudes.







     Because of current regulations on the sulfur content of fuel oil, almost all  low-



sulfur crudes are processed for fuel oil  (with a 25-50 percent yield).  Since most



existing facilities cannot desulfurize sour crude oils to meet the 0.25 percent



sulfur limit for residual oil, there will be additional demands for low-sulfur



crudes.  While Federal  pricing regulations allow refiners to pass on all operating



costs, including depreciation, to consumers, they cannot receive additional returns



for their initial capital investments in  constructing desulfurization facilities.
                                   117

-------
Consequently,  it appears that almost all  of the low-sulfur crudes  will  continue to



be used for residual  oil in the future.   The exact impact of this  anticipated trend



is difficult to predict.  However,  the trend of lower sulfur levels found in



southern California's unleaded-grade gasoline,  currently averaging 290  ppm,  will



probably reverse unless new desulfurization facilities are added or unless foreign



imports of low-sulfur crudes are increased.   Nevertheless, if unleaded  gasoline



sulfur levels remain about the same through 1985,  vehicular sulfate emissions for



southern California will probably not change significantly, assuming that emission



control devices that emit large amounts of sulfuric acid (e.g.,  TWC plus air and



oxidation catalysts) are not used in the 1980 model vehicles.







     According to the National Energy Plan, U.S.  gasoline demand for transportation



use is expected to decrease from a 1980 peak by about 5.2 percent by 1985.  This



decrease will be offset by an increase in diesel  fuel, which contains two to three



times as much sulfur as gasoline.  However, the smaller amount of sulfate



emitted by diesel engines might tend to balance out the sulfate emitted by the



percent increase of oxidation catalyst-equipped vehicles.







     Finally, if this short-term allocation scenario is applied to the  entire



Nation, there may not be enough low-sulfur crude oil at acceptable prices to meet



the transportation demand.  Naturally, California would be hardest hit  in this



scenario, in view of its current sulfur regulations.







     Generally, the short-term allocation of low-sulfur crude oils does not appear



to represent a viable control alternative.  At present, these oils are  available



from only three main sources—one domestic (midcontinent, except west Texas) and two



foreign (Malaysia and Africa).  Not only are these oils expensive, but their
                                   118

-------
supply is so competitively limited that refiners would still have to rely heavily



on the more plentiful sour crudes (e.g., Alaskan North Slope crude) to meet fuel



production demands.   Hence, a short-term allocation of low-sulfur crude oils would



be costly and have little impact on mobile source emissions for the State of



California.   Moreover, California is already increasing its imports of low-sulfur



crude, while roughly 35 percent of the Alaskan North Slope oil is being shipped



through the Panama Canal to other refining districts.   The increased use of imported



oils (from Indonesia and Nigeria) would run counter to the National Energy Plan,



which" stresses reliance on domestic fuel reserves.
                                   119

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Bibliography

Bachman, K.  C.,  E.  L.  Holt, W. R. Leppard, and E. E. Wigg.  An Assessment of
  (Automotive)  Sulfates Emission Control Technology.  Prepared by Exxon Research
  and Engineering,  Linden, N.J., under Contract No.  68-03-0497.  U.S.
  Environmental  Protection Agency.   Ann Arbor, Mich. Publication No.
  EPA-460/3-76-017.   1976.

Base-Case Estimate of 1985 Crude Oil Processing.   U.S. Department of Energy.
  1978.

Cost of Benzene Reduction in Gasoline to the Petroleum Refining Industry.  U.S.
  Environmental  Protection Agency Contract No. 68-02-2859.  February 1978.

Griffith, M. G., R.  A.  Bouffard, E.  L. Holt, M. W.  Pepper, and M. Bettzer.
  Assessment of Automotive Sulfate Emission Control  Technology.  Prepared by
  Exxon Research and Engineering, Linden, N.J., under Contract No. 68-03-0497.
  U.S.  Environmental Protection Agency.  Ann Arbor,  Mich. Publication
  No. EPA-460/3-77-016.  1977.

The Impact of Producing Low-Sulfur,  Unleaded Gasoline on the Petroleum Refining
  Industry.   U.S. Environmental Protection Agency Contract No. 450/3-76-015a.
  May 1976a.

Ingalls, M.  N. ,  and K.  J. Springer.   Durability Demonstrations of Systems for
  Control of Sulfuric Acid.  Monthly Reports submitted under Contract No. 68-03-2481
  U.S.  Environmental Protection Agency.  Ann Arbor,  Mich.  Continuing contract,
  1976-present.

Kittrell, J., and W. L. Short.  Cost of Sulfur Reduction in Mobile-Source Fuels
  to the Petroleum Refining Industry.  U.S. Environmental Protection Agency.
  1978 (to be published).

Maximum Gasoline Production Capabilities of U.S.  Refineries for the Summer of
  1977.   U.S.  Department of Energy.   1975.

Oil and Gas Journal, March 28, 1977.

Petroleum Industry Research Foundation, Inc.  U.S.  Oil Supply  and Demand to 1990.
  October 1977.

Shelton, E.  M.   Aviation Turbine Fuels, 1976, Petroleum Products Survey.  ERDA
  Publication No. BERC/PPS-77/2.  U.S. Energy Research Development Administration,
  Bartlesville Energy Research Center, April 1977.

Somers,  J.  H.,  R. J. Garbe, R. D. Lawrence, and T.  M. Baines.  Automotive Sulfate
  Emissions - A Baseline Study.  SAE Paper No. 770166.  March  1977.

Status Report on Automotive Emission Control Technology.  Ford Motor Company to
  U.S.  Environmental Protection Agency.  January 1978.

Technology Assessment Report - Automobile Sulfuric  Acid Emission Control - The
  Development Status as of December 1975.  U.S. Environmental  Protection Agency.
  Ann Arbor, Mich.   1976b.


                                      120

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                       5.  COST/BENEFIT ANALYSIS







     This chapter summarizes parts of a study by Lee W.  Merkhofer et al.  of SRI



International and J.  W.  Kawecki of Biospherics, Inc., that was designed to analyze



the relative costs and benefits of controlling sulfur-bearing compounds emitted



from mobile sources.   Although the emphasis is on sulfates, sulfur dioxide is



also discussed.   This analysis presents an assessment of exposure to sulfate



compounds emitted from mobile sources; however, no health effects from these



exposures can be determined at this time.







     The assessment is presented for two scenarios.   The first involves in-roadway



modeling studies to determine exposures to vehicle drivers and persons close to



the line source.  The models, which are derived directly from emissions data,



include a worst case for sulfate and sulfur dioxide exposures.  The second



scenario involves an areawide, incremental contribution from mobile sources



in the Los Angeles Basin and the Kansas City, Mo., metropolitan area.   A third



scenario was attempted for a city street canyon, as found in most large cities,



but there were no validated models available for this assessment.







     In addition to these two assessments, the effects on the public welfare are



quantified in the analysis of the costs and benefits of control for the Los



Angeles Basin.  Although the cost/benefit analysis for welfare effects and the



exposure assessment for health are based on limited information, even a rough



projection of the extent to which new catalyst technologies and other control



devices might mitigate the consequences of sulfur pollution should be helpful to



policymakers both in formulating standards and in setting priorities for



further research.
                                  121

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5.1  IN-ROADWAY MODELING STUDIES







     Three roadway modeling-measuring studies are discussed:   the General



Motors Sulfate Dispersion Experiment, the Los Angeles Catalyst Study, and



the Los Angeles Roadway Measurement Study.  A stochastic model is also



included to determine worst-case exposure levels and probabilities.







5.1.1  General Motors Sulfate Dispersion Experiment







     The GM study was designed to determine the relationship between



automotive sulfate emissions and ambient air concentrations.   During



October 1975, a fleet of 350 low-mileage 1975 and 1976 vehicles equipped



with catalysts and air pumps was operated in packs on four lanes on a



10-km north-south straightaway at a speed of 50 mph for 2 hr/day. The



experiment simulated a highway flow rate of 5460 vehicles/hr.  Eight GM



vehicles were equipped to emit sulfur hexafluoride as a tracer, and one



EPA vehicle was equipped to measure sulfate and sulfuric acid emission



rates and particle sizes.  The fuel contained 0.03 percent sulfur by



weight.







     The results of the test were as follows:  the average sulfate emission



rate was calculated as 37 mg/mile; aerosol particle diameters were generally



between 0.01 and 0.1 urn; and more than two-thirds of the sulfate emitted



by the vehicles was measured as sulfuric acid at a distance of 20 m from



the test track.
                                  122

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     Twenty meters downwind of the roadway, average sulfuric acid


concentrations ranged from 1.1 to 5.4 ug/m .   Measurements made from


towers equipped with sampling devices at heights between 0.5 and 9.5 m


showed that sulfate concentrations were highest near the roadway and


decreased rapidly with distance.   Peak sulfate concentrations, averaging 8

    3
ug/m , were measured at a height of 0.5 m at median and roadside towers.


Samples taken farthest (100 m) from the roadway indicated a partial neutral-


ization of the sulfuric acid.   Sulfate concentrations averaged 4 ug/m


inside the test vehicles and 5.2 ug/m  in the roadway median.
     Comparison between computations using the HIWAY model (which simulates


vehicle emissions on a highway by summing several point sources to


integrate numerically the Gaussian point source equation over a specific


distance) and these results showed agreement when meteorological


conditions were unstable and the wind was nearly perpendicular to the


roadway at a speed of 1 m/sec or greater.  Under stable conditions or when


the wind was parallel to the track, the model overpredicted the test


results by a factor of 2 to 3.   These results indicated that previous


worst-case mobile source sulfate models overpredicted concentrations by


about the same factors.




5.1.2  Los Angeles Catalyst Study




     The Los Angeles Catalyst Study (LACS) was designed to investigate


ambient levels of sulfuric acid, sulfate aerosols, and other catalyst


emission products in areas adjacent to a heavily traveled freeway.
                                  123

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Initial LACS summary reports indicated that freeway contributions of


sulfates averaged a high of 5 (jg/m ,  but it was later determined that


these amounts were affected by artifact sulfate formation.  Preliminary


modeling results from the 1977 data indicate an average freeway contribu-

                    2
tion of about 4 ug/m .   The data used for this analysis are not consistent


with regard to sulfate collection methods and previous modeling results


for 1975 and 1976.
5.1.3  Los Angeles Roadway Measurement Study




     The Los Angeles Roadway Measurement Study measured sulfuric acid,


other ultrafine particles, and total sulfur on the roadway.  Comparison of


the results of this study with off-roadway, background concentrations


showed that ultrafine sulfate emissions decreased rapidly with increased


odometer mileage:  at 3500 odometer miles, catalyst-equipped vehicles


emitted 7 mg/mile HUSO, during the FTP driving cycle and 22 ing/mile during


the CUE driving cycle; at 12,550 miles, the corresponding emissions were


2.6 and 10.5 mg/mile.  Worst-case emission estimates showed that 1 percent


of catalyst-equipped vehicles with fewer than 4000 miles emitted 100


mg/mile H?SO., while 5 percent of these vehicles emit more than 50 mg/mile


HpSO..  A recent report by Dzubay et al. (1978) indicates that the in-roadway


concentrations of sulfate particles collected during this study averaged

                  3
less than 1.5 ug/m .
                                  124

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5.1.4  Worst-Case Model







     Typical exposure estimates do not usually include extreme conditions,



which are useful in developing policies to protect the public health and



welfare.   Consequently, this section presents a worst-case scenario for



mobile source emissions of sulfuric acid and sulfur dioxide, using data



derived primarily from a study by Papetti and Horowitz (1975); their



report was amenable to linear scaling to allow for different emission



rates.  A scenario of this type is based on the simultaneous occurrence of



rare events, such as prolonged periods of travel  on high-volume freeways



under meteorological conditions conducive to high pollutant concentrations.



Furthermore, sulfuric acid exposure probabilities are based on the assumption



that all  the vehicles are equipped with catalysts, while sulfur dioxide



exposure probabilities assume that all vehicles are equipped with diesel



engines.







     In this section, the short-term exposures (1-hr average) are estimated



for a particular urban subpopulation:   weekday morning, peak-period travelers



in Los Angeles.   According to Tiao et al. (1974), meteorological  and



traffic conditions between 6 and 9 a.m.  tend to cause above-average concentrations



of sulfur compounds.  The travelers during this period include roughly 30



percent of the total Los Angeles population.







     Two types of data, travel and meteorological, were used in constructing



these exposures.  Travel data were obtained from the Los Angeles Regional



Transportation Study (LARTS), which included 36,733 weekday morning,



peak-period trips along with estimated time spent on city streets and
                                  125

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freeways during each trip.   Meteorological  data from Los  Angeles  International

Airport included wind speed, wind angle,  and stability class during the

morning peak period for 1964.   The authors  noted that meteorological

conditions for that year were not conducive to either high or low pollutant

concentrations.


     Mean travel times are short for most travelers, but  are long for a

few.  For example, 55 percent of the peak-period travelers do not use

freeways during the hour following the start of the morning, peak-period

trip; only 1 percent of the travelers use freeways for at least 56 min

during the hour following the start of the  trip  (see Table 5-1).


     The joint frequency distributions of the 1-hr average concentrations

of sulfuric acid and sulfur dioxide were derived by modifying the HIWAY

diffusion model.  Traffic volumes of 3200 vehicles/hr on  city streets and

17,000 vehicles/hr on freeways were used, corresponding to peak hour

traffic flows in Los Angeles in 1975.  In was assumed (1) that sulfuric

acid and sulfur dioxide were not removed from the atmosphere during the

modeling period and (2) that catalyst equipped vehicles emitted 5 and 17.5
    3
mg/m  H^SO. on city streets and freeways, respectively, and that diesel-powered

vehicles emitted 450 mg/mile SOp.


     As seen in Table 5-1, the peak 1-hr average concentrations on freeways
                            o                        3
could be as high as 145 pg/m  for H^SO, and 1800 ug/m  for SOp.  Ninety-nine
                                                              3
percent of the time, concentrations would be less than 20 ug/m  H^SO^ and
                  3                                        3
less than 500 ug/m  SOp.  On city streets,  less than 2 ug/m  H2$04 could

occur 99 percent of the time.
                                  126

-------
        Table 5-1.   FEATURES OF THE DISTRIBUTION OF TRAVEL TIME
           DURING THE HOUR FOLLOWING THE START OF A MORNING
                    PEAK-PERIOD TRIP IN LOS ANGELES

Time

Average
Median
95th percentile
99th percentile
Maximum
Probability of maximum
on streets,
mm
11
9
29
43
60
0.001
Time on freeways,
mm
6a
Oa
32
56
60
0.008
Total travel
time, min
17
13
52
60
60
0.03
     55 percent of peak-period travelers do not use freeways during the hour
     following the start of the trip.


     For fixed values of city street and freeway travel times and of

sulfuric acid and sulfur dioxide concentrations, exposure during the hour

following the start of a peak-period trip was computed (Table 5-2).
           Table 5-2.   FEATURES OF THE DISTRIBUTION OF CONCENTRATIONS
                 OF AUTOMOBILE-EMITTED SULFURIC ACID ON STREETS
                           AND FREEWAYS IN LOS ANGELES

Average
Median
95th percentile
99th percentile
Maximum
Probability of maximum
City
H2S04
°b5
2
11
8
Concentration,
streets
S02
45
<90
<90
<180
990
x 10-5
jjg/m3
Freeways
H2S04 S04
3.5 90
<2.5 <60
<9.5 <240
<20 <500
145 M800
8 x 10-5
^Concentrations represent increments over background, 1-hr average.
 1 M9/m3 H2S04 is the 98th percentile.
                                  127

-------
     As seen in Table 5-3 and Figures 5-1  and 5-2,  the 99th percentile of


                  3                   3
exposure is 6 ug/m  H^SO. and 150 ug/m  SCL, while  the median value is 1


    3                                3
|jg/m  and H^SO. and less than 35 mg/m  SO,,.   These  data are based on



approximately 109 morning peak-period trips  in Los  Angeles (1967 data).
     Using the variables in this exposure scheme, the following conclusions



can be drawn:
                                                  3                   3
     1.    The median 1-hr exposure will be <1 ug/m  H^SO, and <25 |jg/m



          so2.


                                                  3                  3
     2.    The average 1-hr exposure will be 1 ug/m  HUSO, and 25 ug/m



          S0£.

                                                              3

     3.    The 99th percentile of 1-hr exposures will be 6 ug/m  H?SO. and



          150 ug/m3 SO^.


                                                    3                    3
     4.    The maximum 1-hr exposure will be 145 ug/m  H?SO. and 2600 ug/m


            2                                            -7
          SO  and will occur with a probability of 6 x 10
     The probability of reaching the maximum exposure is 1 hr out of



approximately every 200 years.







5.2  AREAWIDE STUDIES







     These studies show that roadway emissions disperse rapidly and are



not likely to cause high localized levels on or near the roadway.  The
                                  128

-------
   0.70 _
   0.60 _
   0.50 _
~ 0.40 _
S
PQ
o
   0.30_
   0.20 _
   0.10 _
         0
                                     Probability of exposure greater
                                     than 7/
-------
   -0.70 _
   -0.60 _
   -0.50 _.
b  -0.40 -
tt

O
PC
OH
   -0.30 _
        ^
   -0.20-
   -0.10 _
          0
                  I

                  25
                                       Probability of exposure greater

                                       than 175 //,g/m3 is 0.006
 I

50      75

 EXPOSURE
100      125      150     175
             Figure 5-2.   Histogram of sulfur dioxide expsoure.
                                130
-------
            Table 5-3.   FEATURES OF THE DISTRIBUTION OF 1-HR AVERAGE
                  EXPOSURES TO AUTOMOBILE-EMITTED SULFURIC ACID
                    DURING THE HOUR FOLLOWING THE START OF A
                         PEAK-PERIOD TRIP IN LOS ANGELES
                                          Exposure, pg/m3

                                         H2S04        SOg

            Average                        1          25
            Median                        <1        <25
            95th percent!le                3         75
            99th percent!" le                6        150
            Maximum                      145       2600
            Probability of maximum     6 x 10-7


            al |jg/m3 is the 67th percentile.
incremental contribution on background ambient air levels could, however,

be significant.   While mobile sources account for only about 2 percent of

the total anthropogenic sulfur emissions nationwide, in some areas of the

country this percentage would be higher.  The Los Angeles Basin and the

Kansas City, Mo., metropolitan area will be used in this areawide scenario.

A limitation inherent in assessing an areawide contribution from mobile

source sulfur-bearing compounds is that the process by which sulfur emissions

contribute to atmospheric sulfur levels is complex and not fully understood.

Sulfur dioxide (SOp), the primary sulfur compound emitted by fossil fuel

combustion, reacts chemically in the ambient air to form sulfates.  Some

of these sulfate particles are known to be more toxic than SOp and have

been associated with adverse health effects, visibility reduction, and

nonbiological and biological materials damage.
                                  131
-------
5.2.1  Los Angeles Basin Study







     The Los Angeles Basin is a geographic area where high mobile source



sulfate and sulfur oxide emissions could have the greatest areawide effect.



Sulfate levels measured in the Los Angeles Basin are unusually high consider-



ing the area's total sulfur oxide emissions.   This anomaly is attributed



to the basin's meteorological and geographic characteristics, which are



extremely favorable to the buildup of SCL~.  Frequent temperature inversions,



low average wind speeds, and the surrounding mountains limit air movement.



The abundant sunshine and photochemical smog are believed to promote an



unusually rapid and complete conversion of SCL to S0,~.  Furthermore,



limited rainfall precludes frequent clearing of sulfates from the atmosphere.







     Two factors contribute to concern that future sulfate levels in Los



Angeles will be even higher than they are today.  First, forecasts of



sulfur oxide emissions to 1980 indicate significant increases because of



shortages of relatively clean natural gas and increased burning of



sulfur-containing fuel oil (Hunter and Helgeson 1976).  Thus, sulfur



compound levels can be expected to increase because of increased SCL



emissions from stationary sources.







     The second factor causing concern is related to automobile emissions.



Beginning with the  1975 model year, automobile manufacturers began



installing oxidation catalysts on cars as a means of reducing emissions of



carbon monoxide  (CO) and hydrocarbons (HC).  Without a catalytic



converter, sulfur contained in gasoline passes out of the tailpipe mainly



as S0?.  By contrast, cars equipped with oxidation catalysts tend to
                                  132
-------
convert part of the SCL directly into sulfur trioxide, which rapidly



combines with water vapor in the exhaust to form sulfuric acid aerosol.



Sulfuric acid is known to be one of the more harmful forms of sulfate.  As



more stringent standards for CO and HC take effect and as older cars are



removed from the vehicle fleet, there is concern that the high density of



Los Angeles automobile traffic will result in large local sulfate concentra-



tions.







5.2.1.1  Methods for Reducing Automobile Sulfur Emissions— Several approaches



that reduce sulfuric acid and still meet the more stringent standards



established for other pollutants are being investigated.   The obvious way



to avoid the sulfate problem is to desulfurize gasoline.   Sulfur dioxide



and sulfate emission levels are directly proportional to fuel sulfur



level.   Therefore,  reducing the level of sulfur in the fuel will reduce



sulfate as well as  SO,, emissions.   This approach would require the oil



industry to invest  substantial capital in equipment and reduce the net



amount of gasoline  energy obtained per barrel of crude oil.  However,



there is general agreement that most of the sulfur in today's gasoline



could be removed by further refining.







     Another approach is to use chemical sulfate traps to remove particulate



matter from the exhaust.  Some of the designs tested have proven to be



quite effective.  However, a number of problems must be solved before a



practical design exists for vehicle application.  The traps tend to be



fragile and are easily damaged by engine failures.  Problems have also



occurred with the trap causing excessive exhaust pressure buildup, which



causes a loss in automobile fuel economy.
                                  133
-------
     The approach gaining the most attention is to redesign the catalyst



in such a way as to limit the production of sulfates.   Experiments  with



catalysts show that their chemical formulation, physical  shape, temperature,



oxygen pressure, and age all  affect the production of sulfuric acid.   The



most important of these appears to be the oxygen level  in the exhaust gas



to the catalyst:  pumping air into the catalyst (to improve the efficiency



of HC and CO removal) generally results in more sulfuric  acid.   One of the



most promising alternative designs is the three-way catalyst.   With this



approach, the fuel/air mixture to the engine is maintained precisely at



the stoichiometric point (enough air to burn all HC and CO, but not more



than enough).  To maintain the proper mixture ratio, a feedback control is



normally employed with an oxygen sensor in the exhaust.   If an oxidation



catalyst is added to the three-way catalyst, the system is capable  of



meeting even the low 1980 standards for HC and CO with low SO." emission.



However, the complexity of the approach is a drawback.   Controlling the



air injection rate to the oxidation catalyst will probably require  additional



sensing and control devices (Office of Mobile Source Air Pollution  Control



1977).







     For each control category, four levels of control  were considered:



(1) a minimum control level,  little or no effort to reduce emissions;



(2) a base case; (3) a moderate level; and (4) a maximum control level,



theoretical, maximum reduction possible.  Reducing the sulfur content of



the fuel was assumed to apply uniformly to the entire vehicle fleet.



Reductions in SO^ to SO." conversion in the exhaust and the trapping of



S0.~ emissions were assumed to affect the 1979 and 1980 vehicles only.
                                  134
-------
5.2.1.2  Emissions Policies Investigated Analysis—The control methods



mentioned above (as well as the several other approaches that are being



investigated) offer varying degrees of promise for reducing SO/~ emissions



while allowing the levels of other emissions to be reduced still further.



All proposed methods will impose added costs on the drivers of automobiles



through decreased auto performance, higher fuel consumption, or higher



operating and purchase costs.







     Techniques for sulfur emissions control are still in an early stage



of development, and it is difficult to predict either the ultimate costs



of the controls or their efficiency under real-world driving conditions.



Rather than attempt to estimate the ultimate costs and effectiveness of



the various devices that are currently being researched and developed,



this analysis investigated the benefits of achieving various reductions in



average SO^ and SO/" emissions from the automotive fleet mix for the year



1980.







     Table 5-4 summarizes the specific set of assumptions for which benefits



were calculated.   The first control category considered was reduction of



the sulfur content of the fuel.   As stated above, reducing the sulfur in



the fuel proportionally reduces both SOp and S0.~ emissions.  The second



type of control considered was reduction in the percent conversion in the



exhaust of SO* to SO.".  Improved catalysts have the effect of reducing



S0.~ emissions while proportionally increasing SOp emissions.  The third



control considered reducing S0.~ while keeping S0? constant.  Such an



effect is characteristic of "traps."
                                  135
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                                                                136
-------
     For the cost/benefit analysis, the model region chosen was a square



about 85 km on each side overlying the central portion of the Los Angeles



Basin as shown in Figure 5-3.  The region was subdivided by a grid into



169 cells, each roughly 4 miles on a side. (This square region is approximately



2 miles/side larger than the same region modeled by Cass [1978] and Roth



[1974].   The overlap allows us to make use of data and results of these



authors.)  Spatial distribution was obtained by individually estimating



concentrations within each cell.   Mobile emissions within a cell were the



sum of four categories:  automobile (including light trucks), heavy trucks,



aircraft, and ships.







     Automobile emissions were assumed to be proportional to local traffic



density.   Estimates of the spatial distribution of freeway and surface



street traffic for 1969 derived by Roth (1974) were used to estimate the



daily vehicle miles traveled within each cell, as shown in Figures 5-4 and



5-5.







     From these assumptions, the average emission rates for the 1980



on-the-road vehicle fleet were estimated.   Estimates were performed separately



for surface and freeway driving,  assuming a vehicle age and use distribution



given in Nordsieck (1975, p. 19).   All sulfur in gasoline that was not



converted to S0.~ was assumed to be emitted as SCL.  The resulting average



emission rates obtained are summarized in Table 5-5.
                                  137
-------
W« Rti«M Ang* es
         Figure 5-3.  Modeling region and cells defined  for estimation
         of S04=  levels.
                                138
-------
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      436
1198
       144
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             363
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28
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                                         I     T
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                  614
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            603
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            343
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           1036
             892
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     2102
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           226
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                        757
                         564
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                  298
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                        602
                       452
                                 662
                              992
                              1047
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                        144
                        636
                       454
                                                                     624
                                                                    77
                                                               104
1
             Figure 5-4.   Spatial  distribution  of  freeway traffic,1969.
                                      139
-------
Figure 5-5.   Spatial  distribution of surface street traffic,  1969.
                            140
-------

















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141
-------
     Total  SOp and SO.  emission levels from automobiles were obtained by


multiplying emission rates by estimates of surface and freeway vehicle


traffic.   The vehicle traffic estimates used for 1980 were 1974 estimates


inflated to 1980, assuming growth rates by cell that were identical to the


growth rates observed by Cass (1978) between 1969 and 1974.





     Estimated 1980 sulfate concentrations attributable to automobiles

                                                           2
calculated by the model range between zero and about 4 ug/m .   Figure 5-6


shows sulfate concentrations attributable to automobile emissions under


the base case assumption.





     The alternative emission scenarios are summarized in Table 5-4.  The


estimation procedures and assumptions employed were as follows.  The


average SO.  emission ^ats from r,ew autos during the period 1975-78 under


standardized conditions of freeway driving, "3.b miles/gal fuel economy


and 0.03 percent fuel, was assumed to be 15 rug/mile.  As the car aged,


emission rates were assumed to decrease by 25 percent per year because of


deterioration of the catalyst.  The base case emission rate assumption for


1979 and 1980 autos under the same standardized conditions was 20 mg/mile


and 25 mg/mile, respectively.  The assumed increase was to account  for the


possible difficulty in meeting more stringent CO, HC, and NO  emissions
                                                            ){,

standards for 1979 and 1980.  Because of SO ~ storage on the catalyst


substrate, emission rates during surface street driving were assumed to be


only one-third the rate during freeway driving.  Non-catalyst-equipped


vehicles were assumed to emit 1 mg/mile SO." under both surface street and


freeway driving and to comprise a constant 15 percent of each new year's


vehicle fleet.
                                  142
-------
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     It was assumed that the mileage (miles per gallon) of catalyst-equipped cars



to increase linearly from 13.4 in 1975 to 16.5 in 1980, a 23 percent improvement



primarily reflecting the shift to lighter cars.   Because non-catalyst-equipped



autos are generally lighter and smaller than catalyst-equipped cars, It was farther



assumed that their average mileage to equal that of the catalytic fleet in 1980.



For all cars, fuel economy was assumed to be 27 percent better on freeways than on



surface streets.







     Resulting summer and winter ground level concentrations were then integrated



over wind direction and averaged to obtain estimated annual contours of equal



lead concentrations shown in Figure 5-7.  Annual average suspended lead measure-



ments obtained in 1969 from nine sites are also shown.   Comparison of estimated



and measured values is good, considering the approximations employed.







     The mobile source dispersion model was then expanded to treat the simul-



taneous emission of S02 and S0,~ to account for deposition and atmospheric con-



version.  Conversion within a plume was assumed to occur according to a first-



order reaction.  Both compounds were assumed to be removed to the ground at a



constant rate, beginning at the time of emission.  For a given direction of wind,



each mobile point source was assumed to emit a plume the shape of a half-elliptical



cone, with emissions uniformly distributed over each cross section a given distance



downwind from the source.  The dimensions of the plume were chosen so as to approximate



downwind concentrations estimated by the binormal continuous plume dispersion



model of Pasquill and Gifford (Turner  1970) for a source at ground level under



atmospheric stability class C.
                                  144
-------
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 KEY  TO CONTOUR CONCENTRATIONS
     i y
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  222222222222222222222222222222'» 0 17
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            Figure  5-7.   Annual  average  suspended lead  concentrations  for
            1969  in the Los Angeles  Basin.
                                          145
-------
     With the use of lead as a tracer,  the predictive ability of the dispersion



model was evaluated by the same procedure used by Cass (1975).   Roth's automobile



traffic density data were first reduced to account for vehicles not powered by



gasoline.  Emission factors assumed for suspended lead (60 mg/mile in summer,  52



mg/mile in winter) were derived from the analysis by Cass, based on the lead



content of gasoline, vehicle fuel economy, and a detailed analysis of the fate of



lead in gasoline.







     From these assumptions, summer and winter ground level suspended lead



concentrations were estimated for each  average wind speed in each of the 16



azimuthal directions, assuming horizontal plume angles of 22.5 degrees, and



emissions per cell were derived by multiplying gasoline vehicle mileage by the



estimated lead emissions factors.  Wind speed and direction were obtained for



each cell through a linear interpolation of monthly wind data obtained for



three sites.  (Los Angeles International Airport, Burbank Airport, and Long Beach.



Wind data consist of wind speed and percent of time that wind blows from each



direction averaged over summer and winter months.  Source is U.S. Weather Bureau



[1962].)  Wind directions and speeds are assumed to remain constant along the



entire length of each plume.







     Estimated 1973 ground level S0,~ concentration for the Los Angeles Basin



from all sources were obtained by adding mobile and stationary components.  The



1973 mobile component was obtained by using the mobile model with 1973 auto-



mobile emission estimates, vehicle traffic estimates, vehicle traffic growth to
                                  146
-------
1973, vehicle fuel economy, and summer/winter sulfur content of gasoline.   Mobile



components from heavy trucks, aircraft, and ships, also taken from Cass (1978),



were added to the auto component to obtain total SOp and SO.  mobile emissions by



cell.  Using total mobile emissions, the mobile model produces contour plots for



incremental SO.  concentrations contributed by mobile sources.   These mobile



concentrations were then added to stationary contributions to obtain estimates of



total summer/winter SO."".







     The total SO.  estimates yielded by the combined model account for major



stationary and mobile sources but neglect major sources outside of the grid,



minor manmade sources on the grid (which together account for 10 percent of



emissions), and natural sources.   The principal natural source of atmospheric



sulfur oxide is the oxidation of hydrogen sulfide or dimethyl sulfide gas  that



results from decaying vegetation.   Near oceans, significant sulfate is also



emitted as part of the sea spray.   Natural background levels of atmospheric



sulfate in the Los Angeles Basin have been estimated to range between 1 and 4



(jg/m .







     Background SO." concentrations due to sources other than the top 90 percent



of stationary and mobile on-grid sources were estimated through a least-squares



fit of predicted concentrations to available measurements of actual concentra-



tions.   With respective nominal estimates of 2.88 percent/hr and 1.44 percent/hr



for the dry deposition of S0? and SO,", respectively, average summer and winter



mixing layer heights of 325 ms and a summer conversion rate of 6 percent/hr and



winter conversion rate of 2 percent/hr, a best fit was obtained with respective
                                  147
-------
summer and winter background concentrations of 3.3 and 2.0 [jg/m .   Figures



5-8 and 5-9 show 1973 SO ~ levels predicted by the model  when background



concentrations are taken into account.   Totaled 1980 predicted annual



emissions are given in Figure 5-10.   Also shown in the figures are the



summer and winter average values actually measured at various sites.







     Since the model accounts for the spatial distribution of only the top



90 percent of anthropogenic sources, local impacts of small sources are



not taken into account in the estimates.   Consequently, local measurements



may differ significantly from those predicted by the model.  Nevertheless,



predicted values compare reasonably well  with actual measurements.







     The stationary and mobile source dispersion and conversion models



used to estimate the 1973 concentrations shown in Figures 5-8 and 5-9 are



used in the analysis to predict 1980 S0,~ concentrations required by the



cost/benefit analysis.  The only variation was the use of projected 1980



emissions rather than 1973 emission estimates.  In the absence of



better information, emission rates were assumed to change uniformly irrespective



of spatial distribution within each source category.  Nonautomotive mobile



emissions are projected to increase uniformly with a growth rate of 2



percent year.







5.2.1.3  Visibility in the Los Angeles Basin--It is well known that much of



the impairment of visibility in urban areas of the United States is the



result of the scattering of light by airborne particles.  Since evidence



suggests that sulfates may be one of the most important contributors to



visibility reduction by this means, an assessment of the benefits of
                                  148
-------
                                21.3 -.:::.
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       Figure 5-8.  Predicted  and  measured average S04  concentrations for
       summer, 1973, in the  Los Angeles  Basin.   Contours indicate areas
       of approximately constant concentrations.   Actual measured values
       are shown to one decimal, place  adjacent to monitoring sites.
       Numbers on controus indicate  concentration of contour.  All values
       are micrograms per cubic meter.
                                149
-------
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  KEY TO CONTOUR CONCENTRATIONS

           (Winter)
          Figure 5-9.  Predicted and measured  average S04  concentrations
          for winter, 1973,  in  the Los Angeles Basin.  Contours  indicate
          areas of approximately constant concentrations.  Actual  measured
          values are shown  to one decimal place adjacent to monitoring sites.
          Numbers on contours indicate approximate concentration of contour.
          All values are micrograms per cubic  meter.
                                   150
-------
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   Figure 5-10.  Total  predicted annual  average sulfate  concentrations,
                                           1980.
                                 151
-------
reducing sulfur oxide emissions should attempt to account for improvements



that may be obtained in visibility.







     The basic relationship between visibility and the composition of the



atmosphere is given by the Koschmeider equation, V = 0.0024/b, where V is



the meteorological range in miles and b is the extinction coefficient in



units of inverse meters.   In a homogeneous atmosphere, meteorological



range is the distance at which black object can be seen against the horizon.



For the purposes of the analysis, visibility was defined as the meteorological



range as given by the Koschmeider equation.







     The extinction coefficient b is the sum of the extinction coefficients



of the various light-scattering and light-absorbing elements in the atmosphere.



The contribution of sulfates to b is determined not only by the sulfate



mass concentration, but also by relative humidity; high humidity enhances



the light-scattering properties of sulfates.







     An analysis of the effects of atmospheric composition on visibility



in downtown Los Angeles has been performed by Cass (1978).  In this study,



long-term (1965-74) data accumulated by the Los Angeles Air Pollution



control District were used to determine the parameters of a theoretically



motivated form for the extinction coefficient b as  a function of recorded rela-



tive humidity and levels of various atmospheric pollutants, including S0.~.  The



functional form of b was then used to predict the effect of a 50 percent and a
                                  152
-------
75 percent reduction in sulfate concentration on visibility; the historical



data with reduced sulfate levels were used to calculate a reduced extinction



coefficient b and, with the Koschmeider equation, the improved visibility V.



The advantage of this method is that it preserves the correlation among various



particulate levels and meteorological conditions.  The output for each assumed



sulfate reduction is not an average visibility, but a frequency distribution



describing the percent of time that visibility is less than any given value.







     For a given location, frequency distributions describing visibility tend



to have the shape of a log-normal distribution.  This is also true for the



frequency distributions predicted by Cass.   Thus, the results of Cass's analysis



and the assumption of a log-normal frequency distribution for daily average



visibility make it possible to express the parameters of the log-normal dis-



tribution describing visibility in downtown Los Angeles as a function of the



fraction of atmospheric SO/" removed.







     For this analysis, it was necessary to estimate future rather than past



visibilities and to perform this estimate for other areas in the basin in



addition to downtown Los Angeles.  Considerably more data are needed to deter-



mine exactly what variations occur in these frequency distributions from



location to location and from year to year.  For the purpose of this analysis,



the simplifying assumption was made that the relative contributions of the



various components to the extinction coefficient were approximately the same,



regardless of location or year.  With this assumption, the frequency distributions,
                                  153
-------
given no additional controls on SO  emissions, would be identical except for
                                  s\
scaling factors based on differences in total particulate matter concentra-
tions.  Thus, estimates of the frequency distribution describing 1980 visibili-
ties could be obtained at any location given only the total 1980 particulate
level at that location relative to the level in downtown Los Angeles from 1965
to 1974 and given the fraction of the base case SO ~ that is removed from the
atmosphere under the assumed control policy.
     Figure 5-11 shows an example of the results obtained by using this approach.
The figure shows the frequency distribution obtained for 1980 visibilities at
downtown Los Angeles under the base case assumption and under the assumption of
complete desulfurization of gasoline.   At this location, desulfurization resulted
in about a 10 percent improvement in average visibility.  Table 5-6 summarizes
the results for all cells by showing the average visibility obtained under each
of the emission assumptions.
            Table 5-6.  AVERAGE VISIBILITY OVER THE LOS ANGELES BASIN
                  UNDER EACH AUTOMOBILE SOx EMISSION ASSUMPTION
                                   (in miles)

Control
Reduce fuel sulfur
Reduce conversion
Trap S04~
Degree
of control
Minimum Moderate
3.69
3.71
3.74
3.83
3.75
3.75
Maximum
3.85
3.76
3.76
                                  154
-------
                                                 O i—
                                                 CO 10
                                                  I—
                                                         os
                                                 (0 -r-
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      US  N
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     People obviously prefer good to poor visibility,  and it seems likely

that at least some people would be willing to decrease their material

standard of living in order to improve their local  visibility.   However,

very few attempts at estimating a dollar value for visibility have been

made, and there are no published studies of the economic value of visibility

to the residents of Los Angeles.



     To obtain a rough estimate of the dollar value of visibility improvements

to Los Angeles residents, this analysis uses the preliminary results of a

recent study performed in the city of Farmington, located in the scenic

Four Corners region of New Mexico (Blank et al. 1978).  This study employed

a bidding game approach to determine how much each household or visitor in

the area would be willing to pay to avoid reduction of visibility.  The

visibilities considered ranged from 25 to 75 miles.



     Application of these results to Los Angeles, where visibility

averages around 5 miles, required considerable extrapolation.  Two alternative

approaches were considered:  the linear and logarithmic models.



     For the linear model, the simplest interpretation of the Four Corners

data is that the cost of reducing visibility from a value V-, to a value Vp

is simply proportional to the magnitude of the reduction:
                        Social cost per person
                        per year of reducing       = k, (V,
                        visibility from V-, to V«
                                  156
-------
With this interpretation, the Four Corners data yielded an average value
for kj of $0,70 per mile per person per year.   This is computed from an
average of values given in Blank et al, (1977) and assumes 2,57 persons
per household.  The result is in fairly good agreement trith that of Randall
et al. (1974).

     The linear Model predicts a social cost of a 1-mile reduction in
visibility that is the sane whether the reduction occurs where prevalent
visibility is 75 riles or 5 miles.   Another approach is to assume that the
cost of visibility reduction is related to the percentage reduction in
prevalent visibility.   Therefore a logarithmic cost Model was considered
wherein the cost of reducing visibility fron V, to V? is given by:

                        Social cost per person         ~
                        per year of reducing        = k  log .     - (V,A-)
                        visibility fn» V] to V?             Mse *   '  *

The factor k? May be interpreted as the social cost per person of a 50
percent reduction in visibility.   With the Four Corners data, a value of
$24.50 per person per year was obtained for k~.

     Total visibility costs were computed for each of the geographic cells
defined over the Los Angeles Basin by using both the linear and logarithmic
cost models.   The total visibility costs obtained by suMming over cells
are shown for each emission control assumption in Table 5-7.   In all
cases, the visibility costs were measured relative to the situation in
which all SO ~ attributable to automobiles was removed from the atmosphere.
Thus, the values shown in Table 5-7 can be interpreted as the social costs
                                  157
-------
of visibility reduction attributable to automobile SO.   under each emission

control  assumption.
                  Table 5-7.   VISIBILITY COSTS ATTRIBUTABLE TO
                         AUTOMOBILE SOx EMISSIONS,  1980
                              (millions of dollars)

Minimum
Control
Reduce sulfur
Reduce con-
version
Trap S04=
Linear
model
1.1
1.0
0.8
Log
model
17.2
15.5
13.0
Degree of
control
Moderate
Linear
model
0.1
0.7
0.7
Log
model
2.5
10.7
10.8
Maximum
Linear
model
0
0.6
0.6
Log
model
0
9.3
9.2
      Base case:  $0.8 million (linear model); $13.0 million (log model).


     Considerably more visibility costs were predicted under the log model

than under the linear model.  For a conservative estimate (large visibility

costs), total social costs are computed assuming the log model.



5.2.1.4  Damage to vegetation—At this time, there are no reported instances

of vegetational injury induced by sulfur compounds generated by mobile or

line sources.  Recently automobile-generated sulfate aerosol was considered

to be a potential threat to vegetation.  However, based on the ambient air

quality data and preliminary information on vegetational dose-response

relationships to submicron H?SO. aerosols, sulfate aerosols currently are

not considered to be directly injurious to plants in the vicinity of line

sources.
                                  158
-------
     Benedict et al.  (1973) estimated the total losses attributed to

sulfur oxides singly and combined with other pollutants.   According to

their estimates for EPA Region IX (Table 5-8), total losses exceed $80

million.   A best-guess estimate of the damage caused by mobile sources in

the Los Angeles Basin is $1 million.
           Table 5-8.   ESTIMATED DAMAGE TO VEGETATION IN EPA REGION IX
                                    (dollars)



Plants
Citrus
Field crops
Seed crops
Fruits and nuts
Vegetables
Nursery and forest
crop total
Forestry
Highways
Parks
Residential
Urban uses
Rural uses
Ornamentals total
Value in
pol luted
areas
162,650.3
722,905.1
45,610.7
460,158.1
633,731.0
155,077.2
2,180,132.4
419,062.2
22,349.6
38,118.3
39,309.6
2,549.2
27,436.6
548,825.5

Losses due to
sulfur oxides
0.3
1,442.0
1.6
1.4
220.0
0.4
1,665.7
993.1
33.5
40.4
131.1
16.7
142.3
1,357.1
Total loss due to
ozone, SOx, and
fluorides
6,224.5
7,549.9
444.1
8,965.2
10,205.1
18,905.6
52,274.4
20,001.8
2,629.4
2,319.4
3,337.8
127.3
767.5

     Total all plants
2,748,957.9
3,022.8
81,457.6
                                  159
-------
5.2.1.5  Damage to nonbiological materials--Appendix B contains estimates of



materials damage caused by sulfur-bearing compounds emitted from both station-



ary and mobile sources.  The social costs and benefits of controlling the



mobile emissions are determined by factoring the total nationwide damage



estimates by the percent of mobile source emissions.  Less than $1 million in



nonbiological materials damage is attributed to mobile source sulfur emissions



in the Los angeles Basin.







5.2.1.6  Benefits analysis—The estimated social welfare costs and benefits of



automotive sulfur oxide emission controls in the Los Angeles Basin for the yeat*



1980 are listed in Table 5-9.  The social costs of reduced visibility are based



in this section on a 50 percent reduction in sulfur oxide emissions from



stationary sources.  The previous costs of visibility reduction assumed emissions



from stationary sources of 743 tons per day.  The projected annual average



sulfate concentrations under the 50 percent reduction assumption were between



12 and 16 pg/m3.







     The social costs of biological and nonbiological materials damage were



given the nominal value of $2 million.  This value was treated under the



assumption used for estimating visibility costs, i.e., as a function of the



fraction of atmospheric sulfate removed.  All benefits listed in the table are



defined as a decrease  in social costs.
                                  160
-------


















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161
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5.2.1.7  Cost/benefit comparison—Figure 5-12 shows curves obtained from
the results of the benefit analysis when benefits are plotted in terms of dollars
per thousand vehicle miles traveled.   Because each curve is based on only three
or four points and because the exact values of these points are highly uncertain,
these curves must be interpreted with extreme caution.   Benefits accounted for
in the analysis were improved visibility and reduced damage to biological and
nonbiological material.   To facilitate the comparison of benefits with the costs
of controls, benefit estimates were expressed in equivalent dollar values.


     Estimated total benefits were found to be relatively insensitive to the
level of assumed 1980 stationary source emissions:  about $17 million for desul-
furization of gasoline (to 0.01 percent sulfur) and about $3 million for controls
that reduce sulfate emissions only (30 percent reduction in sulfate emissions
for 1979 and 1980 vehicles).


     Unfortunately, little information concerning the costs and effectiveness
of devices for controlling SO  emissions from automobiles was available at the
                             /\
time of this study.  However, the use of the results of the benefit analysis
for performing cost/benefit comparisons are illustrated using preliminary cost
estimates for desulfurization of gasoline.


     From Kittrell and Short (1978), West Coast manufacturing costs for desulfuri-
zing gas to 100 ppm (0.01 percent) were estimated to be roughly $.02 per gallon.
Using base case assumptions for vehicle fuel mileage, an average fuel economy for
1980 on-the-road vehicles of 16.6 miles per gallon was computed.  Assuming an
                                  162
-------
                                         40         80
                                     SULFUR REMOVED
                                     FROM GASOLINE
                                        (Percent)
                           --.20-
                             (a) DESULFURIZATION
                                          REDUCTION IN EXHAUST
                                            CONVERSION RATE,
                                             1979 & 1980 Vehicles
                           (b) IMPROVED CATALYST
                              TRAP EFFICIENCY,
                              1979 & 1980 VEHICLES
                                  (Percent)
                                  (c) TRAP
Figure  5-12.   Benefit per  1000 miles driven versus degree of  control.

                                  163
-------
energy penalty of desulfurization of 1  percent, this results in an estimated



incremental  cost to the consumer of $1.22 per thousand miles driven.   From



Figure 5-lla, the benefits of desulfurization to 0.01 percent were estimated



at $0.34 per thousand miles driven.







     The costs and benefits from controlling automotive sulfur emissions



are the most favorable for fuel desulfurization.  The costs of control



cannot, realistically, be applied to other regions of the United States.



In addition to the uncertainties associated with this analysis, the Los



Angeles Basin is considered as a worst case and should not be compared



with other metropolitan areas.







5.2.2  Kansas City, Mo., Study







     The metropolitan area of Kansas City, Mo., was selected as a typical



large urban area in the United States.   This area also provides data from



a recent diffusion modeling study prepared by PEDCo for the U.S. Environmental



Protection Agency (1978) on particulate emissions from diesel-powered



vehicles.  The data derived in that study were modified for this exposure



assessment to sulfates.







     Base year emissions from mobile sources are calculated from 1974



vehicle exhaust  information and are projected to 1985.  The vehicle miles



traveled (VMT) are estimated  for six vehicle/engine classes.  The percent



of VMT by vehicle type, the vehicle type distribution by age, and the rate



of diesel-powered vehicle  introduction are used in conjunction with the



Kansas City traffic distribution and growth  rate.  The projected motor
                                  164
-------
vehicle sulfate exhaust emissions are noted in Table 5-10.  The emission


rates are based on diesel vehicle introduction rates (Table 5-11) and


fraction of VMT by mobile source catagory (Table 5-12).




     The projected annual average concentrations of sulfates from diesel


exhaust are projected through 1985 in Table 5-13.   The ambient concentrations


from the diesel source incremental contribution were derived from the Air


Quality Display Model.  Under a maximum penetration of diesel-powered

                                                      3
vehicles, a maximum sulfate concentration of 0.02 pg/m  from diesels is


forecasted.  This small increment would not hold true for sulfur dioxide,


which, because of time limitations, was not modeled for this area.




5.3  CONCLUSION




     Two scenarios have been presented to estimate exposure levels to


primary sulfur emissions from mobile sources.   The social welfare costs


and benefits of reducing these emissions were explored for an atypical


area, the Los Angeles Basin.  The emission/modeling studies show that


sulfuric acid emissions from catalyst-equipped automobiles disperse rapidly


into the ambient air.  The automotive increment to the total ambient


sulfate concentrations averages 2 (jg/m .   Levels as high as 8 pg/m  were


found at an elevation of 1.5 feet both above and near the roadway.  Concentrations


occurring inside the automobiles ranged from 1 to 4 ug/m .
                                  165
-------

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166
-------
               Table 5-11.  DIESEL VEHICLE INTRODUCTION RATES






1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
Share of new sales
Light-duty vehicles
and trucks,
%
Best
est. Max.
0.5 0.5
0.5 0.5
0.5 0.5
0.5 0.5
2.0 5.0
4.0 10.0
6.0 15.0
8.0 20.0
10.0 25.0
10.0 25.0
10.0 25.0
by model year

Heavy-duty
%
Best
est.
28.0
28.0
28.0
30.0
31.0
31.0
31.0
31.0
31.0
31.0
33.0

trucks,

Max.
28.0
28.0
28.0
35.0
36.0
38.0
40.0
48.0
57.0
67.0
78.0
Table 5-12.   FRACTION OF URBAN VMT BY MOBILE SOURCE CATEGORY IN PROJECTION YEARS

Fraction of urban VMT




1974

Mobile source category
Light- duty
Light-duty
Heavy-duty
Light-duty
Light-duty
Heavy-duty
gasoline vehicles
gasoline trucks
gasoline trucks
diesel vehicles
diesel trucks
diesel trucks
0.826
0.107
0.036
0.004
0.001
0.026
1981
Best
est.
0.815
0.106
0.035
0.015
0.002
0.027

Max.
0.796
0.104
0.033
0.034
0.004
0.029

1983
Best
est.
0.
0.
0.
0.
0.
0.
798
104
034
032
004
028
1985
Best
Max.
0.
0.
0.
0.
0.
0.
750
098
029
080
010
033
est.
0.
0.
0.
0.
0.
0.
779
102
034
051
006
028
Max.
0.704
0.093
0.023
0.126
0.015
0.039
                                  167
-------
            Table 5-13.   PROJECTED REGIONAL ANNUAL AVERAGE
                CONCENTRATIONS FOR SULFATES FROM DIESEL
                         EXHAUST FOR TEST CITY
                                (|jg/m3)

Year
1974
1981
1983
1985
Diesel
Best
ext.
0.009
0.009
0.011
0.013
growth case
Max.
growth
0.011
0.017
0.023
     The automotive sulfate increment to the total stationary source

sulfate emissions was also modeled for the Los Angeles Basin.  The

benefits are listed in summary Table 5-14.  Benefits are defined as a

decrease in social costs.
        TABLE 5-14.  ESTIMATED SOCIAL WELFARE BENEFITS OF MORE STRINGENT
                    AUTOMATIVE SOx EMISSIONS CONTROLS, 1980
                              (millions of dollars)

Degree of control
Control
Reduce fuel sulfur
Reduce conversion
Trap sulfate emissions
Minimum
-8.1
-5.2
0
Moderate
16.9
3.0
2.6
Maximum
21.2
5.2
5.4
                                  168
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     The costs of reducing mobile source sulfur emissions were estimated



for fuel desulfurization at the moderate control level.  In the Los Angeles



Basin, the costs to the consumer were estimated at $1.22 per thousand



miles driven.   The benefits gained from this control measure are based



primarily on an increase in visibility.   Under the moderate fuel desulfur-



ization scenario, a benefit of approximately $17 million was estimated for



about a 0.1-mile increase in visibility.







     One conclusion that can be, drawn from the emission/modeling data in



this chapter is that although sulfur emissions from mobile sources account



for only about 2 percent of the total anthropogenic sulfur emissions



nationwide, the percent of mobile source sulfate emissions is much higher



than that of stationary source sulfate emissions.







     Finally,  the exposure assessments modeled for sulfate emissions from



mobile sources should help future estimates for health effects once health



effect levels  for sulfates are established.  The worst-case exposure



estimates for  sulfur dioxide indicate that the increase in sulfur dioxide



emissions from an increase in diesel-powered vehicles is not likely to



affect adversely the public health.
                                  169
-------
Bibliography

Air Quality Assessment of Participate Emissions from Diesel-Powered Vehicles.  A
  Report by PEDCo Environmental, Inc., for the U.S.  Environmental Protection
  Agency.   March 1978.

Blank, F.  M. et al.   Valuation of aesthetic preferences:  A case study of the
  economic value of visibility.  Preliminary Draft.   University of Wyoming, 1977.
  Quoted with the permission of R.  d'Arge.

Bowman.  Personal communication.  Florida Department of Environmental Regulation.
  1975.

Cadle, S.  H., D. P.  Chock, J. M. Heuss, and P. R. Monson.  Results of the General
  Motors Sulfate Dispersion Experiment.  GMR-2107.  March 1976.

Cass, G. R.  Lead As a Tracer for Automotive Particulates:  Projecting the Sulfate
  Air Quality Impact of Oxidation Catalyst Equipped Cars in Los Angeles.  Pasadena,
  California, Environmental Quality Laboratory, California Institute of Technology.
  May 1975.

Cass, R.  Methods for Sulfate Air Quality Management with Applications to Los
  Angeles.  Pasadena, California, California Institute of Technology.  1978.

Hunter, S. C., and N. L. Helgeson.   Control of Oxides of Sulfur from Stationary
  Sources in the South Coast Air Basin of California.  Tustin, California KVB Inc.
  Contract 1-ARB4-421.

Kellogg, W. W. et al.  The sulfur cycle.  Science 175:587, 1972.

Kittrell, J.R. and W. L. Short.  Fuel Controls--Desulfurization, Allocation.  Preliminary
  Draft of Section 4.1 prepared for The Effects to the Public  Health and Welfare
  on Sulfur-Bearing Compounds Emitted from Mobile Sources in connection with Section
  403(g) of the 1977 Amendments to the Clean Air Act.  1978.

McJilton, C., and R. Frank.  The role of relative humidity in  the synergistic effect
  of sulfur dioxide aerosol mixture on the lung.  Science 182:503-504, 1973.

Merkhofer, M. W., and R. J. Korsan.  Florida Utility Pollution Control Options and
  Economic Analysis—Volume 2:  Cost-Benefit Analysis of Alternative Florida Sulfur
  Oxide Emissions Control Policies.  SRI Final Report, Project 5080.  Menlo  Park,
  California, SRI International.  January 1978.

Merkhofer, M. W., R. J. Korsan, P.  C. McNamee, and S. M. Olmsted.  Cost/Benefit
  Analysis of Mobile Source SOx Emission Control:  An Analysis of the Benefits of
  Automobile SOx Emission Reduction in the Los Angeles Basin.  Menlo Park,
  California, SRI International.  A Report to Biospherics, Inc., Rockville,  Maryland.
  May 1978.
                                     170
-------
Nordsieck, R.  A.  Air Pollutant Emission Factor Estimates for California Motor
  Vehicles 1967-2000.  Los Angeles, California, California Department of Transpor-
  tation.  January 1975.

North, D., and M. W.  Merkhofer.  Analysis of alternative emissions control strategies.
  Ijn Air Quality Stationary Source Emission Control.  U.S.  Senate Committee on
  Public Works, Serial 94-1, pp. 540-711.  March 1975.

Office of Mobile Source Air Pollution Control.   Second Annual Catalyst Research
  Program Report, Supplement V.  Research Triangle Park, North Carolina, U.S.
  Environmental Protection Agency, Health Effects Research Laboratories, Office of
  Research and Development.  January 1977.

Orange County Services Agency.   Vital Statistics Summary, Orange County, 1976.
  Santa Ana, California,  Public Health and Medical Services, July 1, 1976.

Papetti, B., and J.  Horowitz.   Stochastic Model of Worst Case Exposures to Sulfuric
  Acid from Catalyst-Equipped Vehicles.   U.S.  Environmental Protection Agency In-
  House Report.  November 1975.

Randall, A.  et al.   Bidding games for valuation of aesthetic and environmental
  improvements.  J.  Environ. Econ. ]_, 1974.

Roth, P.  M., et al.   Mathematical modeling of photochemical air pollution—II:  A
  model and inventory of pollutant emissions.   Atmos. Environ.  8:97-130, 1974.

Southern California Association of Governments.  SCAG-76 Growth Forecast Policy.
  Los Angeles, California.   January 1976.

Trijonis, J.  et al.   An Implementation Plan for Suspended Particulate Matter in
  the Los Angeles Region.   Final Report, TRW Transportation and Environmental
  Operations.   San Francisco,  California, prepared for the U.S.  Environmental
  Protection Agency Region IX.   March 1975.

Turner, D. B.   Workbook of Atmospheric Dispersion Estimates.  Research Triangle
  Park, North Carolina, U.S. Environmental  Protection Agency, Environmental
  Health Series (Air Pollution).  Revised 1970.

U.S. Weather Bureau.   Summary of Hourly Observations.  Series No.  82-4, U.S.
  Department of Commerce.   1962.
                                     171
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                        6.   SUMMARY AND CONCLUSIONS







     An estimated 30 million tons of sulfur oxides are emitted annually in



the United States.   Because transportation vehicles account for only about



2 percent of this emission, their contribution to sulfur pollution was at



one time considered relatively minor.   This outlook changed when it was



observed that the oxidation catalyst,  designed to control other pollutants



from automobiles, converted the sulfur dioxide (S0?) in exhaust to sulfuric



acid (HpSO.), a much more toxic compound.







     Initial estimates showed that high amounts of HUSO, were emitted from



catalyst-equipped vehicles, more than twice the actual 10-15 nig/mile rate



determined subsequently.   This preliminary finding led to the establishment



of the U.S. Environmental Protection Agency's Catalyst Research Program,



which assessed the environmental impact of emissions from oxidation catalyst-



equipped vehicles.   This program and other related research projects



identified the types of sulfur compounds emitted from mobile sources.  In



addition to sulfuric acid (which forms sulfate salts) and sulfur dioxide,



hydrogen sulfide and carbonyl sulfide were found, but in trace amounts and



only after control  system failure.   It was determined that high amounts of



sulfates and sulfur dioxide were also produced by light-duty diesel vehicles.



Consequently, the effects on the public health and welfare of these sulfur-



bearing compounds were reviewed for this special report to the U.S. Congress



under Section 403(g) of the 1977 Amendments to the Clean Air Act.







     Toxicological  studies show that sulfuric acid is the most irritating



of the atmospheric sulfate (SO. ) compounds.  As little as 70 ng/m  H?SO.
                                  172
-------
can narrow the larger air passages (bronchi) of the lungs in animals, an



effect which is reflected by an increase in airway resistance.   To produce



the same degree of bronchoconstriction, a more than threefold higher



concentration of SCL is required.   One reason for the relatively high



toxicity of H^SO, is the ability of sulfate particles to reach the deep lungs



more readily than SCL, which tends to be absorbed in the moist mucous membranes



of the upper airways.  When SCL is combined with small particulate matter,



it enters more deeply into the lung and exerts stronger effects.






                                                         o

     Exposure to HUSO, at concentrations of 350-5000 ug/m  for 5-15 min



has been shown to affect respiration rates in healthy adults.   The absence



of effects at lower concentrations, even in sensitive subjects  such as



asthmatics, is apparently due to the presence of ammonia in the mouth,



which neutralizes the acid aerosol at these lower test concentrations.







     For several  years following publication of the criteria documents for



SO  and particles, most of EPA's air pollution studies on sulfates and S09
  X                                                                      ^


were conducted under a large-scale program known as CHESS.   The research



data indicated that acute responses, specifically aggravation of asthma



and symptoms in the elderly, were  associated with 24-hr exposures to 10-15


    3                         3
(jg/m  sulfate and 200-300 (jg/m  SOp.   Chronic effects were observed at



200-400 ug/m3 S02, 7-20 pg/m3 S04=, and 60-165 ug/m3 TSP (total suspended



particles).







     Although the CHESS studies had several flaws, including problems in



sorting out variables that were causally related to the observed effects,



they pointed up the effects on morbidity and mortality of sulfur oxides
                                  173
-------
and associated participate matter.   Additional  research is needed to



establish dose-response relationships for sulfates before public health



effects can be quantified.







     Of all airborne sulfur pollutants,  sulfur dioxide is the most damaging



to vegetation.  This damage ranges  from discoloration and leaf shedding to



reduced growth rates.   Vegetational injury attributed to mobile source



sulfur emissions can be estimated roughly by factoring the damage from all



SO  emissions by the percent of mobile source emissions.  The actual loss
  J\


from damage caused by mobile sources is difficult to determine by current



field assessment methods.   One problem is the inability to sort out the



effects of SOp alone from those of  SOp in combination with other pollutants.







     Assessment of damage to nonbiological materials is plagued by similar



problems.  There have been no studies to isolate the relative contributions



of mobile versus nonmobile sources.  The effects of total emissions from



all sources, however, can be analyzed to estimate the materials damage



from mobile emissions.  Studies show that sulfur oxides, salts, and acids



can etch metal surfaces such as galvanized coatings; discolor painted



surfaces, fabric, and building materials; and leach carbonate building



stone.  Nevertheless, it is difficult to distinguish the damage caused by



sulfur compounds from that caused by other pollutants and natural processes.







     The effects of sulfur compounds on climate cannot yet be determined.



Although sulfate particles can absorb and scatter energy from the sun and,



possibly, affect precipitation, no  relationship between climatic alterations
                                  174
-------
and pollutant concentrations has been established.  Effects on visibility,


however, have been noted.




     Recent studies suggest that sulfates may be a principal cause of


visibility reduction in certain areas of the United States.  For example,


regression models based on variations in pollutant concentration and


visibility indicate that sulfates may account for 50 percent of the total


visibility reduction in the East and along the West Coast.




     Various alternatives to control sulfur emissions from mobile sources


have been investigated.  Of these, fuel desulfurization and the three-way


catalyst (TWC) are considered among the most promising.   Desulfurization


of gasolines and diesel and jet fuels is now both economically and techno-


logically possible.   Both sulfuric acid and sulfur dioxide can be reduced


effectively by this control measure.  However, the cost is high,  $1.22 per


1000 miles driven.   The second control alternative, the TWC, does not


affect total sulfur emissions but does reduce sulfuric acid to less than


half the amount emitted by the oxidation catalyst.  The TWC is currently


used in some domestic and foreign model vehicles to control federally


regulated emissions and provides the additional  cost-free benefit of


controlling sulfuric acid.




     The lack of adequate dose-response data precludes an analysis of the


health benefits to be gained using these control alternatives to reduce


ambient sulfate levels.  Measurements of sulfate levels on busy urban


freeways have shown that the highest concentrations occurring inside the

                          3
vehicles averaged 1-4 ug/m , while typical congested highway exposures
                                  175
-------
                        2
 average  less than 2 (jg/m .  Probability  studies  indicate that even under


 conditions most conducive  to  high  roadway  sulfate  levels, there  is less

                                                                        3
 than  a  1 percent  chance  of  a  several-minute exposure to more than 6


 These various  studies  show  that because  automotive sulfuric acid emissions


 disperse rapidly  into  the ambient air, high localized concentrations  are


 not likely  to  occur.




      The damage to  vegetation and nonbiological materials by mobile source


 sulfur  emissions  can be  quantified  in economic terms more readily than  the


 damage  to visibility.  Vegetation and nonbiological materials  damage


 amounts to  less than $35 million nationwide.  An assessment of the costs


 associated  with visibility  reduction is  based primarily on subjective


 values  and,  consequently, has a greater  margin of error.  Moreover, shifts


 in the  stationary source emission of sulfur oxides would have  significantly


 greater impact on the  mobile  source contribution to visibility reduction


•than  to vegetation  and nonbiological materials damage.




      Current exposure  estimates suggest  that major adverse health and


 welfare effects from mobile source  emissions of sulfur-bearing compounds


 are unlikely.  Consequently,  specific control of the mobile source emissions


 of sulfur-bearing compounds is not  recommended at present.
                                   176
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                       APPENDIX A.   HEALTH EFFECTS







A.1  INTRODUCTION







     After the 1930 air pollution episode in the Meuse Valley, Belgium, a



prediction was made that if a similar episode hit London, England, over



3000 people would die.   In 1952, this prediction came true when a heavy



fog of pollution blanketed London and left 4000 dead and many more thousands



ill.







     Fortunately, disasters such as these occurred rarely and will probably



never occur again.   With the exception of the air pollution episode in



Donora, Pennsylvania, which caused 20 deaths, and in New York City,



pollution episodes  in the United States have been linked more with morbidity



factors than mortality.







     To provide additional information on air pollution and human health,



many investigators  have attempted to delineate the cause-effect relation-



ships of exposure to sulfur-bearing compounds.  This relationship is



complex; nevertheless,  there is sufficient information to conclude that



sulfur-bearing compounds are toxic.  Their toxicity depends on the particular



sulfur compound, the concentration and time of exposure, and other covariants



such as additional  pollutants or preexisting disease.  This type of



information is derived from four major experimental approaches:  laboratory



studies jm vitro, animal toxicology studies HI vivo, human clinical



studies, and epidemiological studies.
                                 177
-------
A.2  IN VITRO







A.2.1  Introduction







     lH vitro studies have disclosed various toxic effects from sulfur dioxide



and sulfate inhalation.   Sulfur dioxide hydrates fairly rapidly in the upper



airways to form several  ions.   One of these, a bisulfite ion, reacts readily



with cellular genetic material, with serum proteins, and probably with cellular



proteins.  Its effects on catalytic proteins, such as enzymes, have varied



from inhibition and stimulation to no observable effect.







     Bisulfite degrades both DMA and RNA significantly—modifications which



can result in mutations.  The mutagenic specificity of bisulfite has been



demonstrated in bacteria, viruses, yeast, and cultured mammalian cells.  This



mutagenic action, however, has not been demonstrated in i_n vivo studies.



Aside from the general lack of bisulfite mutagenesis studies i_n vivo, several



protective mechanisms could increase its chemical transformation or could



sequester it until urinal excretion.  The amount of bisulfite and degree of



ionization determine its ability to enter a cell and affect genetic material.



In addition, bisulfite could be oxidized in the body to the less toxic sulfate



ion.







     Whether S0? inhalation at present atmospheric concentration is likely to



lead to  greater mutations in man cannot be  determined from the available



data.  Mathematical models could be developed to describe SO^ absorption and



the reactions of S0? leading to mutations in an effort to predict the hazard



from present levels.  Direct experiments with animals are not likely to be
                                 178
-------
fruitful, since the mutation rate, if one exists at all, is probably near the



limit of detection by present methods.  This is not to say that a potential



hazard does not exist, only that proper experiments have not been devised to



test this question.







     On the other hand, other effects seen in i_n vitro and i_n vivo studies do



overlap.  Sulfate aerosols (and sulfur dioxide) produce bronchoconstriction



in animals and man.  This constriction appears to arise from the release of



histamine by sulfate salts, probably through an ionic mechanism within the



cell.  In addition, the potency of different sulfate salts to promote broncho-



constriction or to release histamine suggests that different chemical composi-



tions of atmospheric aerosols exert different effects on health.   For instance,



the more potent sulfate salts are those most likely found in the smaller (<3



urn) particles.   The acidity of the aerosol is also important.   Solutions more



acidic or basic than the physiological pH increase the rate of sulfate removal



from the upper airways.  Finally, the chronic effects of sulfate inhalation



are likely to involve cell-mediated inflammation, since sulfate promotes the



release of the highly reactive free-radical  species of oxygen, the superoxide



radical ion.
A.2.2  S02/HS03
A. 2. 2.1  Respiratory tract transport and absorption — Sulfur dioxide is a



highly water-soluble gas which hydrates rapidly in solution to form sulfurous



acid, bisulfite, and sulfite ions:
                                        HS03~ + H+   ->    S03= + 2H+
                                 179
-------
The extent of ionization and relative contribution of each species depends on
the pH and temperature of the solution.   However, the relative significance
and even existence of sulfurous acid in this equilibrium scheme is question-
able (Cotton and Wilkinson 1972).   The chemical state of sulfur dioxide, the
prime determinant of the compound's toxicity, is important only in affecting
the compound's ability to equilibrate with a body compartment.  Therefore,
the terms bisulfite and sulfur dioxide designate the same reactive species
regardless of the chemical used to prepare an experimental solution.

     Sulfur dioxide and sulfite salts enter the body primarily through inhala-
tion of atmospheric sulfur dioxide and ingestion of sulfite salts found in
foods, beverages, and drugs.  In a model using an artificial tracheobronchial
system lined with a simulated airway secretion (bovine serum albumin [BSA]
dissolved in saline), S02 was absorbed primarily in the upper third of the
simulated airway.  Only a small fraction of the initial S02 reached that part
simulating the alveolar and respiratory bronchial region, while none of it
reached the terminal traps.

     These results support known i_n vivo effects, that is, that the rapid
increase in airway resistance and excess mucus production associated with
acute exposure to high concentrations of sulfur dioxide are due in part to
the absorption by the upper airways.  However, these data suggest that the
gas will be readily hydrated in the tracheobronchial fluid and will exist
predominantly as bisulfite, an ionic species which crosses cell membranes
very slowly.  Subsequently, the bisulfite may  be carried up the bronchial
tree by mucociliary transport and be ingested.   It could then enter the
stomach and exist there as sulfurous acid, which could be absorbed by way  of
                                  180
-------
the intestinal tract to the circulatory system and then carried in the blood



to nonpulmonary sites.   Thus, much of inhaled sulfur dioxide may become



ingested bisulfite.  The BSA/saline fluid used in this model, however, may



not accurately reflect the actual biological system.   Although albumin is



often found in airway mucus, it is not the primary functional component of



mucus.  A greater portion of SO^ may be sequestered effectively in the upper



respiratory tract than is reflected in the BSA/saline model system (Cause and



Barker 1978).







     Sulfur dioxide in combination with an aerosol of sodium chloride (NaCl)



was deposited in the more distal parts of the simulated lung than was SO^-



The exact physical-chemical mechanism for this deposition is not clear, but



it appears that aerosol combinations with S0? could lead to altered effects,



since hydration and removal in the upper airways would be circumvented and



since chemical interaction of S0« and the particle could create a potentially



reactive species.







     Another inhalation mechanism involves the adsorption of SO^/HSCL  on



particles in the respirable size range.   Since these particles would penetrate



into the deep lung, S0? would be available to all lung cell types,  such as



alveolar macrophages,  and to fluids of the alveolar region (Novakov et al.



1972).







A.2.2.2  Cellular effects—Alterations in lymphocytes induced by S02/HS03~



may explain the altered immunologic responses seen after i_n vivo inhalation



of sulfur dioxide.
                                 181
-------
     Schneider and Calkins (1970) isolated lymphocytes in a cell  culture
medium containing phytohemagglutinin (PHA), which induces blastogenesis and
mitosis.   After exposure to 500 cc of 5.7 ppm sulfur dioxide at varying time
intervals, there was reduced cell enlargement, reduced DNA synthesis, a lower
mitotic index, and clumping of chromosomes.  All of these effects were most
noticeable in the young cultures in which cells were preparing for DNA synthesis
before mitosis.  The results suggest that S0« induces damage to the genetic
material  of the lymphocyte.

     Evidence for altered membrane function of human lymphocytes has been
presented by Gause and Rowlands (1975), who found that 10   M sulfur dioxide
or bisulfite caused aggregation, internalization, and increased rate of
turnover of cellular membrane proteins.  Alteration of membrane protein on
lymphocytes may result in immunological aberrations i_n vivo, also affecting
antigen recognition.  If alteration of the nuclear material occurs as well,
the composition and conformation of surface proteins may be changed.

     The macrophage populations of a variety of species have also been studied
as model  systems for the action of sulfur dioxide i_n vivo, but i_n vitro
studies in this area are lacking.  Because these cells are scavengers of
foreign materials in the body and are important components of the host defense
system, their alteration by pollutants may have significant systemic or
localized effects.
     Bourbon et al. (1973) determined the ID™ (dose which destroys 50
percent of the organisms studied) for rat alveolar macrophages to be a 1-hr
                                 3
exposure of approximately 10 mg/m  SO^.   An assay of the activity of the
                                 182
-------
Krebs cycle enzymes—lactic, maleic, isocitric, and succinic dehydrogenases--



was also performed.  A great increase in enzyme activity, and therefore



metabolic rate, was observed in the macrophages which survived SCL exposure.







     Gause et al. (1977) extended this work to include both j_n vitro exposure



of baboon alveolar macrophages and i_n vivo exposure/i_n vitro assay of rat



alveolar macrophages.   They noted that macrophage ATPase activity (ATP



utilization) was increased by both j_n vivo and j_n vitro exposure to SCL.  In



addition, the levels of lysozyme activity were also increased by j_n vivo



exposure.







     Relatively few studies have focused on the effects of sulfur on blood



and blood vessels.   However, its effects on blood platelet aggregation and



blood vessel contractility have been studied in isolated systems.







     Kukugawa and lizuka (1972) have shown that 10"3 to 10~2 M bisulfite



inhibits the ADP- and collagen-induced aggregation of platelets, major compo-



nents of the blood coagulating system.   The inhibition was both direct and



reversible, and it occurred in whole blood as well as in platelet-rich plasma.



The mechanism of action and toxicological importance of these observations



are unclear, but transient inhibition of platelet aggregation is probably



not destructive.







     Laszt and Schaad (1974) investigated the effect of bisulfite on the



peripheral and pulmonary circulation by superfusing rings of peripheral blood



vessels of the cow with solutions of 6 mM bisulfite with and without electrical



stimulation.  A gradual loss of tension and contractility of the carotid
                                 183
-------
artery was observed, but the effect was reversible.   In contrast, the pulmonary



artery tone increased after bisulfite, whereas the pulmonary vein tone decreased.



The net effect of inhaled SO,, on vascular smooth muscle is not clear from



these studies.  Nevertheless, the constriction of bronchial smooth muscle



upon S02 inhalation suggests the possibility of a direct action of SO^ and



bisulfite on smooth muscles.







A.2.2.3  Biochemistry of SCL/HSO '--Sulfur dioxide reacts readily with all
         	"	c.	O


major classes of biomolecules.  The reactivity of this agent with nucleic



acids, proteins, lipids, and other biological components has been repeatedly



demonstrated J_n vitro.  The extrapolation of the implications of these



isolated reactions to human toxicity, however, remains a point of controversy.







A.2.2.3.1  Reactions with DMA and RNA in relation to mutagenicity.  The



reactivity of bisulfite with nucleic acids and mutagenesis induced by bisulfite



has been reviewed by Shapiro (1977) and by Fishbein (1976).  The reactions



involved are varied, but the i_n vitro conditions under which they occur are



sufficient to account for many of the mutagenic effects observed as well as



for such functions as chromosome clumping observed by Schneider and Calkins



(1970).  The various mechanisms of reaction of bisulfite with nucleic acids



will  be considered first.







      A specific deamination of cytosine to uracil in single-stranded, but  not



double-stranded, DNA occurs jj] vitro.  The reaction also occurs  in yeast RNA.



The optimum conditions  for  both reactions were pH 5 and high bisulfite concen-



tration.   However, by extrapolation,  Shapiro  (1977) calculates that a con-



centration of 3 x 10    M bisulfite, under physiological conditions, is enough
                                  184
-------
to double the background rate of mutagenesis in mammalian DNA.  Also, while


it is true that mammalian DNA is double stranded, during the transcriptional


process there are regions of single strandedness in the DNA which may be


susceptible to this sort of attack.  Other subtle conformational and chemical


differences in mammalian DNA may exist j_n vivo which may make certain regions


of the chromatin more open to such an agent.





     A second reaction mechanism of bisulfite j_n vitro which may also result


in an alteration of gene function has been described by Shapiro (1977).   This


reaction is a bisulfite-catalyzed linkage of nucleic acid residues with amino


acids and proteins, called transamination.  It occurs maximally at pH 7 and


high bisulfite concentration.   Again, this is thought to be a cytosine-


specific reaction, and only single-stranded DNA reacts.   A cross-link of DNA


with protein or an amino acid would have severe effects on the functioning


of the gene.





     A third reaction mechanism of bisulfite with nucleic acid is the addition


reaction of bisulfite to uracil.  The equilibrium constant for addition to


uracil is 1 x 10  liters/mo! at 25°C, whereas the equilibrium constant for


addition to thymidine is 0.3 liter/mol.   Thus, this reaction may be specific


for RNA and result in a direct inhibition of protein synthesis, interruption


of mitosis, or interference with genetic repair.   Braverman and Shapiro have

                 -2
shown that 1 x 10   M bisulfite blocks the induction of p-galactosidase in


Escherichia coli,  suggesting direct inactivation of protein synthesis.   In


another study by the same investigators, polyuridylic acid (poly U) was


modified by bisulfite at varying concentrations.   The ability of poly U to


serve as a messenger for polyphenylalanine in a cell-free protein-synthesizing
                                 185
-------
system was then tested.   At 10   M bisulfite,  the poly U became 2 percent



saturated, yet it retained only 53 percent of  its messenger function.







     The final reaction mechanism is the free-radical-induced cleavage of



internucleotide bonds in DNA by bisulfite.   This reaction requires oxygen and


  +2
Mn   and is rapid at room temperature at pH 7.   It is also inhibited by



hydroquinone, a scavenger of free radicals.  The degradation occurs during


                                             +2
the autoxidation of bisulfite catalyzed by Mn    ions.  Only low concentrations



of the active species, 'SO- and 'HO,,, are generated during the autoxidation.



At higher concentrations the ionic reactions of bisulfite are favored and the



autoxidation of bisulfite is quenched.   Since  this free-radical chain reaction



occurs at such low concentrations, it may be of true toxicological importance.







     The mutagenic specificity of bisulfite has been demonstrated in bacteria,



viruses, yeast, and cultured mammalian cells.   Mutant reversion studies on E.



coli suggest that bisulfite causes back mutation only in those mutants which



had cytosine-guanine pairing at the site of mutation.  The number of reversions



was optimal at pH 5.2, which presumably reflects a compromise between bacterial



viability and a sufficient quantity of bisulfite in the un-ionized form to



cross the bacterial wall and membrane.   Also,  it should be pointed out that



although bisulfite does not generally affect double-stranded DNA j_n vitro,



it has mutagenic activity in E. coli DNA, which is double stranded.







     The mutagenic properties of bisulfite have also been demonstrated in



phage A. and T4 bacteriophage.  A 10-fold increase in the rate of mutation was



found in phage X exposed to 3 M bisulfite at an acidic pH.  The inactivation



and mutation of T4 is due to a complete shift of guanine-cytosine to adenine-



thymine, induced by bisulfite.  A 2- to 20-fold increase in the mutation rate



                                 186
-------
of the yeast Saccharomyces cerevisiae was observed at 5 x 10   M bisulfite


and pH 3.6.  The molecular nature of the mutation has not been reported.
     Mammalian oocyte damage due to low-level concentrations of bisulfite has


been studied by Jagiello et al.  (1975).   Mouse oocytes exhibited inhibition of

                          -4
meiosis when exposed to 10   M bisulfite, and chromosomal clumping was

                                   -3
observed in oocytes treated with 10   M bisulfite.  Chromosomes of cow

                                                                     -2
oocytes were damaged and meiosis inhibited by treatment with 2.5 x 10   M


sodium bisulfite.   Meiosis of oocytes from the ewe exhibited chromosomal


aberrations, but meiosis was not inhibited at 2.5 x 10   M.
     Given the reaction mechanisms discussed above, bisulfite may be mutagenic


to mammalian cells i_n vivo.   The prerequisite of these reactions is that


enough bisulfite be presented to the cell in a form that will allow it to


enter the cytoplasm or nucleus of the cell.   This capacity is a function of


the state of bisulfite in the blood.  That is, its ability to enter the cell


will depend on the degree of ionization and the amount of bisulfite bound to


plasma proteins.





A.2.2.3.2  Reaction with proteins.  The chemical disposition of bisulfite in


blood is  an important aspect of its ability to react with other body tissues


and fluids, as previously discussed.  Bisulfite reacts reversibly with


plasma proteins by sulfitolysis of disulfide bonds:
                    R-S-S-R'  + HS03"        R-S-S-03" + R'SH
The equilibrium constant for this reaction, with cystine in an isolated

                                       ~2
system at 37°C and pH 7.75, is 8.9 x 10  .   The reaction is essentially


                                 187
-------
complete at low sulfite concentrations.   After a 45-min incubation of 54 nmol



of sulfite in 480 ul  of rabbit plasma under physiological  conditions, nearly



100 percent of the bisulfite existed as S-sulfonates, provided the capacity



of sulfite-reactive groups was not exceeded.







     On the basis of the above findings, Kaplan et al. (1974) have calculated



that under chronic sulfur dioxide exposure, approximately 0.16 percent of



total plasma proteins would be sulfonated.   The alterations in protein structure



induced by sulfonation, although reversible,  may seriously impair enzyme



function.  On the other hand, Gunnison and Palmes (1973) and Shapiro (1977)



concluded that 0.16 percent is a relatively low level of protein alteration



and that sulfitolysis induced by environmental concentrations of sulfur



dioxide is probably not metabolically significant.  S-sulfonation may serve



merely as a vehicle of distribution and storage for bisulfite in the body.







     Regardless of whether S-sulfonation of cysteine residues has a significant



direct effect on overall enzyme function, these residues could react with



other biomolecules.  For instance, cytidine and thymine pyrophosphate,



compounds with which bisulfite is known to react specifically, failed to



react with cysteine S-sulfonate under a variety of experimental conditions.



Since bisulfite exists almost entirely as S-sulfonates in the plasma iji vivo,



the negative results of these experiments bring into question the threat of



mutagenesis from sulfur dioxide inhalation.  Therefore, a number of  investi-



gators suggest that the plasma proteins may serve to sequester bisulfite and



that the reaction  is actually a protective phenomenon.  A more recent model



on the distribution and turnover of plasma sulfite/bisulfite was reported  by



Gunnison and Palmes (1976).   In their study, sulfite clearance was calculated



using plasma decay data obtained from one intravenous  injection of sulfite.



                                 188
-------
By measuring the urinary sulfite following the intravenous administration and


using the model conversion rates, they showed that sulfite clearance occurs


predominantly by metabolism to sulfate.  Their finding indicates that sulfite


clearance depends primarily on the efficiency of sulfite oxidase.  This


enzymatic oxidation may occur within the intermembranous spaces of the mito-


chondria.  They conclude that the sulfate produced jjj vi vo from injected


sulfite is not instantaneously accessible to the plasma because the appearance


of plasma sulfate lags behind the disappearance of sulfite after equilibrium.





A.2.2.3.3  Reaction with lipids.   The interaction of bisulfite with lipids,


though not well understood, could greatly alter the structure and function


of cellular membranes and upset hormonal activities j_n vivo.





     Bisulfite initiates lipid oxidation in a model system consisting of a


Tween 80-corn oil emulsion in water.   The oxidative effects of 0.5 to 10 mM


bisulfite were assayed for thiobarbituric acid-reactive material.  A dose-


response relationship for the reaction was observed, and the reaction was
quenched by BHT (2,6,di-t-butyl-4-hydroxymethyl phenol), an antioxidant, and


10"3 M Mn+2.   The inhibition of th


suggests a free-radical mechanism.
  _3     +2                                                             +2
10   M Mn  .   The inhibition of the autoxidation of lipids by BHT and Mn
     Pulmonary surfactant is a complex lipid composed primarily of dipalmitoyl


phosphatidylcholine (DPI), which is required for normal respiration.   SOp


promotes the hydrolysis of DPL jm vitro by an unknown mechanism.   Twenty to


40 percent hydrolysis has been observed.   Should such a degradation occur jm


vivo, pulmonary edema and atelectasis might occur.
                                 189
-------
     Finally, Parkes and Eling (1975) found no effects of 500 ppm sulfur



dioxide on the synthesis and degradation of prostaglandins ij} vitro.







A.2.2.3.4  Reaction with pyridine and flavins.  The ionic reaction of bisulfite



with NAD  and flavins has been described by a number of authors.   Bisulfite



adds reversibly to the 4 positions of NAD  with K = 36 M   at pH 7.   This



adduct was found to be greatly stabilized in the presence of protein since a



stoichiometric reaction of bisulfite occurs in low concentrations with



protein-bound NAD .   A similar enhancement of the binding constant of bisulfite



with flavins associated with proteins has been observed.







     Two reaction mechanisms of bisulfite with NADH have been described.  The



first is a slow ionic reaction in which bisulfite acts as a general  acid



catalyst to hydrate the 5,6 double bond.  The second reaction is a free-



radical oxidation of NADH to the pyridinium salt.  It is inhibited by super-



oxide dismutase, hydroquinone, and EDTA, which suggests a requirement for



trace metals.







A.2.2.4  Protective mechanisms—It is evident from the previous discussion



that bisulfite is very reactive with a wide range of biomolecules j_n vitro.



The manifestation of the effects of  such reactions i_n vivo depends on the



molecule's ability to reach appropriate sites of reactivity and the ability



of the body to counter the threat through chemical transformation of bisulfite



or sequestration of the molecule by  serum protein until  it can be removed  by



urinal excretion.  The latter mechanism has already been described.







     One method that the body may have  to protect itself from the effects  of



sulfur dioxide intoxication is its ability to oxidize bisulfite to the  less



                                 190
-------
toxic sulfate ion.   A microsomal liver enzyme, sulfite oxidase, has been



purified and characterized.   This enzyme, which also occurs in the lung,



contains two types of prosthetic groups which perform separate electron



transfer functions.   The overall reaction is:
This oxidative mechanism may help protect the body from endogenous sulfites



produced in normal metabolism, as well as consumed or inhaled sulfites.



However, lung levels appear to be low, and saturation of the enzyme with



inhaled SOp could occur.   Also, since this enzyme is subject to end-product



inhibition--!".e. , inhibition by the sulfate formed—it could also be inhibited



by sulfate inhaled along with SOp (Rajagopalan and Johnson 1977).
A.2.3  S03-H2S04-X2S04
     In the atmosphere, it is possible for sulfur dioxide to undergo a catalytic



oxidation to sulfur trioxide in the presence of sunlight or metallic oxides.



This species can be readily hydrated to sulfuric acid, bisulfite,  and sulfate,



either in the atmosphere or within the bronchial tree.  It has been shown



that the sulfate particles so formed are of a size that will deposit pre-



dominantly on the gas-exchange regions of the lungs.   Inhalation of these



particles may result in a variety of pulmonary pathophysiological  symptoms.



Few studies at the cellular and biochemical level have been performed to



elucidate the nature of the effects of sulfate inhalation.  (Under conditions



of high humidity, atmospheric SO^, either as aerosol  droplets of aqueous



solutions or adsorbed on the surfaces of particulates, also undergoes reduction



by light in the visible region or by metals such as manganese to produce the



                                 191
-------
SCL free radical which is extremely persistent due to resonance and may be
inhaled as such [Cause et al.  1977].)


A.2.3.1  Respiratory tract transport and absorption—The isolated, ventilated,
and perfused rat lung has been used to study the kinetics of sulfate transport
across the pulmonary and capillary membranes.  The t, ,„ (time) of removal of
sodium sulfate was approximately 8.4 min at doses of 0.5 umol/lung, and this
removal occurred by a process of simple absorption.  The absorption kinetics
were greatly influenced by the cationic species associated with the sulfate
                                                         +2    +2    +2
anion.  The absorption was enhanced with ammonium ion, Co  , Ni   , Zn  ,
  +2    +2        +2                 +2
Cd  , Fe  , and Hg  , but not with Mn  .  Furthermore, the process was
unidirectional  in that absorption from the vasculature to the airways did not
occur.


A.2.3.2  Biochemical effects of XpSO/1--Sulfate salts have also been demonstrated
to cause histamine release from lung fragments i_n vitro, and this has been
postulated as a mechanism of bronchoconstriction observed \r\ vivo.  A synergistic
action of sulfate and its cationic species has been  postulated, since sodium
sulfate does not cause a marked release of histamine, whereas ammonium sulfate
does.  Ammonium chloride, however, results in only a 50 percent release of
histamine as compared with ammonium  sulfate.  These  results suggest that
entry into cells is important for the release of histamine and that a change
in the cationic species may permit an alteration in  membrane permeability to
sulfate and thus alter the effects of pollutant on the  lungs.


      The  rate of removal of sulfate  from the airways  also depends upon the  pH
of the solution containing  the sulfate  salt.  Values  removed from the physiological
                                  192
-------
pH of 7.4 on either the acidic or basic side promote sulfate removal.  There



is a similarity in ranking of different sulfate salts in their rate of removal



from the airways in the presence of metal ions and in their bronchoconstrictive



potency.  Sulfuric acid aerosols are also more potent than sodium sulfate in



production of bronchoconstriction, and, similarly, acid solutions of sulfate



salts are more readily removed than are neutral solutions.   The flux of



sulfate ions through the pulmonary mast cells may be the determining factor



in the potency of different sulfate salts observed i_n vivo.







     Chronic exposure conditions are difficult to produce j_n vitro.   An



interesting hypothesis dealing with the basic mechanism of inflammation has



proposed a central role for superoxide radical anion, 'Op .   Superoxide may



promote chronic inflammation through its action on lysosomes and on intra-



cellular organelles containing degradative enzymes, and by the production of



chemotactic factors, attractive agents for inflammatory cells.   The release



of histamine described above is likely to produce only a transient broncho-



constriction.   Sulfate ions have recently been shown to stimulate the



production of superoxide through a mechanism involving intact peritoneal



macrophages.   Pulmonary macrophages containing superoxide-generating systems



are similar to those described for peritoneal macrophages,  and thus sulfate



salt inhalation could stimulate pulmonary inflammation independent of the



acidic nature of the aerosol.   This free-radical form of S0? is quite long-



lived in both biochemical and atmospheric chemistry model systems.   According



to Cause et al. (1977), this SCL free radical could be important in the



radiomimetic effects of S0~ and in protein thiol-disulfide and 1 ipid-peroxida-



tion reactions.  Chronic release of histamine is also likely to stimulate the



attraction of other inflammatory cells from the blood and to sustain a local
                                 193
-------
inflammatory response.   Pulmonary inflammation is thought to underlie many of


the chronic lung diseases seen in man, and these may be linked through such


mechanisms.
A.2.4  H2S and COS
     Hydrogen sulfide (H^S) is a noxious gas with an odor characteristic of


rotten eggs.  It is heavier than air and is soluble in both water and non-


polar solvents.  At a physiological pH of 7.4, roughly two-thirds of the


hydrogen sulfide exists as HS , while only trace amounts exist as divalent


sulfur (S~), as seen by its acid dissociation constants:
            H9S     -»•       HS" + H+           pK  = 7
             c.      ^~                            a


            HS"     -»        S=  + H+           pK  = 12
                    ^~                             a
Historically, most studies reported on the effects of hydrogen sulfide on


hemoglobin.  These studies focused on i_n vitro blood exposure to H~S, causing


a reversible reaction product, sulfhemoglobin--a combination of sulfur with


heme.  Unfortunately, many of these early studies are unreliable, and later


work is confusing.  This problem arises from the lack of knowledge of the


chemistry  of sulfhemoglobin, which has never been observed following i_n vivo


exposure.





     Sulfhemoglobin is formed from the reaction of the prosthetic groups of


ferric myoglobin  binding with sulfur after a sequential reaction with peroxide


and hydrogen sulfide.  It occurs also from the binding of the sulfide to the


heme iron.
                                 194
-------
     Several biochemical lesions have been reported following J_n vitro exposure



of HLS, particularly on respiratory chain electron transfer.   Submitochondrial



studies indicate that sulfide is more potent than cyanide in inhibiting



cytochrome aa~, the terminal enzyme in the respiratory chain.  This mechanism



could be responsible for the toxic effects caused by acute high-concentration



exposures.   Sulfide binds to cytochrome aa., regardless of the cytochrome



redox state.  The undissociated sulfide-cytochrome species is a more active



inhibitor than the anionic species.







     Generally, the toxicologic mechanisms of hydrogen sulfide seem to parallel



those of cyanide; both substances inhibit cytochrome aa3.  In addition,



sulfide can also inhibit red blood cell glutathione peroxidase, the enzyme



involved in protecting the cell from oxidative damage.   A number of other



enzymes, such as horseradish peroxidase, potato "polyphenol  oxidase," uricase,



amine oxidase, and catalase, can also be inhibited by sulfide.







     Carbonyl sulfide (carbon oxysulfide [COS]) was discovered by Than through



the reaction of sulfuric acid on potassium thiocyanate.   Because COS hydrolyzes



rapidly in water, forming carbon dioxide and hydrogen sulfide,  it occurs at



only relatively low concentrations from fossil fuel burning.   As seen in the



summary table of Chapter 2, COS is emitted in only trace amounts from mobile



sources, primarily during failure modes.







     Carbonyl sulfide is discussed briefly in the j_n vitro literature as a



metabolic product of carbon disulfide.   In a study by Dalvi  et al.  (1975),



carbon disulfide (CS?) was incubated with rat liver microsomes in the presence



of NADPH, producing COS.  COS was then metabolized by the mixed-function
                                 195
-------
oxidase enzyme system to carbon dioxide.   In a reaction analogous to the



metabolism of CSp to COS, COS then released its sulfur atom, which bound



to the microsomes.   This binding mechanism inhibited benzphetamine metabolism



and decreased the concentration of cytochrome P-450.







     Although COS is shown HI vitro only to inhibit drug metabolism, specifically



benzphetamine, Dalvi et al. also note that COS might combine with trace



metals such as copper and zinc in animal systems.







     COS also affects the nervous system in various animal species; however,



there are no i_n vitro data explaining this mechanism.







A.2.5  Summary







     Studies of the properties of the hydrated forms of sulfur oxides point to



a number of potential toxic actions.  Sulfur dioxide on hydration forms the



bisulfite ion, which is highly reactive, especially with the cell's genetic



material.  There is little doubt that bisulfite produces significant degrada-



tion of both DNA and RNA and that these modifications can result in mutations.



Bisulfite also reacts readily with serum proteins and probably with cellular



proteins.  The net effect of sulfitolysis on catalytic proteins such as



enzymes is not clear from the experiments performed to date.  Inhibition,



stimulation, and no effect have been described from this reaction.  Sulfitolysis



of  serum proteins may be a protective mechanism reducing the amount of



mutagenic bisulfite ion that is free in the blood to diffuse into cells and



to  react with cellular genetic mechanisms.  Detoxification enzymes exist in



the liver to remove bisulfite from the blood.  Variations in the activity of
                                 196
-------
these detoxifying enzymes may affect the ability of an individual to resist



chronic SCL exposure.   Whether SCL inhalation at present atmospheric concentra-



tions is likely to lead to greater mutations in man cannot be determined



from the presently available data.







     Sulfate aerosols produce bronchoconstriction in animals and man apparently



due to the release of histamine by sulfate salts, probably through an ionic



mechanism within the cell.  The chemical nature of sulfate aerosols in the



atmosphere is not known, but the potency of different sulfate salts to promote



bronchoconstriction i_n vivo or the release of histamine ex vivo and rn vitro



suggests that different chemical compositions of the natural aerosols are



likely to produce large differences in their health effects.  Some of the



more potent sulfate salts are those likely to be found in the smaller (<3 urn)



particles, and the acidity of the aerosol is also highly important.   Studies



using model systems such as the isolated, ventilated, and perfused lung have



proven the utility of measurements ex vivo; many of the transient effects



could not be measured j_n vivo.   Lastly, the chronic effects of sulfate inhalation



are likely to involve cell-mediated inflammation.
                                 197
-------
Bibliography

Anderson, I., G.  R. Lundquist, P.  L. Jensen, and D. F. Proctor. Arch. Environ.
  Health 28:31, 1974.

Andrews, J.  C.  Reduction of certain sulfur compounds to hydrogen sulfide by the
  intestinal microorganisms of the dog.  J. Biol. Chem. 222:687-692, 1937-38.

Baxter, C.  F. , and R.  van Reen.  Some aspects of sulfide oxidation by rat-liver
  preparations.  Biochim.  Biophys. Acta 28:567-573,  1958.

Baxter, C.  F. , and R.  van Reen.  The oxidation of sulfide to thiosulfate by metallo-
  protein complexes and by ferritin.  Biochim.  Biophys. Acta  28:573-578, 1958.

Baxter, C.  F., R. van Reen, P. B.  Pearson, and C. Rosenberg.   Sulfide oxidation in
  rat tissues.  Biochim. Biophys.  Acta 27:584-591, 1958.

Beerman, H.  Some physiological actions of hydrogen sulphide.   J. Exp. Zool. 41:33-
  43, 1924.

Bhaghat, B.  ,  and M. F. Lockett.  The absorption and elimination of metabisulphite
  and thiosulphate by rats.  J. Pharm. Pharmacol. ^2:690-694,  1960.

Blanchette,  A. R. , and A. D. Cooper.  Determination of hydrogen sulfide and methyl
  mercaptan in mouth air at the parts-per-billion level by gas chromatography.
  Anal. Chem. 48:729-731, 1976.

Bourbon, P.,  G. Bompart, and P. Levy.  Uptake and transformation of  sulfur dioxide
  in blood  in vitro.  J. Eur. Toxicol. 4:205-207, 1973.   (In French.)

Bourbon, P.,  G. Bompart, and P. Levy.  Action of sulfur dioxide and  sulfites on
  plasma.  Trib.  Cebedeau 28:59-64, 1975.  (In French.)

Bourbon, P.,  G. Bompart, P. Levy, and M. F. Bergeal.   Effect of sulfur dioxide on
  free  sulfur containing amino acids of blood.  J. Eur. Toxicol. 6:147-157,  1973.
  (In French.)

Bourbon, P.  ,  P. Levy, G. Bompart, and J. L. Laborie.   Contribution to the study of
  the action  of sulfur dioxide on alveolar macrophages  in rats.  J.  Eur. Toxicol.
  6:32-35,  1973.    (In French.)

Braverman,  B. Bisulfite modified polyuridylic acid.   Model for the effects of  S02 on
  RNA.  Diss. Abstr.  Int. B. 34:5854,  1974.

Braverman,  B., R.  Shapiro, T.  Rossman, and W. Troll.   Bisulfite binds to RNA  and
  inhibits  induction  of p galactosidase in E. coli.  (Submitted for publication,
  1977.)

Cantor, M.   0., and J.  E. Weiler.  Effect of hydrogen  sulfide upon  intestinal  decom-
  pression  tubes.  An jji vivo  and j_n vitro study.  Am.  J. Gastroenterol. 38:583-586,
  1962.
                                     198
-------
Charles, J. M., and D. B. Menzel.  Ammonium and sulfate  ion  release  of  histamine
  from lung fragments.  Arch. Environ. Health 30:314-316,  1975.

Charles, J. M., and D. B. Menzel.  Sulfate mediated  histamine  release from  lung mast
  cells.  Fed. Proc. 34:718, 1975.

Charles, J. M., and D. B. Menzel.  Augmentation of sulfate ion  absorption from the
  rat lung by heavy metals.   Pharmacologist ^8:125,  1976.

Charles, J. M., and D. B. Menzel.  Heavy metal enhancement of  airway sulfate  absorp-
  tion in the perfused rat lung.  Res. Commun. Chem. Pathol. Pharm.  15:627-639,
  1976.

Cohen, H. J., S. Betcher-Lange, D. L. Kessler, and K. V. Rajagopalan.   Hepatic
  sulfite oxidase.  Congruency  in mitochondria of prosthetic groups  and activity.
  J. Biol. Chem. 247:7759, 1972.

Cohen, H. J., R. T. Drew, J. L. Johnson, and K. V. Rajagopalan.  Molecular  basis  of
  the biological function of molybdenum.  The relationship between sulfite  oxidase
  and the acute toxicity of bisulfite and S02.  Proc. Natl. Acad. Sci.  U.S.A.
  70:3655, 1973.

Cohen, H. J. , and  I. Fridovich.  Hepatic sulfite oxidase.  J.  Biol.  Chem. 246:  359-
  366, 1971.

Cohen, H. J., and  I. Fridovich.  Hepatic sulfite oxidase - The  nature and function
  of the heme prosthetic groups.  J.  Biol.  Chem. 246:367-373,  1971.

Cohen, H. J., I. Fridovich,  and K. V. Rajagopalan.   Hepatic sulfite  oxidase -  A
  functional  role  for molybdenum.  J. Biol. Chem. 246:374-382,  1971.

Cotton,  F. A., and G.  Wilkinson.  Advanced Inorganic Chemistry, a Comprehensive
  Text.   3rd edition.   New York, Interscience. 1972. p. 447.

Dalvi, R. R. , A. L. Hunter,  and R. A. Neal.  Toxicological implications of  the
  mixed-function oxidase catalyzed metabolism of carbon disulfide.   Chem. Biol.
  Interact.  J0(5):349-361,  1975.

Denis, W., and L.  Reed.  The action of blood on sulfides.  J.  Biol.  Chem. 72:385-
  394, 1927.

Dorange, J. L., and P. Dupuy.  Mise en evidence d'une action mutagene du sulfite  de
  sodium sur la levure.  C.  R.  Acad.  Sci. Paris Ser. D 274:2798-2800, 1972.

Douste-Blazy, L.,  and M.  C.  Prevost.   Biochemical modification  of alveolar  surface-
  active film due  to effects of some pollutants.  Rev. French  Mol. Respir.  4:77-84,
  1976.   (In French.)

Drew, R. T.,  J. L. Johnson,  and K. V. Rajagopalan.   Sulfite oxidase  deficiency
  (letter).  Arch. Environ.  Health 32:141-142, 1977.

Dziewiatkowski, D. D.   Fate of  ingested sulfide sulfur labeled  with  radioactive
  sulfur  in the rat.  J.  Biol.   Chem.  161:723-729, 1945.
                                    199
-------
Eickenroht, E.  Y.,  E. M. Cause, and J. R. Rowlands.  The interaction of
  S02 with proteins.   Environ. Lett. 9:265-277, 1975.

Fishbein, L. Atmospheric mutagens.  I. Sulfur oxides and nitrogen oxides.
  Mutat.  Res.  32:309-330, 1976.

Fischer,  R.  Biochem. Z. ^5:12-24, 48-68.  (Chem. Abstr.  HJ:964.)

Gause, E. M.,  and M.  Barker.  Interaction of inhaled sulfur dioxide with
  mucus glycoproteins.  Proc. Western Pharmacol.  Soc. ,  1978.   (In press.)

Gause, E. M.,  N. D. Greene, M. L. Melty, and J. R. Rowlands.   JTI vivo  and
  i_n vitro effects of sulfur dioxide upon biochemical and  immunological
  parameters.   In:   Biochemical Effects  of Environmental Pollutants.   S.
  D. Lee (ed.).  Ann Arbor, Mich.,  Ann Arbor Science Publishers, Inc.
  1977.

Gause, E. M.,  and J.  R. Rowlands.   Effects of S02  and bisulfite  ion upon
  human lymphocyte membranes.  Environ.  Lett. 9:293-305, 1975.

Gibson, W. B., and F. M. Strong.  Metabolism and  elimination  of  sulfite
  by rats, mice and monkeys.  Food  Cosmet. Toxicol.  VM85, 1973.

Gunnison, A. F., and A. W.  Benton.  Sulfur dioxide:  Sulfite  interaction
  with mammalian serum  and  plasma.  Arch. Environ. Health  2^:381-388,
  1971.

Gunnison, A. F., and E. D.  Palmes.  Persistence of plasma  S-sulfonates
  following exposure of rabbits to  sulfite and sulfur dioxide.   Toxicol.
  Appl. Pharmacol.  24:266-278, 1973.

Gunnison, A. F. , and E. D.  Palmes.  A model for the  metabolism of sulfite
  in mammals.   Toxicol. Appl. Pharmacol. 38:111-126, 1976.

Hayatsu, H., and R. C.  Miller, Jr.  The  cleavage  of  DNA by 02 dependent
  reaction of bisulfite.  Biochem.  Biophys. Res.  Commun. 46:120, 1972.

Hayatsu, H., and A. Muira.  The mutagenic action  of  sodium bisulfite.
  Biochem. Biophys.  Res. Commun.  39:156, 1970.

Hayatsu, H., Y. Watayu, and K. Kai.  The addition of sodium bisulfite  to
  uracil and to cytosine.   J. Am. Chem.  Soc.  92:724, 1970.

Heimberg, M. ,  I. Fridovich,  and  P.  Handler.  The  enzymatic oxidation  of
  sulfite.  J. Biol. Chem.  204:913, 1953.

Hempel, W. Z.   Angew. Chem.  T4:865868,  1901.

Hunter, F. E., and L. Ford.   Phosphorylation coupled with  sulfite oxidation
  in liver mitochondria.  Fed. Proc.  1_3:234, 1954.

Huovinen, J. A., and B. E.  Gustafsson.   Inorganic sulphate, sulphite  and
  sulphide as  sulphur donors  in  the biosynthesis  of  sulphur amino acids
  in germ-free and conventional  rats.   Biochim. Biophys. Acta ]_36:441-447, 1967.


                                    200
-------
Ichioka, M.  Model experiments on absorbability of the airway mucous  membrane  of
  S02 and N02 gases.   Bull. Tokyo Med. Dent. Univ. ]9:361-375,  1972.

Ito, A.   Hepatic sulfite oxidase identified as cytochrome  bs-like  pigment  extract-
  able from mitochondria by hypotonic treatment.  J. Biochem. 70:1061,  1971.

Jagiello, G. M., J. S. Lin, and M.  B. Ducayen.  S02 and  its metabolite:  Effects  on
  mammalian egg chromosomes.  Environ. Res.  9:84-93, 1975.

Johnson, J. L.,  H. J. Cohen, and K. V. Rajagopalan.  Molecular  basis  of the  bio-
  logical function of molybdenum.  Effect of tungsten on xanthine  oxidase  and  sul-
  fite oxidase in the rat.   J. Biol. Chem. 249:859, 1974.

Johnson, J. L.,  and K. V. Rajagopalan.  Purification and properties of  sulfite
  oxidase from human liver.  J.  Clin. Invest.  58:543, 1976.

Kaplan,  D.  M.,  D. L.  Luchtel, and C. E. McJilton.  Chronic exposure to  S02 - Pos-
  sible effects  at the cellular level.  Environ.  Lett.   7:303-310, 1974.

Kaplan,  D. , C.  McJilton, and D.  Luchtel.   Bisulfite induced lipid  oxidation.   Arch.
  Environ.  Health 30:507-508, 1975.

Kessler, D. L.,  J. L. Johnson, H. J. Cohen, and K. V. Rajagopalan.  Visualization of
  hepatic sulfite oxidase in crude tissue preparations by electron paramagnetic
  resonance spectroscopy.  Biochim. Biophys. Acta 334:86,  1974.

Kessler, D. L.,  and K. V. Rajagopalan.  Purification and properties of  sulfite
  oxidase from chicken liver.   J. Biol. Chem. 247:6566,  1972.

Klason,  P.   J.  Prakt.  Chem. 36(2):64-74, 1887.

Klason,  P.   Ber.  20:2380, 1887.

Korochanskaya,  S. P.   Hydrogen sulfide oxidation with the blood and tissues.
  Farmakol.  Toxshikol. 28:490-492,  1965.   (In Russian, summary  in  English.)

Kukugawa, K., and K.  lizuka.  Inhibition of platelet aggregation by bisulfite-       »
  sulfite.   J.  Pharm. Sci.   61:1904-1907, 1972.                                       •

Laszt, L. ,  and R. Schaad.  Acute effects of S02 on the circulation of animals  as
  well as on the contractility of isolated blood vessels.  Atmos.  Environ. 8:1049-
  1059,  1974.  (In German.)

Laug, E. P., and J. H. Draize.  The percutaneous absorption of  ammonium hydrogen
  sulfide and hydrogen sulfide.   J. Pharmacol. Exp. Ther. 76:179-188, 1942.

Levitt,  M.  D.,  R. B.  Lasser, J.  S.  Schwartz, and J. H. Bond.  Studies of a flatulent
  patient.   N.  Engl.  J.  Med. 295:260-262, 1976.

MacLeod, R. M.,  W. Farkas,  I.  Fridovich, and K. V. Rajagopalan.  Purification  and
  properties of hepatic sulfite oxidase.   J. Biol. Chem. 236:1841, 1961.

Mitchell, C. W., and S.  J.  Davenport.  Hydrogen sulphide literature.  Public Health
  Rep. 39:1-13,  1924.


                                    201
-------
Mukai,  F.,  I. Hawryluk, and R. Shapiro.  The mutagenic specificity of sodium bisul-
  fite.   Biochem. Biophys. Res. Commun.  39:983-988, 1970.

Novakov, T. , P. K. Mueller, A. E.  Alcocer, and J. W. Otvos.  Chemical composition  of
  Pasadena aerosol by particle size and time of day.  J. Colloid Interface Sci.
  39(1):225, 1972.

Oshino,  N., and B. Chance.  The properties of sulfite oxidation in perfused rat
  liver; interaction of sulfite oxidase with the mitochondrial respiratory chain.
  Arch.  Biochem. Biophys.  ]_70:514, 1975.

Oyanagui, Y.  Role of phosphate, pyrophosphate, adenine nucleotides, and  sulfate  in
  activating production of the superoxide radical by macrophages, and in  formation
  of rat paw edema.  Agents Actions 7:125-132, 1977.

Parkes,  D.  G., and T. E.  Eling.  Influence of environmental agents on prostaglandin
  biosynthesis and metabolism  in the lung.  Inhibition of  lung 15-hydroxyprostaglandins
  dehydrogenase by exposure of guinea pigs to 100% 09 at atmospheric pressure.
  Biochem.  J. T46:549-556, 1975.                    ^

Petering, D. H., and N. T. Shih.  Biochemistry of bisulfite-S02.  Environ. Res.
  9:55-65,  1975.

Rajagopalan, K. V., and J. L  Johnson.  Biological origin  and metabolism  of S02.
  In:  Biochemical Effects of  Environmental Pollutants.  S. D. Lee (ed.). Ann  Arbor,
  Mich., Ann Arbor Science Publishers,  Inc.  1977.

Saltzman, H. A., and H. 0. Sieker.  Intestinal response to changing gaseous environ-
  ments:  Normobaric and  hyperbaric observations.  Ann. N.Y. Acad. Sci. 150:31-39,
  1968.

Schneider, L. K., and C.  A. Calkins.  Sulfur dioxide-induced lymphocyte defects  in
  human peripheral blood  cultures.  Environ. Res.  3:473-483, 1970.

Shapiro, R.  Bisulfate  inflicted damage to nucleic acids.  Mutat. Res. Sect.  Environ.
  Mutag. Rehab. Subj.   21:234-235, 1973.

Shapiro, R.  Genetic effects  of bisulfite.  Mutat. Res.  39:149-175,  1977.

Shapiro, R., and B. Braverman.  Modification of poly U  by  bisulfite:  Effect  of
  double helix  formation  and  coding properties.  Bioch. Biophys.  Res. Commun.  47:544,
  1972.

Shapiro, R., B. I. Cohen,  and  R. E. Servis.  Specific deamination of  RNA  by NaHS03.
  Nature (London)  227:1047,  1970.

Shapiro, R., and J. M.  Weisgras.  Bisulfite catalyzed transamination  of cytosine and
  cytidine.  Biochem. Biophys.  Res. Commun.  40:839-843,  1970.

Shih, N. T., and D. H.  Petering.  Model reactions for the  study of the  interaction
  of S02 with mammalian organisms.  Biochem. Biophys. Res. Commun.   55:1319-1325.
  1973.
                                     202
-------
Siegelman, S.,  J. C. K. Loo, and M. Rowland.  Shortcomings in pharmacokinetic analy-
  sis by conceiving the body to exhibit properties of a single compartment. J.
  Pharm. Sci. 57:117-123, 1968.

Smith, R.  P., and R. A. Abbanat.  Protective effect of oxidized glutathione in acute
  sulfide poisoning.  Toxicol. Appl. Pharmacol.   9:209-217, 1966.

Sorbo, B.   On the formation of thiosulfate from inorganic sulfide by liver tissues
  and heme compounds.   Biochim. Biophys. Acta  27:324-329, 1958.

Sorbo, B.   On the mechanism of sulfide oxidation in biological systems.  Biochim.
  Biophys. Acta 38:349-351, 1960.

Summers, G.  A., and J.  W. Drake.  Bisulfite mutagenesis in bacteriophage T4.
  Genetics  68:603-607, 1971.

Thompson,  J.  R., and D. M. Pace.  The effects of S02 upon established cell lines
  cultivated in vitro.   Can. J. Biochem. Phys.   40:207-217, 1962.

Tuazon, P. T.,  and S.  L.  Johnson.  Free radical  and ionic reaction of bisulfite with
  reduced nicotinamide adenine dinucleotide and its analogues.  Biochemistry 1_6:1183,
  1977.

Wattiaux-De Coninck, S.,  and R. Wattiaux.   Subcellular distribution of sulfite
  cytochrome c  reductase in rat liver tissue.  Eur. J.  Biochem.  J9:552, 1971.
                                    203
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A. 3  IN VIVO







A. 3.1  Introduction







     Chronic low-level exposure to sulfur-bearing compounds in the ambient



air may have significant effects on human health.  However, relatively little



research has been done on animals to explore these effects for compounds



other than S02 or H?SO..  Most J_n vivo work has utilized short-term exposure



schedules, and these studies have been limited, for the most part, to pollutant



effects on cardiopulmonary function.  Thus, vast areas remain to be explored--



long-term exposure regimens, the impact of other sulfur-bearing compounds



present in the atmosphere, and the various other physiological parameters



that may be affected.  The following discussion deals with animal exposure



studies that have been conducted to date.  For convenience, the presentation



is organized by the types of compounds studied, including sulfur dioxide,



sulfuric acid, sulfates and sulfites, and pollutant combinations. The textual



discussion of these various compounds is supplemented by summary tables,



which appear at the end of this section.







A.3.2  Sulfur Dioxide







     Over a short period of exposure, only extremely large concentrations of



sulfur dioxide are lethal.  In fact, studies have shown that brief exposure



to a concentration of the gas exceeding the ambient air level by a thousand



times may not prove  fatal.  Extended exposure to relatively high concentra-



tions may, however,  result in death.  For example, a continuous-exposure



study showed that a  concentration of 130 ppm SO- took 154  hr to  kill  half the



guinea pigs exposed.  Mice were more resistant,  and it required  847 hr of



                                  204
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continuous exposure at a 150-ppm concentration to kill half their population.



At exposures of about 1000 ppm, survival time was greatly reduced and species



sensitivity was reversed.  At this concentration, half the mice died within 4



hr, and half the guinea pigs died within 20 hr (Hazelton Laboratories Report



1969b).







     Leong et al.  (1961) exposed animals to extremely high concentrations of



S02 (up to 5000 ppm).   Some of the subjects were pretreated with histamine to



simulate respiratory disability.  Others had been adrenalectomized to simulate



the condition of humans with low resistance to nonspecific stress.   Both



treatments shortened survival time as compared with that of a control group.



The lung pathology observed postmortem was primarily dependent on exposure



duration.   In animals that had not been pretreated, pulmonary edema and areas



of consolidation were evident.   In both the histamine-pretreated and adrenalecto-



mized animals, bronchial obstruction was seen.   In guinea pigs that succumbed



rapidly, there was occlusion of the bronchioles and venous congestion with



little or no fluid in the alveoli.   Examination of animals that survived for



2 to 4 hr revealed fluid in the alveoli, distended bronchioles, and partial



desquamation of the mucosal membranes.







     SO,, is an upper respiratory tract irritant that is absorbed readily by



the mucous membranes of the upper airway.   At relatively high concentrations,



most of the SO* that is inspired is absorbed in the upper respiratory airways



and thus prevented from directly reaching the deep lungs.  Only at low concentra-



tions is this absorption effect reduced.  Strandberg (1964) demonstrated this



phenomenon in rabbits, as indicated below.
                                  205
-------
so?
mg/m
26
52
13
1.3
0.26
concentration
3 ppm
100
20
5.0
0.5
0.1
Absorption,
95
95
80
50
5
Range,
90-98
75-95
50-90
10-60
1-10
Source:   Strandberg (1964).

However, SOp is delivered in a dose-related manner by two routes, inhalation

and the circulatory system.   For example, Frank and Speizer (1965) noted that

radio!abeled SO^ absorbed in the upper airway entered the blood and thereby

reached the lung.



     Shortly after inhalation, SO^ decreases respiratory rate and narrows the

bronchial tubes, resulting in an increase in airway resistance.  This acute

effect is reversible.   Corn (1972) and Frank (1965) noted that S02 concentrations

greater than 1 ppm generally increased pulmonary flow resistance in various

animal species.  The effects were dose related and diminished shortly after

cessation of exposure.   Amdur (1973) found that 1 hr of exposure to as little

as 0.5 ppm S02 increased pulmonary flow resistance in guinea pigs.  The

increase peaked at about 10 percent and abated after the exposure period.



     Among the various species that have been tested, guinea pigs show the

longest persistance of SCL effects on air flow.  Amdur (1961) observed the

following effects after a 1-hr exposure:


                                                Duration of increased flow
         S02 concentration,                        resistance following
         	mg/m3	exposure, hr	

               260                                          1
               780                                          2
               800                                         >2
         Source:  Amdur (1961).
                                  206
-------
     Alarie (1973) administered 17 ppm S02 to mice and noted a decrease in



respiratory rate.  After repeated exposures lasting 3-10 min each, the effect



disappeared.   Wakisaka (1975) examined SO,,-induced changes in respiratory



rate in two groups of mice:  one group had been exposed to SO,, previously,



and the other had no prior exposure.   The animals previously exposed showed



less of a decline in respiratory rate.








     Other effects may result from acute high doses of SO,,.  For example,



Knauss et al.  (1976) exposed rats continuously to 600-700 ppm SO^ and found



an increase in tracheal mucus after 9 hr.  However, Spiegelman et al. (1968)



did not observe any effect on bronchial clearance in donkeys exposed for 30



min to SOp in the dose range of 25-713 ppm.








     Lee et al. (1966) exposed guinea pigs to 7-20 ppm SO,, for 2-1/2 hr and



found that hemoglobin increased in linear proportion to the dose.  This



relationship was not found at higher exposure levels (21-320 ppm).








     Long-term exposures to SO,, show varying results, depending on concentra-



tion, duration, and animal species.   Generally, relatively high concentrations



are required to produce a chronic response in animals, such as alteration of



pulmonary structures and ventilatory function.  As in the case of acute



effects, chronic effects appear in animals only at concentrations far above



ambient air levels.








     Hirsch et al. (1975) exposed beagles to 1 ppm SO,, twice daily for 1-1/2



hr over a 12-month period.  No significant changes in respiratory mechanics



or pulmonary function were observed.   A similar finding was obtained by
                                  207
-------
Alarie (1970, 1972), who exposed guinea pigs continuously to 1-5 ppm S02 for



1  year and monkeys to 0.5-1.3 ppm for 78 weeks.   Lewis et al.  (1969), however,



found changes in the respiratory mechanics of dogs after 225 days of continuous



exposure to 5 ppm SOp.   These changes included increased pulmonary flow



resistance and decreased lung compliance (a measure of lung distensibility).



Asmundsson et al.  (1973) found that exposing animals to SCL concentrations of



40 or 100 ppm for 6 weeks continuously did not produce bronchial damage, but



that such damage did occur when a 200-ppm concentration was used.







     Significant deterioration in pulmonary function was also observed in



monkeys (Alarie 1972) after an accidental high dose of SCL.  Following a 30-



week continuous exposure to 5 ppm SOp, a dose of 200-1000 ppm was inadvertently



administered to the test animals for approximately 90 min.  The subjects



exhibited dilation of the bronchioles and chronic dilatation of the bronchi.



These effects did not occur when Alarie (1975) repeated the original experiment,



involving continuous exposure to 5 ppm for 78 weeks.







     Weiss and Weiss (1976) noted alterations in pulmonary function in mice



following continuous exposure for 6-9 days to 40 ppm S0?.  In addition to an



increase in  static lung compliance and a decrease in lung surface tension,



there was a  21 percent weight loss.







     Reid (1963) exposed rats to 300-400 ppm S0? for 3 months and observed  a



hypersecretion of mucus, an effect which simulated one of the conditions of



chronic bronchitis in humans.  In addition to increased numbers of mucous



cells in the main bronchi, mucous cells also were noted in the peripheral



airways, where they are normally absent.  Dalhamn et al.  (1956) exposed rats



continuously to 10 ppm  SOp for 6 weeks and observed a thickening of the



                                  208
-------
mucous layer.   The cilia could not clear away the mucus because of its thick-



ness, and the clearance of foreign bodies from the respiratory system was



consequently decreased.  Fraser et al.  (1968) did not find a change in ciliary



activity after exposing rats to 300 ppm S0? for 12 hr daily over 4 months.







     Chakrin et al.  (1974) observed changes in the goblet cells of bronchi



and bronchioles in beagles exposed to 500-600 ppm S0? for 2 hr twice a week



for 4-5 weeks.  These changes produced a pus-like exudate in the bronchial



tree.







A. 3. 3  Sulfuric Acid







     Sulfuric acid mist rapidly disperses into dilute suspensions and reacts



with ions in the atmosphere, such as ammonia, to form atmospheric sulfate



salts.  The hLSO, contained in an aerosol is particulate matter, and its



toxicity therefore depends upon its deposition and retention in the respiratory



tract.  Sulfuric acid particles in the submicron size range are deposited at



a high rate by the mechanism of Brownian movement, although the rate depends



also on relative humidity.  As compared with other sulfate particles, H^SO,



particles are more numerous and have greater surface area per unit volume.



Green and Lane (1964) note that foreign nuclei, such as salts, in hygroscopic



vapors may affect the size, and hence the toxicity, of the aerosol.  These



factors contribute to the toxic potential of the compound. In studies of both



short-term exposure (Amdur 1970) and long-term exposure (Alarie 1973, 1975),



sulfuric acid has been found to be the most irritating of the particulate



sulfur species.  Amdur (1978) observed that equimolar amounts of hLSO,



more than tripled the increase in pulmonary flow resistance caused by SO-.
                                  209
-------
     Treon (1950) observed that H,,S04 toxicity varied among four animal


species.  These animals,  in order of increasing sensitivity, were:   rabbits <


rats < mice < guinea pigs.  This variation may have arisen from differences


in respiratory function  and structure.   However,  it has also been suggested


that guinea pigs are particularly susceptible because of their high histamine


content.   Cockrell et al.  (1976) noted that exposure to 100 mg/m  HUSO,  for 2


hr was fatal to guinea pigs, while the same concentration did not kill  rats


even after 6 months of exposure.




     Animal health and age may also influence the toxic response to H?SO,.


Amdur et al. (1952) noted that among guinea pigs  1-2 months old, half could

                                       3
not survive an 8-hr exposure to 18 mg/m  H^SO,, while among animals 18 months


old, a concentration of  50 mg/m  was required to  achieve a 50 percent mortality.



                                                    3
     Sackner et al. (1977) exposed animals to 1 mg/m  H^SO, for 10 min and


found no change in respiratory flow.  However, unlike SO,,, sulfuric acid may


cause damage not reflected in respiratory frequency changes.  For example,


Amdur et al. (1975) found that H^SO. altered lung resistance and compliance


at concentrations which did not decrease breathing rate.




     In a short-term study, Amdur (1958) found an increase in flow resistance


and a decrease in lung compliance in guinea pigs  after 1 hr of exposure to

                                                                 3
various H^SO. aerosols differing in concentrations (0.2-40.0 mg/m ) and


particle size (7, 2.5, 0.8, and 0.3 urn).  These changes occurred as the


concentration increased and the particle size decreased.




     A recent study by Amdur (1978) examined the  irritant effects of H^SO.,


several inorganic sulfates, and pollutant combinations with S0~ in guinea


                                  210
-------
pigs.   One-hour exposures of 1  mg/m  H^SO,  and less  at  particle  sizes  of  1


and 0.3 pm caused significant increases in  resistance.   The  smaller  particles


produced a greater response at  a given concentration than  the  1-pm particles.


Amdur noted that the response to 0.1  mg/m  with  1-pm particles was slight  and


rapidly reversible,  while the same concentration with 0.3-um particles was


greater in magnitude and not rapidly  reversible  (see Figure  A-l).
                              H2S04-0.3m

                              • 0.1 mg/m3 (23)
                              • 1.0 mg/m3 (25)
                  0
                              5    10    15   20

                              Post-exposure (min)
25   30
Figure A-l.   Post-exposure changes  in  pulmonary  flow  resistance  produced by
0.3-um sulfuric acid.   Numbers  in parentheses  are  numbers  of  animals  exposed.


Source:   Amdur (1978).



     In chronic studies by Amdur et al.  (1975),  flow  resistance  increased

                                                                     3
with exposure to H^SO,  within a concentration  range of  0.07-0.86 mg/m  for


l-|jm particles.   The irritant potency  also  increased  for HpSO, particles


ranging from 0.1-2.5 urn,  the size which  can be deposited in the  gaseous
                                  211
-------
exchange regions of the lung.   Following exposure to 0.4-0.6 mg/m3 concentra-


tions made up of particles in this size range, lung resistance and compliance

values were altered.
     Long-term continuous exposures to low concentrations of H2  4  °

appear to affect pulmonary function to the same degree as short-term exposures

to high concentrations.  Lewis et al.  (1975) continuously exposed dogs to 800
    3
pg/m  H^SO. (particle size: 0.5 pm) and noted a decrease in pulmonary function

after 225 days.  After 621 days of exposure, lung volumes were reduced, heart

weights were decreased, and total pulmonary resistance was elevated.
                                                  3
     Alarie (1975) exposed guinea pigs to 0.1 mg/m  (particle size:  2.78

             3
and 0.08 mg/m  (particle size: 0.84 pm) H?SO, for 12 months.  Although effects


in pulmonary mechanics, diffusing capacity, and ventilation distribution were


found, comparison with a control group showed that these changes were not

                                                    3
significant.  Monkeys were exposed to 0.38-4.79 mg/m  HUSO, (particle size:


0.54-3.6 urn) for 18 months.  Although breathing frequency was elevated, lung


compliance and inspiratory and respiratory resistance did not differ signifi-


cantly from that of control group animals.  However, over 78 weeks of exposure


to HpSO,, monkeys exhibited deleterious effects on pulmonary structures


(Alarie 1973).  The critical concentrations were 4.79 mg/m  with 0.73-[jm

                       3
particles and 2.73 mg/m  with 3.60-|jm particles.
     Generally, the differences noted between short-term exposures to high

doses and chronic exposures to low doses might be explained by the presence

of ammonia in the upper airways.   Larson (1977) suggested that ammonia may

mitigate the effects of inhaled acid sulfate, particularly at low concentra-


tion levels.



                                  212
-------
A.3.4  Sulfates and Sulfites








     Suspended sulfate levels have been associated with cardiopulmonary symptoms



in the elderly and asthmatics.   However, there are not sufficient data to



quantitatively link ambient air levels with health effects.   It is still not



known whether the metal salts themselves or the acid precursors of these



salts are the actual irritants.








     Inhalation studies with animals have shown that sulfates are more irritating



to the respiratory system than SO,, alone or in the presence of an insoluble



salt.  The various sulfate salts that have been studied have different irritant



potencies.  The following compounds may be ranked in order of irritant



potency on a scale of 1 to 100:   HUSO,, 100; zinc ammonium sulfate, 33;



ferric sulfate, 26; zinc sulfate, 19; ammonium sulfate, 10;  ammonium bisulfate,



3;  copper sulfate, 2; ferrous sulfate, 0.7; sodium sulfate,  0.7;  manganous



sulfate, -0.9 (not significant).  These rankings were based on studies with



guinea pigs (Amdur 1978).








     Amdur (1978) examined the comparative irritant potency of ammonium



sulfate, ammonium bisulfate, copper sulfate, and sodium sulfate.   The concentra-



tions and sizes of the salts were (NH4)2S04, 0.5-9.5 mg/m3,  0.13-0.81 urn



(HMD); NH4HS04, 0.9-10.9 mg/m3,  0.13-0.77 urn (MMD); CuS04, 0.4-2.4 mg/m3,



0.11-0.33 um (MMD); and Na2S04,  0.9 mg/m3, 0.11 ym (MMD).   Ammonium sulfate



caused a statistically significant decrease in compliance at all  concentrations



and particle sizes.  Except for a minimal response to the 0.2-pm particles,



the response per microgram of sulfate increased as particle size decreased.



Ammonium bisulfate showed significant changes in resistance and compliance,
                                  213
-------
                                                                          3
but was less irritating than ammonium sulfate.   Copper sulfate at 0.4 mg/m


(0.1 urn) produced a slight but significant change in compliance but not in


resistance.   At twice this concentration, changes in resistance and compliance


were observed for 0.1- and 0.3-um particles.   The degree of response was less


with the larger particles.  Sodium sulfate did not significantly change


resistance or compliance.   A further discussion of these sulfate salts appears


in the pollutant combination section.



                                                                3
     Nadel et al.  (1965) exposed anesthetized cats to 40-50 mg/m  zinc ammonium


sulfate (particle size: 0.1-1.5 urn) for 3 months.  Pathological examination

showed a narrowing of the bronchioles, which correlated with increased pulmonary


resistance, decreased compliance, and increased end-expiratory transpulmonary


pressure.



                                                                 3
     Bell and Hackney (1976) exposed squirrel monkeys to 2.5 mg/m  ammonium

sulfate for 1 hr and found a significant increase in flow resistance.  In
                                                                        3
another short-term study, Sackner et al.  (1976) exposed dogs to 4.6 mg/m

ammonium sulfate for 75 min and found no pulmonary changes within 30 min

after the exposure period.  They did find, however, that a smaller exposure

          3
(0.94 mg/m ) exerted effects within 1-2 hr after the termination of exposure:


while no change in flow resistance or functional residual capacity was noted,


there was a 20 percent decrease in lung compliance.




     Bell and Hackney (1977) presented priority criteria for restudying


sulfate salts.  Charlson et al. (1977) noted that the most abundant sulfate


aerosols are those formed by the neutralization of H^SO. and NH^, such as


ammonium sulfate, ammonium bisulfate, and the mixed salt (NH.^SO.   It
                                  214
-------
was also noted that the bisulfate ion (HSO,  ) may be intrinsically more


irritating than the sulfate ion (SO ~) in an aqueous solution.   Particle


size may be an important factor in the irritancy of sulfate salts.   For


example, in guinea pigs, Amdur and Corn (1963) found an increase in flow


resistance with decreasing mean particle diameter at 1-mg/m  concentrations


of zinc ammonium sulfate (Figure A-2).
           140
           120
           100
CD
O
c
03


I   80
0)
       CO
       V)
       CO
       CD

       O
       c
                  I   I  I   I   I   I
                                       I  I  I   I   I   I  I   I
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                                        a  0.54   o  1.4
        -12
            60


            40


            20


             0
              0   0.4   0.8   1.2   1.6  2.0   2.4  2.8   3.2   3.6

                         Zincammonium sulfate, mg/m3


Figure A-2.   Dose-response  curve of zinc  ammonium  sulfate  aerosol  for  different
particle sizes.   Numerals beside each point indicate  the number  of animals.

Source:   Amdur and Corn  (1963).
     The toxicology of inhaled metal  sulfites  has  not  been  studied  extensively.


However, it has been found that sodium metabisulfite  is  a sensory irritant


when inhaled by mice.   Alarie et al.  (1973)  noted  that at 1  ppm, the  meta-


bisulfite affected the respiratory rate to a greater  extent  than did  SCL.   At


this concentration, sodium sulfite was inactive.
                                  215
-------









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216
-------
     When McJilton et al. (1973) exposed guinea pigs to an aerosol containing


S02 and sodium chloride, they noted an increase in pulmonary flow resistance


only at high relative humidity (80 percent).  This effect could have been


associated with the presence of a bisulfite ion, which was noted in the


chemical analysis of the aerosol.




     In studying the combined effects of SO™ and various sulfate salts, Amdur


(1975) found that a combination including copper sulfate exhibited the greatest


degree of synergism.   It was noted, however, that since divalent copper


readily forms sulfite complexes, the observed effects may have resulted from


a copper sulfite aerosol.




     In an inhalation study, Ehrlich et al.  (1978) investigated the suscepti-


bility to respiratory infection of mice exposed for 3 hr to filtered air,


zinc sulfate, ammonium sulfate, or zinc ammonium sulfate, followed by a


respiratory challenge with viable bacteria (Streptococcus pyogenes).   Approxi-


mately 90 percent of the particles were less than 3 urn in diameter.   Table A-l


shows the mortality and survival rates of the test animals.   No deaths were


noted among mice exposed to sulfate aerosols only.  The death rates for


control mice challenged with S. pyogenes averaged 22.1 percent.  Using regres-


sion analysis, Ehrlich et al.  calculated a concentration relationship between


the metal sulfate salts and enhanced mortality caused by the infection.  A

                                       3
zinc sulfate concentration of 1.45 mg/m  was required to induce 20 percent

                                   3
excess mortality, while a 2.40-mg/m  concentration of zinc ammonium sulfate


was required to produce the same effect.   Ammonium sulfate did not affect


susceptibility to infection.
                                  217
-------
A.3.5  Pollutant Combinations




     The combination of air pollutants, such as exists in the ambient atmosphere,


appears to exert greater effects on human health than do individual pollutants.


Animal studies have demonstrated the operation of a synergistic principle in


the effects of these combinations.




     Amdur (1961) and Amdur and Underhill (1968) studied the effects of SCL


in combination with various "inert" aerosols (i.e., not injurious at the


experimental levels tested).  For example, they exposed animals to various


concentrations of the sulfur compound along with sodium chloride (NaCl)

                    3
aerosol at a 10-mg/m  concentration.  They observed that when NaCl aerosol


was present, not only was the response to S0? greater, but also the return to


control values was delayed.




     Amdur (1968) found that in guinea pigs a combination of SO^ and various


salts (manganese chloride, ferrous sulfate, and sodium orthovanadate) produced


effects on mechanical function which exceeded those produced by SCL alone and


which were totally absent when only the  salts were present.  The author


hypothesized that soluble metal salts can catalyze the conversion of S02 to


sulfuric acid, which causes a synergistic (or exaggerated) response.  Thus,


a possible explanation for this action is that a gas-aerosol reaction occurred


in the high relative humidity of the upper respiratory tract. To generalize


from this example, such a  reaction would depend on the solubility of SOp in


the aerosol of a given salt.
                                  218
-------
     Amdur (1978) combined SO,,  exposure  with  exposure  to the four sulfate

salts noted previously.   In all  the  exposures  to  guinea pigs, SCL at 0.3 ppm

and sulfate particle sizes of 0.1  urn,  there was a statistically significant

change in resistance and compliance.   Ammonium sulfate, ammonium bisulfate,

and sodium sulfate did not potentiate  the  response to  S02-  However, copper

sulfate,  a relatively mild irritant  compared  with other sulfate salts, gave

more than an additive effect with  S0?.   Figure A-3 shows the combination and

individual exposures.
          s
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60
50
40
30
20
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 0
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-------
centration of 1.1  mg/m  produced increased total  lung capacity.   Irradiated


auto exhaust alone and with SCL increased respiratory resistance.
     Gillespie et al.  compared pulmonary function measurements obtained at


the conclusion of the exposure period with measurements made 2 years later.


All the dogs, except for those breathing filtered air, showed an increased


total lung capacity.  Flow resistance was elevated in animals exposed to


irradiated and nonirradiated exhaust in combination with SCk and HpSCL.  It


was concluded that alterations in pulmonary function occurred even after


termination of the exposure period.  Gillespie et al. and Hyde et al.  further


observed that dogs exposed to irradiated exhaust exhibited an increase in


flow resistance, with a loss of dynamic lung compliance.  Hyde et al.  examined


the lungs of these dogs 2-1/2 to 3 years after the termination of exposure.


They observed minimal increases in enzyme production among animals exposed to


sulfur oxides alone, but no significant increase among animals exposed to


sulfur oxides combined with auto exhaust.




     In another study, Lewis et al. (1969) showed an increase in pulmonary


resistance and a decrease in lung  compliance and residual volume in beagles.


These effects arose from a continuous exposure for 225 days of H^SO. mist in

                                                          3
combination with SO,, at concentrations of 0.8 and 1.3 mg/m  , respectively.




     Gardner et al. (1977) examined the effect of HUSO-  (2-hr exposure to a


900-ug/m  concentration with particles of 0.23-|jm volume mean diameter)


and/or ozone (3-hr  exposure to a 196-(jg/m  concentration) on susceptibility


to pulmonary infectious disease in mice.  After exposure, the animals were


challenged with an  aerosol of viable bacteria (Streptococcus pyogenes) and
                                  220
-------
were returned to clean air for a 15-day holding period.  Exposure to either

the acid or ozone alone had no effect on mortality, nor did a sequential

exposure first to the acid and then to ozone.   However, as shown in Table

A-2, when the animals received sequential exposure first to ozone and then to

the acid, significant mortality effects occurred.


          Table A-2.   PERCENT MORTALITY (TREATED-AIR CONTROL)
                     FOR VARIOUS EXPOSURE REGIMENS

                              	Exposure regimen	
                               Air    H2S04    Air    03     H2S04    03
Summary                         +       +       +     +        +      +
 data	H2S04    Air	Q3   Air	03	H2S04

Number of                       9      10       9    10       11     10
  experiments

Average                         2.2     6.0     6.1   7.0      5.0   10.8
  % mortality

Standard error                  5.0     5.7     5.9   4.8      4.4    4.2

Source:Gardner et al.(1977).
     Amdur (1978) exposed guinea pigs for 2 hr to 0.2, 0.4, or 0.8 ppm 0,

singly or in combination with equal concentrations of SO,,.   The two higher

ozone concentrations caused a decrease in compliance.   The SOp exposures did

not significantly change resistance.   The 0^/SOy combination produced responses

similar to that of 0, alone.   Thus, no interactive effects were observed from

this pollutant combination.  When the animals were exposed to 1 or 10 ppm SOp
                           o
and motor oil mist (10 mg/m ), the irritant effects of S0? (resistance increase)

were antagonized.  Mineral oil (medicinal-grade naphthalene), however, did not

counter the S02 effects.  But when the detergent or dispersant component used

in the motor oil was added to the mineral oil, a protection against SOp was

observed.  Lastly, the addition of alpha-tocopherol to the mineral oil also
                                  221
-------
protected against SO,,.   The study did not attempt to determine whether this

was a local effect in the lung or an effect that could be produced if the

vitamin was administered orally or by injection.



     Laskin et al. (1970) exposed rats and hamsters to S0? alone, and combined

with benzo(a)pyrene (BP) to determine carcinogenesis from inhaling two

combined urban air pollutants.  In isolation exposure chambers, rats and

hamsters were exposed to SO,, for 6 hr/day, 5 days/week.   An equal number of

control animals received prefiltered air only.   Animals from each group were

transferred to an internal inhalation chamber for the BP/S02 exposure of 1

hr/day, 5 days/week (Table A-3).
          Table A-3.  INHALATION EXPOSURES OF RATS AND HAMSTER'
           TO SULFUR DIOXIDE AND/OR BENZO(a)PYRENE ATMOSPHERES'
                      Exposure pattern,                  Exposure period,
               	5 days/week	    794 calendar days
Exposure       Irritant,         Carcinogen-irritant,    Exposure (days)
  type         6 hr/day                1 hr/day             I       CI


A (fresh air)
A + CI                       10 mg/m3 BP + 3.5 ppm S02     534      494
I              10 ppm S02
I + CI         10 ppm S02    10 mg/m3 BP + 3.5 ppm S02     534      494


alsolated living quarters contained prefiltered, conditioned fresh air
 during nonexperimental periods.
     No significant pathology was found in hamsters, but squamous cell

carcinoma was noted in rats (Table A-4).  Of the 21 rats exposed to S0£ (I)

and carcinogen-irritant (CI), 5 had squamous cell carcinoma of the lung

appearing after 547 to 794 calendar days of exposure.  The earliest cancer
                                  222
-------
showed local extension and metastasis to the kidney.  Two additional animals

had advanced squamous metaplasia 485 and 715 days.
           Table A-4.   INHALATION EXPOSURES TO SULFUR DIOXIDE
                  AND/OR BENZO(a)PYRENE ATMOSPHERES


Exposure
type
A
A + CI
I
I + CI

Number of
animals
3
21
3
21
Number with
advanced
squamous metaplasia
0/3
1/21
0/3
2/21
Number with
squamous cell
carcinoma
0/3
2/21
0/3 .
5/2 lb
.Expressed as a ratio of tumors found to animals observed.
 Secondary squamous cell carcinoma in kidney.
     Table A-5 shows some correlations between results of i_n vitro and j_n vivo

studies of sulfur-bearing compounds.
                                  223
-------
           Table A-5.   COMPARISONS BETWEEN IH VITRO AND IN VIVO
                  STUDIES OF SULFUR-BEARING COMPOUNDS
                                             Effects
   Chemical
      In vitro
       In vivo
Zn(NH4)2(S04)2


S04=


S02/HS03-


MnS04) Na2S04


MnS04


(NH4)2S04


S02 + NaCl



S02 + CuS04


S02/HS03-



S02/HS03-



S02/HS03-, S04=
Changes in alveolar
macrophages

Histamine release from
lung fragments

Mutagenesis in cultured
mammalian cells
Increased susceptibility
to disease in mice

Bronchoconstriction
With BP, pulmonary
carcinogenesis in rats
No substantial histamine  No bronchoconstriction
release
No enhanced absorption
with manganese cations

Marked increase in
histamine release

Deposited to more
distal parts of a
simulated lung

Divalent copper readily
forms sulfite complexes

Increased ATPase acti-
vity in rat alveolar
macrophages

S02 absorbed in a sim-
ulated tracheobronchial
system

 Greater amounts of
histamine release in
guinea pigs
No effects of pulmonary
mechanics

Bronchoconstri cti on
Increased changes in pulmonary
mechanics
Caused more than an additive
effect on pulmonary function

Increased ATPase and lysozyme
activity in baboon alveolar
macrophages

In most animals, >90% S02 is
absorbed in upper airways
 Higher sensitivity to S02 +
S04= aerosols in guinea
pigs
                                  224
-------
         Table A-6.   SUMMARY TABLE:   DOSE EFFECTS OF SULFUR-BEARING
                  COMPOUNDS ON VARIOUS ANIMAL SPECIES

Chemical
H2S04
H2S04
Concentration,
mg/m3
0.1-1.0
1
Time
30 min
2 hr
Species
Guinea
pig
Hamsters
Rabbits
Effect
Increased pulmonary

resistance
Decreased ciliary activity;
hemato logical changes, but
H2S04
               2.4 and 4.8    2 hr     Monkeys
ZnS04 or       1.3 or 2.1      3 hr     Mice
Zn(NH4)2(S04)
(NH4)2S0
S02 with and
without carbon
particles

H2S04 on carbon
particles
                  5.2
03 + H2S04
               0.2 + 1.0
Zn(NH4)2(S04)2    1.1
ZnS04
NH4S04
FeS04
Fe2(S04)3
MnS04
                  0.9
                  1.0
                  1.0
                  1.0
                  4.0
                               3 hr     Mice
102 days   Mice
192 days
                            3 hr/day,   Mice
                            5 days/wk,
                            20 wk
3 hr +
 2 hr

  1 hr
  1 hr


  1 hr


  1 hr


  1 hr


  1 hr
Mice


Guinea
pig

Guinea
pig

Guinea
pig

Guinea
pig

Guinea
pig

Guinea
pig
          no immune changes

          Pulmonary function changes and
          alteration of lung structure

          Increased susceptibility to
          infection (dose-response
          effects)

           No increased susceptibility
          to infection

          Changed immune system
                     Altered immune system and
                     lung structure
Increased susceptibility to
infection

81% increase in pulmonary
resistance

40% increase in pulmonary
resistance

22% increase in pulmonary
resistance

77% increase in pulmonary
resistance

2% increase in pulmonary
resistance

No increase in pulmonary
resistance
                                  225
-------
 Table A-6 (Continued).   SUMMARY TABLE:   DOSE EFFECTS  OF SULFUR-BEARING
                  COMPOUNDS ON VARIOUS ANIMAL SPECIES
Chemical
Concentration,
    mg/m3       Time
Species
Effect
S02 + NaCl     0.41-26.0
S02

S02
                1  hr     Guinea
                         pig
    2.6         2 hr     Monkeys

  2.6-26.0    20-40 min  Dogs
S09 + Oo   0.5-2.1 + 0.4-1.6  2 hr     Guinea
                                       pig
          Increased pulmonary resis-
          tance, tidal volume, and
          frequency of breathing;
          decreased minute ventilation

          No observed effects

          Increased pulmonary resis-
          tance; decreased lung
          distensibility

          No interactive effects
          from pollutant combination
                                  226
-------
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Bibliography

Alarie, Y.,  W. M. Busey, A. A. Krumm, and C. E. Ulrich.  Long-term continuous
  exposure to sulfuric acid mist in cynomolgus monkeys and guinea pigs.  Arch.
  Environ.  Health 27:16-24, 1973.

Alarie, Y.  C. , A. A. Krumm, W. M. Busey et al.   Long-term exposure to  sulfur
  dioxide sulfuric acid mist, fly ash and their mixtures.  Arch. Environ.  Health
  30:254-262, 1975.

Alarie, Y.,  A. A. Krumm, H. J. Jennings, and R. H. Haddock.   Distribution  of
  ventilation in cynomolgus monkeys; measurement with  real time digital  comput-
  erization.  Arch.  Environ. Health 22:633-642, 1971.

Alarie, Y.,  C. E. Ulrich, W. M. Busey et al.   Long-term  continuous exposure to
  sulfur dioxide in cynomolgus monkeys.  Arch. Environ.  Health 24:115-128,  1972.

Alarie, Y.,  C. E. Ulrich, W. M. Busey et al.   Long-term  continuous exposure of
  guinea pigs to sulfur dioxide.  Arch. Environ. Health  2Jh 769-777,  1970.

Alarie, Y.,  I. Wakisaka, and S. Oka.  Sensory  irritation by  sulfite  aerosols.
  Environ.  Physiol.  Biochem. 3:182-184, 1973.

Albert, R.  E. , J. Berger,  K. Sanborn, and M. Lippmann.   Effects of cigarette
  smoke components on bronchial clearance in the donkey.  Arch. Environ. Health
  12:96-101,  1974.

Allison, D.  J., T. P. Clay, J. M. B. Hughes et al.   Effects  of nasal  stimulation
  on total respiratory resistance in the rabbit.  J.  Physiol. 239:23P-24P,  1974.
  (Abstr.)

Amdur, M. 0.  Animal studies.  Jji:  Assembly of Life  Sciences-National  Academy
  of Sciences-National Research Council.  Proceedings  of the Conference on
  Health Effects of Air Pollutants, Washington, D.C.,  October 1973.   Washington,
  D.C., U.S.  Government Printing Office.  1973.  p.  175-205.

Amdur, M. 0.  The physiological response of guinea pigs  to atmospheric pollut-
  ants.  Int. J. Air Pollut.  ]_: 170-183, 1959.

Amdur, M. 0.  Toxicologic  appraisal of particulate matter, oxides of sulfur,  and
  sulfuric acid.  J. Air Pollut. Control Assoc.   1_9:638, 1969.

Amdur, M.O.    Physiological  Response to Atmospheric Pollutants.  U.S.
  Environmental  Protection  Agency Contract  No. 600/1-78-021.  March  1978.

Amdur, M. 0., J. Bayles, V. Ugro et al.  Respiratory  response of guinea pigs  to
  sulfuric acid  and sulfate salts.  Presented  at  the  Symposium on Sulfur Pollu-
  tion and Research Approaches, Duke University,  1975.

Amdur, M. 0., and M. Corn.  The  irritant potency  of  zinc ammonium sulfate  of
  different particle sizes.   Am. Ind.  Hyg.  Assoc. J.  24(4):326-33,  1963.
                                        256
-------
Amdur, M.  0.,  and J. Mead.  A method for studying the mechanical properties  of
  the lungs of unanesthetized aniirals:   Application to the  study of  respiratory
  irritants.   In:  Proceedings of the Third National Air Pollution Symposium,
  Pasadena, California, April 1955.  p. 150-159.

Amdur, M.  0.,  and D. Underbill.   The effect of various aerosols on the  responses
  of guinea pigs to sulfur dioxide.  Arch.  Environ. Health  T6:460-468,  1968.

Amdur, M.  0.,  and D. W. Underhill.   Response of guinea pigs to a combination of
  sulfur dioxide and open hearth dust.   J.  Air Pollut. Control Assoc. 20:31-34,
  1970.

Amdur, M.  0.  et al.   Toxicity of sulfuric acid mist to guinea pigs.
  Arch.  Ind.  Hyg. 5:318-329, 1952.

Antweiler, H.,  and A.  Brockhaus.   Respiratory frequency, flowrate and minute
  volume in non-anesthetized guinea pigs during prolonged exposure to low concen-
  trations of S02 and N02.  Ann.  Occup. Hyg. T9:13-16, 1976.

Asmundsson, T., and K.  H.  Kilburn.   Mucociliary clearance rates at various  levels
  in dog lungs.   Am. Rev.  Respir. Dis.   ]_02: 388-397, 1970.

Asmundsson, T. , K.  H.  Kilburn, and W.  N. McKenzie.  Injury  and metaplasia of air-
  way cells due to S02.  Lab. Invest.  29:41, 1973.

Balchum, 0. J., J.  Dybicki, and G.  R.  Meneely.   Adsorption  and distribution  of
  S3502, inhaled through the nose and mouth by dogs.  Am. J. Physiol. 197:1317-
  1321,  1959.

Balchum, 0. J., J.  Dybicki, and G.  R.  Meneely.   The dynamics of sulfur  dioxide
  inhalation (absorption,  distribution, and retention).  Am. Med. Assoc. Arch.
  Ind. Health  2J:564-569,  1960.

Balchum, 0. J., J.  Dybicki, and G.  R.  Meneely.   Pulmonary resistance and compliance
  with concurrent radioactive sulfur distribution in dogs breathing  35S02.   J.
  Appl.  Physiol.  1960.

Ballenger, J.  J.   A study of ciliary activity in the respiratory tract  of animals.
  Ann. Otol.  Rhinol. Laryngol.  58:351-369, 1949.

Battigelli, M.  C.,  H.  M.  Cole, D. A.  Fraser, and R. A. Mah.   Sulfur  dioxide  and
  graphite dust on rats.   Arch.  Environ. Health T8:603, 1969.

Battigelli, M.  C.,  and J.  F. Gamble.   Review of Inhalation  Toxicology of Sulfuric
  Acid and Sulfates.  Washington, D.C., American Petroleum  Institute.

Bell, K. A.,  and J.  D.  Hackney.   Effects of Nitrate and/or  Sulfate Aerosols  upon
  Cardio-Pulmonary Function.  New York, Coordinating Research Council,  Inc.  1976.

Bell, K. A.,  and J.  D.  Hackney.   Effects of Sulphate Aerosols upon Human
  Cardiopulmonary Function.  Downey,  Calif.,  The Professional Staff Association of
  Rancho Los Amigos Hospital.  1977.
                                       257
-------
Bloch, W.  N. ,  Jr.,  W.  C.  Crocker, T.  K.  Wessendarp, and T. R. Lewis.  Electro-
  cardiographic telemetry with arrhythmia recording on dogs chronically exposed
  to air pollutants.  Toxicol. Appl.  Pharm.  J_9:390, 1971.

Bloch, W.  N.,  Jr.,  T.  R.  Lewis, K.  A.  Busch et al.  Cardiovascular status of fe-
  male beagles exposed to air pollutants.  Arch.  Environ. Health 24:342, 1972.

Bushtueva, K.  A.   Experimental studies on the effect of low oxides of sulfur con-
  centrations on the animal organism.   In:  Limits of Allowable Concentrations
  of Atmospheric Pollutants, Book 5.   V.  A.  Ryazanov (ed.).  Translated by B. S.
  Levine.   Washington, D.C., U.S. Department of Commerce, Office of Technical
  Services.  1962.   p. 92-102.

Bushtueva, K.  A.   Toxicity of sulfur oxides inhalation in chronic continuous
  experiments.  In:  Biological Effect and Hygienic Significance of Atmospheric
  Pollutants,  Book 1/9.  V. Ryazanov and H.  Holdberg (eds.).  Washington, D.C.,
  U.S. Department of Commerce, Office of Technical Services.  1968.  Also in:
  U.S.S.R. Lit. Air Pollut. Related Occup. Dis. J6:82-9,  1968.

Bystrova,  T.  A. Effects of sulfur dioxide studied with the use of labeled
   atoms.  Gig. Sanit.  20:30-77, 1957.   In:  U.S.S.R. Lit. Air Pollut. Related
  Occup. Dis.  Washington, D.C., U.S.  Department of Commerce, Office of
  Technical Services.   1961.  p. 89-97.

Callanan,  D.,  M.  Dixon et al.  The acute effects of S02 on pulmonary mechanics,
  breathing patterns and pulmonary vagal afferent receptors  in the  rabbit.
  Physiol. Soc. 247:23-24, 1975.

Casarett,  L.  J., and J. Doull (eds.).   Toxicology:  The Basic Science of Toxicol-
  ogy.  New York, Macmillan.  1975.  p.   133-147, 527-554.

Chakrin, L. W., and L. Z. Saunders.  Experimental chronic bronchitis pathology
  in the dog.   Lab. Invest.  30:145-154, 1974.

Charles, D. B., and D. B. Menzel.  Absorption of sulfate  ions in the rat lung.
  Res. Commun. Chem. Pathol. Pharmacol.   12:389-396, 1975.

Charlson,  R.  J. , A. H. Vanderpol, D.  S.   Covert et al.  H2S04/(NH4)2S04 back-
  ground aerosol:  Optical detection in  the St. Louis region.  Atmos. Environ.
  8:1257-1267, 1974.

Cockrell,  B.  Y., W. M. Busey et al.  Light and electron microscopic pulmonary
  changes in rats and guinea pigs exposed to sulfuric acid mist.  Paper
  presented at the Annual Meeting of the American Lung Association, May
  1976, New Orleans, La.

Corn, M.,  N.  Kotske, D. Stanton et al.   Response of cats  to  inhaled mixtures  of
  S02 and S02-NaCl  aerosol in air.   Arch. Environ. Health 24:248-256, 1972.

Dalhamn, T.  Mucous flow and ciliary activity  in the trachea  of healthy cats  and
  rats exposed to respiratory irritant gases (S02, H3N, HCHO):  A functional  and
  morphologic  (light microscopic and electron microscopic) study, with special
  reference to technique.  Acta Physiol. Scand. 36(Suppl.  123):9-161, 1956.


                                       258
-------
Dalhamn, T.   Studies on the effect of sulfur dioxide on ciliary activity  in
  rabbit trachea in vivo and in vitro and on the nasal cavity.  Am. Rev.  Respir.
  Dis.   83:566-567, 1961.

Dalhamn, T. ,  and J. Rohdin.  Mucus flow and ciliary activity  in the trachea of
  rats exposed to pulmonary irritant gas.  Br.  J. Ind. Med.  ]_3:110-113,  1956.

Dalhamn, T. ,  and J. Sioholm.  Studies on S02, N02, and NH3:   Effect on ciliary
  activity in rabbit trachea of single in vitro exposure and  resorption of rab-
  bit nasal  cavity.  Acta Physio!.  Scand. 58:287-291, 1963.

Dalhamn, T.,  and L. Strandberg.   Acute effect of sulfur dioxide on the rate
  of ciliary beat in the trachea of rabbit, in vivo and in vitro, with studies
  on the absorptional capacity of the nasal cavity.   Int.  J. Air Water Pollut.
  4:154-167,  1961.

Dalhamn, T.,  and L. Strandberg.  Synergism between sulphur dioxide and carbon
  particles:   Studies on adsorption and on ciliary movements  in the rabbit
  trachea in vivo.   Int. J. Air Water Pollut.  7:517-529, 1963.

Eatough, D.  J.,  and A.  V.  Colucci.   Determination and Possible Public Health
  Impact of Transition Metal Sulfite Aerosol Species.  Prepared for the Electric
  Power Research Institute, December 30, 1975.

Ehrlich, R.,  J.  C.  Findlay, and D.  E. Gardner.   Susceptibility to bacterial pneumo-
  nia of animals exposed to sulfates.  Toxicol. Lett. ^:325-330, 1978.

Electrical Power Research Institute.   Sulfur Oxides Current Status of Knowledge.
  Prepared by Greenfield,  Attaway and Tyler, 1976.

Fairchild, G.  A.,  P. Kane, B.  Adams,  and D. Coffin.   Sulfuric acid and streptococci
  clearance from respiratory tracts of mice.  Arch.  Environ. Health 30:538-545,
  1975.

Fairchild, G.  A.,  J. Roan, and J. R.  McCarroll.  Effect of S02 on influenza in-
  fection in mice.   Arch.  Environ.  Health  25:174-182, 1972.

Fairchild, G.  A.,  S. Stultz, and D.  L.  Coffin.   Sulfuric acid effect on the de-
  position of radioactive aerosol in the respiratory tract of guinea pigs.  Am.
  Ind.  Hyg.  Assoc.  J.  37(8):584-594, 1975.

Ferin,  J., and L.  J. Leach.  The effect of S02 on lung clearance of Ti02  particles
  in rats.   Am.  Ind. Hyg.  Assoc.  J.   34:260, 1973.

Frank,  N.  R.,  and F. E. Speizer.   S02 effects on the respiratory system in dogs:
  Changes in mechanical behavior at different levels of respiratory system
  during acute exposure to the gas.   Arch.  Environ.  Health  JJ_:624-634, 1965.

Frank,  N.  R. ,  R.  E. Yoder, E.  Yokoyama, and F.  E. Speizer.  The diffusion of
  35S02 from tissue fluids into the lungs following exposure  of dogs to 35S02.
  Health Phys.   13:31-36,  1967.
                                       259
-------
Fraser, D.  A., M.  C. Battigelli, and M. N. Cole.  Ciliary activity and pulmonary
  retention of inhaled dust in rats exposed to sulfur dioxide.  J. Air Pollut.
  Control Assoc.   ]8:821-823, 1968.

Gardner, D. E.,  F.  J. Miller, J. W. Illig, and J. M. Kirtz.   Increased infectivity
  with exposure to ozone and sulfuric acid.  Toxicol. Lett. Tj 59-64,  1977.

Giddens, W. E.,  Jr., and G. Fairchild.  Histopathologic effects of S02 on the
  nasal mucosa of mice from defined flora and conventional colonies.  Arch.
  Environ.  Health  2_5:166-173, 1972.

Gil, J., and E.  R.  Weibel.  Extracellular lining of bronchioles after perfusion-
  fixation of rat lungs for electron microscopy.  Anat. Rec.  169:185-200,  1971.

Gillespie,  J. R., J. D. Berry et al.  Pulmonary  Function Changes  in the  Period
  Following Termination of Air Pollution  Exposure in Beagles.  Presented at the
  Annual Meeting of the American Lung Association, New Orleans, May 1976.

Gillespie,  J. R., J. D. Berry, Y.  Yang et al.  Cardiovascular and pulmonary
  function studies on beagles exposed for 68 months to auto exhaust and  other air
  pollutants.  Am.  Rev. Respir. Dis., 1978.  (Submitted for publication.)

Goco, R. V., M.  B.  Dress,  and 0. C. Brantigan.   Comparison of mucus glands  in
  the tracheobronchial tree of man  and animals.  Ann. N.Y. Acad.  Sci.  106:555-
  571,  1963.

Goldring,  I. P.,  P. Cooper, I. N.  Ratner  et al.  Pulmonary effects of sulfur di-
  oxide exposure in the Syrian hamster.   Arch. Environ. Health  ]_5:167-176, 1967.

Green,  H.  L., and W. R. Lane.  Particle Clouds:  Dusts, Smokes, and Mists.
  London,  E. and F. N. Spon, Ltd.   1964.

Hatch,  M.  T., A.  Biermain  et al.   Effect  of sulfur dioxide on the pathogenesis
  of a  model respiratory pathogen  in the  NAMRU-mouse.  Proc.  Am.  Soc. Microbiol.
  74:91, 1974.

Hazelton Laboratories Report Chronic Exposure of Guinea Pigs  to Sulfur Dioxide.
  Submitted to Electric Power Research Council Project RP-74, 1969a.

Hazelton Laboratories Report.   1969b.  From:  M. Q. Amdur, Air pollution.   In:
  Toxicology.  L. J. Casarett and  J. Doull  (eds.).  New York, Macmillan.   1975.
  p. 531-532.

Hazelton Laboratories Report Effects of Inhaling Sulfur Dioxide,  Sulfuric Acid,
  and Flyash.  Electric Power Research Council RP-74,  1975.

Hinners, R. G. , J.  K. Burkart, and G.  L.  Contner.  Animal  exposure chambers in
  air pollution studies.   Arch. Environ.  Health  ]_3:209,  1966.

Hirsch, J.  A., E. W. Swenson, and  A. Wanner.  Tracheal mucous transport  in
  beagles  after long-term  exposure to  1 ppm sulfur  dioxide.   Arch.  Environ.
  Health   30:249-253,  1975.
                                        260
-------
Hueter, F.  G.,  G. L.  Contner, K. A. Busch, and R. G. Hinners.  Biological effects
  of atmospheres contaminated by auto exhaust.  Arch. Environ. Health  12:553,
  1966.

Hyde, D.,  J.  Orthoefer, D.  Dungworth et al.  Morphometric and morphological eval-
  uation of pulmonary lesions in beagle dogs chronically exposed to high ambient
  levels of air pollutants.   Lab. Invest., 1978.   (To be published.)

Hyde, D.,  A.  Wiggins, D.  Dungworth et al.   Automated measurements of airspaces
  in lungs  from dogs  chronically exposed to air pollutants.  (Unpublished manu-
  script. )

Knauss, W.  J.,  and T. C.  Medici.  Cell vs noncell airway temporal response  in
  rats exposed  to sulfur dioxide.  Arch. Environ. Health 3H(5):241-247,  1976.

Kornienko,  A.  P.  Gigienicheskaia ossenka semsi aerozolia sernoi kilsloty,
  sernistogo angridrida,  okislov azota i ammiaka kak zagriaznitelei atmosfernogo
  uozkukha.  Gig. Sanit.   37:8-10, 1972.  (In Russian.)

Krishman,  B.,  and T.  K. Nambinarayanan.  Effect of sulfuric acid fumes on lung
  surfactant.   Ind.  J.  Exp.  Biol.  |2:524-527, 1974.

Larson, T.  V.,  D. S.  Covert, R.  Frank, and R.  J.  Charlson.  Ammonia in the
  human airways:  Neutralization of inspired acid sulfate aerosols.  Science
  197:161-163,  1977.

Laskin, S.  , M.  Kuschner,  and R.  T. Drew.  Studies in pulmonary carcinogenesis.
  Jji:  Conference on  Inhalation Carcinogenesis.  M.  G.  Hanna, Jr., P.   Nettesheim,
  and J.  R. Gilbert (eds.).   Oak Ridge, Tenn., U.S.  Atomic Energy Commission.
  1970.  p. 321-351.

Lebowitz,  M.  D., and  G. A.  Fairchild.   The effects of sulfur dioxide and A2 in-
  fluenza virus in pneumonia and weight reduction in mice.  An analysis  of
  stimulus-response relationships.  Chem.  Biol. Interact.  7:317-326,  1973.

Lee, S. E., and R.  M. Danner.  Biological  effects of S02 exposures on  guinea pigs.
  Arch. Environ. Health  J2:583-587, 1966.

Leong, K.  J.,  H. A.  MacFarland,  and E. A.  Sellers.  Acute S02 toxicity:  Effects
  of histamine  liberation.   Arch. Environ. Health 3:668-675, 1961.

Lewis, T.  R.,  D. E.  Campbell, and T. R. Vaught, Jr.   Effects on canine pulmonary
  functions via induced N02 impairment, particulate interaction and subsequent
  S0x.  Arch.  Environ.  Health  18:596-601, 1969.

Lewis, T.  R.,  W. J.  Moorman et al.  Long-term exposure to auto exhaust and  other
  pollutant mixtures, effects on pulmonary function in the beagle.  Arch. Environ.
  Health  29:102-106, 1974.

Lewis, T.  R.,  W. J.  Moorman, W.  F. Ludmann, and E. I. Campbell.  Toxicity of long-
  term exposure to oxides of sulfur.  Arch. Environ. Health  26:16-21, 1973.
                                       261
-------
MacFarland, H.  N.,  C.  E.  Ulrich, A.  Martin et al.   Chronic exposure of cynomolgus
  monkeys to fly ash.   In:   Inhaled Particles III, Vol. 1.  Proceedings of an
  International Symposium organized by the British Occupational Hygiene Society,
  London, September 1970.  W.  H. Walton (ed.).  Old Woking, Surrey, England,
  Unwin Brothers Limited.  1971.  p. 313-327.

McJilton, E. E. , N. R. Frank et al.   Roles of relative humidity in the synergistic
  effect of a sulfur dioxide-aerosol mixture  in the lung.   Science  182:503-504,
  1973.

McLaughlin, R.  F. ,  Jr., W.  S.  Tyler, and R. 0. Canada.  Subgross pulmonary anatomy
  of the rabbit, rat,  and guinea pig, with additional notes on the human lung.
  Am. Rev. Respir.  Dis.  94:380-387, 1966.

Mathur, K. , and P.  Olmstead.   Inhalation Toxicity of H2S04 Mist. Thesis, Harvard
  University.  Cambridge, Mass.  1949.  Quoted in:   M. 0. Amdur, R. Z. Schultz,
  and P. Drinker,  Ind. Hyg. Occup. Med. 6:305-313, 1952.

Mawdesley-Thomas,  L. E., P. Healey, and D. H. Barry.  Experimental bronchitis  in
  animals due to sulphur dioxide and cigarette smoke, an automated quantitative
  study.  Inhaled Part. Vap.   3:509-26, 1970.

Miller, C. E.  Streamlines, streak lines, and particle path lines associated with
  a mechanically-induced flow homorphic with  the mammalian mucociliary system.
  Biorheology 6:127-135, 1969.

Murphy, S. D.  A review of effects on animals of exposure to auto exhaust and
  some of its components.  J.  Air Pollut. Control  Assoc.  J4;:308, 1964.

Murphy, S. D., J.  K. Leng, C.  E. Ulrich, and  H. V. Davis.   Effects on animals  of
  exposure to auto exhaust.  Arch. Environ. Health  7:66, 1963.

Nadel, J. A., H. Salem, B.  Tamplin, and Y. Yokiwa.  Mechanism  of bronchoconstric-
  tion.  Arch.  Environ. Health  TJ): 171-178, 1965.

Navrotskii, V.  K.   Effects of chronic low concentration sulfur dioxide poisoning
  on the immuno-biological reactivity of rabbits.   Gig. Sanit. 24:21-25, 1959.
  In:  U.S.S.R. Lit. Air Pollut. Related Occup. Dis.  Washington, D.C., U.S.
  Department of Commerce, Office of Technical Services.   1961.  p. 81-86.

Pattle, R. E. , F.  Burgess, and  H. Cullumbine.  The effects of  cold environment
  and ammonia on the toxicity of sulphuric acid mist to guinea pigs.  J. Pathol.
  Bacteriol.  72:219-232,  1956.

Peacock, P. R., and J. B. Spence.  Incidence  of lung tumors in LX mice exposed
  to (1) free radicals, (2) S02. Br. J. Cancer.  2J:606-618, 1967.

Prokhorov, Yu.  D.,  and A. A.  Rogov. Histopathological and histochemical changes
  in the organs of rabbits after prolonged exposure to carbon  monoxide and
  their combination.  Gig. Sanit.  24:22-26,  1959.  J_n:   U.S.S.R. Lit. Air
  Pollut. Related Occup. Dis.  Washington, D.C., U.S. Department of Commerce,  Office
  of Technical Services.   1961.   p. 81-86.
                                       262
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Rail, D. P. Review of the health effects of sulfur oxides.   Environ.  Health
  Perspect.  8:97-121, 1974.

Reid, L.  An experimental study of hypersecretion of mucus  in  the bronchial  tree.
  Br. J. Exp.  Pathol.  44:437-445, 1963.

Reif, I. S. , and D. Cohen.  Retrospective radiographic analysis of  pulmonary
  disease in rural and urban dogs.  Arch. Environ. Health   2JJ:684,  1970.

Robinson, N.  E.,  J. R. Gillespie, J. D. Berry et al.  Lung  compliance,
  lung volumes,  and single-breath diffusing capacity in dogs.  J. Appl.  Physiol.
  33:808, 1972.

Roth, R. P., and M. F. Tansey.  Effects of gaseous air pollutants on  gastric
  secreto-motor activities  in the rat.  J. Air Pollut. Control Assoc.   2^:706-9,
  1972.

Rylander, R.,  M.  Ohrstrom,  P.  A. Hellstrom, and R. Bergstrom.  S02  and  particles--
  synergistic effects on guinea pig lungs.  _In:  Inhaled Particles  III.   Proceed-
  ings of an International  Symposium organized by the British  Occupational Hygiene
  Society, London, September 1970.  W. H. Walton (ed.).  Old Woking,  Surrey,
  England, Unwin Brothers Limited.  1971.  p.  535-541.

Sackner, M. A.,  R. D. Dougherty et al.  Effect of Inorganic  Nitrate and Sulfate
  Salts.  Presented at the  Annual Meeting of the American Lung Association,  New
  Orleans, May 1976.

Salem, H., and H.  Cullumbine.   Kerosine smoke and atmospheric  pollutants.
  Arch.  Environ.  Health 2:641, 1961.

Spiegelman, J.  R., G. D.  Hanson, A.  Lazarus et al.  Effect  of  acute sulfur dioxide
  exposure on bronchial clearance in the donkey.   Arch. Environ. Health  17:321-326,
  1968.

Strandberg, L.  G.   S02 absorption in the respiratory tract.  Arch.  Environ.
  Health  9:160-166,  1964.

Thomas,  M.  D.,  R.  H.  Hendricks, F. D.  Gunn, and T. Critchlow.  Prolonged exposure
  of guinea pigs  to sulfuric acid aerosol.  AMA Arch. Ind.  Health   17:70-80,
  1958.

Treon, J. F.,  F.  R. Dutra,  J.  Cappel et al.  Toxicity of sulfuric acid  mist.   Arch.
  Ind. Hyg. Occup. Med.  2:716, 1950.

Vaughan, T. R. ,  L. F. Jannelle, and T. R. Lewis.   Long-term  exposure  to low  levels
  of air pollutants.   Effects on pulmonary function in the  beagle.  Arch.  Environ.
  Health  V9:45,  1969.

Weiss, K. D.,  and H.  S. Weiss.  Increased lung compliance in mice exposed to
  sulfur dioxide.   Res. Commun. Chem.  Pathol.  Pharmacol.  j_3:133-136,  1976.

Zarkower, A.   Alterations in antibody induced by chronic  inhalation of  sulfur
  dioxide and carbon.  Arch. Environ.  Health 25:45-50, 1972
                                       263
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A.4  CLINICAL STUDIES








     In attempting to relate dose-response effects in the laboratory to



those occurring under ambient conditions, many parameters must be considered.



For instance, it should be noted that a low dose causing some subjective



discomfort or after-effect in an individual may not be measurable in the



clinical setting.   On the other hand, a slight effect measured in the upper



airways during a clinical exposure may go unnoticed by the experimental



subject.  Such an effect would also go unnoticed by an individual exposed



under ambient conditions.







     Of the sulfur compounds emitted from mobile sources, sulfur dioxide and



sulfuric acid have received the most clinical study because of their abundance



in the ambient air and in the workplace.   Less research has been done on



sulfate, hydrogen sulfide, and carbonyl sulfide.  Because the latter two



compounds occur at relatively small concentrations in the ambient air--they



form sulfur oxides fairly rapidly in the presence of oxygen--they are not



considered as potentially hazardous mobile source emissions.  Suspended



sulfates, however, not only are potentially hazardous, but have been



demonstrated in some animal and human studies to be the most toxic of the



sulfur compounds discussed.







     Sulfur dioxide concentrations of about 1-5 ppm, levels which exist



during air pollution episodes, have been found to exert measurable effects on



lung function in the laboratory.  Clinical tests indicate that some individuals



are more susceptible than others to the effects of SO,,.  Within the concentra-



tions tested, however, the effects of this pollutant have been transitory.
                                 264
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     Studies of sulfuric acid show effects occurring at 1.0 mg/m .   These



effects, revealed by an increase in respiratory rate, have been found to be



partially dependent on the size of the particles in the mist.   Clinical



studies of pollutant combinations have, like some animal experiments, suggested



the existence of a synergistic effect under certain conditions.








A.4.1   Sulfur Dioxide








     Pulmonary mechanics can be altered in human subjects exposed briefly to



sulfur dioxide.   Frank et al.  (1962) exposed 11 subjects for 10 min to three



concentrations of the gas (1,  5, and 13 ppm) and observed concentration-



related effects on pulmonary flow resistance.   The low concentration produced



an increase in resistance in one subject,  while the high concentration



produced an increase in all  subjects.   The intermediate concentration was



associated with a 39 percent increase in the flow resistance of the group.



Under the 10-min exposure schedule, the observed effects appeared within 1



min and peaked within 5 min  of the beginning of the period.   When the exposure



period was lengthened to 30  min, the percent increase in flow resistance was



less than that noted after the 10-min exposure.








     Weir and Bromberg (1972,  1973) exposed 19 males to three concentrations



of S02 (0.3, 1.0, and 3.0 ppm) for 96 and  120 hr.   Twelve of the subjects



were in a normal state of health, while the other seven were smokers with



early symptoms of chronic pulmonary disease.  The seven smokers exhibited no



significant increase in pulmonary flow resistance in response to any of the



test exposures.   The 12 healthy subjects,  however, showed significant increases



in airway resistance at the high exposure concentration, an effect which



disappeared within 48 hr after the end of the exposure.  These findings led



                                 265
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the investigators to conclude that persons with preexisting peripheral  airway



disease are not significantly more susceptible to S0? effects than are  healthy



persons.







     Speizer and Frank (1965) ran a series of experiments to compare the



effects of sulfur dioxide (15 and 28 ppm for 10 min) when breathed in by the



mouth and when breathed in by the nose.   They found that breathing S0?  by



mouth increased flow resistance in 9 of 12 experiments, while breathing S0?



by nose increased resistance in 3 of 12 experiments.  The data indicated that



less than 1 percent of the S0» entering the nose reached the oropharynx.







     A subsequent study by Anderson et al. (1974) examined the effects  of



nasal breathing of sulfur dioxide on lung mechanics, mucus flow rate, and



subject discomfort.  Fifteen young male subjects were exposed for 6 hr to S02



concentrations of 1, 5, and 25 ppm.  At the two higher concentrations,  the



subjects exhibited a significant decrease in nasal flow rate, particularly in



the anterior nose.  This effect was especially marked in individuals with



initially slow mucus flow rates.  In support of previous studies indicating



that the nose acts as an SO^ scrubber, the investigators found that pharyngeal



air samples from the subjects contained less than 1 percent of the total SO*



inhaled.   Although changes were noted in nasal flow resistance and forced



expiratory volume, the closing volumes, which will reflect changes at the



smaller airways, were not affected by the two higher concentrations.  The 1-



ppm concentrations, however, caused a general constriction in the upper



airways.   Finally, dryness and/or slight pain in the nose and pharynx occurred



at the higher doses.  Subject ratings of discomfort were proportional to the



exposure concentration.
                                 266
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     Before the study by Anderson et al., Cralley (1942) investigated the



effects on mucus flow and ciliary action of short-term SCL exposures.  He



noted a small decrease in the rate of mucus removal  after a 60-min exposure



to 10-15 ppm.  A nearly 50 percent decrease in ciliary activity was noted



with a 30- to 60-min exposure to 25 ppm.   When a 30-min treatment of 50 ppm was



administered, a nearly 70 percent reduction in ciliary activity was observed.



Considered within the limits and conditions of the test design, these effects



were judged to be dose related.







     Because mucus traps microbes and other particles inhaled from the ambient



air and participates in pulmonary clearance, a reduction in its flow rate



could increase susceptibility to infectious disease.   To test this hypothesis,



Anderson et al. (1977) inoculated 32 subjects with rhinovirus type 3 and



exposed half the group to 5 ppm SO- for 4 hr.  Although a 50 percent decrease



in mucus flow rate occurred in the subjects exposed to S0?, there was no



increase in the number of colds they developed.   In fact, the investigators



noted that the SO^-exposed subjects had fewer symptoms and a more persistent,



but lower, level of virus proliferation.







     Newhouse et al.  (1978) assessed bronchial clearance and pulmonary function



in healthy nonsmoking males and females exposed via the mouth to 5 ppm S02



for up to 2-1/2 hr.  The subjects exercised strenuously and periodically



during the exposure (the heart rate remained at 70-75 percent of the predicted



maximum).  In addition, the clearance of a radioactive aerosol (3-pm mean mass



diameter [MMD]), deposited before S02 exposure, was measured.  After a 2-hr



exposure to S0?, the clearance of the inhaled particles increased, accompanied



by a decrease in the maximum mid-expiratory flow rates.  No significant



effects on vital capacity or forced expiratory volume were observed.





                                 267
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     Lawther et al.  (1975) conducted a 4-year study with 25 healthy male and



female subjects to examine the effect of sulfur dioxide on pulmonary function.



They used the product of two parameters (airway resistance and thoracic gas



volume) to describe specific airway resistance (SR  ).   Reaffirming much of
                                                  dw


the previously reported research, they found an increase in SR   in mouth-
                                                              dw


breathing subjects exposed to 1-3 ppm SCL.   In one study, an increase in this



value was observed after only eight deep breaths of a 3-ppm concentration.



Changes in ventilatory function occurred throughout the exposure schemes, but



these changes were transient and varied among the subjects.







     Jaeger and Wittig (1978) studied S02 effects in normal subjects and in



asthmatic patients.   Among the 40 normal subjects, an exposure of 0.5 ppm S02



produced pulmonary changes in only one individual — a transient episode of



wheezing dyspnea.  A similar exposure produced slight changes in several of



the 40 asthmatics.  In terms of group averages, mid-expiratory flow rates



were 3 percent lower in the asthmatic subjects than in the normal subjects.



Two of the asthmatics experienced wheezing dyspnea.  (Since fumes from a



kerosene space heater were sometimes present in the chamber, it is difficult



to interpret the relative role of S0? in this study.  However, in a study by



Salem and Cullumbine [1961], kerosene smoke did not potentiate the effects



of SOp or H?SO,  in guinea pigs or mice.)







     Snashall and Lewin (1976) examined, among other things, the inhibitory



effects of atropine and sodium cromoglycate (SCG) on bronchial response  in



normal and asthmatic subjects exposed to SO,,.  (The drug atropine will block



some vagally mediated effects, while SCG prevents the release of histamine



and other vasoactive substances from mast cells.)  As expected, a 3-min



exposure to 3 ppm S0? increased airway resistance in all subjects.  However,



                                 268
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atropine did not inhibit the respiratory hyperactivity associated with S0~


exposure in either normal or asthmatic subjects.   This lack of inhibition


led the researchers to conclude that vagal mechanisms play little role in


causing hyperreactivity associated with sulfur dioxide.




A.4.2  Sulfuric Acid and Sulfates




     As noted in the discussion of animal j_n vivo studies, sulfuric acid is


more irritating (exerts greater effects on flow resistance and respiratory


rate) than sulfur dioxide.   Its action varies according to relative humidity,


aerosol particle size, and individual response, but studies generally have

                                                              3
shown that ^SO. increases airway resistance at about a 1-mg/m  concentra-


tion.  Relatively little research has focused on the effects of smaller


concentrations on human subjects.  In evaluating the effects of sulfuric acid


emissions, it should be noted that H?SCL reacts in the atmosphere to form


various sulfate salts.



                                                                              o
     Amdur et al.  (1952) exposed 15 normal human subjects to 0.35- to 5.0-mg/m


sulfuric acid concentrations for 5 to 15 min.  The mist caused changes in

                                                                   3
respiration at all test concentrations.  Between 0.35- and 0.5-mg/m  con-


centrations, the respiration rate increased by about 30 percent,  coinciding


with a 28 percent decrease in deep breathing.  Similar findings were reported


by Bushtueva (1957) and Morando (1956).  This change may have been a reflex


response to protect against the retention of the acid particles.
                                             3
     The effects of a 2-hr exposure to 1 mg/m  H?SO. (0.5-(jm MMD) on bronchial


clearance and pulmonary function were investigated by Newhouse et al. (1978).
                                 269
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The 10 subjects were healthy,  male and female nonsmokers who exercised during



the exposure.   In addition, prior to exposure, all  subjects inhaled radiolabeled



particles (3-um HMD).   After the exposure, five of the subjects had a marked



increase in clearance of the particles.   There was no significant alteration



of vital capacity or forced expiratory volume.  However, there was a marginally



significant decrease of 1.4 percent (P = 0.09) in the maximum mid-expiratory



flow rate.








     Recently, Larson et al. (1977) considered the presence of ammonia in the



upper airways as a neutralizer of sulfuric acid.   On the basis of a diffusion



calculation, they noted that at 30 percent relative humidity, a 20-ug/m



concentration of sulfuric acid mist of 0.3-um particles should be completely



neutralized after about 0.5 sec in the nose and 0.1 sec in the mouth.  This



calculation suggests that the mouth is more efficient than the nose in neu-



tralizing acid aerosol.








     Although a number of animal studies have considered the effects of



exposure to sulfate salts, which are present during air pollution episodes,



relatively little research has been reported for humans.  Animal studies have



demonstrated that the toxicity of these salts is influenced by particle size



and the metal ions present in them.  One of these salts, zinc ammonium sulfate,



which has been demonstrated as a respiratory irritant in animals, was reported



as a constituent of the Donora, Pennsylvania, pollution episode of 1948.








     Hackney et al. (1978) exposed normal, sensitive, and asthmatic subjects



for 2-1/2 hr daily over several successive days to 100 ug/m  ammonium sulfate,


       3                               3
85 ug/m  ammonium bisulfate, or 75 (jg/m  sulfuric acid aerosol.  The particle
                                 270
-------
size of all three compounds was nominally 0.3 pm (MMD).   The exposure



concentrations were chosen on the basis of the highest reported sulfate ion



concentrations detected in ambient air pollution episodes in the Los Angeles



Basin.   During the test exposure intervals, in which the chamber temperature



was maintained at 31°C, the subjects engaged in intermittent light exercise



to simulate typical outdoor activity such as might occur during a summer day



pollution episode.  In general, the investigators found little or no evidence



of health effects from these exposures in terms of changes in various



respiratory measurements.   These studies failed to confirm the association



between sulfates and morbidity often observed in epidemiological studies.



According to the investigators, one possible explanation is that sulfates



produce adverse health effects through additive or synergistic interaction



with coexisting pollutants.








A.4.3  Pollutant Interactions








     In 1964, Frank et al.  reported a study comparing the effects of S0?



alone and in combination with sodium chloride (NaCl).   Healthy adults were



exposed to 1-2, 4-6, or 14-17 ppm S0« for 30 min in the presence or absence



of an NaCl aerosol of submicron particles.   No systemic differences were



found between the gas and gas-aerosol exposures.  Basically, the same dose-



response relationship existed under both circumstances.   As noted in the j_n



vivo section, when Amdur (1959) exposed guinea pigs to this combination, it



produced greater changes in pulmonary mechanics than did SCL alone.  This



difference in species response has not been explained.








     Toyama (1962) exposed 13 subjects to S0? with and without NaCl aerosol.



After initial control measurements, the subjects were exposed sequentially



                                 271
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for 5 min to NaCl  (0.22-|jm count median diameter [CMD]), SOp (1.6-56 ppm),



and an SO^-NaCl combination.   An increase in flow resistance occurred after



exposure to SO^-   When SO™ was combined with NaCl aerosol, the increase in



flow resistance was greater.   Similar results were reported by Nakamura



in 1964.
     Using lower concentrations of the same compounds, Burton et al.  (1969)



exposed 10 healthy adult males to 2-2.7 mg/m3 NaCl (1-um CMD) and 1-3 ppm



SOp.  Neither SOp alone nor combined with the NaCl aerosol altered pulmonary



mechanics.  At the concentrations used, this result correlates with data



based on animal studies by Amdur (1960).
     Hazucha and Bates (1975) measured the effect of a combination of SOp and



ozone on pulmonary function.  Eight healthy young adults were exposed to 0.37



ppm ozone and/or 0.37 ppm sulfur dioxide for 2 hr.   While the extent of



ventilatory function effects varied considerably among the individual subjects,



it was evident that these changes were greater for the pollutant combination



than for either pollutant alone.  The combination decreased forced expiratory



volume by 22 percent, peak expiratory flow rate by 21 percent, and vital



capacity by 8 percent.







     A similar study by Bell et al. (1975, 1977) examined the effects of the



same pollutant concentrations on eight Los Angeles residents, four of whom



had respiratory conditions which rendered them sensitive to changes in air



quality.   In this study, the effect of acute exposure to the combination was



greater than that exerted by 03 alone, but the magnitude of response was



considerably less than that reported by Hazucha and Bates.
                                 272
-------
     Horvath and Folinsbee (1977) exposed young human males to SCL and 0.,



singly and combined under one environmental condition--25°C and 45 percent



relative humidity.   All nine subjects had 15-min intervals of walking and



resting during a 2-hr exposure scheme.   The subjects exposed to filtered air



or 0.40 ppm SO,, showed no significant changes in pulmonary functions.  Those



exposed to 0.40 ppm 03 singly or combined with 0.40 ppm SO,, had significant



decreases in maximum expiratory flow, forced vital capacity, and inspiratory



capacity.  However, these decreased pulmonary functions were attributed to



Oo alone and not to the pollutant combination.   One of the subjects had an



enhanced sensitivity to the O^-SOp combination.   This general absence of



synergistic effect correlates with the Amdur study (1978) showing no synergistic



effect in guinea pigs exposed to the SOp-O- combination.








     von Nieding and co-workers (1977) exposed nine human volunteers to



combined N09, Ov and S09 at up to 5, 1, and 5 ppm, respectively.   They found
           L,   O        C.


significant increases in airway resistance and reductions in arterial oxygen



partial pressure.  The POp returned to normal values 1 hr following the



termination of exposure, while the airway resistance remained slightly elevated.



In addition, bronchial challenge with an aerosol containing 1-3 percent



acetylcholine (a bronchoconstricting agent) produced an increase in bronchial



reaction following exposure to the combined gases.








     In conclusion, clinical studies show that most human subjects respond to



5 ppm (13,000 ug/m ) SOp, while certain sensitive subjects respond to 1-2 ppm



(2600-5200 ug/m ) SO,,.  The typical response is an increase in pulmonary flow



resistance, although at lower levels, e.g., 1 ppm SOp (2600 ug/m ), significant



decreases in nasal mucus flow rate have been demonstrated.  Unlike HpSO^, SOp



is removed more efficiently through nose breathing than through mouth breathing.






                                 273
-------
     The effects of HLSO.  on human subjects involve primarily changes in



respiration rate and bronchoconstriction at concentrations of 0.35-5.0 pg/m



for 5-15 min.   The presence of ammonia in the upper airways seems to mitigate



some effects of H^SO. through neutralization.   Nevertheless,  the percent



relative humidity and particle size seem to determine the relative toxicity of



sulfate aerosols.







     Finally,  recent animal and human studies indicate that S02 may not have



synergistic activity in combination with 0.,.   A summary of some human responses



to sulfur-bearing compounds is given in Table A-11.
                                 274
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Bibliography

Acheson, E. D.,  R. H.  Cowdell,  and E. Rang.  Adenocarcinoma of the nasal
  cavity and sinuses in England and Wales.  Br. J. Ind. Med. 29:21-30,
  1972.

Air Quality Criteria for Sulfur Oxides.   Washington, D.C., U.S. Department
  Consumer Protection and Environmental  Health Service, National Air
  Pollution Control Administration,  1971.

Albert,  R. E.,  M.  Lippmann, and W. Briscoe.  The characteristics of
  bronchial clearance in humans and  the effects of cigarette smoking.
  Arch.  Environ.  Health ]8:738-755,  1969.

Albert,  R. E.,  M.  Lippmann, H.  T.  Peterson, Jr., et al.  Bronchial deposi-
  tion and clearance of aerosols.   Arch.  Intern. Med.  131:115-127, 1973.

Albert,  R. E.,  H.  T. Peterson,  Jr.,  D. E. Bohning, and M. Lippmann.  Short-
  term effects  of cigarette smoking  on bronchial clearance in  humans.
  Arch.  Environ.  Health 30:361-367,  1975.

Altshuler, B.,  E.  D. Palmes, and N.  Nelson.  Regional  aerosol  deposition
  in the human respiratory tract.   In:  Inhaled Particles and  Vapours  II.
  Proceedings of an International  Symposium organized  by the British
  Occupational  Hygiene Society, Cambridge, September-October 1965. C.  N.
  Davies (ed.).   Oxford, Pergamon Press.  1967.

Altshuler, B.,  L.  Yarmus, E. D. Palmes, and N. Nelson.  Aerosol deposition
  in the human respiratory tract.   I.  Experimental procedures and total
  deposition.   AMA Arch. Ind. Health ]jj: 293-303, 1957.

Amdur, M. 0., and M. Corn.   The irritant  potency of zinc ammonium sulfate
  of different particle sizes.   Am.  Ind.  Hyg. Assoc. J. 24:326-333,  1963.

Amdur, M. 0., W.  W. Melvin, and P. Drinker.  Effects of inhalation of  sulphur
  dioxide by man.   Lancet 2:758-759,  1953.

Amdur, M. 0., L.  Silverman, and P. Drinker.  Inhalation of sulfuric  acid
  mist by human subjects.  AMA Arch.  Ind. Hyg. Occup.  Med. 6:305-313,  1952.

Andersen, I., G.  R. Lundqvist,  P.  L.  Jensen, and D. F. Proctor.  Human response
  to controlled levels of sulfur dioxide.  Arch. Environ. Health 28:31-39,
  1974.

Andersen, I. B.,  P. L. Jensen et al.  Induced  rhinovirus infection under
  controlled exposure to sulfuric acid.    Arch. Environ. Health, May/June
  1977,  p. 120-126.

Angel, J. H., C.  M. Fletcher, I. D.  Hill, and  C. M. Tinker.  Respiratory
  illness in factory and office workers.  A study of minor respiratory
  illnesses in relation to changes in ventilatory capacity, sputum charac-
  teristics, and atmospheric pollution.    Br. J. Dis. Chest 59:66-80, 1965.


                              276
-------
Bates, D.  V., G.  Bell et al.   Short-term effects of ozone on the  lung.
  J.  Appl.  Physiol.  32:176-181, 1972.

Bates, D.  V.  , C.  A.  Gordon, G. I.  Paul et al.  Chronic bronchitis:  Report
  on the third and fourth stages of the co-ordinated study of chronic
  bronchitis  in the Department of Veterans Affairs, Canada.   Med. Serv. J.
  Can. 22:5-61, 1966.

Bates, D.  V., C.  R.  Woolf, and G.  I. Paul.  Chronic bronchitis.   A report
  on the first two stages of the co-ordinated study of chronic bronchitis
  in the Department of Veterans Affairs, Canada.  Med.  Serv. J. Can.
  18:211-305, 1962.

Bell, K. A.,  and S.  K. Friedlander.   Aerosol deposition in models of a
  human lung bifurcation.  Staub-Reinhalt. Luft 33(4):178-182, 1973.

Bell, K. A.,  W.  S.  Linn et al.  Effects on pulmonary function of  humans
  exposed to  mixtures of ozone, sulfur dioxide and their reaction products.
  Fed. Proc.  34(3):428, 1975.

Bell, K. A.,  W.  S.  Linn, M. Hazucha et al.  Respiratory effects of exposure
  to ozone plus sulfur dioxide in Southern Californians and Eastern
  Canadians.   (Unpublished.)

Blair, W.  H., M.  C.  Henry, and R.  Ehrlich.  Chronic toxicity of nitrogen
  dioxide.   II.  Effects on histopathology of lung tissue.  Arch.  Environ.
  Health J8:186-192, 1969.

Bradley, W.  H., W.  P. D. Logan, and A. E.  Martin.  The London fog of December
  2nd-5th,  1957.   Monthly Bull. Min. Health V7:156-166, 1958.

Brown, J.  H., K.  M.  Cook, F.  G. Ney, and T. Hatch.  Influence of  particle
  size upon the retention of particulate matter in the human lung.
  Am. J. Public Health 40:450-458, 480, 1950.

Brundelet,  P. J.   Experimental study of the dust-clearance mechanism of
  the lung.   I.  Histological  study in rats of the intra-pulmonary bronchial
  route of elimination.  Acta Pathol. Microbiol. Scand. Suppl. 175:1-141,
  1965.

Buechley,  R.  W.,  W.  B. Riggan, V.  Hasselblad, and J. B. VanBruggen.  S02
  levels and  perturbations in mortality.  A study in the New York-New
  Jersey metropolis.  Arch. Environ. Health 27:134-137, 1973.

Buell, G.  C.   Biochemical parameters in inhalation carcinogenesis.  In:
  Inhalation  Carcinogenesis.   M.  G.  Hanna, P. Nettesheim, and J.  R. Gilbert
  (eds.).   Oak Ridge, Tenn. , U.S.  Atomic Energy Commission.   1970.  p. 209-228.

Buok, S. F.,  and D.  A. Brown.   Mortality from Lung Cancer and Bronchitis
  in Relation to Smoke and Sulphur Dioxide Concentration, Population
  Density and Social Index.  London, Waterlow and Sons, Ltd.  1964.
  27 p.   Tobacco Research Council  Research Paper No. 7.
                              277
-------
Burgess, S.  G.,  and C.  W.  Shaddick.   Bronchitis and air pollution.  Roy.
  Soc.  Health J.  79:10-24, 1959.

Burn, J. L.,  and J. Pemberton.  Air pollution bronchitis and lung cancer
  in Salford.  Int. J.  Air Water Pollut. 7:5-16, 1963.

Burrows, B.,  A.  L.  Kellogg, and J.  Buskey.  Relationship of symptoms of
  chronic bronchitis and emphysema to weather and air pollution.  Arch.
  Environ.  Health ]6:406-413, 1968.

Burton, G.  G.,  M.  Corn et al.  Response of healthy men to inhaled low
  concentration of 'gas-aerosol mixtures.  Arch. Environ. Health 18:681-692,
  1969.

Bushtueva,  K. A.   New studies of the effect of sulfur dioxide and of
  sulfuric acid aerosol on reflex activity of man.  ITI:  Limits of
  Allowable Concentrations of Atmospheric Pollutants, Book 5.  Washington,
  D.C., U.S.  Department of Commerce, Office of Technical Services.  1962.
  p. 86-92.

Bushtueva,  K. A.   Threshold reflex effect of S02 and sulfuric acid aerosol
  simultaneously present in the air.  I_n:  Limits of Allowable Concentra-
  tions of Atmospheric Pollutants,  Book 4.  Washington, D.C., U.S. Depart-
  ment of Commerce, Office of Technical Services.  1961.  p. 72-79.

Bushtueva,  K. A.   The toxicity of H2S04 aerosol.  U.S.S.R. Lit. Air Pollut.
  Related Occup.  Dis. l_:63-66b, 1960.

Bushtueva,  K. A.   The determination of the limit of allowable concentration
  of sulfuric acid in atmospheric air.  In:  Limits of Allowable Concentra-
  tions of Atmospheric Pollutants,  Book 3.  Washington, D.C., U.S. Depart-
  ment of Commerce.  1957.  p. 20-36.

Bushtueva,  K. A., E. F. Polezhaev,  and A. P. Semenenko.  Electroencephalo-
  graphic determination of threshold reflex effect of atmospheric pollutants.
  Gig.  Sanit. 25:54-61, 1960.  In:   U.S.S.R. Lit. Air Pollut. Related
  Occup. Dis. 7:137-142, 1962.

Camner, P., C.  Jarstrand, and K. Philipson.  Tracheobronchial clearance
  in patients infected with microplasma pneumoniae.   In:  Airborne Trans-
  mission and Airborne Infection:  Concepts and Methods.  J. F. Ph. Hers
  and K. C.  Winkler  (eds.).  New York, John Wiley and Sons.  1973.

Carnow, B.  W.,  M. H. Lepper, R. B.  Shekelle, and J. Stamler.  Chicago  air
  pollution study.   S02 levels and acute  illness in patients with chronic
  bronchopulmonary disease.  Arch.  Environ. Health 28:768-776,  1969.

Carnow, B.  W. ,  and P. Meier.  Air pollution and pulmonary cancer.  Arch.
  Environ.  Health 27:207-218, 1973.

Chapman, R.  S., C. M. Shy, J. F. Finklea  et al.  Chronic respiratory disease
  in military inductees and parents of  schoolchildren.  Arch. Environ.
  Health 27:138-142, 1973.
                              278
-------
Charman, J.,  and L.  Reid.  Sputum viscosity in chronic bronchitis,
  bronchiectasis, asthma and cystic fibrosis.   Biorheology 9:185-199, 1972.

Christensen,  0.  W.,  and C.  H. Wood.  Bronchitis mortality rates in England
  and Wales  and Denmark.   Br. Med. J.  1:620-622, 1958.

Cohen, A.  A., S. Bromberg,  R. W. Buechley et al.  Asthma and air pollution from
  a coal-fueled power plant.   Am.  J.  Public Health 62:1181-1188, 1972.

Colley, J.  R. T., and W.  W.  Holland.   Social and environmental factors in
  respiratory disease.   Arch. Environ.  Health J_4: 157-161, 1967.

Colley, J.  R. T., and D.  D.  Reid.   Urban and social origins of childhood
  bronchitis  in England and Wales.  Br. Med. J. 2:213-217, 1970.

Colucci, A.   Sulfur Oxides:   Current Status of Knowledge.  San
  Rafael,  Calif., Greenfield, Attaway & Tyler, Inc.   1976.  EPRI EA-316,
  prepared for Electric Power Research Institute.

Committee on  the Challenge of Modern Society.   Air Pollution:  Air Quality
  Criteria for Particulate Matter.  North Atlantic Treaty Organization,
  1971.

Committee on  the Challenge of Modern Society.   Air Pollution:  Air Quality
  Criteria for Sulfur Oxides.  North Atlantic Treaty  Organization, 1971.

Constantine,  H., L.  Dautrebande, N. Kaltreider et al.   Influence of
  carbachol  and of fine dust aerosols upon the breathing mechanics and
  the lung volumes of normal subjects and of patients with chronic
  respiratory disease before and after administering  sympathomimetic
  aerosols.   Arch.  Int. Pharmacodyn.  Ther. ]_23: 239-252, 1959.

Cornwall,  C.  J.  , and P. A.  B. Raffle.   Bronchitis—sickness absence in London
  transport.   Br. J.  Ind. Med.  J8:24-32, 1961.

Cralley, L.  V.   The effect of irritant gases upon the rate of ciliary
  activity.   J.  Ind.  Hyg. Toxic. 24(7):193-198, 1942.

Daly, C.  Air pollution and causes of death.  Br. J.  Prev. Soc. Med.
  13:14-27,  1959.

Daly, C.  Air pollution and bronchitis.  Br. Med. J.  2:687-688, 1954.

Davies, C.  N.  The deposition of aerosol in the human lung.  In: Aerosole
  in Physik,  Medizin and Technik.   V.  Bohlau (ed.).   Bad Soden, West
  Germany,  Gesellschaft fur Aerosolforschung.   1973.  p. 90-99.

Davies, C.  N.  Deposition and retention of dust in the human respiratory
  tract.  Ann.  Occup. Hyg.  7:169-183,  1964.

Davies, C.  N.,  J. Heyder, and M. C. Subba Ramu.  Breathing of half-micron
  aerosols.   I.  Experimental.  J.  Appl. Physiol. 32:591-600, 1972.
                              279
-------
Dean, G.   Lung cancer and bronchitis in northern Ireland, 1960-2.  Br.
  Med.  J.  1:1506-1514, 1966.

Deane,  M., J.  R.  Goldsmith, and D. Tuma.  Respiratory conditions in outside
  workers.   Report on outside plant telephone workers in San Francisco
  and Los Angeles.  Arch. Environ. Health 1_0: 323-331, 1965.

Dohan,  F.  C.   Air pollutants and incidence of respiratory disease.  Arch.
  Environ.  Health 3:387-395, 1961.

Dohan,  F.  C.,  and E.  W. Taylor.  Air pollution and respiratory disease.  A
  preliminary report.  Am. J. Med. Sci. 240:337-339, 1960.

Doll, R.  (ed.)  Methods of Geographical Pathology.   Report of the study
  group convened by the Council for International Organizations of
  Medical Sciences established under the joint auspices of UNESCO and
  WHO.   Oxford, Blackwell Scientific Publications, Ltd.  1959.  72 p.

Douglas,  J. W. B. , and R. E. Waller.  Air pollution  and respiratory^infection
  in children.  Br. J. Prev. Soc. Med.  20:1-8, 1966.

Dubrovskaya, F. I.  Hygienic evaluation of pollution of atmospheric air  of
  a large city with sulfur dioxide gas.  In:  Limits of Allowable Concen-
  tration of Atmospheric  Pollutants, Book 3.  Medgiz, Moscow.  1957.  Also  in:
  U.S.S.R. Lit. Air Pollut.  Related Occup. Dis. 1:37-51, 1960.

Ehrlich,  R., and M. C. Henry.  Chronic  toxicity of nitrogen dioxide.  I.
  Effect on resistance to bacterial pneumonia.  Arch. Environ. Health
  17:860-865,  1968.

Emerson,  P. A.  Air pollution, atmospheric conditions and chronic airways
  obstruction.  J. Occup. Med. 1_5: 635-638, 1973.

Fairbairn, A.  S., and D.  D.  Reid.  Air  pollution and other local factors in
  respiratory disease.  Br.  J. Prev. Soc. Med. 12:94-103, 1958.

Fenters,  J. D., J. Bradof, and R. Ehrlich.   Illinois Institute Technology
  Research Institute.  Final Report, IITRI No. 16080-12.  U.S. Environmental
  Protection Agency Coontract No. 68-02-1717.  1977.

Ferris, B. G.   Effects of air pollution on school absences and differences
  in lung function in first  and second  grades in Berlin, New Hampshire,
  January 1966 to June 1967.  Am. Rev.  Respir. Dis.  102:591-606, 1970.

Ferris, B. G., Jr., and D. 0. Anderson.  Epidemiological studies related to
  air pollution:   A comparison of Berlin, New Hampshire, and Chilliwack,
  British Columbia.   Proc. Roy. Soc. Med. 57:979-987, 1964.

Ferris, B. G., Jr., and D. 0. Anderson.  The prevalence of chronic  respira-
  tory disease in a New Hampshire town.  Am. Rev. Respir. Dis. 86:165-177,
  1962.
                              280
-------
Ferris,  B.  G.,  Jr.,  I.  T.  T.  Higgins, M.  W.  Higgins, and J. M. Peters.  Chronic
  nonspecific respiratory disease in Berlin, New Hampshire, 1961 to 1967.
  A follow-up study.   Am.  Rev.  Respir.  Dis.  J07: 110-122, 1973.

Finklea, J.  F. ,  D.  C.  Calafiore, C.  J.  Nelson et al.  Aggravation of asthma
  by air pollutants:   1971 Salt Lake Basin studies.  I_n:  Health
  Consequences  of Sulfur Oxides:  A Report from CHESS, 1970-1971.  U.S.
  Environmental  Protection Agency, Office of Research and Development.
  Washington,  D.C.,  U.S.  Government Printing Office.  1974.  p. 2-75 to
  2-91.   Publication No.  EPA-650/1-74-004.

Finklea, J.  F.,  J.  H.  Farmer, G. J.  Love et al.   Aggravation of asthma by
  air pollutants:   1970-1971  New York studies.   I_n:  Health Consequences
  of Sulfur Oxides:   A Report from CHESS, 1970-1971.  U.S.  Environmental
  Protection Agency,  Office of Research and Development.  Washington,
  D.C.,  U.S.  Government Printing Office.   1974.   p. 5-71 to 5-84.
  Publication No.  EPA-650/1-74-004.

Finklea, J.  F.,  J.  G.  French, G. R.  Lowrimore et al.  Prospective surveys
  of acute respiratory disease in volunteer families:  Chicago nursery
  school study,  1969-1970.  In:   Health Consequences of Sulfur Oxides:
  A Report from CHESS,  1970-1971.   U.S.  Environmental Protection Agency,
  Office of Research and Development.  Washington, D.C., U.S.  Government
  Printing Office.   1974.   p. 4-37 to 4-55.   Publication No. EPA-650/1-74-004.

Finklea, J.  F.,  D.  I.  Hammer, D. E.  House et al.  Frequency of acute lower
  respiratory disease in children:  Retrospective survey of five Rocky
  Mountain communities, 1967-1970.  In:   Health Consequences of Sulfur
  Oxides:   A Report from CHESS,  1970-1971.  U.S. Environmental Protection
  Agency,  Office of Research and Development.  Washington,  D.C., U.S.
  Government Printing Office.  1974.  p.  3-35 to 3-56.  Publication No.
  EPA-650/1-74-004.

Finklea, J.  F.,  C.  M.  Shy, G. J. Love et al.  Health consequence of sulfur
  oxides:   Summary and conclusions based upon CHESS studies of 1970-1971.
  Jji:   Health Consequences of Sulfur Oxides:  A Report from CHESS, 1970-
  1971.   U.S.  Environmental Protection Agency,  Office of Research and
  Development.   Washington, D.C.,  U.S.  Government Printing Office.  1974.
  p.  7-3 to 7-24.   Publication No. EPA-650/1-74-004.

Fletcher,  C.  M., C.  M.  Tinker,  I.  D. Hill, and F.  E. Speizer.   A five-year
  prospective field study of early obstructive airway disease.  In:
  Current Research in Chronic Respiratory Disease, Proceedings of the
  Eleventh Aspen Conference,  U.S.  Department of Health, Education, and
  Welfare, Public Health Service.   Washington,  D.C., U.S.  Government
  Printing Office.   1968.   p. 249-251.

Frank, R.   The  effects of inhaled pollutants on nasal and pulmonary
  flow-resistance.   Ann.  Otol.  Rhinol.  Laryngol. 79:540-546, 1970.

Frank, N.  R. , M. 0.  Amdur, and J.  L. Whittenberger.  A comparison of the
  acute effects of S02 administered alone or in combination with NaCl
  particles on  the respiratory mechanics of healthy adults.  Int. J.
  Air Water Pollut.  8:125-133,  1964.
                              281
-------
Frank, N.  R.,  M.  0.  Amdur, J.  Worcester, and J.  L. Whittenberger.  Effects
  of acute controlled exposure to S02 on respiratory mechanics in healthy
  male adults.   J.  Appl.  Physiol. V7:252-258, 1962.

Frank, N.  R.,  R.  E.  Yoder, J.  D.  Brain, and E.  Yokoyama.  S02 (35S labeled)
  absorption by the nose and mouth under conditions of varying concentra-
  tion and flow.   Arch.  Environ.  Health ]8:315-322, 1969.

French, J. G.,  G.  Lowrimore, W.  C. Nelson et al.   The effect of  sulfur
  dioxide and suspended sulfates on acute respiratory disease.   Arch.
  Environ. Health 27:129-133,  1973.

Gardner, D.  E. , D.  L. Coffin,  M.  A. Pinigin, and G. I. Sidorenko.  The role
  of time as a factor in toxicity of chemical compounds  in intermittent
  and continuous exposure.  Parts I and II.  J.  Tox. Environ. Health
  3:811-820, 821-828, 1977.

Gilboa, A.,  and A.  Silberberg.  Characterization of epithelial mucus
  and its function in clearance by ciliary propulsion.   In:  Air
  Pollution and the Lung.   E.  F.  Aharonson, A.  Ben-David, and M. A.
  Klingberg (eds.).   New York, John Wiley & Sons,  Inc.   1976.  p. 49-63.

Glasser, M. , and L.  Greenburg.  Air pollution, mortality, and weather.
  New York City, 1960-1964.  Arch. Environ. Health 22:334-343, 1971.

Glasser, M., L. Greenburg, and F. Field.  Mortality and  morbidity during
  a period of high levels of air pollution.  New York, Nov. 23 to 25, 1966.
  Arch. Environ.  Health 1J5:684-694, 1967.

Goco, R. V., M. B.  Kress, and 0.  C. Brantigan.  Comparison of mucus  glands
  in the tracheobronchial tree of man and animals.  Ann. N.Y. Acad.  Sci.
  106:555-571, 1963.

Goldberg, H. E., A.  A. Cohen,  J.  F. Finklea et al.  Frequency and severity
  of cardiopulmonary symptoms in adult panels:  1970-1971 New York studies.
  _In:  Health Consequences of Sulfur Oxides:  A Report from CHESS,
  1970-1971.  U.S.  Environmental Protection Agency, Office of Research
  and Development.   Washington, D.C., U.S. Government Printing
  Office.   1974.   p. 5-85 to 5-108.  Publication No. EPA-650/1-74-004.

Goldberg, H. E., J.  F. Finklea, C. J. Nelson et al.  Prevalence  of chronic
  respiratory disease symptoms in adults:  1970 survey of New York com-
  munities.   Jji:   Health Consequences of Sulfur Oxides:  A Report from
  CHESS, 1970-1971.   U.S. Environmental Protection Agency, Office of
  Research and Development.  Washington, D.C., U.S. Government Printing
  Office.   1974.   p. 5-33 to 5-47.  Publication No. EPA-650/1-74-004.

Gore, A. T., and C.  W. Shaddick.   Atmospheric pollution  and mortality in  the
  County of London.   Br. J. Prev. Soc. Med. 12:104-113,  1958.

Gorham, E.  Pneumonia and atmospheric sulphate deposit.  Lancet  2:287-288,
  1959.
                              282
-------
Green, G.  M.  Integrated defense mechanisms in models of chronic pulmonary
  disease.  Arch. Intern. Med. J26:500-503, 1970.

Greenburg, L.,  C. Erhardt, F. Field et al.  Intermittent air pollution
  episode in New York City,  1962.  Public Health Rep. 78:1061-1064,  1963.

Greenburg, L.,  F. Field, C.  L. Erhardt et al.   Air pollution, influenza,
  and mortality in New York  City, January-February 1963.  Arch.  Environ.
  Health ]5:430-438, 1967.

Greenburg, L.,  F. Field, J.  I. Reed, and C. L. Erhardt.  Air pollution and
  morbidity in New York City.  J. Am. Med. Assoc. 182:161-164, 1962.

Greenburg, L.,  M. B. Jacobs, B.  M. Drolette et al.  Report of an air
  pollution incident in New  York City, November  1953.  Public Health
  Rep. 77:7-16, 1962.

Gunnison,  A. F., and A. W. Benton.  Sulfur dioxide:  Sulfite, interaction
  with mammalian serum and plasma.  Arch. Environ. Health 22:381-388.
  1971.

Gunnison,  A. F., and E. D. Palmes.  S-sulfonates in human plasma following
  exposure to sulfur dioxide.  In:  Effects of Sulfur Dioxide on Human
  Subjects Exhibiting Peripheral Airway Impairment.  F. W. Weir and  P. A.
  Bromberg (eds.).   Columbus, Ohio, The Ohio State University Research Founda-
  tion.  1973.

Gunnison,  A. F., E.  D.  Palmes.  S-sulfonate in human plasma following
  inhalation of sulfur dioxide.   Am. Ind. Hyg. Assoc. J. 35:288, 1974.

Hackney, J.  D., W.  S. Linn et al.  Experimental  studies on human health
  effects  of air pollutants.  II. Four-hour exposure to ozone alone  and
  in combination with other  pollutant gases.   Arch. Environ. Health
  30:378-384,  1975.

Hackney, J.  D., W.  S. Linn et al.  Experimental  studies on human health
  effects  of air pollutants.  III. Two-hour exposure to ozone alone  and
  in combination with other  pollutant gases.   Arch. Environ. Health
  30:385-390,  1975.

Hackney, J.  D., W.  S. Linn et al. Health effects of ozone exposure in
  Canadians versus Southern  Californians.  Am. Rev. Respir. Dis. 111(6):
  902, 1975.

Hatch, T.  F,,  and P. Gross.  Pulmonary Deposition and Retention of
  Inhaled  Aerosols.   New York, Academic Press.   1964.  192 p.

Hayes, C.  G.,  D.  I.  Hammer,  C. M. Shy et al.   Prevalence of chronic
  respiratory disease symptoms in adults:  1970  survey of five Rocky
  Mountain communities.  In:  Health Consequences of Sulfur Oxides:
  A Report from CHESS,  1970-1971. U.S. Environmental Protection Agency,
  Office of Research and Development.  Washington, D.C., U.S. Government
  Printing Office.   1974.  p. 3-19 to 3-33.  Publication No. EPA-650/1-74-004.
                              283
-------
Hazel ton Laboratories Report, 1969.
  In:  Toxicology.  L. J. Casarett and J.
  Macmillan.  1975.   p.  538.
From:   M.  0.  Amdur, Air pollution.
     Doull (eds.).   New York,
Hazucha, B.,  and D.  V. Bates.  Combined effect of ozone and sulphur
  dioxide on human pulmonary function.  Nature 257(5521):50-51, 1975.

Hazucha, B.,  F. Silverman et al.   Pulmonary function in man after
  short-term exposure to ozone.  Arch. Environ. Health 27:183-188,
  1973.
Hewitt, D.  Mortality in the London boroughs, 1950-52, with special
  reference to respiratory disease.  Br. J. Prev. Soc. Med. 10:45-57,
  1956.

Heyder, J., L. Armbruster, J. Gebhart, and W. Stahlhofen.  Deposition
  of aerosol particles in the human respiratory tract.   In:  Aerosole
  in Physik, Medizin und Technik.  V. Bohlau (ed.).  Bad Soden, West
  Germany, Gesellschaft fur Aerosolforschung.  1973.  p. 122-125.

Heyder, J., J. Gebhart, G. Heigwer et al.   Experimental  studies of
  the total deposition of aerosol particles in the human respiratory
  tract.  Aerosol Sci. 4:191-208, 1973.

Higgins,  I. T. T. (ed.).  Airborne Particles.  Washington, D.C., Airborne
  Particles Subcommittee, National Academy of Sciences,  National Research
  Council.  1977.  p. 278.

Higgins,  I. T. T.  Epidemiological evidence on the carcinogenic risk of
  air pollution.  In:  Environmental Pollution and Carcinogenic Risks.
  C. Rosenfeld and W. Davis (eds.).  Paris, INSERM (Institut National
  de la Sante et de la Recherche Medicale).  1976.  p. 41-52.  INSERM
  Symposium Series Vol. 52.  IARC Scientific Publications  13.

Higgins,  I. T. T.  Sulfur oxides and particulates.  In:  Medical Aspects
  of Air  Pollution.  New York, Society of Automotive Engineers, Inc.
  1971.   p. 20-33.

Hinton, D. 0., T. D. English, B. F. Parr et al.    Human exposure to  air
  pollutants  in the Chicago-Northwest Indiana metropolitan region,
  1950-1971.  In:  Health Consequences of Sulfur  Oxides:   A Report
  from CHESS, 1970-1971.  U.S. Environmental Protection  Agency, Office
  of Research and Development.  Washington, D.C., U.S. Government
  Printing Office.  1974.  p. 4-3 to 4-21.  Publication  No. EPA-650/1-74-004.

Hitosugi, M.  Epidemiological study of lung cancer with  special reference
  to the  effect of air pollution and smoking habits.   Inst. Pub. Health
  Bull. V7:237-256, 1968.
Hodgson, T. A., Jr.  Short-term effects of
  in New York  City.  Environ. Sci. Techno!
      air pollution on mortality
       4:589-597, 1970.
                              284
-------
Holland, W.  W. ,  T.  Halil, A. E. Bennett, and A. Elliott.  Factors  influencing
  the onset of chronic respiratory disease.  Br. Med. J. 2:205-208,  1969.

Holland, W.  W. ,  and D. D. Reid.  The urban factor in chronic bronchitis.
  Lancet ]_:445-448, 1965.

Holland, W.  W.,  D.  D.  Reid, R.  Seltser, and R.  W.  Stone.  Respiratory
  disease in England and the United States.  Studies of comparative
  prevalence.   Arch.  Environ.  Health U):338-343, 1965.

Horsfield, K. ,  G.  Dart, D.  E.  Olson et al.   Models of the human bronchial
  tree.   J.  Appl.  Physiol.  31:207-217, 1971.

Horvath, S.  M.,  and L. J. Folinsbee.   Interaction of Two Air Pollutants,
  Sulfur Dioxide and Ozone, on Lung Function.   Sponsored by the California
  Air Resources  Board, Grant ARB 4-1266.   1977.

Hounam,  R. F.,  A.  Black, and M. Walsh.  Deposition of aerosol particles
  in the nasopharyngeal region of the human respiratory tract.  Nature
  221:1254-1255, 1969.

House, D.  E.,  J. F. Finklea, C. M. Shy et al.   Prevalence of chronic
  respiratory disease symptoms in adults:  1970 survey of Salt Lake
  Basin  communities.   In:  Health Consequences of Sulfur Oxides:    A
  Report from CHESS,  1970-1971.  U.S.  Environmental Protection Agency,
  Office of Research and Development.   Washington, D.C., U.S. Government
  Printing Office.   1974.  p.  2-41 to 2-54.  Publication No. EPA-650/1-74-004.

Ipsen, J., M.  Deane,  and F. E.  Ingenito.  Relationships of acute respira-
  tory disease to atmospheric pollution and meteorological conditions.
  Arch.  Environ. Health 18:462-472, 1969.

Iravani, J.   Clearance function of the respiratory ciliated epithelium
  in normal  and  bronchitic rats.   In:   Inhaled Particles III, Vol.  I.
  Proceedings  of an International Symposium organized by the British
  Occupational  Hygiene Society in London, September 1970.  W. H.  Walton
  (ed.).  Old Woking,  Surrey,  England, Unwin Brothers Limited.  1971.
  p. 143-146.

Kagawa,  J.,  T.  Toyama, and M.  Nakaza.   Pulmonary function test in  children
  exposed to air pollution.  In:   Clinical  Implications of Air Pollution
  Research.   Finkel and Duel (eds.).   Acton,  Mass., Publishing Science
  Group.  1976.   p. 305-320.

Kilburn, K.  H.   A hypothesis for pulmonary clearance and its implications.
  Am. Rev. Respir.  Dis. 98:449-463, 1968.

LaBelle, C.  W.,  and H. Brieger.  Synergistic effects of aerosols.  II.
  Effects on rate of clearance from lung.  AMA Arch. Ind. Health 20:100-105,
  1959.

LaBelle, C.  W.,  J.  E.  Long, and E. E.  Cristofano.   Synergistic effects of
  aerosols.   Particulates as carriers of toxic vapors.  Arch. Ind.  Health
  JJ:297-304,  1955.


                              285
-------
Lambert, P.  M.,  and D.  D.  Reid.   Smoking, air pollution, and bronchitis  in
  Britain.   Lancet 1:853-857, 1970.

Landahl, H.  D.   On the removal of air-borne droplets by the human respira-
  tory tract:   I.  The lung.   Bull.  Math. Biophys. 12:43-56, 1950.

Landahl, H.  D.   Particle removal by the respiratory system.  Note on the
  removal of airborne particulates by the human respiratory tract with
  particular reference to the role of diffusion.  Bull. Math.  Biophys.
  25:29-39,  1963.

Landahl, H.  D.,  T. N. Tracewell, and W. H. Lassen.  On the retention of
  air-borne particulates in the human lung:   II. AMA Arch. Ind. Hyg.
  Occup. Med.  3:359-366, 1951.

Landahl, H.  D.,  T. N. Tracewell, and W. H. Lassen.  Retention of air-borne
  particulates in the human lung:  III. AMA Arch. Ind. Hyg. Occup. Med.
  6:508-511, 1952.

Larson, T.  V., D.  S.  Covert, R.  Frank, and R. J. Charlson.  Ammonia in the
  human airways:   Neutralization of inspired acid sulfate aerosols.
  Science 197:161-163, 1977.

Lave, L. B., and E. P.  Seskin.  Air pollution, climate, and home heating:
  Their effects  on U.S. mortality rates.  Am. J. Public Health
  62:909-916,  1972.

Lave, L. B., and E. P.  Seskin.  Air pollution and human health.  The
  quantitative effect, with an estimate of the dollar benefit of
  pollution abatement, is considered.  Science 169:723-733, 1970.

Lawther, P.  J.  Effects of inhalation of sulphur dioxide on respiration
  and pulse-rate in normal subjects.  Lancet 2:745-748, 1955.

Lawther, P.  J.,  A. G. F. Brooks, P. W. Lord, and R. E. Waller.  Day-to-day
  changes in ventilatory function in relation to the environment.   Part
  I. Spirometric values.  Environ. Res. 7:27-40, 1974.

Lawther, P.  J. ,  A. G. F. Brooks, P. W. Lord, and R. E. Waller.  Day-to-day
  changes in ventilatory function in relation to the environment.   Part
  II.  Peak expiratory flow values.  Environ. Res. 7:41-53, 1974.

Lawther, P.  J.,  A. G. F. Brooks, P. W. Lord, and R. E. Waller.  Day-to-day
  changes in ventilatory function in relation to the environment.   Part
  III.  Frequent measurements of peak flow.  Environ.  Res. 8:119-130,  1974.

Lawther, P.  J.,  A. J. MacFarlane et al.  Pulmonary function and sulphur
  dioxide,  some preliminary findings.  Environ.  Res. l_0:355-367,  1975.

Lawther, P.  J.,  R. E. Waller, and M. Henderson.  Air pollution and  exacer-
  bations of bronchitis.  Thorax 25:525-539, 1970.

Lawther, P.  J.,  R. E. Waller, and A. E. Martin.  Clean  air and health  in
  London.   I_n:  National Society for Clean Air,  Clean  Air  Conference,
  Eastbourne, October  1969.   Part  1, Pre-prints  of Papers.  London,
  Spottiswoode,  Ballantyne and  Co. Ltd.   1969.   p. 71-78.

                              286
-------
Lee, R.  E.,  Jr., and F.  V.  Duffield.  EPA's catalyst research program:
  Environmental impact of sulfuric acid emissions.  Air Pollut. Control
  Assoc.  J.  27:631-635,  1977.

Lewis, T.  R.,  W. J.  Moorman, Y. Yang, and J. F. Stara.  Long-term exposure
  to acute exhaust and other pollutant mixtures.  Arch. Environ. Health
  29:102-106,  1974.

Lippmann,  M.   Regional deposition of particles in the human respiratory
  tract.   In:   Handbook of Physiology, Section 9: Reactions to Environmental
  Agents.   D.  H. K.  Lee, H.  L.  Falk. and S. D. Murphy (eds.).  Bethesda, Md.,
  The American Physiological Society.  1977.  p. 213-232.

Lippmann,  M. ,  and R. E.  Albert.  The effect of particle size on the regional
  deposition of inhaled aerosols in the human respiratory tract.  Am.  Ind.
  Hyg. Assoc.  J. 30:257-275, 1969.

Lippman,  M.,  R. E.  Albert,  and H.  T. Peterson, Jr.  The regional deposition
  of inhaled aerosols in man.   In:  Inhaled Particles III, Vol. I.  W.  H.
  Walton (ed.).  Old Woking, Surrey, Unwin Brothers, Ltd.  1971.  p.  105-120.

Logan, W.  P.  D.  Mortality in the London fog incident.  Lancet J:336-338, 1953.

Lourenco,  R.  V., M.  F. Klimek,  and C. J.  Borowski.  Deposition and clearance of
  2 (j particles in the tracheobronchial tree of normal subjects--smokers and
  nonsmokers.   J.  Clin.  Invest. 50:1411-1419, 1971.

Lourenco,  R.  V., R.  Loddenkemper,  and R.  W. Carton.   Patterns of distribution
  and clearance of aerosols  in patients with bronchiectasis.   Am. Rev.
  Respir.  Dis.  K)6:857-866,  1972.

Love, G.  J.,  A. A.  Cohen, J. F. Finklea et al.  Prospective surveys of acute
  respiratory disease in volunteer families:  1970-1971 New York studies.
  I_n:  Health Consequences  of Sulfur Oxides:  A Report from CHESS, 1970-1971.
  U.S. Environmental Protection Agency, Office of Research and Development.
  Washington,  D.C.,  U.S. Government Printing Office.  1974.  p. 5-49  to
  5-69.   Publication No. EPA-650/1-74-004.

Love, R.  G.,  and D.  C. F. Muir.  Aerosol  deposition and airway obstruction.
  Am. Rev.  Respir.  Dis.  m: 891-897, 1976.

Lovejoy,  F.  W., Jr., H.  Constantine, J. Flatley et al.  Measurement of
  gas trapped in the lungs  during acute changes in airway resistance  in
  normal  subjects and in patients with chronic pulmonary disease.  Am.
  J. Med.  _30: 884-892, 1961.

Lowe, C.  R. ,  H, Campbell, and T. Khosla.   Bronchitis in two integrated steel
  works.   III.  Respiratory symptoms and ventilatory capacity related  to
  atmospheric pollution.  Br.  J. Ind. Med.  27:121-129, 1970.

Lowe, C.  R.,  P. L.  Pelmear,  H.  Campbell et al.  Bronchitis in two integrated
  steel  works.   I.  Ventilatory capacity,  age, and physique of non-bronchitic
  men.  Br.  J.  Prev. Soc. Med.  22:1-11, 1968.
                              287
-------
Luchsinger, P.  C.,  B.  LaGarde, and J. E. Kilfeather.  Particle clearance from
  the human tracheobronchial tree.  Am.  Rev. Respir. Dis. 97:1046-1050, 1968.

Lunn, J.  E.,  J.  Knowelden, and A.  J.  Handyside.  Patterns of respiratory
  illness in Sheffield infant school  children.   Br. J.  Prev. Soc. Med.
  21:7-16, 1967.

Lunn, J.  E.,  J.  Knowelden, and J.  W.  Roe.   Patterns of respiratory illness
  in Sheffield junior school children.  A follow-up study.  Br. J. Prev.
  Soc.  Med. 24:223-228, 1970.

McCarroll, J.,  and W.  Bradley.  Excess mortality as an indicator of health
  effects of air pollution.  Am.  J. Public Health 56:1933-1942, 1966.

McCarroll, J.,  E.  J. Cassell, D.  W. Wolter et al.   Health and urban environ-
  ment.  V. Air pollution and illness in a normal  urban population.  Arch.
  Environ. Health 14:178-184, 1967.

McCarthy, D.  S., R.  Spencer, R. Greene, and J.  Milic-Emili.  Measurement of
  "closing volume" as a simple and sensitive test for early detection of
  small airway disease.  Am. J. Med.  52:747-753, 1972.

McJilton, C. , R. Frank, and  R. Charlson.  Role of relative humidity in the
  synergistic effect of a sulfur dioxide-aerosol mixture  on the lung.
  Science ]82:503-504, 1973.

McLaughlin, R.  F., Jr., W. S. Tyler,  and R. 0.  Canada.   Subgross pulmonary
  anatomy of the rabbit, rat, and guinea pig, with additional notes on the
  human lung.   Am.  Rev. Respir. Dis.  94:380-387, 1966.

Manos, N. E.   Comparative Mortality Among Metropolitan Areas of the United
  States, 1949-1951, 102 Causes of Death.   Ratios of Observed to Expected
  Mortality for 163 Metropolitan Areas, Mortality Rates and Ratios by
  Degree of Urbanization for the Total United States, and Other Background
  Information Necessary to the Interpretation of These Rates and Ratios.
  Washington, D.C., U.S. Government  Printing Office.  1957.  143 p.   Public
  Health Service Publication No.  562.

Martin, A. E.   Mortality and morbidity statistics and air pollution.  Proc.
  Roy. Soc. Med. 57:969-975, 1964.

Martin, A. E., and W. H. Bradley.   Mortality, fog, and atmospheric pollution.
  An investigation during the winter of 1958-59.  Monthly Bull. Min.  Health
  Pub. Health Lab.  Serv. 19:56-73, 1960.

Matthews, L.  W., S. Spector, J. Lemm, and J. L. Potter.   Studies on pulmonary
  secretions.   I. The over-all chemical composition of pulmonary secretions
  from patients with cystic  fibrosis, bronchiectasis, and laryngectomy.
  Am. Rev. Respir.  Dis. 88:199-204,  1963.

Mead, J.   The lung's "quiet  zone."   N. Engl. J. Med. 282:1318-1319,  1970.

Melville, G.  N.  Changes  in  specific airway conductance  in  healthy volunteers
  following nasal and oral  inhalation of S02.  West Ind.  Med. J. 19:231-35,
  1970.

                              288
-------
Mercer, T. T.  Aerosol Technology in Hazard Evaluation.  New York, Academic
  Press.  1973.  394 p.

Mercer, T. T.  On the role of particle size in the dissolution of  lung burdens.
  Health Phys. U: 1211-1221, 1967.

Mercer, T. T., P. E. Morrow, and W.  Stober (eds.).  Assessment of  Airborne
  Particles.   Fundamentals, Applications, and Implications to Inhalation
  Toxicity,   Springfield, 111., Charles C. Thomas.  1972.  540 p.

Milburn, R.  H., W.  L. Crider, and S. D. Morton.   The retention of  hygroscopic
  dusts in the human lungs.  AMA Arch.  Ind.  Health T5_: 59-62, 1957.

Ministry of Health (Great Britain).   Mortality and Morbidity During the
  London Fog of December 1952.   London, Her Majesty's Stationery Office,
  1954.  61  p.  Report by a Committee of Departmental Officers and Expert
  Advisers appointed by the Minister of Health.

Mork, T.  A comparative study of respiratory disease in England and Wales
  and Norway.  Acta Med.  Scand. V72(Suppl. 384):1-100, 1962.

Morrow, P. E., F. R. Gibb, and K.  Gazioglu.   The clearance of dust from the
  lower respiratory tract of man.   An experimental study.  In:  Inhaled
  Particles and Vapours II.  C. N. Davies (ed.).  Oxford, Pergamon Press.
  1967.  p.  351-358.

Morrow, P. E., F. R. Gibb, and K.  M. Gazioglu.  A study of particulate clearance
  from the human lungs.  Am.  Rev.  Respir. Dis. 96:1209-1221, 1967.

Muir, D. C.  F., and C.  N. Davies.   The deposition of 0.5 p diameter aerosols
  in the lungs of man.   Ann.  Occup.  Hyg. TO: 161-174, 1967.

Nadel, J.  A.   Mechanism of bronchoconstriction during inhalation of sulfur
  dioxide.  J. Appl. Physiol. 20:164-167, 1965.

Nadel, J.  A., H.  Salem, B. Tamp!in,  and Y. Yokiwa.  Mechanism of broncho-
  constriction during inhalation of sulfur dioxide.  J. Appl. Physiol.
  20:164-167, 1965.

Nadel, J.  A., D.  F.  Tierney et al.  Pulmonary responses to aerosols.  In:
  Proceedings of the 3rd Annual Air Pollution Medical Research Conference.
  Los Angeles, California State Department of Public Health.  1959.  p. 66-74.

Nadel, J.  A., and J. G. Widdicombe.   Reflex effects of upper airway irritation
  on total lung resistance and blood pressure.  J. Appl.  Physiol.  17:861-
  865, 1962.

Nakamura,  K.   Response of pulmonary airway resistance by interaction of
  aerosols and gases of different physical and chemical nature.  Jpn. J. Hyg.
  |9:322-333, 1964.   (In Japanese.)  (Translated by EPA; available from
  the Air Pollution Technical Center, Research Triangle Park, N.C., as
  APTIC No.  11425.)
                              289
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Natusch, D.  F.  S.,  and J. R.  Wallace.  Urban aerosol toxicity:  The influence
  of particle size.   Science 18j6:695-699, 1974.

Nelson, W.  C.,  J.  F.  Finklea, D.  E.  House et al.   Frequency of acute lower
  respiratory disease in children:   Retrospective survey of Salt Lake Basin
  communities,  1967-1970.  .In:   Health Consequences of Sulfur Oxides:  A
  Report from CHESS,  1970-1971.  U.S. Environmental Protection Agency, Office
  of Research and Development.   Washington, D.C., U.S. Government Printing
  Office.  1974.   p.  2-55 to 2-73.   Publication No. EPA-650/1-74-004.

Newhouse, M.  T.,  M.  Dolovich, G.  Obminski, and R. K. Wolff.  Effect of TLV
  levels of S02 and H2S04 on bronchial clearance in exercising man.  Arch.
  Environ.  Health 33:24-32, 1978.

Palmes, E.  D.,  and M. Lippmann.  Influence of respiratory air space dimensions
  on aerosol  deposition.  In:  Inhaled Particles IV.  W. H. Walton (ed.).
  London, Pergamon Press Ltd.  1977.  p. 127-136.

Pattle, R.  E.  The retention of gases and particles in the human nose.  In:
  Inhaled Particles and Vapours.   C. N. Davies. (ed.).  Oxford, Pergamon
  Press.  1961.   p.  302-309.

Pedley, T.  J.,  R.  C.  Schroter,  and M. F. Sudlow.   Flow and pressure drop  in
  systems of repeatedly branching tubes.  J. Fluid Mech. 46:365-383, 1971.

Petrilli, F.  L.,  G.  Agnese, and S.  Kanitz.  Epidemiologic studies of air
  pollution effects in Genoa, Italy.  Arch. Environ. Health 1_2:733-740,
  1966.

Prindle, R.  A., G.  W. Wright, R.  0.  McCaldin et al.  Comparison of pulmonary
  function and other parameters in two communities with widely different
  air pollution levels.  Am.  J. Public Health 53:200-217, 1963.-

Rall, 0. P.   Review of the health effects of sulfur oxides.  Environ.
  Health Perspect.  8:97-121, 1974.

Reid, D. D.   Air pollution as a cause of chronic bronchitis.  Proc. Roy.
  Soc. Med.  57:965-968, 1964.

Rundolf, G., and J.  Heyder.  Deposition of aerosol particles  in the
  human nose.  In:   Aerosole in Naturwissenschaft, Medizin und Technik.
  V. Bohlau (ed.).   Bad Soden,  West Germany, Gesellschaft fur Aerosol-
  forschung.   1974.

Salamberidze, 0.  P.   The joint action of small concentrations of sulfur
  dioxide and nitrogen dioxide gases under condition of a chronic test.
  Gig. Sanit. 4:10-14, 1969.

Salem, H., and H.  Cullumbine.  Kerosene smoke and atmospheric pollutants.
  Arch. Environ.  Health 2:641-647,  1961.

Schlesinger, R.  B., and M. Lippmann.  Particle deposition  in  casts of
  the human upper tracheobronchial  tree.   Am.  Ind. Hyg. Assoc. J.
  33:237-251, 1972.


                               290
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Schimmel,  H.,  and L.  Greenburg.  A study of the relation of pollution to
  mortality.   New York City, 1963-1968.  J. Air Pollut, Control Assoc.
  22:607-616,  1972.

Schimmel,  H. ,  and T.  J.  Murawski.  S02--harmful pollutant or air quality
  indicator?   J.  Air Pollut. Control Assoc. 25:739-740, 1975.

Schrenk, H.  H.,  H.  Heimann, G.  D. Clayton et al.  Air Pollution in Donora,
  Pennsylvania.   Epidemiology of the Unusual Smog Episode of October  1948.
  Washington,  D.C. ,  U.S.  Government Printing Office.  1949.  173 p.   Pre-
  liminary Report.   Public Health Bulletin No.  306.

Scott, J.  A.   The London fog of December, 1962.  Med. Off. 109:250-252,
  1963.

Scott, J.  A.   Fog and deaths in London, December 1952.  Public Health Rep.
  68:474-479,  1953.

Scott, J.  A.,  I.  Taylor,  A. T.  Gore, and C. W.  Shaddick.  Mortality in London
  in the winter of 1962-63.  Med. Off.  KM:327-330,  1964.

Shy, C.  M.,  J.  P. Creason, M. E.  Pearlman, K.  E. McClain,  and F.  B. Benson.
  The Chattanooga school  children study.   Parts I and II.   J. Air Pollut.
  Control  Assoc.  20:539-545, 582-588, 1970.

Shy, C.  M.,  V.  Hasselblad, R. M.  Burton et al.   Air pollution effects on
  ventilatory function of U.S.  schoolchildren.   Results of studies in
  Cincinnati,  Chattanooga, and New York.   Arch. Environ. Health 27:124-128,
  1973.

Shy, C.  M.,  V.  Hasselblad, J. F.  Finklea et al. Ventilatory function
  in school  children:   1970-1971  New York studies.   In:  Health Con-
  sequences  of Sulfur Oxides:  A Report from CHESS,  1970-1971.   U.S.
  Environmental  Protection Agency, Office of Research and Development.
  Washington,  D.C.,  U.S.  Government Printing Office.  1974. p.  5-109
  to 5-119.   Publication No. EPA-650/1-74-004.

Shy, C.  M.,  C.  J. Nelson, F. B. Benson et al.   Ventilatory function in school
  children:   1967-1968 testing in Cincinnati neighborhoods,  jn:   Health
  Consequences of Sulfur Oxides:   A Report from CHESS,  1970-1971.   U.S.
  Environmental  Protection Agency, Office of Research and Development.
  Washington,  D.C.,  U.S.  Government Printing Office.  1974.  p. 6-3 to
  6-14.   Publication No.  EPA-650/1-74-004.

Sim, V.  M.,  and R.  E.  Pattle.  Effect of possible smog  irritants on human
  subjects.   J.  Am.  Med.  Assoc. 165:1908-1913,  1957.

Snashall,  P.  D ,  and C.  Lewin.   Mechanisms of sulfur dioxide induced
  bronchoconstriction in man.  Am. Rev. Respir. Dis., Vol. 113, April 1976.

Snell, R.  E. ,  and P.  C.  Luchsinger.  Effects of sulfur  dioxide on expiratory
  flow rates  and total respiratory resistance in normal human subjects.
  Arch.  Environ.  Health 18:693-698, 1969.
                              291
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Speizer, F.  E.   An epidemiologies! appraisal of the effects of ambient air on
  health:   Participates and oxides of sulfur.  J.  Air Pollut. Control Assoc.
  J9:647-655, 1969.

Speizer, F.  E.,  and B.  J.  Ferris, Jr.  Exposure to automobile exhaust.  I. Prev-
  alence of respiratory symptoms and disease.  Arch. Environ. Health
  26:313-318, 1973.

Speizer, F.  E.,  and N.  R.  Frank.  A comparison of changes in pulmonary flow
  resistance in healthy volunteers acutely exposed to S02 by mouth and by nose.
  Br. J. Ind. Med. 23:75-79, 1966.

Speizer, F., and N.  R.  Frank.  The uptake and release of S02 by the human nose.
  Arch.  Environ. Health ]2:725-728, 1966.

Spicer,  W.  S.,  Jr., P.  B.  Storey, W. K. C. Morgan et al.   Variation in respiratory
  function in selected patients and its relation to air pollution.  Am. Rev.
  Respir.  Dis.  86:705-712, 1962.

Sterling,  T. D.  , J.  J.  Phair, S. V. Pollack et al.  Urban morbidity and air
  pollution.  A first report.  Arch. Environ. Health V3:158-170,  1966.

Stocks,  P.   Cancer and bronchitis mortality in relation to atmospheric deposit
  and smoke.  Br. Med.  J.  1:74-79, 1959.

Stocks,  P.   Lung cancer and bronchitis in relation to cigarette smoking and
  fuel consumption in 20 countries.  Br. J. Prev.  Soc. Med. 2J:181-185, 1967.

Tomono,  Y.   Effects of S02 on human pulmonary functions.   Jpn. J. Ind. Health
  3:77-85,  1961.

Toyama,  T.   Air pollution and its health effects in Japan.  Arch. Environ.
  Health 8:153-173, 1964.

Toyama,  T.   Studies on aerosols:  1. Synergistic response of the  pulmonary
  airway resistance on inhaling sodium chloride aerosols and S02  in man.
  Jpn. J.  Ind.  Med.  4:86-92, 1962.

Toyama,  T., and K. Nakamura.  Synergistic response of hydrogen peroxide aerosols
  and sulfur dioxide to pulmonary airway resistance.  Ind. Health 2:35-45,
  1964.

U.S. Department of Health, Education and Welfare.   Air Quality Criteria for
  Sulfur Oxides.  Washington, D.C., U.S. Government Printing Office.  1970.
  178 p.  National Air Pollution Control Administration Publication No. AP-50.

U.S. Department of Health, Education, and Welfare.  Air Quality Criteria  for
  Particulate Matter.  Washington, D.C., U.S. Government Printing Office.  1969.
  211 p.  National Air Pollution Control Administration Publication No. AP-49.

U.S. Environmental Protection Agency.  Scientific and Technical Data  Base for
  Criteria and Hazardous Pollutions 1975 ERC/RTP Review.   Research Triangle
  Park,  N.C., Health Effects Research Laboratory.    1976.   p. 192-194, 206-207.
  Publication No. EPA-600/1-76-023.


                              292
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U.S. Environmental Protection Agency, Office of Air and Waste Management,
  Office of Air Quality Planning and Standards.  Position Paper on Regulation
  of Atmospheric Sulfates.  Research Triangle Park, N.C., U.S. Environmental
  Protection Agency,   1975.  Publication No. EPA-450/2-75-007.

von Nieding, G., M. Wagner, H.  Loellgen, and H. Krekeler.   Zur akuten Wirkung
  von Ozone auf die Lungenfunktion des Menschen.  Verein Deutschen Ingenieure--
  Berichte Nr 270:123-129, 1977.

Wahdan, M. H.   Atmospheric pollution and other environmental factors in
  respiratory disease in children.  Ph.D. Thesis, University of London, London,
  England.  1963.   240 p.

Warner, C. G., G.  M.  Davies, J.  G. Jones, and C. R. Lowe.   Bronchitis in two
  integrated steel works.   II.  Sulfur dioxide and particulate atmospheric
  pollution in and around two works.  Ann.  Occup. Hyg. ]_2:150-170, 1969.

Watanbe, H.  Air pollution and its health effects in Osaka, Japan.  Presented
  at the 58th Annual  Meeting, Air Pollution Control Association, Toronto,
  Canada, June 20-24, 1965.  (Preprint.)

Weir, F. W. , and P. A. Bromberg.   Effects of sulfur dioxide on human subjects
  exhibiting peripheral airway impairment.   Sponsored by the American Petroleum
  Institute Project No. CAWC S-15.  1973.  p. 1-18.

Weir, F. W., and P. A. Bromberg.   Further investigation of the effects of sulfur
  dioxide on human subjects.  Annual Report of Project No. CAWC S-15 prepared
  for the American Petroleum Institute.   1972.

Winkelstein, W., Jr., and S. Kantor.  Respiratory symptoms and air pollution
  in an urban population of northeastern United States.  Arch. Environ. Health
  18:760-767,  1969.

Winkelstein, W., Jr., S. Kantor,  E.  W. Davis et al.  The relationship of air
  pollution and economic status to total mortality and selected respiratory
  system mortality in men.  I.  Suspended particulates.  Arch. Environ. Health
  14:162-171,  1967.

Winkelstein, W., Jr., S. Kantor,  E.  W. Davis et al.  The relationship of air
  pollution and economic status to total mortality and selected respiratory
  system mortality in men.  II.  Oxides of sulfur.  Arch. Environ.  Health
  ^6:401-405,  1968.

Wolff, R. K. ,  M. Dolovich, G. Obminski,  and M.  T. Newhouse.  Effects of sulfur
  dioxide on tracheobronchial clearance at rest and during exercise.   In:
  Inhaled Particles IV.  W. H.  Walton (ed.).  London, Pergamon Press Ltd.  1977.

Wolff, R. K. ,  M. Dolovich, C. Rossman, and M. T. Newhouse.  Sulfur dioxide and
  tracheobronchial clearance in man.  Arch. Environ. Health 30:521-527, 1975.

Yeates, D. B.   The clearance of soluble and particulate aerosols deposited
  in the human lung.   Ph.D. Thesis, University of Toronto.  Ontario,
  Canada.   1974.
                              293
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Zarkower, A.  Alterations in antibody response induced by chronic inhalation
  of S02 and carbon.  Arch.  Environ. Health ^5:45-50, 1972.

Zeidberg, L. D., R. J. M. Horton, E. Landau et al.  The Nashville air pollution
  study.  V. Mortality from diseases of the respiratory system in relation to
  air pollution.  Arch. Environ. Health J5:214-224, 1967.

Zeidberg, L. D. , R. A. Prindle, and E.  Landau.  The Nashville air pollution study.
  III.  Morbidity in relation to air pollution.  Am. J. Public Health 54:85-97,
  1964.

Zeidberg, L. D. , R. A. Prindle, and E.  Landau.  The Nashville air pollution study.
  I. Sulfur dioxide and bronchial asthma.  A preliminary report.  Am. Rev.
  Respir. Dis.  84:489-503, 1961.
                              294
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A.5  EPIDEMIOLOGY







     As compared with laboratory studies,  the epidemiological  approach to



investigating air pollutant effects involves considering many variables over



long periods of time.   However,  when designed and executed properly,  these



studies provide very useful information.   Moreover,  epidemiological  surveys



are necessary to ascertain the minimal  concentrations of air pollutants that



produce deleterious health effects in human populations.  For example, informa-



tion derived in part through epidemiological investigation formed the basis



for Federal air quality standards.   The current primary standard for  sulfur



dioxide, considered as the maximum limit,  beyond which health effects may



occur, states that concentrations averaged over a given 24-hr period  may not


               3                                                         3
exceed 365 M9/m  ar>d must be held to an annual  arithmetic mean of 80  ug/m .







     To date, epidemiological  studies on ambient sulfur compounds have focused



primarily on stationary sources, which account for about 98 percent of sulfur



emissions.   Nevertheless, certain inferences regarding emissions from mobile



sources may be made from the information these studies have provided.   Table A-12



summarizes data from several studies which have linked pollution with human



mortality and morbidity.   Included are pollution episodes and their effects



on the general population, as  well  as on especially sensitive groups  such as



cardiopulmonary patients, bronchitis patients,  and children with asthma.   While



these studies are of little direct help in determining the health consequences



of mobile source emissions, they do help to establish conditions under which



pollutant concentrations are likely to be  hazardous.
                                 295
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     At present, it is virtually impossible to sort out the roles  of the



various sulfur compounds exerting effects on health.   Acute pollution episodes



are characterized by high levels of sulfur dioxide and particles,  along



with high humidity and weather conditions which prevent dispersion of con-



taminants.   Most studies have not isolated sulfate from other types of suspended



particles.   These unknowns make it difficult to establish emissions/health



relationships in specific terms.







     In assessing a health hazard, a number of factors should be considered,



such as the duration and concentration of exposure, the level of activity, and



preexisting illness or sensitivity (e.g., pregnancy).   For example, it should



be remembered that a mean ambient concentration is often less significant than



the variations around the mean.  Thus, a short-term peak within a 24-hr mean



concentration could have more effect than a low, long-term exposure.  Another



consideration is the level of activity of individuals.  Children in strenuous



play would in effect have more exposure to ambient pollutants than the elderly



in retirement.  In addition, functional and structural dimensions of the



respiratory system also determine dose response.  Thus, preexisting disease



in the airway can affect the distribution and clearance of particles; some



regions could become "hot spots."







     In reviewing the epidemiological literature, it becomes evident that



acute pollution episodes with high sulfur dioxide and total suspended particle



(TSP) levels may lead to fatalities within the exposed population.  The fog



which occurred in the Meuse Valley, Belgium, in 1930 was associated with



60 excess deaths in a small community.  The levels of atmospheric pollutants,



particularly sulfur dioxide, though not measured, were thought to be very high
                                 302
-------
(Firket 1931).   A similar incident occurred in Donora,  Pennsylvania,  in 1948,


causing 20 deaths and acute illness in about 6000 individuals.   In all,


nearly half the population of 13,000 was affected (Schrenk et a "I.  1949).




     These are striking examples of air pollution disasters,  but the  specific


pollutant concentrations occurring during these episodes were not quantitatively


measured.   Other studies of mortality have considered long-term, low-level


exposure as opposed to episodic exposure.  For example, Buechley et al. (1973)


studied mortality patterns and pollution levels over a  4-year period  in the


New York metropolitan region and found that death rates correlated with S0?


concentrations.  Taking into account other variables affecting mortality (such


as extreme weather conditions), they determined that mortality was 1.5 percent


less than average on days when SO^ levels were below 0.03 mg/m  and 20 percent


higher than average on days when S0? levels exceeded 0.5 mg/m .




     In London, a 4-day "killer" fog occurred in December 1952,  during which

                                         3
time smoke levels reached nearly 4.5 mg/m  and sulfur dioxide levels  reached

        3
2.8 mg/m  (48-hr average).   Studies have estimated that 4000  deaths resulted


from this exposure (for example, Logan 1953).   The death rate began to rise


within 24 hr of the beginning of the pollution episode  and fell  abruptly to


near-normal levels when the fog abated.   Most deaths occurred among people


with preexisting disease, including bronchitis (tenfold increase in deaths)


and coronary heart disease (threefold increase).




     Studies of this episode reported an increase of nearly 50 percent in


admissions to hospitals in Greater London, due almost entirely to patients


admitted with respiratory disease (Ministry of Health 1954).   The effects on
                                 303
-------
one doctor's general  family practice in London (Fry 1953) during the week of



the fog and the week following included twice as many cases of upper respiratory



symptoms (sore throat,  cough, nasal  discharge) as usual  and three times as



many cases of lower respiratory disease.   Of the 105 patients with known



chronic respiratory disease, two died and another 35 were affected to some



degree.







     Studies of subsequent fog episodes in London have correlated daily mortality



with daily levels of SO- and particles.  Martin (1964) reviewed studies of



several incidents of polluted fog in London after 1952,  presenting his own



results for the winters of 1958-59 and 1959-60.  He measured the number of



deaths from all causes and the number of applications for emergency medical



service related to cardiovascular and respiratory conditions.  He then matched



these measures of mortality and morbidity each day with the levels of sulfur



dioxide and particles on the same day.   On days of high levels of either



pollutant there were high levels of mortality and morbidity.  The results are



shown in Table A-13.







     The effect of acute episodes of very high pollution is a dramatic



increase in mortality and morbidity, predominantly among the elderly or those



with chronic preexisting disease.  The effect of exposure to more moderate



levels of sulfur dioxide and other sulfur compounds over longer periods of



time has also been examined.  Studies have been of several types:  surveys of



populations with different exposure levels, longitudinal studies of populations



in the same geographic area, and comparisons over time of populations in



different geographic areas.  The variables used to investigate the presumed



effects of sulfur compounds have included measures of respiratory function,
                                 304
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the prevalence of respiratory disease,  and the incidence and course of acute



disease.   There is a large body of evidence relating S0~ and chronic bronchitis,



but the exact mechanism of the relationship is unknown.   Further long-term



population studies are needed, along with animal  studies, to investigate the



role of SOp in the onset, prevalence, and course  of chronic bronchitis.







     Among adults without preexisting illness, the relationship between acute



respiratory disease and S02 is more tenuous than  it is in children.   Epidemi-



ological  studies regarding community and industrial exposures have produced



inconsistent results, subject to interpretation.   Limited experimental studies



have not shown increased rates or severity of respiratory infection resulting



from S02 exposure, although it is generally conceded that data gathered under



controlled conditions may not reflect conditions  measured epidemiologically.







     Pulmonary function has been the most extensively studied biologic response



to SOp, primarily because it is a convenient, noninvasive technique.  Evidence



from several lines of investigation, including epidemiological studies, has



supported laboratory studies showing that S02 impairs pulmonary function by



increasing airway resistance.  The link between this altered pulmonary function



and subsequent disease states is still  unknown.







     Sulfur oxide exposure and respiratory morbidity in children have recently



been reviewed by Hammer (1977).  Studies from several countries clearly associate



excess lower respiratory tract morbidity in the young with exposure to sulfur



oxides.  For example, Douglas and Waller (1966) conducted a long-term study of



British school children and found increased frequency and severity of lower



respiratory diseases in association with annual mean smoke concentrations
                                 306
-------
              3                                         3
above 130 ug/m  and sulfur dioxide levels above 130 ug/m .   Both acute and



chronic upper respiratory disease in children have also been linked to sulfur



oxide exposure,   Lunn et al.  (1967) studied 819 school  children in Sheffield,



England, and found that both  upper and lower respiratory tract infections were



related to actual  air pollution measurements.   The mean daily averages measured


                                 3                       3
at a single station were 300  ug/m  for smoke and 275 ug/m  for S0?.   Several



studies have found that pulmonary function in children  varies inversely with



pollution exposure (Hammer 1977).
     Relatively few studies have been concerned with air pollution and asthmatic



children per se, and there is little information available on the prevalence



of childhood asthma in communities with high and low pollution levels.   No



consistent trends of asthma prevalence and air pollution were found in three



surveys of American studies (Hammer 1977).   A recent report from Japan did



find an increased prevalence of asthma and related allergic conditions in a



high-pollution community which apparently had exposure to petrochemical  wastes



as well as sulfur dioxide and total suspended particulate matter (Yoshida



1976).







     As was pointed out earlier, one of the problems associated with the



epidemiological study of air pollution effects is the difficulty of sorting



out the specific roles of the various compounds emitted.   Especially elusive



are the effects of sulfuric acid aerosol, a mobile source contaminant of



concern.  The problem is that the technology is just now becoming available



for ambient measurements of this aerosol on a community-wide scale.  Some



studies have been conducted on exposure in industrial settings where con-



centrations far exceed ambient concentrations.  For example, Williams (1970)
                                 307
-------
reported a 12-year study of sickness absence and pulmonary function in a group


of English factory workers exposed to sulfuric acid aerosol.   He found that


workers exposed to high levels of aerosol suffered more spells of absence due


to influenza, other upper respiratory tract disease, and bronchitis than did


workers exposed to low levels of aerosol.  Sulfuric acid aerosol concentrations


were not monitored over the course of the study.  However, a 1-day independent


measure made in a high-exposure area of the factory showed concentrations

                                 3
varying between 3.0 and 16.6 mg/m ,  levels which so far exceed the probable


limit of ambient concentrations as to render the results of this study value-


less in terms of community epidemiology.




     Rail (1974) reviewed the health effects of sulfur oxides and concluded


that air pollution is caused by a complex mixture of chemical substances of


varying toxicity of which the sulfur oxides are a principal component (see


Table A-14).  He recognized that the components which pose the primary hazards


to human health and their respective contributions to human diseases have not


been fully established as yet and that this is a source of some difficulty and


controversy.  However, there was a considerable body of evidence suggesting


that there may be discernible human health effects from exposure to concentra-


tions of SOp in the ambient air at levels close to current Federal primary


standards.




     Between 1967 and 1975, a series of studies was conducted to assess


health effects from air pollutants.   The U.S.  Environmental Protection


Agency formally titled a portion of these studies Community Health and


Environmental Surveillance System (CHESS).  One of the goals of CHESS
                                 308
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was to provide a sound basis for relating human health effects to sulfur

oxides and sulfates and to provide a reliable record of improvement in health

for the U.S.  population after reduction in air pollution.




     Unfortunately, in the attempt to provide a large amount of data as quickly

as possible,  studies within the CHESS project showed defects in design,

methods, and execution.  Though generalizations from this group of studies were

difficult, Finklea examined the body of data and presented best-judgment

estimates of the threshold levels at which SCL and TSP may exert effects on

health.  In terms of annual concentrations, Finklea1 s estimate for threshold

limits of SOp and particles was compatible with the results of earlier

studies on which the Federal primary standards for these pollutants were based
        3
(80 ug/m ).  However, in terms of maximum 24-hr concentrations, his threshold

estimate suggested that significant health effects occur at exposure levels

well below the Federal primary standards for SO™ and particles (365 and 260
    3
ug/m , respectively).  Questions regarding the validity of this finding have

not been resolved.  Nevertheless, the overall CHESS program does corroborate

the notion that elevated air pollutants cause adverse health effects.   But

the precise relationship between sulfates and health effects cannot be quantified

at present using data from this program.




     To date, these and other epidemiological studies on sulfur compounds have

focused primarily on stationary sources, which are responsible for 98 percent

of the sulfur emissions.  There are virtually no data showing effects on persons

living near heavily traveled roadways, on automobile and airplane operators

and passengers, or on bikers, joggers, and other pedestrians who could be

exposed to the emissions.  Nevertheless, data from the Los Angeles catalyst
                                 310
-------
study provide a good empirical estimate of roadway exposure in one large


metropolitan area.   On the basis of nearly 2 years of sampling, average 24-hr


freeway contributions of sulfur dioxide and suspended sulfate were estimated

                      3
at about 12 and 1  ug/m ,  respectively.
     In rare instances, sulfate emissions could amount to several micrograms


per cubic meter and be associated with health effects.   However, there are no


sound epidemiological data to determine what the health effects might be.   A


cost/benefit analysis (Chapter 5) was initially performed for this report to


assess those data.   However, because of the difficulty in determining a

threshold level at which health effects occur for sulfates, no real estimates


could be made.




     In conclusion, it appears that emissions of sulfur-bearing compounds

from mobile sources at current emission rates pose no real hazard to the


general population.
                                 311
-------
Bibliography

Air Pollution in Donora, Pennsylvania:  Epidemiology of unusual smog episode of
  October, 1948.  Public Health Bull. No.  306, p. 1973 + ff. ix, 1949.

Air Quality and Automobile Emission Control.  A  Report by the Coordinating
  Committee on Public Works, United States Senate.  Serial No. 93-15.
  Stock No. 5270-02105.  Washington, D.C.   November 1973.

Air Quality and Stationary Source Emission Control.  A Report by the Commission on
  Natural Resources, National Academy of Sciences, National Research Council, Com-
  mittee on Public Works, U.S. Senate.  March 1975.

Air Quality Criteria and Guides for Urban Pollutants.  WHO Technical Report Series
  No. 506.  1972.  p. 35.

Air Quality Criteria for Particulate Matter.  U.S. Department of Health,  Education
  and Welfare, NAPCA.  No. AP-49.  Washington, D.C.  1969.  p. 211 + ff.  xiv.

Air Quality Criteria for Sulfur Oxides.  U.S. Department of Health, Education and
  Welfare, NAPCA.  No. AP-50.  Washington, D.C.   1969.  p.  178 + ff. xi.

Air Quality Criteria for Sulfur Oxides.  A Report by CCMS/NATO Expert  Panel.
  Washington, D.C., U.S. Government Printing Office.  1972.  484-484/120, 1-3.

Amdur, M. 0.  Animal studies.  In:  Proceedings  of the Conference on the  Health
  Effects of Air Pollution.  Committee on Public Works, U.S. Senate.   1973. p. 175-
  206.

Angel, J. H. , C. M. Fletcher et al.  Respiratory illness in factory and office
  workers.  A study of minor respiratory illness in relation to changes in venti-
  latory capacity, sputum characteristics, and atmospheric pollution.  Br. J. Dis.
  Chest 59:66-80, 1965.

Becker, W. H., F. J. Schilling, and M. P.  Verma.  The effect on health of
  the 1966 eastern seaboard air pollution episode.  Arch. Environ. Health
  16:414-419, 1968.

Bell, K. A., W. S. Linn et al.  Respiratory effects of exposure to ozone  plus sulfur
  dioxide  in Southern Californians and Eastern Canadians.  Am. Ind. Hyg.  J. 38:696-
  706, 1977.

Biersteker, K.  Air pollution incident in Rotterdam, 1971.  Environ.  Res. K)(3): 348-
  354, 1975.

Binder, R. E., C. A. Mitchell et  al.   Importance of the  indoor environment in air
  pollution exposure.  Arch.  Environ.  Health 31_(6): 277-279, 1976.

Bradley, W. H., W. P. D.  Logan, and A. E.  Martin.  The London  fog of
  December 2nd-5th,  1957.  Monthly Bull. Min. Health 1_7:156-166, 1958.

Brasser,  L. J. , P. E. Joosting, and D. von Zuilen.  Sulfur  Dioxide—To
  What Level  Is It Acceptable?  Delft, The Netherlands,  Research Institute
  for Public Health  Engineering.   Report G-300.   July 1967.   (Originally
  published in Dutch,  September  1966.)

                                      312
-------
Buechley, R. W.  S02 Levels, 1967-1972, and Perturbations  in Mortality.  A
  Further Study in the New York-New Jersey Metropolis.  (Draft report).
  Presented March 6, 1975, at New York University.

Buechley, R. W.,  M.  H.  Lepper et al.  Chicago air pollution study.  S02
  levels and perturbation in mortality.  A study in the New York-New
  Jersey metropolis.  Arch.  Environ. Health 27:134-137, 1973.

Carnow, B.  W.,  M.  H. Lepper et al.   Chicago air pollution  study.  S02  levels
  and acute illness in patients with chronic bronchopulmonary disease.  Arch.
  Environ.  Health Jj3: 768-776, 1969.

Code of Federal Regulations.  Title 40, Parts 50.4-50.7 (40 CFR 50.4-50.7).
  National  Ambient Air Quality Standards for Sulfur Dioxide and Participates.
  1977.

Cohen, A. A.,  S.  Bromberg et al.   Asthma and air pollution from a coal-fueled
  power plant.   Am.  J.  Public Health 62(9):1181-1188, 1972.

Cohen, A. A.,  C.  J.  Nelson et al.  Symptom reporting during recent publicized
  and unpublicized air pollution episodes.   Am.  J. Public  Health 64(5):442-449,
  1974.

Commins, B.  T., and R.  E. Waller.  Observations from a ten-year study  of
  pollution at a site in the City of London.   Atmos.  Environ. h49~68, 1967.

Douglas, J.  W.  B., and R. E. Waller.  Air pollution and respiratory infection
  in children.   Br.  J.  Prev. Soc. Med.  20:1-8, 1966.

Durham, W.  H.   Air pollution and student health.   Arch. Environ. Health 28:
  241-245,  1974.

Ferris, B.  G.,  H.  Chen et al.   Chronic nonspecific respiratory disease in
  Berlin, New Hampshire, 1967 to 1973.   A further follow-up study.  Am. Rev.
  Respir. Dis.  JJ3:475-485,  1976.

Ferris, B.  G.,  I.  T. T.  Higgins et al.   Chronic nonspecific respiratory disease,
  Berlin, New Hampshire, 1961-1967:   A cross-sectional study.  Am. Rev. Respir.
  Dis. 104:232-244,  1971.

Ferris, B.  G. ,  J.  R. Mahoney et al.   Air quality, Berlin,  New Hampshire,
  March, 1966-December,  1967.   Am.  Rev. Respir.  Dis.  |08(1):77-84, 1973.

Finklea, J.  F., D.  C.  Calafiore et al.   Aggravation of asthma by air pollutants:
  1971 Salt Lake Basin studies.   .In:  Health Consequences  of Sulfur Oxides:
  A Report from CHESS,  1970-1971.  Research Triangle Park, N.C., U.S.
  Environmental Protection Agency.   1974.

Firket, J.   Fog along the Meuse Valley.  Faraday Soc. Trans. 32:1102-1197,
  1931.

Fry, J. Effects of fog on general practice.  Lancet 1:235, 1953.
                                    313
-------
Goldberg, H.  E., A. A.  Cohen et al.  Frequency and severity of cardiopulmonary
  symptoms in adult panels:   1970-1971 New York studies.  In:  Health
  Consequences of Sulfur Oxides:  A Report from CHESS, 1970-1971.  Research
  Triangle Park, N.C.,  U.S.  Environmental Protection Agency.  1974. p. 5-85
  to 5-108.

Greenburg, L., G. Field et al.   Air pollution and morbidity in New York
  City.  J.  Am. Med. Assoc.  ]82(2):159-164, 1962.

Greenburg, L., M. Jacogs et al.   Report of an air pollution incident  in New
  York City.   Public Health Rep. 77(1):7-16, 1962.

Hammer, D. I.  Respiratory Disease in Children Exposed to Sulphur Oxides and
  Particulates.  Environmental  Health Effects Research Series, EPA 600/1-77-043.
  Research Triangle Park, N.C.   U.S.  Environmental Protection Agency.
  September 1977. p. 95, 133 + ff. xiii.

Hazucha, B.,  and D. V.  Bates.  Combined effect of ozone and sulfur dioxide on
  human pulmonary function.   Nature 257:50-51, 1975.

Holland, W.  W.  Air Pollution and Respiratory Disease.  Westport, Conn. Technomic
  Publishing Co., Inc.   1972.  p. 164 + ff. vii.

Holland, W.  W.  Effects of air pollution on children.  Pediatrics 53(5):839-841,
  1974.

Holma, B. , and J. Stokholm.   Study on Chronic Non-Specific  Lung  Diseases Among
  Children in Relation to Air Pollution, Denmark.  Working  Document.   Copenhagen,
  Regional Office for Europe, World Health Organization.  1973.

Jaeger, M. J., D. Tribble, and H. Wittig.  Effect of 0.5 ppm Sulfur Dioxide on  the
  Respiratory Function of Normal and Asthmatic Subjects.  Report prepared for the
  Florida Sulfur Oxides Study,  Inc.  1977.

Jeck, J., and J. Kaspar.  Study on Chronic Respiratory Diseases  in Children in
  Relation to Air Pollution, Czechoslovakia.  Working Document.  Copenhagen, Regional
  Office  for Europe, World Health Organization.   1973.

Kagawa, J. , and T. Toyama.  Photochemical air pollution.  Arch.  Environ. Health
  30:117-122, 1975.

Kagawa, J. , T. Toyama et al.  Pulmonary function  test in children exposed to air
  pollution.   I_n:   Clinical Implications of Air  Pollution  Research.   A. J. Finkel
  and W.  C.  Duel (eds.).  Acton, Mass., Publishers Sciences Group.   1976.  p. 305-
  320.

Kerrebijn, K. F., A. R. M. Mourmans et  al.  Study on the relationship of
  air pollution to  respiratory disease  in schoolchildren.   Environ.  Res.
  K): 14-28,  1975.

Kurata, J. H. , M. M. Glovsky et al.  A  multifactorial study of patients
  with asthma.  Part II:  Air pollution,  animal  dander  and  asthma  symptoms.
  Ann. Allergy 37(6):398-409, 1976.


                                    314
-------
Lambert, P.  M., and D. D. Reid.  Smoking, air pollution, and bronchitis  in
  Britain.   Lancet Jh853-857,  1970.

Lawther, P.  J.  Compliance with the Clean Air Act:  Medical aspects.   J.
  Inst. Fuel 36:341-344, 1963.

Lebowitz, M. D.,  P. Bendheim et al.  The effect of air pollution and weather
  on lung function in exercising children and adolescents.  Am. Rev. Respir.
  Dis.  ]_09(2): 262-273, 1974.

Lee R.  E. ,  Jr., and F. V. Duffield.  EPA's catalyst research program:
  Environmental  impact of sulfuric acid emissions.  J. Air  Pollut.  Control
  Assoc. 27(7):63i~635,  1977.

Linn, W. S., J.  D.  Hackney et al.  Respiratory function and symptoms in
  urban office workers in relation to oxidant air pollution.  Am. Rev.
  Respir. Dis. 1_I4(3):477-483, 1973.

Logan,  W. P. D.   Mortality in the London fog incident.  Lance L:336-338,  1953.

The Los Angeles Catalyst Study Symposium.  Environmental Monitoring Series,
  EPA-600/4-77-034.  Research Triangle Park, N.C.  U.S. Environmental
  Protection Agency.   June 1977.   p.  466 + ff.  viii.

Lunn, J. E.  , J.  Knowelden, and A. J.  Handyside.  Patterns of respiratory
  illness in Sheffield infant schoolchildren.  Br. J. Prev. Soc. Med.
  21:7, 1967.

Lyster, W.  R.   Altered sex ratio after the London smog of 1952 and  the
  Brisbane  flood  of 1965.  J. Obstet.  Gynecol.  Br. Commonw. 81_: 626-631,
  1974.

McCarroll,  J., and W.  Bradley.  Excess mortality as an indicator of health
  effects of air  pollution.   Am.  J. Public Health 56:1933-1942, 1966.

McCarroll,  J., E.  J.  Cassell, D.  W. Wolter et al.  Health and urban
  environment.  V.  Air pollution and illness in a normal urban population,
  Arch. Environ.  Health ]4:178-184, 1967.

Magie,  A. R.,  R.  H. Burke et al.   Respiratory Disease Hospitalizations
  Associated with Photo-Chemical  Air Pollution.  Presented  at the American
  Public Health Association Meeting,  Miami Beach, Florida,  Oct. 18, 1976.

Mandi,  A.,  E.  Galambos et al.  Relationship between lung function values
  and air pollution data, in Budapest school children.  Pneumonologie
  J50:217-225, 1974.

Martin, A.  E.   Mortality and morbidity statistics and air pollution.
  Proc. Roy. Soc.  Med. 5_7:969, 1964.

Morris, S.  C., M.  A.  Shapiro et al.  Adult mortality  in two communities
  with widely different  air pollution levels.  Arch.  Environ. Health
  31(5):248-254,  1976.
                                    315
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Mortality and Morbidity During the London Fog of December, 1952.  Reports
  on Public Health and Related Subjects, No. 95.  London, Ministry of
  Health.  1954.

Muskie, E.  Air Pollution and Public Health.  Congressional Record Senate.
  Stock No. 6625-6644.  April 4, 1973.

Neri,  L. C.,  J. S. Mandel et al.  Chronic obstructive pulmonary disease in
  two cities  of contrasting air quality.  Can. Med. Assoc. 113(11-12):1043-
  1046, 1975.

Prindle, R. A., et al.  Comparison of pulmonary function and other parameters in
  two communities with widely different air pollution levels.  Am. J.
  Public Health 53:200-217, 1963.

Rail,  D. P.  Review of the health effects of sulfur oxides.  Environ.
  Health Perspect. 8:97-121, 1974.

Rudnik, J., and F. Sawicki.  A Study on Chronic Respiratory Diseases  in
  Children in Relation to Air Pollution.  Pilot Study.  DOCHP Rabka,
  Poland.  1972.

Schimmel, H., and L.  Greenburg.  A study of the relation of pollution to
  mortality.   New York City, 1963-1968.  J. Air Pollut. Control Assoc.
  22:607-616, 1972.

Schrenk, H. H., H. Heimann, G. D. Clayton et al.  Air Pollution in Donora,
  Pennsylvania.  Epidemiology of the Unusual Smog Episode of October  1948.
  Washington, D.C., U.S. Government Printing Office.  1949.  173 p.
  Preliminary Report.  Public Health Bulletin No. 306.

Smithurst, V. A., and G. M. Williams.  A study of chronic bronchitis  in
  Brisbane in two groups of workers:  The effects of cigarette smoking,
  pollution and industrial exposure on the disease.  Public Health London
  90:149-156, 1976.

Sterling, T.  D. , J. J. Phair, S. V. Pollack et al.  Urban morbidity and
  air pollution.  A first report.  Arch. Environ. Health ]_3:158-170,  1966.

Subcommittee on the Environment and the Atmosphere.  The Environmental
  Protection Agency's Research Program, with Primary Emphasis on the
  Community Health and Environmental Surveillance System (CHESS):  An
  Investigative Report.  U.S. House of Representatives, Ninety-Fourth
  Congress.  November 1975.

Toyama, T.  Studies on aerosols:  1. Synergistic response of the pulmonary
  airway resistance on inhaling sodium chloride aerosols and S02 in man.
  Jpn. J.  Ind. Med. 4:86-92, 1962.

Toyama, T., and S. Adachi.  Seasonal variations of daily mortality in Tokyo  City.
  Keio J. Med. 24:253-260, 1975.
                                    316
-------
U.S. Environmental Protection Agency.  Health Consequences of Sulfur
  Oxides: A Report from CHESS, 1970-1971.  EPA-650/1-74-004.  May 1974.

U.S. Senate.  Proceedings of the Conference on Health Effects of Air
  Pollutants.  National Academy of Sciences, National Research Council,
  Oct.  3-5, 1973.

Van der Lende, R., C.  Huygen et al.   A temporary decrease in the ventilatory
  function of an urban population during an acute increase in air pollution.
  Bull. Physio-pathol. Respir. JJ:31-43, 1975.

Weir, F.  W., and P.  A. Bromberg.   Effects of Sulfur Dioxide on Healthy and
  Peripheral Airway Impaired Subjects.  Presented at the International
  Symposium on Recent Advances in the Assessment of the Health Effects of
  Environmental Pollution, Paris, France, June 24-28, 1974.

Wilkins,  E. T.  Air pollution aspects of the London fog of December 1952.
  Roy.  Meteorol.   Soc. J.  80:267-271, 1954.

Winkelstein, W.,  S.  Kantor et al.  The relationship of air pollution and
  economic status to total mortality and selected respiratory system
  mortality in men.    II.   Oxides of sulfur.  Arch.  Environ.  Health 16:401-
  405,  1968.

World Health Organization.  Chronic Respiratory Diseases in Children in
  Relation to Air Pollution.   Report on a Working Group, Dusseldorf, 17-19
  April,  1974.  Copenhagen, Regional Office for Europe, World Health
  Organization.  1974.  69 p.

World Health Organization.  Working Group on the Study on Chronic Respiratory
  Diseases in Children in Relation to Air Pollution.  Rotterdam, 26-28
  February, 1973.  Copenhagen, Regional Office for Europe, World Health
  Organization.

Yoshida,  R., K. Motomiya et al.   Clinical and epidemiological studies on
  childhood asthma in air polluted areas in Japan.   In:  Clinical Implica-
  tions of Air Pollution Research.  A. J. Finkel and W. C. Duel (eds.).
  Acton,  Mass., Publishers Sciences Group.   1976.  p. 165-176.
                                    317
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                          APPENDIX B.   WELFARE EFFECTS







B.1  VEGETATION







B.I.I  Introduction







     This section reviews the effects of sulfur compounds on plant life.   Sulfur



dioxide (SOp is the most damaging of these compounds and is therefore reviewed in



considerable detail.  The effects of HLS, H2S04, and other sulfur compounds, though



less documented, are also discussed.







     Several early reports of damage from sulfur dioxide are of interest in that



this pollutant was the first to be recognized for its phytotoxicity (Stoeckhardt



1871).   Hartig (1896), Haselhoff and Lindau (1903), Sorauer (1904), Dana (1908), anc



Spaulding (1909) published various papers indicating that fume damage (most probably



SOp) was responsible for injury to various crops.  A small amount of research fol-



lowed these initial studies until the 1920's, when the theory of "invisible injury"



was proposed by Stoklasa (1923).   Reports of sulfur dioxide-induced injury and its



symptoms were scattered throughout the literature during the next two decades.



Zimmerman and Crocker (1934), Whitby (1939), Thornton and Setterstrom (1940), and



Katz (1949) added significantly to the accumulating information.   Following the



increased levels of emissions brought about by industrialization and associated



power demands in the eastern portions of the United States and in Great Britain and



Central Europe, reports of S0~ injury to many forms of vegetation likewise dra-



matically increased.  Recent advances in technology for monitoring various sulfur



forms and analyzing plant tissue have once again spurred research in this area.
                                  318
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Several  major topics of research have emerged in the past 10 years and will continue



to be emphasized in the future:



     1.    Interaction of pollutants such as S0?, ozone, nitrogen oxides, peroxy-



          acytyl-nitrates,  and halogens in combination.



     2.    Effects of long-term,  low-level  exposure.



     3.    Growth and yield  effects observed in the field using air filtration



          systems.



     4.    Long-distance transport of polluted air masses and associated impacts of



          acidic rainfall at such distances.



     5.    Influence of the  environment on  the plant response.



     6.    Effects of sequential  fumigations with single and multiple pollutants.



     7.    Pollutant and plant parasite interactions.








     It should be noted that at  this time  there are no reported instances of vege-



tational injury induced by  sulfur compounds generated by mobile (as distinct from



stationary) sources.   Recently,  transportation-generated sulfate aerosol was thought



to be a potential threat to vegetation.   However, this possibility was refuted on



the basis of ambient air quality data and  information on vegetational dose-response



relationships.








     Nevertheless,  the S0?  emitted from mobile sources may be significant in causing



plant injury when combined  with  other pollutants emitted into the urban environ-



ments.   It is virtually impossible to separate out the combination effects of mobile



versus point source S0? emissions once they have entered into gaseous mixtures with



other pol1utants.








     Of final concern in making estimates  of loss due to SCL emissions (or any other



pollutant) is the concept of "hidden injury11 as proposed by Stoklasa (1923).  Such



                                  319
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induced injury requires the measurement of some parameter,  such as yield,  that has



been affected without the presence of visible symptoms.   This concept has  primarily



been tested in relation to stationary sources of S0? emission.   It remains to be



thoroughly tested in relation to an urban environment where mobile and point sources



emit numerous pollutants other than, or including,  S0?.







B.I.2  Chemistry







B.I.2.1  Forms of sulfur in the atmosphere and sulfur compounds affecting  plant life—



SOp constitutes the largest component of the gaseous sulfur compounds in the atmosphere



and constitutes >95 percent of the sulfur compounds produced by the combustion of



sulfur-containing fossil fuels.  Moreover, most of the hLS emitted into the atmosphere



is rapidly oxidized to S02.







     Sulfur dioxide is catalyzed by a variety of homogeneous and heterogeneous



reactions to sulfates.  One species of sulfate aerosol,  sulfuric acid (HLSCL), is



largely related to the major stationary sources of SOp emission.   Transportation is



not currently considered to be a major source for the acid aerosol, H~S, or COS



(U.S. Environmental Protection Agency 1977).  Inorganic SO." aerosols also include



(NH4)2S04, NH4HS04, and others (Weiss et al. 1977).







     In the coarse-particle range, sulfur is associated with both organic  and



inorganic particles and with the cations (Krupa 1978).  These coarse particles



consist of a combination of emissions, wind-blown dust,  sea spray, volcanic pro-



ducts, and plant material (Whitby 1977) (Figure B-l).







     Both dry and wet processes are involved in the deposition of gases, aerosols,



and coarse particles to the ground.  Dry fallout occurs most of the time,  while wet



                                  320
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                           Chemical Conversion
                            of Gases lo Low
                           Volotil it y Vapors
                  Condensation
   LOW
VOLATILITY
  VAPOR
                              Homogeneous
                              Nucleation
                                         WIND BLOWN DUST
                                         EMISSIONS
                                         SEA SPRAY
                                         VOLCANOS
                                         PLANT PARTICLES

Transient Nuclei
< 	 — or —
Nuclei Range
Particle Diameter
— ?k — Accumulation -
Range
Particles 	 	 	
Micrometer
-^k — Mechanically Generated*
Aerosol Range
-^4-t- Coarse Particles - — 	 	 >
Figure  B-l.   Schematic  showing an  atmospheric aerosol  surface
area  distribution representing three modes,  the main  source of
mass  for each mode, the  principal  process  involved  in inserting
mass  into each  mode, and the principal removal  mechanisms.

Source:   Whitby (1977).
                           321
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fallout (rain and snow) depends on the frequency of precipitation and the geographic



area.   Acidic rain is one form of wet fallout that is of major concern.   While the



acidity of rain can be attributed to a great number of hydrogen ion donors in rain,



many scientists believe that H2S04 and HN03 are the major contributors (USDA Forest



Service 1976).







B.I.2.2  Deposition rates of sulfur compounds—Deposition processes limit the



lifetime of sulfur compounds in the atmosphere, the distance they travel, and their



atmospheric concentrations (Garland 1977).   Sulfur dioxide and particulate sulfate



are the predominant forms of sulfur present in the atmosphere.  Other atmospheric



sulfur compounds, such as H?S, dimethyl sulfide, and methyl mercaptan, are most



likely deposited only after conversion to SCL or SO.".







B.I.2.2.1  Dry deposition.  Table B-l summarizes the results obtained from



several studies on SO^ deposition.  It is notable that the mean deposition velocities



are similar for the wide range of surfaces listed.







     There have been several studies of the deposition of particulate material on



natural surfaces (Schnel and Hodgson 1974; Chamberlain 1975; Little and Wiffen



1977).   Very large particles are chiefly deposited by sedimentation.   Smaller par-



ticles, in the range of 1 to 100 urn, are borne by turbulence toward the surface,



where sedimentation effects supplement their deposition.  Submicron particles (HpSO.



aerosols) diffuse by Brownian motion through the thin laminar layers close to the



surface elements, often followed by active uptake in the case of plant leaves.







     Dry deposition can remove the larger particles from the atmosphere within 2 or



3 days, but this process would require several weeks to remove the submicron fraction.
                                  322
-------
  Table B-1.   RESULTS OF SEVERAL EXPERIMENTAL INVESTIGATIONS OF S02 DEPOSITION

Surface
Calcareous soil
Acid soil
Calcareous soil
Grass

Grass
Short grass
Medium grass
Medium grass
Cotton sedgemoor
Wheat
Wheat
Soybean
Pine forest
Pine forest
Method, etc.
Laboratory, mass
balance
Laboratory, mass
balance
Gradient, field
Gradient, field
Summer
Autumn
35S02 tracer,
field
Gradient, field
Gradient, field
Tracer, field
Gradient, field
Gradient, field


Tracer
Tracer

g
scm-1


1.2
0.8
0.3
0.8
0.85
0.89
0.19
0.7
0.74
0.44
1.25
0. 1-0.6
1.0
Mean
r r
g s
scm-1 scm-1
0.24-0.39
1.2-3.8
0.83 0.01
0.8
3.0

1.2 0.34
0.46 0.66
0.38 0.45
-
1-2.5
0.28 2.0
0.11 0.69
0.1 1.5-5.0

Notes:   r  = gas plus resistance, r  = surface resistance; S02 deposition
        expressed in terms of deposition velocity relative to 1 m.
Source:   Table summarized by Garland (1977).
                                  323
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B.I.2.2.2  Wet deposition.   Both SO^ and SO.  can be dissolved in rain.


Hogstrom (1973) found that sulfur emitted by a stationary source in Sweden was


deposited by rain within 1  or 2 hr of its emission.   However,  Granat and Rodhe


(1973) found that of the total amount of sulfur emitted from the tall  stacks of a


power-generating station, less than 6 percent was deposited by rain within a radius


of 15 km.  Davies (1976) measured the dissolved SOp in rainwater in England and


found about 3 mg/liter   when the corresponding air concentration was about 100


pg/m .
     Garland (1977) summarized removal of sulfur from the atmosphere as follows:


     1.   SOp is removed by dry deposition at a deposition velocity of approximately


          0.8 cm/sec   for most surfaces.


     2.   The deposition velocity of sulfate is no greater than 0.1 cm/sec

                                                                            -4    -i
     3.   Sulfate is removed by rain with a time constant on the order of 10  /sec  .


     4.   S02 removal by rain is approximately one order of magnitude less efficient.
B.I.2.3  Sulfur as a plant nutrient—Sulfur is a plant nutrient essential to the


formation of amino acids.   It occurs in plants as inorganic sulfate and as organically


bonded sulfahydryl, disulfide, and sulfonic groups; it is also bonded in hetero-


cyclic rings.   The sulfahydryl form is important in producing the amino acids


cysteine and methionine and in catalyzing coenzyme A.   Organically bonded sulfur


also contributes to the Calvin cycle of photosynthesis.




     Inorganic sulfur occurs in plants as sulfate, which activates fermentation,


maintains colloidal structure of protoplasm, increases assimilation activity (metab-


olism), and stimulates carbohydrate formation.  Excess sulfate is stored in cell


vacuoles as a sulfur reserve.  Inorganic sulfate can exceed the level of organic



                                  324
-------
sulfur by 5 to 10 times before injury occurs.  Since the amount of stored sulfur



has little effect on the level of organically bonded sulfur (Guderian 1970), the



phytotoxicity can be attributed to inorganic sulfur.








     The only positive effects of plant uptake of atmospheric sulfur dioxide occur



areas with low-sulfur soils.   Faller (1970) found that fumigating sulfur-deficient



sunflower, corn, and tobacco plants with sulfur dioxide for several weeks promoted



normal plant growth.  Saalbach et al.  (1962) found a slight increase in morrowstem



yield by applying ammonium sulfate nitrate compared with lime nitrate or ammonium



nitrate.   Estimates show that 13 kg of sulfur per hectare (2.47 acres) was removed



from soils by harvested products, similar to the amount of phosphorus thus removed,



while the amount of sulfur removed through washout equaled 60 kg/ha.   This yearly



loss (73 kg/ha) was replaced by fertilizer (19 kg/ha) and by dry and wet deposition



of sulfur (68 kg/ha).








B.I.3  Sensitivity








B.I.3.1  Higher plants--








B.1.3.1.1  Symptoms.  The damaging effects of sulfur compounds on plants are



often accompanied by observable symptoms.   The acute symptoms of S0? exposure have



been documented for a number of plant types (Taylor 1973; Barrett and Benedict 1970;



Linzon 1965), as have the acute effects of hLS exposure (Thompson and Kats 1978;



Benedict and Breen 1955).  For example, acute SO,, exposure of broadleaf plants may



cause partial necrosis and discoloration in specific parts of the leaf, possibly



leading to shedding of the leaf.   Less is known of the acute effects of exposure to



HpSO, mist or aerosol, but some symptoms have been defined (Middleton et al. 1950,



1958, 1965; Lang and Krupa 1977, 1978).






                                  325
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     Chronic exposure of broad!eaf plants to low concentrations of S0~ may lead to



varied color patterns, suggesting senescence.   As with acute exposure, the sympto-



matic effects of which may occur simultaneously, leaf shedding may result (U.S.



Environmental Protection Agency 1973).   There is little information on the symp-



tomatic effects of chronic exposure to H^S or hLSO. mists and aerosols.







     Certain physiological disturbances unaccompanied by apparent signs of exposure



may occur.   For example, Keller (1977) found that SCL reduced photosynthesis in fir



and spruce that showed no visible symptoms.







B.I.3.1.2  Dose response.  Information on S0« doses causing acute injury to



sensitive plant species is summarized in Table B-2.  Table B-3 provides some



of the data on growth reductions in vegetation exposed to sulfur dioxide for several



hours.  Figure B-2 depicts an effects model  of threshold injury from S02 exposure.







     Table B-4 shows some of the results of studies on average S0? concentrations



inducing a reduction in epiphytic lichens and bryophytes.  Lichens are well accepted



as bioindicators of sulfur dioxide pollution of the atmosphere.







     Only recently has some information been found regarding dose-response relation-



ships for hydrogen sulfide (Thompson and Kats 1978).  Tables B-5 through B-8



summarize the effects of prolonged H«S exposures on vegetation (Thompson and Kats



1978).







     At this time, no definitive information is available on dose-response relation-



ships for submicron sulfuric acid aerosols and acute injury on vegetation.
                                  326
-------
  Table B-2.   SULFUR DIOXIDE CONCENTRATIONS CAUSING THRESHOLD INJURY TO VARIOUS
                       SENSITIVITY GROUPINGS OF  VEGETATION
                                     Sensitivity grouping
Maximum
average
concentration
Peak
1-Hr
3-Hr









Sensitive
(ppm S02)
1.0-1.5
0.5-1.0
0.3-0.6
Ragweeds
Legumes
Blackberry
Southern pines
Red and black oaks
White ash
Sumacs


Intermediate
(ppm S02)
1.5-2.0
1.0-2.0
0.6-0.8
Maples
Locust
Sweetgum
Cherry
Elms
Tuliptree
Many crop and
garden species

Resistant
(ppm S02)
>2.0
>2.0
>0.8
White oaks
Potato
Upland cotton
Corn
Dogwood
Peach


 Based on observations over a 20-year period of visible injury occurring on
 over 120 species growing in the vicinities  of coal-fired power plants in
 the southeastern United States.

Source:   Jones et al.  (1974).
                                  327
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  Table  B-3.   GROWTH  REDUCTION  IN  VEGETATION EXPOSED  TO SULFUR DIOXIDE IN FIELD
                    EXPOSURE  CHAMBERS  FOR SHORT TIME  PERIODS

Species
Crimson clover
(Tribolium incarnatum L. )
Red clover
(Tri folium pratense L. )
Italian rye
(Lolium multiflorum Lmk. )
Mixtures of:
T. pratense and
L. multiflorum
Vetch (Vicia sativa L. and
V. faba L.), pea (Pi sum
arvense L.), and lupine
(Lupinus lentens L.)

Concentration3
Exposure
time
ug/m3 ppm (hr) Effect
2489 0.95 8 Reduced
growth
2489 0.95 12 Reduced
growth
2489 0.95 12 Reduced
growth
Reduced
growth
2489 0.95 12
Growth not
affected
Reduced
growth
for all
996 0.38 48 species
 Average concentrations over the reported time periods.   Inaccuracies associated
 with instrumentation result in deviations as great as ±10 percent.

Source:   U.S.  Environmental  Protection Agency (1973).
                                  328
-------
E
Q.
Q.
c"
o
c
ID
O
C
                                            DAMAGE IS LIKELY
 RESISTANCEGROUP3
       TRUCKCROPS
        OLEAGINOUS SPECIE
              (Rape)////////
                CABBAGE SPECIES
7RESISTANCEGROUP 2
/"""""" CEREALS//
            LEAFYVEGETABLE
            BEANS, STRAWBERRIES
                ROSES'
        RESISTANCE GROUP
         'CLOVER-LIKE FORAGE SPECIES
          DAM AGE IS UNLIKELY
                                    10    20
                          Exposure period,  hr
         Figure  B-2.   Sulfur dioxide concentrations that may produce
         threshold injury (hatched area) to vegetation with continuous
         exposure for various periods of time.

         Source:   Zahn (1961).
                            329
-------
         Table B-4.   AVERAGE SULFUR DIOXIDE CONCENTRATIONS RESULTING IN
                A DECREASE IN THE NUMBER OF EPIPHYTIC LICHEN AND
                                BRYOPHYTE SPECIES
S02 concentration,
        ppm
   Averaging
    period
    Research
      area
       0.015

       0.020


    0.015-0.03

    0.005-0.01
    Annual

Winter (Oct.-
  Apri1)

    Annual

 Summer (May-
   Oct.)
Stockholm, Sweden

Newcastle, England


Belfast, Ireland

Sudbury, Canada
Source:   Jones et al.  (1974).
        Table B-5.   EFFECTS OF CONTINUOUS H2S FUMIGATION  ON GROWTH AND
                         SULFUR ACCUMULATION IN ALFALFA





Cutting
#1



#2





H2S,
ppb
0
30
300
3000
0
30
300
Eldorado
Avg
dry wt/
pot,
g
52 yb
51 y
42 y
16 z
45 y
46 y
31 z
Hayden

Total S
as S04=,
%
1.03
1.23
2.45
4.85
0.94
1.10
3.00
Avg
dry wt/
pot,
g
52 x
52 x
32 y
11 z
46 y
43 y
28 z

Total S
as S04=,
%
0.92
1.36
2.44
5.20
1.00
1.29
3.41
.Days of fumigation: 28 to 35.
 Values followed by different letters are different at the 1% level.

Source:  Thompson and Kats (1978).
                                  330
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      Table B-6.   EFFECTS OF INCREASING LEVELS OF H2S ON CANE LENGTH,  DEAD
               LENGTH,  AND DRY WEIGHT OF THOMPSON SEEDLESS GRAPES3

Total Dead %
H2S, length, length, Dead
ppb cm cm
0 1252.9 yb 572.1 x 63. 1 y
30 1160.0 y 422.2 x 53.3 y
300 1090.1 y 212.4 x 18.7 z
3000 673.5 z 191.3 z 15.5 z
Total
dry wt,
g
145.0 x
143.1 x
72.5 y
38.0 z
•Days of fumigation: 117.
Values followed by different letters are different at the
Source: Thompson and Kats (1978).
Table B-7. EFFECTS OF INCREASING
AND CANE WEIGHTS OF

LEVELS OF H
GRAPES
Total sulfur as
S04 in leaves,
%
0.78
1.26
3.33
4.50
1% level.

2S ON LEAF

Leaves
H2S, Fresh wt, Dry
ppb g g
0 265.6 ab 78.6
30 375.6 b 97.0
100 298.4 b 80.6
300 260.4 a 57.0

wt,
a
a
a
b
Canes
Fresh wt, Dry wt,
g g
267.2 a 123.8 a
251.8 a 115.8 ab
219.6 a 86.0 be
152.0 b 62.8 c
.Days of fumigation:  145.
 Values followed by different letters are different at the

Source:  Thompson and Kats (1978).
level.
                                  331
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            Table B-8.   YIELD OF  LEAVES,  ROOTS,  AND SUGAR CONTENT OF
                SUGAR BEETS EXPOSED TO INCREASING LEVELS OF H2Sa

Leaves
H2S,
ppb
0
30
100
300
Fresh wt,
9
149.6 be
210.5 a
200.8 ab
127.6 c
D ry wt ,
g
19.8 be
25.2 b
23.3 b
15.2 c
Sulfate,
%
0.66
0.93
1.33
1.88
                                      Roots

0
30
100
300
Fresh wt,
g
291.3 be
440.6 a
370.7 ab
219.6 c
Sugar,
%
19.3 a
18.3 a
18.2 a
15.8 b
Sulfate,
%
0.05
0.06
0.08
0.12



0
30
100
300
Total ,
Fresh wt,
leaves, g
1242.0 c
2037.6 a
1874.8
1640.8 abc
3 beets/pot
Dry wt,
leaves, g
126.2 c
194.0 a
176.8 ab
137.0 be

Fresh wt,
roots, g
643.0 be
881.0 ab
1034.2 a
502.2 c
.Days of fumigation:  123.
 Values followed by different letters are different at the 5% level.

Source:  Thompson and Kats (1978).
                                  332
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     Shriner and Mclaughlin (personal  communication, 1977) evaluated the effects of



long-term exposure of beans to COS (carbonyl sulfide).   Root biomass ranged from



0-21 percent of the controls when the  plants were exposed to 0 and 0.30 ppm COS,



respectively, for 3 hr per day, 4 days per week for 4 weeks (total, 48 hr).   Accord-



ing to the investigators,  this dose appeared to be slightly below that required for



consistent reduction in growth or yield of bean.








B.I.3.1.3  Sensitive species.   For a variety of reasons, certain plants have



become well known as bioindicators for the detection of air pollution.   Their low



injury thresholds, specificity of response to certain pollutants, wide geographic



range, low cost, ease of operation, and availability for use throughout all  study



areas have been suggested as reasons for their use over more costly and sophisticate



instrumentation.  Plant bioindicators  will not replace such instrumentation for



monitoring purposes, but such plants have been used to assist in evaluating pollutan



levels present in a given area.  Table B-9 presents a partial listing of sensitive



plants identified as potential bioindicators.








     Extensive efforts have also been  made to develop certain plant species as



bioindicators.   Perhaps the most widely examined plants for this use are eastern



white pine (Pinus strobus) and numerous species of lichens.  Table B-10 shows a



listing of plants most commonly developed for use as bioindicators.








B.I.3.2  Lower plants - microorganisms--In recent years, various studies have been



conducted to examine the effects of SO,, on microorganisms, including fungi,  algae,



and bacteria.  Under laboratory conditions, high levels of exposure have produced



marked effects, such as reduced growth.  Generally, the effects of S0? at ambient
                                  333
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          Table B-9.   PARTIAL LIST OF PLANTS KNOWN TO BE SENSITIVE TO
                      S02 UNDER FIELD EXPOSURE CONDITIONS
Cultivated crops
   Alfalfa - Medicago sativa L.
    ^rlpv - HnrHpnm yulnarp L.
airaira - neaicago sative
Barley - Hordeum vulgare
Bean - Phaseolus vulgaris L.
Bluegrass - Poa annua L.
Cabbage - Brassica oleracea L.
Cucumber - Cucumls sali'vus '
Oats - Avena sativa L.
                              L.
Pea - Pisurn sativum L.
Radish -  Raphanus sativus L.
Rhubarb - Rheum rhaporiticum L.
Rye - Secale cereale L.
Soybean - Glycine max Merr.
Spinach - Sjn'nacia oleracea L.
Tobacco - Nicotiana tobacum L.
Weed species
                    Big-leaved aster - Aster macrophyllum
                    Binweed - Convolvulus arvensis
                    Blueberry - Vaccinium angustifolium
                    Curly dock - Rumex crispus
                    Dandelion - Taraxacum officianle
                    Fleabane - Erigeron canadensis
                    Lambs quarter - Chenopodium album
                    Pigweed - Amaranthus retroflexus
                    Plantain -
                    Ragweed -
                            Plantago major
                           Ambrosia spp.
                                    spp.
                    Raspberry - Rhubus
                    Smartweed - Polygon'urn
                    Wildgrape - Vitis spp.
                                        spp.
Forest trees
                    Ash, mountain - Sorbus aucuparia
                    Ash, white - Fraxinus americana
                    Aspen, large tooth - Populus grandidentata
                    Birch - Betula spp.
                    Elm - Ulmus spp.
                    Fir, Douglas - Pseudotsugae menziesii
                    Hybrid poplar - Populus
                    Larch - Larix spp.
                    Maple - Acer spp.
                          jack - Pinus ponderosae
                 Pine,
                 Pine,
                 Pine,
                          ponderosa - Pinus banksiana
                          eastern white - Pinus strobus
                    Willow - Salix spp.
Ornamentals and flowers

   Aster - Aster bigelovi i
   Azalea - Rhododendron spp.
   Bachelor's button - Centarea
   Begonia - Begonia spp.
   Cosmos - Cosmos bipi nnatus
   Four o'clock - Mirabilis
                                        Morningglory - Ipomoea purpurea
                                        Petunia - Petunia hybrida
                                        Sweet pea - Lathyrus odoratus
                                        Verbena - Verbena canadensis
                                        Violet - Viola spp.
                                        Zinnia - Zinnea elegans
                                      334
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Table B-10.   LISTING OF PLANTS THAT HAVE BEEN SELECTED FOR
      SPECIFIC USE AS BIOINDICATORS OF S02 IN VARIOUS
            INVESTIGATIONS UNDER FIELD CONDITIONS
    Plant	Latin name	

    Alfalfa                     Medicago sativum
    Ash, white                  Fraxinus americanum
    Beans                       Phaseolus vulgan's
    Hybrid poplar               Populus deltoides cv.  Angulata x
                                                      Trichocarpa
    Petunia
      (white flowering)         Petunia hybrida
    Pine, eastern white         Pinus strobus
    Pine, loblolly              Pinus taeda
    Sycamore                    Platanus occidental is
    Tobacco                     Nicotiana tobacum
                       335
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levels appear minimal.   However, the overall effect on the numerous pi ant/environ-



ment/mi croorgam'sm interactions must not be overlooked.   Since SO- affects soil pH,



leaf surfaces, and related factors, the associated microorganisms may also be affected.



For example, Mrvka and Grunda (1969) found that bacterial populations were drastically



reduced where soil pH,  soil potassium, and soil magnesium were likewise decreased.







B.I.3.3  Environmental  factors—Plants are subjected to many changes in the



environment during their life cycle.  Thus, it is important to understand the response



of plants to sulfur compounds under varying environmental conditions.  Parameters of



interest consist of temperature, light, humidity, carbon dioxide concentration, soil



moisture, and soil nutrients.  Almost all the published literature on this subject



pertains to SOp.







     Temperature before, during, and after exposure generally appears to be directly



related to the SO,, sensitivity of trees (Davis 1975).   The European literature gen-



erally considers S0? sensitivity to be directly related to temperatures above 40°F



(4°C) (Van Haut and Stratmann 1970).  More recently, Heck and Dunning (1978) showed



increased sensitivity of oaks to S0? at higher growth temperatures within a range of



18-30°C.







      Plant sensitivity tends to increase with increasing humidity.  Oaks are more



sensitive to S02 at 80 percent than at 55 percent relative humidity (Heck and Dunning



1978).







     Zimmerman  (1955) reported that S02 sensitivity of plants was directly related to



increasing light intensity,  up to about 3000 ft-c.  Plants grown  in direct sunlight
                                  336
-------
prior to exposure were more resistant than plants grown under a 65 percent reductio1



in intensity.   Similarly, minimum plant injury occurs in the field when bright sunn



days follow an SCL fumigation (see Davis 1975).







     Plants are more sensitive to S0? when adequate soil moisture is available for



normal plant growth (U.S. Environmental Protection Agency 1973).   Plant resistance



increases as the soil  moisture content approaches the wilting point.







     Plant resistance  increases with increased soil fertilization in rape, spinach,



and radish (U.S.  Environmental Protection Agency 1973).   In contrast, deficiencies



of nitrogen and sulfur were correlated with increased resistance in tobacco and



tomato (Leone and Brennan 1972).







     Few studies have  evaluated the influence of soil structure,  temperature, aera-



tion, and related variables on response to S0?.   In studies involving three plant



species and four soil  types, Guderian (1971) found that plant injury varied depending



on soil type,  nitrogen applications, and plant species.







B.I.4  Interactive Effects







B.I.4.1  Synergism of  sulfur compounds with other pollutants—In the ambient atmos-



phere, specific air pollutants do not occur individually but in combination with



other pollutants.   Interactions between these pollutants cause vegetational injury



classified as antagonistic (less injury), additive (increased injury), or synergistic



(greater than additive injury).  Most of the research on pollutant combinations has



focused on SCL and CL  (ozone), with less emphasis on SCL and NO,, (nitrogen dioxide),



SOp and F (fluorides), and SO?-NO«-03 combinations.
                                  337
-------
     Menser and Heggestad (1966) were the first to report on 0~-SO? synergistic



effects on tobacco plants.   Later Tingey et al.  (1973) used ambient levels of SO- and



0- individually and in combination on 11 different crop species and demonstrated



several synergistic responses.   Most of the work in this area has focused on foliar



symptoms, although Tingey and Reinert (1975) showed additive effects and greater



reductions after low exposures of S0»-03.  Other species that have been studied for



sensitivity to S02 combinations include the eastern white pine (Gerhold 1977) and



several hardwood species (Karnosky 1976).







     The studies of SO?-NQp combinations show interactive effects considerably less



pronounced than those involving S09-0~ (Reinert 1971; Tingey et al. 1971; Bennett and
                                  C~  J


Hill 1975; Skelly et al. 1972).







     SOp-NOp-O.^ combinations have been investigated by Kress and Skelly (1977) and by



Kress (1978).  Significant growth reductions of sycamore and loblolly pine resulted



from 6-hr daily doses of 5 pphm 0,,, 14 pphm S0~, and 10 pphm NOp over 28 days.  In



1973, Fujiwara et al. reported that the addition of NO- to a SOp-Q., combination did



not significantly increase effects already exerted by SO--0., on peas and spinach.







B.I.4.2  Interaction between sulfur dioxide and plant parasites—Plant disease is



caused by the interaction of a plant and a pathogen acting under suitable environ-



mental  conditions.  Although,  in the strict sense, a pollutant can be classified as a



pathogen, this section will limit the definition to biological parasites affecting



plants.  The parasites range from fungi to insects.







     In general, sulfur dioxide is harmful to plant parasites, depending on con-



centration and exposure.  In 1973, Heagle reviewed pollutant-parasite research and
                                  338
-------
            Table B-ll.   EFFECTS OF SULFUR DIOXIDE ON PLANT DISEASES
 Pollutant and
disease affected
      Effects
Pollutant
   dose
Location
Wheat stem rust

Tree rusts

Wood rots

Needle cast on juniper

Needle cast on larch
  and pine

Rhytisma on maple

Hysterium on alder
  and birch

Apple scab

Oak powdery mildew

Lilac powdery mildew

Rose black spot

Rose black spot

Dwarf mistletoe on
  larch and pine

Armillaria in trees



Wood rots

Needle cast on spruce
Decreased incidence      Ambient

Decreased incidence      Ambient

Decreased incidence      Ambient

Decreased incidence      Ambient


Decreased incidence      Ambient

Decreased incidence      Ambient


Decreased incidence      Ambient

Decreased incidence      Ambient

Decreased incidence      Ambient

Decreased incidence      Ambient

Decreased incidence      Ambient

  Smaller lesions    0.04 ppm, 48 hr


Decreased incidence      Ambient

Increased incidence      Ambient



Increased incidence      Ambient

Increased incidence      Ambient
                  Sweden

                  Canada

              Czechoslovakia

                  England


                  Canada

                  England


                  Sweden

                  Poland

                  Austria

                   U.S.A.

                  England

                  England


                  Canada

                  Canada,
              Czechoslovakia,
              Poland,  Germany

              Czechoslovakia

                  Poland
                                  339
-------
noted certain effects of pollutants on plant parasites.   As seen in Table B-ll,



ambient levels of SO,, generally decreased the incidence  of fungal  disease on various



forest trees.







     Similarly, Hibben and Taylor (1975) observed that mildew infection was reduced



by acute and chronic doses of S02, which they labeled as fungicidal to that specific



mildew.  Several other studies also support this fungicidal action in various species



(Koch 1935; Majernik 1971; Saunders 1966; Scheffer and Hedgcock 1955; Linzon 1958).



In addition, SCL is used extensively to prevent grape mold and rot during storage and



shipment (Nelson 1958; Nelson and Ahmedullah 1972; Soto  et al. 1973).







     However, SQp does not harm all fungi.   Weinstein et al.  (1975) showed that while



SCK decreased the severity of bean rust, it had no effect on tomato blight.  Far more



important, however, is that S0? generally weakens plants, and in doing so makes the



plant more vulnerable to parasitic attack (Donaubauer 1968; Jancarik 1961; Kudela and



Novakova 1962).







     This same selective parasiticidal action holds true for higher organisms.



Stewart et al. (1973) reported that SCL may or may not repel  lice, depending on plant



species infested.  Weber et al. (1974) reported a similar finding using S0~ and 0-,



singly and in combination against nematode infestation.







     Although no direct effects of S0? on plant pathogenic bacteria have been reported,



certain indirect effects may be exerted by changes in soil acidity and nutrient



change (Heagle 1973).  Shriner (1978) reported on the effects of simulated acid rain



on host-parasite interactions in plant disease development.
                                  340
-------
B.I.5  Physiological  Effects





B.I. 5.1  Ingress of S0? into plants and stomatal  influences--The stomates of


leaves are the major avenue of S0? entrance into  plants (Guderian 1977;  Katz 1949


Thomas 1951; Thomas and Hendricks 1956; U.S.  Environmental  Protection Agency 1973


but there is no general agreement regarding the role of stomata in plant sensitiv


There appear to be numerous factors which govern  the mechanism of stomatal  openin


and closing.  Ting and Dugger (1968) have reported that there is no linear relati


ship between pore size and permeability of leaves to gases.   Gas exchange through


stomata is a dynamic process influenced by gas diffusion coefficient, pressure in:


and outside the leaf, stomatal resistance, and other variables.   In addition,  phy-


sical factors such as light, leaf surface moisture, relative humidity, and soil


moisture may actually play the major role in plant sensitivity,  while S02 enters J


leaf by passive means (Setterstrom and Zimmerman  1939; Zimmerman 1950; Meidner anc


Mansfield 1968; Spedding 1969; Domes 1971).  S0?  may also enter plants through the


leaf cuticle during periods of stomatal closure in the presence of dew (Garland an


Branson 1978; Fowler 1976).





     The numbers and size of stomates of the individual species or species genotypi


could influence pollutant ingress.  For example,  Nikolaevskii (1971) reported that


SCL damage to several woody plants was greatest at midday even though the degree o


stomatal opening did not change during the diurnal cycle.   He concluded that cer-

                                                                  2
tain sensitive species generally had a larger number of stomata/mm  of leaf area a


a greater degree of natural stomatal opening than did certain resistant trees.





     Ricks and Williams (1974) looked at the leaves of oak (Quercus petraea) in an


area of woodland subjected to a differential gradient of industrial particulate
                                  341
-------
pollution and compared them to leaves from an unpolluted rural  woodland.   They found



that an accumulation of particles on the lower surfaces of the leaves mechanically



prevented normal stomatal closure at night.   Overall  rates of water loss were increased



as diffusive resistance decreased, and the uptake of SCL was subsequently enhanced



for extended periods of time.







B.I.5.2  Stomatal response to S0,,--Jensen and Koslowski (1975) found that sulfur



absorption rates varied among several species of forest trees fumigated with SOp, as



did the onset of resistance to absorption.  The sulfur content of the foliage of all



species increased, and at 8 days following fumigation with radioactively labeled SOp,



varying amounts were found throughout the plants, including the roots.  It was



observed that a plant's tolerance to SCk may depend less on the amount of pollutant



absorbed than on the ability of the plant to move S0? out of the leaf and into other



plant tissues.







     While SOp-induced closure has been observed elsewhere (Bonte et al.  1975), other



reports indicate that SOp may exert an opposite effect under certain conditions.  For



example, stomatal opening or closing in response to SOp may depend upon the duration



of exposure (Buron and Cornic 1973), relative humidity (Majernik and Mansfield 1970;



Mansfield and Majernik 1970), or drought versus nondrought conditions (Schramel



1975).  Unsworth et al.  (1972) reported that the stomatal opening of the leaves of



many crops was increased by ambient S0? levels.  Uniformly increasing the SOp con-



centration up to 2.0 ppm on beans and corn reduced stomatal diffusive resistance,



with young leaves exhibiting the lowest resistances.   The effect of SOp on stomatal



resistance was greater on all leaves of water-stressed plants.







     For further discussion on variables affecting plant sensitivity to SOp^ see



"Environmental factors"  (Section B.I.3.3 of this appendix).





                                  342
-------
B.1.6  Acidic Rain







B.I.6.1  Formation of acidic rain--The acidity of rainfall in many geographic



areas has been increasing in recent years.   This increase appears to stem from the



atmospheric loading of SO  and NO ,  as emitted from fossil fuel combustion.   Although
                         A.       X


a rain pH of 2.1 was noted by Likens and Bormann (1974), the mean pH for precipita-



tion nationwide ranges from 4.0 in the New England States to 6.1 in the Pacific



Southwest (see Figure B-3).   For comparison, the pH of an unpolluted atmosphere



would be 5.7.







     Sulfur was first recognized as a component of rainwater by Wilson in 1926.



Since then, over 22 different species of atmospheric sulfur have been suggested.   Of



these, SO,,, S0,~, S0.,~, and S^Og can contribute to the acidity of rain.   Unfortu-



nately, despite years of research, the chemistry of sulfur in the atmosphere, par-



ticularly sulfate formation, is only partially understood.  Nevertheless some of the



forms of sulfur found in rain have been characterized.   Hales (1977) found that up to



30 percent of the sulfur found in rain occurred as sulfite.   Essman and Fergus (1975)



suggested that the major sulfur source of acidic rain in Pennsylvania occurred as



dithionate (S^Og).  Generally, the data seem to indicate that the acidity of rain



and the role each sulfur species plays may vary with time and place.







     Gambel1 and Fisher (1966) argue that anthropogenic sulfur is not the control-



ling factor of rain acidity.  However, Leland (1952) and others note an increase in



sulfate during the winter months, which they attribute to increased coal and oil



burning.  This increase could contribute to rain acidity.  Many researchers believe



that sulfate is formed through a catalytic oxidation process (Georgii 1970; Junge



1960; Meszaros 1970; Rodhe 1970).  One probable method of formation is the "S02-NH3-



H20" system.





                                  343
-------
                                                   ro

                                                   CM
                                                    s-
                                                    o
                                                    CO
                                                    OJ
                                                    (O
                                                    "O
                                                    O)
                                                    c
                                                    ID

                                                    (U
                                                     S-
                                                     O)
                                                     c:
                                                     o
                                                     o
                                                     01
                                                     S-
                                                     CL
O

in
Q-
                                                     ro
                                                     o>
                                                     T3
                                                     

                                                     O)
                                                     CO
                                                      I
                                                     CO

                                                     O)
                                                     S-
                                                     3
                                                     en
                                                            ro
                                                            o
                                                            o
                                                            o
       c:
       o
       U)
       S-
       o>
       Q.
                                                            OJ
        cu
        o

        3
        o
       oo
344
-------
     Several Scandinavian investigators believe that most of the sulfur found in

precipitation arises from global, upper-atmospheric sources rather than anthropogf

sources (Oden 1964).  In support of this belief, Gambell and Fisher (1964) found

the concentration of sulfate in the lower atmosphere remained at high levels throi

out the course of rainstorms.



     However, Bielke and Georgii (1968) estimate that the concentration of S0? in

the lowest kilometer of the atmosphere exceeds that in higher altitudes according

the following table:
                                           SO £	Aerosol  SO/

          Rainout
            (cloud contribution)           5%            20%

          Washout
            (sub-cloud contribution)      70%             5%
The relatively high S02 levels in the lower atmosphere could contribute extensively

to the gaseous sulfate in rain.   But Miller and de Pena (1972),  who measured the

contribution of scavenged gas to the sulfate content of rain, concluded that washec

out particles are the major contributors.



     Most of the acid rain studies have been based on correlations between pH and

sulfate deposition (Galloway and Parker, unpublished).  Johnson  et al.  (1972) and

Krupa (1976) presented data indicating that atmospheric sulfuric acid  concentratio

are not sufficient to reduce rain pH to below 3.0.   Johnson et al.  (1972) calculat

that 3-4 mg/liter sulfate would lower the pH of rain to 4.4-4.1.   Consequently,

other active anions must be present to account for the low observed pH of rain.


                                  345
-------
Likens et al.  (1976) suggest that anthropogenic SO,   and NCk  (as sulfuric acid



and nitric acid) contribute most to the acidity of rain.








     Studies  at the University of Maryland have measured rain pH and composition



in the Washington, D.C., metropolitan area at various locations, including areas



near power plant stacks.  One particular study by Muhlbaier (1978) involved measur-



ing rain pH at and near a power plant fueled by coal  and oil.  Sufficient quantities



of NO  and SO  were found in the rainwater to account for the low rain pH.  In
     A       /\


addition, since SO." dominated atmospheric acid species, Muhlbaier concluded that



in the microclimate around the power plant, sulfate concentrations correlated well



with the acidity of the rain.








     Although Frohliger (1976) found that the pK values indicate that rain has a weak



acid character, Krupa et al. (1976) showed that rain contained both strong, volatile



acids and weak, nonvolatile acids.  Nevertheless, measurements made by Oden (1968),



Anderson (1969), and Krupa et al. (1976) could not correlate change in pH with sul-



fate concentrations in the atmosphere.   An important fact in understanding acid rain



components was brought up by Whitby (1977), who noted that the non-neutralized sul-



fate (i.e., sulfuric acid) particles (0.01-0.1 pm in diameter) are too small to be



removed and deposited by rain.








     Although mobile sources produce significant amounts of  nitrogen oxides which



could increase rain acidity, the sulfate particles they produce, particularly sul-



furic acid, not only are insignificant in amount but also are in the submicron size



range.








B.I.6.2  Vegetational effects of acidic rain—Acidic rain has been implicated in



the increased leaching of nutrients from soils (Overrein 1972) and decreased pH



                                  346
-------
      Table B-12.   EFFECTS OF ARTIFICIAL ACID RAIN ON VARIOUS PLANT SPECIES
Researchers
Plant species
Effects
Gordon (1972)

Shriner (1974)

Wood and Bormann (1975)
Wood and Pennypaker
  (unpublished)

Evans (personal
  communication, 1978)
Shriner (personal
  communication, 1978)
Pine needles

Oak and bean leaves

Yellow birch and sugar maple
seedlings


Scotch pine


Bean plants
Bean plants
50% growth reduction

Cuticle erosion

Foliar spot necrosis;
irregular leaf develop-
ment

Needle necrosis
Leaf lesions; decreased
leaf expansion; prema-
ture defoliation; fewer
and smaller pods/plant

No change in foliage
dry wt
In combination with
ozone - reduction in
foliage dry wt
                                  347
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values of lakes and streams (Oden and Ahl 1970).   Little is known,  however, of the



direct effects of acidic precipitation on terrestrial vegetation.   A review of the



literature reveals no published reports demonstrating vegetational  injury from



naturally occurring acidic rainfall.   Several investigators, however, have reported



direct injury of various plant species by artificially applied acid mists and acidic



solutions (Ferenbaugh 1976; Shriner et al.  1974;  Wood and Bormann 1974) (see Table



B-12).  According to Wood (1975), the changes acidic rain may induce in natural



ecosystems are likely to be widespread but difficult to detect over short periods of



time.







     The available literature indicates that pollution in rainfall  may cause direct



injury to foliage, deposition of other harmful substances on the plant tissue,



effects on host-parasite relationships, and effects on the soil.







     Crowther and Ruston (1911) were the earliest investigators to ascribe plant



damage to the acidic nature of polluted precipitation in Leeds, England.  They



described direct leaf toxicity and "less nutritious timothy grass"  as manifestations



of the pollution in rain.  Syratt and Wainstall (1968) suggested that the acidic



nature of S0? at high humidity (sulfurous acid) degrades chlorophyll.  Oden (1963)



stated that the acidic nature of most sulfurous compounds may plasmolyze plant cells



at high concentrations and destroy chlorophyll at lower concentrations.  He also



noted that acidic rains significantly affect coniferous vegetation because of the



accumulative properties of the needles.  Likens et al. (1972) reported that Sweden



suffers an annual reduction in forest growth as a result of acidic rainfall.







     Shriner (personal communication, 1978) studied the effects of simulated acidic



rain (sulfuric acid) on host-parasite interactions at pH 3.2.  Acid treatments
                                  348
-------
A
3 2
\
H2S03
T i
4 6
L
8
HS03 S032"
                                                                 Plant cell
                                                                 Vacuole

                                                                 Nucleus
                                                               4- Chloroplast
Figure B-4.  Emissions and  transformation of S02 and S03.   The figure shows
the probable transformations of  S02  in  air and water.   The arrows into the cell
give an approximate picture of the permeability of the various sulfurous com-
pounds.  The distribution of the various  dissociation states of H2SCU at differed
pH values is shown in the pH scale below  the cell.

Source:  Sundstrom and Hallgren  (1973).
                                  349
-------
resulted in:   an 86 percent inhibition in the number of telia produced by the



oak-pine rust on willow oak;  a 66 percent inhibition in the reproduction of a root



nematode on field-grown kidney beans;  a 29 percent decrease in the leaf area of



field-grown kidney beans affected by rust; and either stimulation or inhibition



in the development of halo blight on kidney beans.   In the last case,  the effect



varied in relation to the disease cycle.







     Much of the discussion on the action of S0? damage to plants has  arisen from



studies on lichens and bryophytes.  Sundstrom and Hallgren (1973) portray the "prob-



able" picture of the relationship between the plant cell and the sulfur pollution



relative to lichen sensitivity (Figure B-4).   Accordingly, they state:   "It is



reasonable to suppose that in the event of sulfurous pollutions, the transport of SO^



or H2S03 and HS03  through the membranes is much more rapid than the uptake of the



more charged S03~ ion.  This selective uptake of undissociated molecules, and to



some degree HS03 , is followed by their dissociation in the cell, resulting in an



accumulation of charged HS03  and S03~ ions and an acidification of the cell."







     Mounting acid inputs may cause decreases in the fertility of forest soils.  It



has been suggested that increased rain acidity accelerates the leaching of potassium,



magnesium, and calcium (Overrein 1972).  Field studies in Sweden correlate increased



acidic rain inputs with decreases in soil pH (Oden et al.  1972).







     Conversely, increased soil fertility may also result from acidic rain.  For



example, this rain may add nitrate and sulfate ions, common components of chemical



fertilizers.   In fact, Wood and Bormann (cf.  Wood 1975) found that mean produc-



tivity of white pine seedlings subjected to artificial rains containing sulfuric,



nitric, and hydrochloric acids was 20 percent greater at pH 2.3 than at less acidic



concentrations.
-------
     Plants constitute rather effective filters, according to Eaton et al. (1973).



They observed that during growing seasons, forest canopies filter 90 percent of the



hydrogen ions from pH 4.0 rainwater.   As a result, less acidic solutions (pH 5.0)



reach the forest floor.
                                  351
-------
Bibliography

Babich, J.,  and G. Stotsky.  Ecological ramifications of air pollution.
  Transactions of the International Congress on Transportation Conference
  SAE 193-214.  1972.

Bach, W.   Atmospheric Pollution.  McGraw-Hill, N.Y.  1972.  143 p.

Banfield, W.  Sulfur dioxide-ozone synergism on western larch and three pines.
  Presented at the 2nd International Congress on Plant Pathology, Minneapolis,
  Minn. ,  1973.

Banfield, W. M.  Sulfur dioxide-ozone synergism on eastern white pine.  Phyto-
  pathology 62:493,  1972.

Barrett,  T.  W., and  H. M. Benedict.  Sulfur dioxide.  In: Recognition  of Air
  Pollution Injury to Vegetation:  A Pictorial Atlas. J. S. Jacobson and A. C.
  Hill (eds.).  Pittsburgh, Pa., Air Pollution Control Association.  1970.

Barrett,  E., and G.  Brodin.  The acidity of Scandinavian precipitation.  Tellus
  7:251-257, 1955.

Basshant,  J.  A., A. A. Benson et al.  The path of carbon in photosynthesis.  XXI.
  The cyclic regeneration of carbon dioxide acceptor.  In:  The Photosynthesis
  of Carbon Compounds.  M. Calvin and J. B. Bassham  (eds.).  New York, W. A.
  Benjamin, Inc.   1962.

Benedict, H. M., and W. H. Breen.  The  use of weeds  as a means of evaluating
  vegetation damage  caused by air pollution.  Proceedings of the 3rd National
  Ait Pollution Symposium.  1955.  p. 177.

Benedict, H. M., D.  D. Davis, and A. S. Heagle.  Dose responses of vegetation
  to minor pollutants.  Proc. Air Pollut. Control  Assoc. 6th Annu. Meet.  229:1-20,
  1974.

Benedict, H. M., C.  J. Miller,  and J. S. Smith.  Assessment of economic impact of
  air pollutants on  vegetation  in the United States.  1969 and 1971.   Menlo Park,
  Calif., Stanford Research Institute.  1973.  96  p.

Bennett,  J. H., and  A. C. Hill.  Acute  effects of  combination of  sulfur dioxide
  and nitrogen  dixoide on plants.  Environ. Pollut.  9:127-32, 1975.

Bennett,  J. H., A. C. Hill, A.  Soleimani, and W. H.  Edwards.  Acute effects of
  combination  of sulfur dioxide and nitrogen dioxide on plants.   Environ. Pollut.
  9:127-132,  1975.

Bielke,  S., and H. W. Georgii.  Investigation on the incorporation of  S02 into
  fog and rain  droplets.  Tellus 20:435-442, 1968.

Bielke,  S. , and G. Gravenhorst.  Heterogeneous S02 oxidation in the droplet
  phase.   In:   Proceedings of the  International Symposium on Sulfur in the
  Atmosphere,  Dubrovnik, Yugoslavia, 1977.  (In press.)
                                  352
-------
Biscoe, P.  V.,  M. H.  Unsworth, and H. R. Pinckney.  Effects of low concentrations
  of sulfur dioxide on stomatal behavior in Vicia faba.  New Phytol. 72:1299-1306,
  1973.

Bonte, J.,  L.  De Cormis, and P. Louguet.  Effect of sulfur dioxide pollution on
  the degree of opening of Pelargonium x horiorum stomata.  C. R. Hebd. Seances
  Acad. Sci.  Ser. D 280:2377-2380, 1975.

Bovay, E.   The effects of sulfur dioxide and fluorine compounds on plants.  In:
  Proceedings of the 1st European Congress on the Influence of Air Pollution
  on Plants and Animals, Wageningen, The Netherlands.   1968.  p.  111-135.

Brezonik,  P.  L., W.  H.  Morgan, E.  E. Shannon, and H. D. Putnam.  Eutrophication
  factors  in north central Florida lakes.  Eng.  Progress at the University of
  Florida.   Fol.  XXIII, Bull. Series No. 134, Water Resources Research Center
  Paper No. 5.   1969.   23 p.

Burghardt,  H.   Uber die Bedeutung des Chlors fuer die Pflanzenernahrung unter
  besonderer Berucksichtigung des Chlorid/Sulfat.  Prob.  Angew. Botan. 36:203-257,
  1962.                                                                ~~

Buron, A.,  and G. Comic.  Effect of sulfur dioxide on gas exchange in white
  mustard  (Sinapis alba).  Bull.  Soc. Vaudoise Sci.  Natur. 7^:451-461, 1973.

Cadle, R.  D.   The sulfur cycle.  In:  Sulfur in the Environment.   St.  Louis, Mo.,
  Missouri  Botanical  Garden.   1975.   189 p.

Chamberlain,  A.  C.   The movement of particles in plant communities.  In:  Vege-
  tation and the Atmosphere,  Vol.  1.  J. L.  Monteith (ed.).  New York, Academic
  Press.   1975.   p.  155-204.

Charlson,  R.  H., D.  S.  Covert, and T. V. Larson.  Chemical properties of tro-
  pospheric sulfur aerosols.   In:   Proceedings of the International Symposium on
  Sulfur in the Atmosphere, Dubrovnik, Yugoslavia, 1977.   (In press.)

Cogbill,  C. V.   The history and character of acid precipitation in eastern North
  America.   In:   Proceedings  of the 1st International  Symposium on Acid Precipi-
  tation and the Forest Ecosystem.  USDA Forestry Service General Technical
  Report No.  N-23.   1975.  p. 363-370.

Couey, H.  M., and Millota.  Effect of concentration, exposure time, temperature,
  and relative humidity on the toxicity of sulfur dioxide to the spores of
  Botrytis  cinerea.   Phytopathology 5J: 739-814,  1961.

Craker, L.  E. ,  and W.  J. Manning.   Sulfur dioxide uptake by soil fungi.  Environ.
  Pollut.  6:309-311 ,  1974.

Crowther,  C., and H.  Ruston.   The nature, distribution and effects upon vege-
  tation of atmospheric impurities near an industrial  town.  J. Agr. Sci.
  4:25-55,  1911.
                                 353
-------
Daessler, H.  G.,  H.  Ranft, and K.  H.  Rehn.  The susceptibility of woody plants
  exposed to fluorine compounds and sulfur dioxide.  Flora (Jean) 161:289-302,
  1972.

Dana, S.  T.   Extent and Importance of the White Pine Blight.   U.S. Forestry
  Service Leaflet.  1908.   p. 1-4.

Davies,  T. 0.  Precipitation scavenging of sulfur dioxide in an industrial area.
  Atmos.  Environ. K):879-890, 1976.

Davis, D. D.   Variables in free response due to environmental factors - climatic.
  Ijy.  Air Pollution and Metropolitan Woody Vegetation.  W. H. Smith and  L. S.
  Dochinger (eds.).   The Air Pollution Working Group, Pinchot Institute.   1975.
  74 p.

Davis, D. D., and R. G. Wilhour.  Susceptibility of woody plants  to sulfur
  dioxide and photochemical oxidants:  A literature review.  Ecological Research
  Service.  1976.  71 p.

Demeritt, M.  E.,  Jr., W. M. Chang, J. D. Murphy, and H. D. Gerhold.  Selection
  system for evaluating resistance of Scotch pine seedlings to ozone and  sulfur
  dioxide.  Proceedings of the 19th Northeastern Forest Tree Improvement  Con-
  ference.  1971.

Dochinger, L. S., and W. W. Heck.   An ozone-sulfur dioxide synergism produces
  symptoms of chlorotic dwarf disease of eastern white pine.   Phytopathology
  59:399, 1969.

Domes, W.  Unterschiedliche  C02-Abhangigkeit des Gasaustaushes beider  Blattseiten
  von Zea mays.   Planta 98:186-189, 1971.

Donaubauer, E.   Sekundarshaden in Osterreichischen Rauchschadensgebieten.
  Schwierigkeiten Der diagnose und Bewertung.  Niedzynarodowej Konf. Wplyw
  Zanieczyszczen Powietrza na Lasy, 6th.  Katowice, Poland.  1968.

Dreisinger, B. R., and P.  C. McGovern.  Monitoring atmospheric sulfur dioxide
  and correlating its effects on crops and forests in the Sudbury area.   In:
  Impact of Air  Pollution on Vegetation Conference.  S. N. Linzon (ed.).
  Toronto, Ontario Department of Energy and Resource Management.  1970.
  p.  11-28.

Eatough, T. H.,  T. Major, J. Ryder et al.  The formation and stability  of sulfite
  species in aerosols.  In:  Proceedings of the International Symposium on Sulfur
  in the Environment, Dubrovnik, Yugoslavia, 1977.  (In press.)

Essman, N. A. , and R. B. Fergus.  S02-NH3-particulate matter - H20  reaction
  system as related to the rainfall acidity.  In:  Proceedings of the 1st Inter-
  national Symposium on Acid Precipitation and the Forest Ecosystem.  USDA Forestry
  Service Technical Report No. NE-23.   1975.  1074 p.

Evans, L. S., and P. R. Miller.  Histological comparison of single  and
  additive 03 and S02  injuries to elongating ponderosa pine needles.  Am.  J.
  Bot. 62:416-421, 1975.


                                  354
-------
Faller, N.   Schwefeldioxid aus der Luft als entscheidende Nahrstoffauel le  fuer
  die Pflanze.   Landwirtschforsch.  18(25):48-54, 1970.

Ferenbaugh, R.  W.   Effects of simulated acid rain on Phaseolus vulgaris  L.
  (Fabaceae).   Am. J.  Bot. 63:283-288, 1976.

Finklea, J. R.  et al.   Status report on sulfur oxides; health consequences
  environmental controls:  Impact of mobile emission controls.  Durham,  N.C.
  April 16-17,  1974.   Preprint.

Fowler, D.   Uptake of Sulfur Dioxide by Crops and Soil.  Ph.D. Thesis,  University
  of Nottingham, England.  1976.

Francis, C. W., G. Chesters, and W.  Erhardt.  Polonium entry  into plants.
  Environ.  Sci. Technol.  2:690-695,  1968.

Friend, J.  P.   The global sulfur cycle.  In:  Chemistry of the Lower Atmosphere.
  S. T. Rasool  (ed.).   New York, Plenum Press.   1973.  335 p.

Frohliger,  J.  0.  Chemical and biological aspects of urban precipitation.
  Ann.  Am.  Chem. Soc.  Mid Atlantic Reg., Philadelphia, Pa.  1976.   (Abstr.)

Fujiwara, T.,  T. Umezawa, and H.  Ishikawa.   Effects of mixed  air pollutants on
  vegetation.   I.   Effects of combinations of S02, N02, and 03.  Research  Report
  No. 72007.   Inst.  Agric. Elec. , Cent. Inst.  Elec.  Power, Japan.   1973.   24 p.

Gambell, A. W., and D. W. Fisher.   Occurrence of sulfur and nitrate in  rainfall.
  J. Geophys.  Res. 69:4203-4210, 1964.

Gambell, A. W., and D. W. Fisher.   Chemical composition of rainfall in  eastern
  North Carolina and Southeast Virginia.  U.S.G.S.  Water Supply Paper  No.  1535-k.
  1966.

Garland, J. A.   Dry and wet removal  of sulfur from the atmosphere.  In:   Proceed-
  ings of the  International Symposium  in Sulfur in the Environment, Dubrovnik,
  Yugoslavia,  1977.   (In press.)

Garland, J. A.   The dry deposition of  sulfur dioxide to land  and water  surfaces.
  Proc. Roy.  Soc.  London Ser. A 345:245-268, 1977.

Garland, J. A., and J. R. Branson.  The deposition of sulfur  dioxide to  pine
  forest assessed by a radioactive method.   Tellus,  1978.  (In press.)

Caspar, P.  R.   Sulfur in the atmosphere.  In:   Sulfur in the  Environment.  St.
  Louis, Mo.,  Missouri Botanical Garden.  1975.   189 p.

Gatz, D. F.,  and A.  N. Dingle.  Trace  substances in rain water: Concentration
  variations  during convective rains and their interpretation.  Tellus  23:14-27,
  1971.

Georgii, H. W.   Contribution to the atmospheric sulfur budget.  J.  Geophys.
  Res.  75:2365-2371, 1970.
                                 355
-------
Gerhold, H. D.  Effect of air pollution on Pinus strobus L. and genetic
  resistance.   Prepared by Corvallis Environmental Research Laboratory,
  Corvallis, Ore.   U.S. Environmental Protection Agency.  Research
  Triangle Park, N.C.  Publication No. EPA-600/3-77-002.  1977.

Granat, L., and R. Rodhe.  Study of fallout by precipitation around an
  oil fired power plant.   Atmos. Environ. 2:781-792, 1973.

Guderian,  R.  Air Pollution:  Phytotoxicity of Acidic Gases and Its Signifi-
  cance in Air Pollution Control.  Berlin, Springer-Verlag.  1977.  127 p.

Guderian,  R.  Einfluss der Naehrstoffversorgung auf die Aufnahme von
  Schwefeldioxid aus der Luft und auf die Pflanzenanfael1igkeit.  Essen,
  West Germany, Schriftenr.  Landes Norhrehein-Westfalen.  Ann. Rep. No.
  23, 1971.

Guderian,  R.  Unterschungen uber quantitaiven beziehungen Zweschen dem
  Schwefelgehalt von Pflanzen und dem Schwefeldioxidgehalt der  Luft.
  2.  Pflanzenkrankh.  Pflanzenschutz Vol. 77; I Tie!, 200-220; II Tie!,
  289-308; III Tie!, 387-399, 1970.

Hales, J.  M.  Wet removal of sulfur compounds from the atmosphere.  .In:
  Proceedings of the International Symposium on Sulfur in the Atmosphere,
  Dubrovnik, Yugoslavia, 1977.   (In press.)

Ham, D. L.  The Biological Interactions of Sulfur Dioxide and Scirrhia
  acico1 a  on Loblolly  Pine.  Ph.D. Thesis, Duke University.  Durham, N.C.
  1971.

Hart.ig, R.  Uber die Einwirkung  des Huttenund Steinkohlenrauches auf die
  Gesunheit der nadelwald Baume.  Forsch. Naturwiss. Z. 5:245-290, 1896.

Haselhoff, E., and G.  Lindau.  Die Beschadigung der Vegetation  Durch Rauch.
  Berlin,  Borntraeger.   1903.

Heagle, A. S.   Interactions between air pollutants and plant parasites.
  Annu. Rev. Phytopathol. !_]_: 365-388, 1973.

Heagle, A. S., D. E. Body, and G. E. Neely.  Injury and yield responses of
  soybean  to chronic doses of ozone and sulfur dioxide in the field.
  Phytopathology 64:132-136, 1974.

Heck, W. W., and J. A. Dunning.  Response of oats to sulfur dioxide:
  Interactions of growth temperature with exposure temperature  of humidity.
  J. Air  Pollut. Control Assoc.  28:241-246, 1978.

Heggestad, H.  E., K. L.  Tuthill, and R. N. Stewart.  Differences among
  poinsettias in tolerance to sulfur dioxide.  Hort. Sci. 8:337-338, 1973.

Herman, F. A., and E.  Gorham.  Total mineral material, sulfur and nitrogen
  in rain  and snow at  Kentville, Nova Scotia.  Tellus 9:180-183,  1957.

Hesketh,  H. E.  Understanding and Controlling Air Pollution.  Ann Arbor,
  Mich.,  Ann Arbor Science Publications.  1973.
                                  356
-------
Hibben, C.  R.   Sensitivity of fungal spores to sulfur dioxide and  ozone.
  Phytopathology 56:880, ~1966.

Hibben, C.  R.,  and M. P. Taylor.  Ozone and sulfur dioxide effects  on  the
  lilac powdery mildew fungus.  Environ. Pollut.  9:107-114,  1975.

Hill, A.  C.,  S. Hill, C. Lamb, and T. W. Barrett.  Sensitivity of  native
  desert vegetation to S02 and S02 and N02 combined.  J. Air Pollut. Control
  Assoc.  24:153-157, 1974.

Hogstrom, U.   Residue times of sulfurous air pollutants from a local source
  during precipitation.   Ambio 2:37-41, 1973.

Houston,  D.  B.   Response of selected Pinus strobus L. clones to  fumigation
  with sulfur dioxide and ozone.  Can.  J.  For. Res. 4:65-68, 1974.

Houston,  D.  B., and G.  R. Stairs.   Genetic control of sulfur dioxide and
  ozone tolerance of eastern white pine.  For. Sci. |9:267-271,  1973.

Husar, R. B.,  D. E. Patterson, J.  D. Husar et al.  Sulfur budget of a  power
  plant plume.   Proceedings of the International  Symposium on Sulfur in the
  Atmosphere,  Dubrovnik, Yugoslavia, 1977.  (In press.)

Husar, R. B. ,  D. E. Patterson, C.  C. Paley, and N. V. Gil lam'.  Ozone  in
  hazy air masses.   In:   International  Congress on Photochemical Oxidant
  Pollution and Its Control, Proc. Vol. II.  U.S. Environmental  Protection
  Agency.  Research Triangle Park, N.C.  Report No. 600/3-77-0016,  Ecology
  Research Series.   1977.  1169 p.

Jacobson, J.  S., and L.  J. Colavito.  The combined effect of sulfur dioxide
  and ozone on bean and tobacco plants.  Environ. Exp. Bot. ]_6: 277-285, 1976.

Jacobson, J.  S., and A.  C. Hill (eds.).  Recognition of Air  Pollution
  Injury to Vegetation:   A Pictorial Atlas.  Pittsburgh, Pa., Air  Pollution
  Control Association.   1970.

Jancarik, V.   Vyskyt drevokaznych hub v hourem poskozovani oblasti  Krusnych
  hor. Lesnictvi 7:677-692, 1961.

Jensen, K.  R.,  and T. T. Koslowski.  Absorption and translocation  of sulfur
  dioxide by seedlings of four forest tree species.  J. Environ. Qua!.
  4:379-382,  1975.

Johnson,  N.  M., R.  Reynolds, and G. E.  Likens.  Atmospheric  sulfur:  Its
  effects on the chemical weathering of New England.  Science 177:514-515,
  1972.

Jones, H. C.,  D. Weber, and D. Balsillie.   Acceptable limits for air pollution
  dosages and vegetation effects:   Sulfur dioxide.  Air Pollut.  Control Assoc.
  Report No.  74-225.  1974.  31 p.

Junge, C. E.   Sulfur in the atmosphere.  J. Geophys. Res. 65:227-237,  1960.

Junge, C. E.   Chemical composition of precipitation,  jjr.  Air Chemistry  and
  Radioactivity. New York, Academic  Press.  1963.  p. 311-351.

                                      357
-------
Karnosky, D.  F.   Threshold levels for foliar injury to Populus tremuloides
  by sulfur dioxide and ozone.   Can.  J.  For. Res.  6:66-169, 1976.

Katz, M.   Sulfur dioxide in the atmosphere and its relation to plant life.
  Ind.  Eng. Chem.  41; 2350-2465, 1949.

Keller, T.   The effect of long enduring, low S02 concentrations upon photo-
  synthesis of conifers.  Proceedings of the 4th International Clean Air
  Congress, Tokyo, Japan.  1977.   p.  81-83.

Kellogg,  W. W., R. D.  Cadle, E. R.  Allen et al.   The sulfur cycle.  Science
  V75:587-596, 1972.

Khemani,  L. T., and V. Murty.   Chemical  composition of rain water and rain
  characteristics at Delhi.  Tellus 20:284-292,  1968.

Koch, G.   Eichenmehltau und Rauchgass-schaden.  Z. Pflanzenkr.  T4:44-45,
  1935.

Kochurova,  A.  I., and T. N. Karpova.   Combined effect of sulfur dioxide and
  carbon dioxide gases on mild fungi.  Vinodel.  Vinograd S.S.S.R. 6:36-38,
  1974.

Kodata, M., and T. Inoue.  Invading path of sulfur dioxide into pine leaves
  as revealed by microradioauthography.   J.  For. Soc.  54:207-208, 1972.

Kohut,  R. J. ,  and S.  V. Krupa.   Evaluation of subtle effects on soybean
  through an open-top field chamber study in Sherburne County, Minnesota.
  Annual  Report of the State Planning Agency, Minnesota.  1976.

Kress,  L. W.   The interaction of 03,  S02, and N02 singly and in combination
  and their effects on the growth of loblolly pine (Pinus taeda L.) and
  American sycamore (Platanus occidental is L.).   Ph.D. Thesis, Virginia
  Polytechnic Institute and State University.  Blacksburg, Va.  1978.

Kress,  L. W.,  and J.  M. Skelly.  The interaction of 03, S02, and  N02 and
  its effect on the growth of two forest tree species.  In:  Proceedings
  of the Cottrell Centennial Symposium:   Air Pollution and Its Impact on
  Agriculture.  Stanislaus, Calif., California State College.  1977.
  p. 128-152.

Kress,  L. W.,  and J.  M. Skelly.  Pinus taeda L.  and Platanus occidental is  L.
  seedling height growth suppression in response to long-term  low levels  of
  02) N02 and/or S02.    In:  Proceedings of the 3rd International  Congress
  on Plant Pathology,  Munich, West Germany, 1978.   (In press.)

Krupa,  S. V.   Impact of stark emissions from the Northern States  Power
  Company SHERCO power generating plant on terrestrial vegetation,  1976-1977.
  Annual  Report of the Northern States Power Company, Minneapolis,  Minn.,
  1978.  (In press.)
                                 358
-------
Krupa, S. ,  B.  I.  Chevone, S. Fagerlie et al.   Impact of air pollutants on
  terrestrial  vegetation.  In:   The Role of Disease in Environmental and
  Ecological Management of National Parks, Vol.  1.  F. A. Wood (ed.).
  Annual Report to National Park Service,  Washington, D.C., U.S. Government
  Printing  Office.  1976.  p.  43-96.

Krupa, S.  V.,  M.  R,  Coscio, Jr., and F.  A. Wood.  Evidence for multiple
  hydrogen-ion donor systems in rain.   Water Air Soil Pollut.  6:415-422,
  1976.

Krupa, S.  V.,  R.  S.  Kohut, and J.  A. Lawrence.  Air pollution vegetation
  effects  studies in two national  parks.  In:   Proceedings of the 1st
  Conference on Scientific Research in National  Parks, sponsored by the U.S.
  Department of the Interior,  1977.  (In press.)

Kudela,  M., and E. Novakova.  1962.  Lesnf skudci a skody zveri v lesich
  poskozovanych Kourum.   Lesnictvi 6:493-502,  1962.

Kurmies, B.  Uber den Schwefelhaushalt des Bodens.  Phosphosaure 17:259-278,
  1957.

Lang, D. S., and S.  V.  Krupa.   Effect of submicron sulfuric acid aerosols
  on vegetation.   Proceedings  of the Annual Meeting of the American Phytopathic
  Society,  East Lansing, Mich., 1977.   (In press.)

Lang, D. S., D.  S. Shriner, and S. V.  Krupa.   Injury to vegetation initiated
  by sulfuric  acid aerosols and by acidic rain.   Proceedings of the Annual
  Meeting  of the Air Pollution Control Association,  Houston, Texas, 1978.

LeBlanc, F. , and D.  N.  Rao.  Effects of air pollutants on lichens and bryophytes.
  .In:  Responses of Plants to  Air Pollution.   J. B.  Mudd and T. T.  Koslowski (eds.).
  New York, Academic Press.  1975.  p. 237-272.

Lee, R. , and D.  M. Gates.  Diffusion resistance in leaves as related to their
  stomatal  anatomy and microstructure.  Am. J. Bot.  5J_: 963-975, 1964.

Leland,  E.  W.   Nitrogen and sulfur in the precipitation at Ithaca, New York.
  Agron. J. 44:172-175,  1952.

Leone, I.  A.,  and E.  Brennan.   Modification of sulfur dioxide injury to tobacco
  and tomato by:   Varying nitrogen and sulfur nutrition.   J. Air Pollut. Control
  Assoc. 22:544-547,  1972.

Likens,  G.  E.   The chemistry of precipitation in the central Finger Lakes region.
  Cornell  Univ.  Water Res. Mar. Sci. Center,  Ithaca, N.Y. Tech. Rep. No. 50.
  1972.   62 p.

Likens,  G.  E.   Acid precipitation.  Chem. Eng. News 22:29-44, 1976.

Likens,  G.  E., and F.  H. Bormann.   Acid rain:   A serious regional environmental
  problem.   Science 184:1176-1179, 1974.
                                 359
-------
Likens,  G.  E. ,  F.  H.  Bormann, J.  S.  Eaton et al.   Hydrogen ion input to the
  Hubbard Brook Experimental Forest, New Hampshire, during the last decade.
  I_n:   Proceedings of the 1st International Symposium on Acid Precipitation
  and the Forest Ecosystem.   USDA Forest Service Technical Report No. NE-23.  1975.
  1074 p.

Likens,  G.  E.,  F.  H.  Bormann, and N. M.  Johnson.   Acid rain.   Environment
  J4:33-40, 1972.

Linzon,  S.  N.   The Influence of Smelter Fumes on the Growth of White Pine  in
  the Sudbury Region.  Canadian Department of Agriculture Publication.
  Ontario Department of Lands and Forests, 1958.   45 p.

Linzon,  S.  N.   Sulfur dioxide injury to trees in the vicinity of petroleum
  refineries.   Forest Chron. 41_: 245-250, 1965.

Little,  P., and R. D. Wiffen.  Deposition of Pb in petrol engine exhaust to
  plant and soil surfaces.  In:  Proceedings of the International Symposium
  on Sulfur in the Environment, Dubrovnik, Yugoslavia, 1977.   (In press.)

McCallan, S.  E. A., and F. R. Weedon.  Toxicity of ammonia, chlorine, hydrogen
  cyanide,  hydrogen sulfide, and sulfur dioxide gases.  II.  Fungi and bacteria.
  Contrib.  Boyce Thompson Inst. Vh 331-342, 1940.

Majernik, 0.   Physiological  study of the effects of sulfur dioxide pollution,
  phenylmercuric acetate sprays.   2) Parasitic infection on stomatal behavior
  and aging in barley.  Phytopathology 72:255-268, 1971.

Majerr.'k, 0.,  and T.  A. Mansfield.   Direct effect of S02 pollution on the
  degree of opening of stomata.  Nature 227:377-378, 1970.

Mandl, R. H.,  L. H. Weinstein, and M. Keveny.  Effects of hydrogen fluoride
  and sulfur dioxide alone and in combination on several species of plants.
  Environ.  Pollut. 9:133-143, 1975.

Mansfield,  T.  A., and 0.  Majernik.   Can stomata play a part in protecting  plants
  against air pollution?  Environ.  Pollut. J:149-154,  1970.

Marten, E. A., and S. Poet.  Residence times of natural and pollutant aerosols
  in the troposphere.  Jin:  Air and Water Pollution, Boulder, Colo., Colorado
  Associated University Press, University of Colorado.  1970.  p. 459-476.

Matsushima, J., and R. R. Brewer.  Influence of sulfur dioxide and hydrogen
  fluoride as a mix of reciprocal exposure on citrus growth and development.
  J. Air Pollut. Control Assoc. 22:710-713, 1972.

Meidner, H.,  and T. A. Mansfield.  Physiology of Stomata.  London, McGraw-Hill.
  1968.   128 p.

Menser,  H.  A. ,  and H. E.  Heggestad.   Ozone and sulfur  dioxide synergism:   Injury
  to tobacco plants.   Science j_53:424-425, 1966.

Meszaros, E.   Seasonal and diurnal variation of atmospheric sulfate particles.
  Tellus 23:235-238, 1970.


                                 360
-------
Middleton, J. T. ,  E. F. Darley, and R. F. Brewer.  Damage to vegetation
  from polluted atmosphere.  J. Air Pollut. Control Assoc. 8:9-15,  1958.

Middleton, J. T.,  L. 0. Emik, and 0. C. Taylor.  Air quality criteria  and
  standards for agriculture.  J. Air Pollut. Control Assoc. Jj>:476-480,  1965.

Middleton, J. T.,  J. B. Kendrick, Jr., and H. W. Schwalm.  Injury to herbaceous
  plants by smog or air pollution.  Plant Dis. Rep. 34:245-252,  1950.

Miller, J. M.,  and R.  G. de Pena.  Contribution of scavenged sulfur dioxide  to
  the sulfate content of rain water.  J. Geophys. Res. 27:5405,  1972.

Miller, P. R.,  and J.  R. McBride.  Effects of air pollutants on  forests.   In:
  Responses of Plants to Air Pollution.  J. B. Mudd and T. T.  Koslowski  (eds.).
  New York, Academic Press.  1975.  p. 195-235.

Mrose, H.   Measurements of pH and chemical analysis of rain, snow and  fog
  water.  Tellus J8:266-270, 1968.

Mrvka, R., and B.  Grunda.   Einfluss von Immisionen auf die Walkboden und
  ihre Mikroflora im Gebiet von Sudmahren.  Acta Univ. Agr. Brno 38:247-270,
  1969.

Mudd, J. B.  Sulfur dioxide.  _In:  Responses of Plants to Air  Pollution.
  J. B. Mudd and T.  T.  Koslowski (eds.).  New York, Academic Press.  1975.
  p. 9-22.

Muhlbaier, J.  The Chemistry of Precipitation near the Chalk Point  Power Plant.
  Ph.D. Thesis, University of Maryland.  College Park, Md. 1978.

Murray, J. J.,  R.  K. Howe11, and A. C. Wilton.  Differential response  of
  seventeen Poa pratensis cultivars to ozone and sulfur dioxide.  Plant  Dis.
  Rep. 59:10, 1975.

Nelson, K. E.  Some studies of the action of sulfur dioxide in the  control of
  Botrytis rot of tokay grapes.  Proc. Am. Soc. Hort. Sci. 71_: 183-189, 1958.

Nelson, K. E.,  and M.  Ahmedullah.  Effect of type of in-package  sulfur
  dioxide generator and packaging materials on quality of stored table grapes.
  Am. J. Enol.  Viticulture 23:78-85, 1972.

Nicholson, C. R.  The Response of 12 Clones of Eastern White Pine (Pinus
  strobus) to Ozone and Nitrogen Dioxide.  M.S. Thesis, Virginia Polytechnical
  Institute and State University.  Blacksburg, Va. 1977.  141  p.

Nielson, D. G., L. E.  Terrell, and T. C. Weidensaul.  Phytotoxicity of ozone
  and sulfur dioxide to laboratory fumigated Scotch pine.  Plant Dis.  Rep.
  61:699-703, 1977.

Nikolaevskii, V. A.   Mechanisms of sulfur dioxide absorption by woody  plants.
  Uch. Zap., Perm. Cos. Univ. 277:29-35, 1971.
                                 361
-------
Oden, S.   The extent and effects of atmospheric pollution on soils.  TAO
  Conference.  1963.  20 p.

Oden, S.   Aspects of the atmospheric corrosion climate.  In:  Conference on
  Current Corrosion Research, Helsinki, Finland.  1964.  13 p.

Oden, S.   The acidification of air and precipitation and its consequences on
  the natural environment.   Swedish Nat.  Sci. Res. Council, Ecol. Committee
  Bull.  No. TR-1172.  1968.  86 p.

Oden, S., and T.  Ahl.   The acidification of Scandinavian lakes and rivers.
  Ymer Arsbok.  1970.   p.  103-122.

Oden, S. , R. Andersson, and M. Bartling.   The long term changes  in the chemistry
  of soils in Scandinavia  due to acid precipitation.   In:   Sweden's Case Study
  for the United Nations Conference on the Human  Environment.  B. Bolin (ed.).
  Stockholm, Sweden, Royal  Ministry of Agriculture.  1972.  20 p.

Overrein, L. N.  Sulfur pollution patterns observed; leaching of calcium in
  forest soil determined.  Ambio 1_: 145-147, 1972.

Pearson, F. J., and D. W.  Fisher.  Chemical composition of  atmospheric precipi-
  tation in the northeastern United States.  Washington, D.C., U.S. Government
  Printing Office.  U.S.G.S. Water Supply Paper No. 1535-P.  1971.  69 p.

Petrenshuck, 0. P., and E.  Selezneva.  Chemical composition of precipitation  in
  regions of the Soviet Union.  J. Geophys. Res.  7_5: 3629-3634, 1970.

Phillips, S. 0., J.  M. Skelly, and H. E.  Burkhart.  Growth  fluctuations of
  loblolly pine (Pinus taeda L.) proximal to a periodic source of air pollu-
  tion.   Phytopathology 67:716-720, 1977a.

Phillips, S. 0., J.  M. Skelly, and H. E.  Burkhart.  Inhibition of growth in
  asymptomatic white pine  exposed to fluctuating  levels of  air pollution.
  Phytopathology 67:721-725, 1977b.

Pollanschutz, J.  The susceptibility of various tree species to  sulfur dioxide,
  hydrogen fluoride and magnesite dust pollution.   I_n:  Proceedings of the  1st
  European Congress on the Influence of Air Pollution  on Plants  and Animals,
  Wageningen, The Netherlands.   1968.  p. 371-377.

Reinert, R. A.  Monitoring detecting and effects  of air pollutants on horti-
  cultural crops sensitivity of genera and species.  Hort.  Sci.  1C):495-500,
  1975.

Reinert, R. A.  Pollutant  interactions and their  effects on plants.  Environ.
  Pollut. 9:115-116,  1975.

Reinert, R. A., A.  S. Heagle, and W. W. Heck.   Plant response to pollutant
  combinations.  Ijy.  Responses of Plants to Air  Pollutants.  J. B. Mudd and
  T. T.  Koslowski (eds.).  New York, Academic Press.   1975.  383 p.

Reinert, R. A., A.  S. Heagle, J.  R. Miller et al.   Field studies of air
  pollution  injury  to vegetation  in Cincinnati, Ohio.   Plant Dis.  Rep. 54:8-11,
  1970.

                                  362
-------
Ricks,  G.  R.,  and R.  J.  Williams.   Effects of atmospheric pollution on
  deciduous woodland.   2)  Effects of particulate matter upon stomatal
  diffusion resistance in leaves of Quercus petraea.   Environ. Pollut.
  6:87-109, 1974.

Roberts, B. R.   Absorption of gaseous pollutants by individual leaves:  Sulfur
  dioxide.   Phytopathology 64:585, 1974.

Rodhe,  H.   On the residence time of anthropogenic sulfur in the atmosphere.
  Tellus 22:137-139,  1970.

Rodhe,  H.   A study of the sulfur budget for the atmosphere over northern
  Europe.   Tellus 24:128-137, 1972.

Saalbach,  E.,  G.  K.  Judel, and G.  Kesse.   Uber den Einfluss des sulfatgehaltes
  im Boden auf die Wirkung einer Schwefeldungung.  Z.  Pflanzenernaehr.  Dueng.
  Bodenk.  99:177-182,  1962.

Saunders,  P.  J.  W.  The toxicity of sulfur dioxide to Diplocarpon rosae Wolf
  causing blackspot of roses.  Ann. Appl.  Biol. 58:103, 1966.

Scheffer,  T.  C.,  and G.  G. Hedgcock.   Injury to northwestern forest trees by
  sulfur dioxide  from smelters.   USDA Technical Bulletin No. 1117.  1955.  49 p.

Schnel,  G.  A.,  and W.  A.  Hodgson.   Predicted dry deposition velocities.  In:
  Atmosphere-Surface Exchange of Particulate and Gaseous Pollutants Symposium.
  Conf-740921.   1974.

Scott,  W.  D.,  and P.  V.  Hobbs.  The formation of sulfate in water droplets.
  J.  Atmos. Sci.  24:54,  1967.

Setterstrom,  C.,  and P.  W. Zimmerman.   Factors influencing susceptibility of
  plants to sulfur dioxide injury.  Contrib. Boyce Thompson Inst. 10:155-186,
  1939.

Shramel, M.  Influence of sulfur dioxide on stomatal  apertures and diffusive
  resistance of leaves in various species of cultivated plants under optimum
  soil  moisture and drought conditions.   Bull. Acad.  Pol. Sci. Ser. Sci. Biol.
  23:57-63, 1975.

Shriner, D. S.   Effects of Simulated Rain Acidified with Sulfuric Acid on
  Host-Parasite Interactions.  Ph.D.  Thesis, North Carolina State University.
  Raleigh,  N.C.   1974.

Shriner, D. S.   1978.   Effects of simulated acidic rain on host parasite
  interactions in plant diseases.   Phytopathology ^8:213-218, 1978.

Skelly,  J.  M.,  and J.  W.  Johnston.  Oxidant levels and their associated impact
  to Pinus strobus in the Blue Ridge Mountains of Virginia.  In:   Proceedings
  of the 3rd International Congress on Plant Pathology, Munich, West Germany,
  1978.   (In press.)

Skelly,  J.  M.,  and R.  C.   Lambe.   The Diagnosis of Air Pollution Damage to Plants.
  Virginia Cooperative Extension Service Publication No. 568.  1974.   16 p.


                                 363
-------
Skelly, J.M.,  L.D.  Moore, and L.L.  Stone.   Symptom expression of eastern
  white pine located near a source of oxides of nitrogen and sulfur dioxide.
  Plant Dis.  Rep.  56:3-6, 1972.

Solberg, R.A., and D.F. Adams.  Histological responses of some plant leaves
  to hydrogen fluoride and sulfur dioxide.  Am. J. Bot. 43:755-760, 1956.

Sorauer, P.  Anatomic analysis of plants damaged by smoke.  Landw. Jahrb.
  585-664, 1904.

Soto, A.E.,  A. Pinto de Torres,  and E.L. Cancino.  Preventive Control of
  Postharvest Rotting of Table Grapes.  Agr. Technol. 33:176-182,1973.

Spaulding, P.   The Present Status of the White Pine Blights.   U.S. Department
  of Agruculture Circular 35.  1909. p. 1-12.
Spedding, D.J.  Uptake of sulfur dioxide by barley leaves at low sulfur
  dioxide concentrations.  Nature 2_24:1229-1231, 1969.

Steinhardt,  I., D.G. Fox, and W.E.  Merlatt.  Modeling the Uptake of
  Sulfur Dioxide by Vegetation.   USDA Forest Service General  Technical
  Report RM 32:209-213, 1976.

Stewart, D., M. Treshow, and F.M. Harner.   Sulfur dioxide and hydrogen fluprode
  emissions in regard to phytopathology.  Can. J. Bot. 51:983-988, 1973.

Stoeckhardt, A.  Untersuchungen ueber die schaedliche Einwirkung des Huettenund
  Steinkohlenrauches auf das Wachsthum der Pflanzed, Insbesondere der Fichte
  und Tanne.  Tharandt. Forstl.  Jahrb.  21:281-154, 1871.

Stoklasa, J.  Die Beschadigungen der Vegetation Durch Rauchgase und Fabrikexha-
  lationen.   Berlin-Wein, Urban u.  Schwarzenberg.  1923.

Stone, L.L., and J.M. Skelly.  The growth of two forest tree species adjacent
  to a periodic source of air pollutants.   Phytopathology 6_4:773-778, 1974.

Stotzky. G.   Air Pollution and Microbial Effects.  Yonkers, N.Y., National  Air
  Pollution Workshop.  1971.  (Mimeograph)

Sundstrom, K.R., and J.B. Hallgren.  Using lichens as physiological indicators
  of sulfurous pollutants.  Ambio 2:13-25, 1973.

Syratt, W.J., and P.J. Wainstall.  The effect  of S02 on epiphytic bryophytes.
  In:  Proceedings of the 1st European Congress on the Influence of Air  Pollu-
  tion on Plants and Animals, Wageningen, The  Netherlands.  1968.  p. 79-85.

Tarrant, R.F., K.C. Lu, and W.B. Bollen.  Nitrogen content of precipitation
  in a coastal Oregon forest opening.  Tellus  20:554-556, 1968.

Taylor, O.C.  Acute responses of plants to aerial pollutants.   In:  Air  Pollu-
  tion Damage to Vegetation.  J.A.  Naegele (ed.).  Washington,  D.C., American
  Chemical Society.  1973.  137 p.   Advances in Chemistry Series 122.
                                 364
-------
Thomas, M. D.   Effects of air pollution on plants.   In:  Air  Pollution.   New
  York, Columbia University Press.  World Health Organization Monograph  Series
  No.  46.   1961.   p. 233-278.

Thomas, M. D. ,  and R. H. Hendricks.  Effect of air pollution  on  plants.   In:
  Air Pollution Handbook.  P.  L. Magill et al.  (eds.).  New  York.   1956.
  p.  1-44.

Thompson,  C.  R., and G. Kats.   Effects of continuous H2S fumigation  on crop
  and forest plants.  Environ. Sci. Technol. J_2:550-553, 1978.

Thornton,  C.  C., and C. Setterstrom.  Toxicity of ammonia, chlorine,  hydrogen
  cyanide, hydrogen sulfide and sulfur dioxide gasses.  III.  Contrib. Boyce
  Thompson Inst.   1_1_(5):343-356, 1940.

Ting,  I.  P.,  and W.  M. Dugger.  Factors affecting ozone sensitivity  and  sus-
  ceptibility of cotton plants.  J. Air Poll lit. Control Assoc.   18:810-813,
  1968.

Ting,  I.  P.,  M. L.  Thompson, and W. M. Dugger.  Leaf resistance  to water va-
  por transfer in succulent plants:  Effect of thermoperiod.  Am. J.  Bot.
  54:245-251,  1967.

Tingey, D. T.,  and R. A. Reinert.  Effect of ozone and sulfur dioxide singly
  and in combination on plant growth.  Environ. Pollut. 9:117-25, 1975.

Tingey, D. T.,  R.  A. Reinert,  J. A. Dunning, and W. W. Heck.  Vegetation
  injury from the interaction of nitrogen dioxide and sulfur  dioxide.
  Phytopathology 61_: 1506-1511, 1971.

Tingey, D. T.,  R.  A. Reinert,  J. A. Dunning, and W. W. Heck.  Foliar injury
  responses of eleven plant species to ozone/sulfur dioxide mixtures.  Atmos.
  Environ. 2:201-208, 1973.

Tingey, D. R. ,  R.  A. Reinert,  C. Wickliff, and W. W. Heck.  Chronic  ozone
  or sulfur dioxide exposures or both affect the early vegetative growth of
  soybean.  Can.  J.  Plant Sci. 53:875-879, 1973.

Unsworth,  M.  H., P.  V. Biscoe, and H. R. Pinckney.  Stomatal  responses to
  sulfur dioxide.   Nature 239:458-459, 1972.

USDA Forest Service General Technical Report.  Proceedings of the First  Inter-
  national Symposium on Acid Precipitation and Forest Ecosystem.  NE-23.   1976.
  1074 p.

U.S.  Environmental  Protection Agency.  Effects of Sulfur Oxides  in the Atmos-
  phere on Vegetation.  Raleigh, N.C., National Environmental Research Center.
  Report No.  EPA-R3-73-030.  1973.  43 p.
                                 365
-------
j.S.  Environmental Protection Agency.  Second Annual Catalyst Research Pro-
  gram Report:   Summary.   Report No. EPA-600/3-77-008.  1977.  72 p.

Ian Haut, H.,  and H.  Stratmann.   Farbtafelatlas uber Schwefeldioxid-Wirkungen
  an Pflanzen.   Essen, West Germany, Verlag W. Girardet.  1970.   206 p.

teddell,  T. E.,  and D. G. Gillette.  Methods of assessing air pollution injury.
  Section X.   |n:  Handbook of Effects Assessment—Vegetation Damage.  N. L.
  Lacasee and W. J. Moroz (eds.).  University Park, CAES Publications,
  Pennsylvania State University.   1969.

Gagman, J.  Influence of some atmospheric variables on the concentration of
  sulfate in urban air.   Atmos.  Environ. 2:479-489, 1967.

Weber, D. E.,  R. A. Reinert, and K. R. Barker.  The effects of ozone and sulfur
  dioxide in selected species of plant parasitic nematodes.  Proc. Am. Phyto-
  pathol. Soc.  1:133, 1974.

a/eber, E.  1970.  Contribution to the residence time of sulfur dioxide in a
  polluted atmosphere.  J.  Geophys. Res. 75:2909-2921, 1970.

Veidensaul, T.  C., and N. L. Lacasse.  Results of the 1969 statewide survey
  of air pollution damage to vegetation in Pennsylvania.  Plant Dis. Rep.
  56:701-704,  1972.

Weinstein, L.  H., D.  C.  McCune, A. L. Aluisio, and P. Van Leuken.  Effect of
  sulfur dioxide on the incidence and severity of bean rust and early blight
  of tomato.   Environ. Pollut. 9:145-155, 1975.

tfeiss, R. E. ,  A. P. Waggoner, R.  J. Charlson, and N. C. Ahlquist.  Sulfate
  aerosol:  Its geographic extent in the Midwestern and Southern United States.
  Science J95:979-981, 1977.

Whitby, G. S.   The effects of sulfur dioxides on vegetation.  Chem.  Ind. 17:991-999,
  1939.

Whitby, K. T.   The physical characteristics of sulfur aerosols.  Jjn:  Proceedings
  of the International Symposium on Sulfur in the Environment, Dubrovnik,
  Yugoslavia,  1977.  (In press.)

White, K. L.,  A. C. Hill, and J.  H. Bennett.  Synergistic inhibition of apparent
  phytosynthesis rate of alfalfa by combinations of sulfur dioxide and nitrogen
  dioxide.  Environ.  Sci. Techno!. 8:574-576, 1974.

Whitehead, H.  C., and J.  H. Feth.  Chemical composition of rain, dry fallout,
  and bulk precipitation at Menlo Park, California; 1957-1959.  J. Geophys.
  Res. 69:3319-3333, 1964.
                                 366
-------
Wieler, A.   Uber unsichtbare Rauchsaden.  Z. Forst Jagdwes.  35:204-225, 1903.

Wilson, B.  J.   Nitrogen and sulfur in rain water in New York.  J. Am. Soc.  Agron.
  ]8:1103-1112, 1926.

Wodzinski,  R.,  D.  P.  Labeda, and M. Alexander.   Effects of low sulfur dioxide
  concentrations on algae.  Annu. Meet.  Am.  Soc. Microbiol.  77:233, 1977.

Wood, F. A.  Sources of plant-pathogenic air pollutants.  Phytopathology
  58:1075-1084, 1968.

Wood, T.  Acid precipitation.  In:  Sulfur in the Environment.  St.  Louis,
  Mo., Missouri Botanical Garden.  1975.  189 p.

Wood, T.,  and F. H.  Bormann.  The effects of an artificial acid mist upon the
  growth of Betula alleghaniensis Britt.  Environ.  Pollut.  7:259-268,  1974.

Wrobel, S.   Effect of sulfur dioxide on aquatic organisms.  Fortschr.  Wasserchem.
  Ihrer Grenzget.   V*:181-185, 1972.

Zimmerman,  P.  W.  Chemicals involved in air pollution and their effects upon
  vegetation.   Prof.  Papers Boyce Thompson Inst.  2:124-145, 1955.

Zimmerman,  P.  W.  Impurities in the air and their influence on plant life.   In:
  Proceedings of the 1st National Air Pollution Symposium.  1950.  p. 135-141.

Zimmerman,  P.  W.,  and W. Crocker.  Toxicity of air containing sulfur dioxide
  gas.  Contrib. Boyce Thompson Inst.  6:455-470, 1934.
                                 367
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B.2  EFFECT ON NONBIOLOGICAL MATERIALS







B.2.1  Introduction







     The damaging effects of air pollution on nonliving objects can be



quantified in economic terms by a materials damage estimate.   This estimate,



based on complex methods of data selection and analysis, helps to assess



the relative costs and benefits of attempts to reduce or prevent pollution.



On the basis of studies conducted to date, a best-guess estimate of materials



damage from sulfur-bearing compounds emitted by mobile sources (2 percent



contribution) is $30 million annually.   It should be noted,  however, that



the state of the art in making materials damage estimates is  relativity



undeveloped.   The accuracy and validity of these estimates could be improved



greatly by refining the economic damage function, which is a  measure of



the cost of damage relative to the degree of pollution.   Better methods



for assessing various indirect costs are needed as well.







     Mobile sources account nationwide for an average of less than 2



percent of all manmade sulfur compound emissions (stationary  sources



account for most sulfur emissions).   There are no data relating materials



damage to mobile sources per se, only a large body of data relating materials



damage to specific levels of certain sulfur-bearing compounds.  Since it



is not possible in ambient air measurements to identify unequivocally the



source of these compounds, the only available way to estimate damage by a



sulfur-bearing compound from mobile sources is to multiply the overall



damage values by the relative proportion of mobile sources to all sources



(2 percent).   No studies have been conducted to isolate the relative
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contribution of mobile versus nonmobile sources in particular areas, such



as roadways, where the mobile source contribution might be much higher



than the nonmobile source contribution.







     In terms of potential damage to materials, the most significant



sulfur compounds emitted from mobile sources are sulfur dioxide (SCL),



hydrogen sulfide (H^S), sulfuric acid (HpSO.), and absorbed sulfates



(SO.).   Less significant species such as organic sulfides, disulfides, and



thiophenes are present, if at all, at relatively low concentrations.



Since these organic compounds react minimally with common nonliving materials,



they  are not considered in this report.







     It is important to consider damage to materials by the type of sulfur



compound emitted by mobile sources.   The various species of sulfur compounds



emitted directly from these sources are often transformed into other



species.   These transformed products may have damaging effects different



from those of the original compounds.  Therefore, knowing what compounds



are emitted is not always sufficient to predict subsequent damage to



materials.







B.2.2  Physical Damage







B.2.2.1  Types and mechanisms of damage—General 1y, air pollutants damage



materials by five principal mechanisms:  abrasion, direct and indirect



chemical  attack, corrosion, and particle deposition and removal.
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     There is insignificant damage from abrasion attributable to mobile



source pollution.   Direct chemical attack can occur,  however, including



the etching of metallic surfaces by acid mists (e.g.,  H^SO.), blackening



of lead-based paints (e.g., by hLS), or leaching or spelling of carbonate



building stone (e.g., by S02).   Indirect chemical attack can also occur in



certain materials that absorb pollutants which cause  damage when they



undergo chemical change.







     Some atmospheric pollutants speed up the rate of corrosion considerably.



One particular corrosion mechanism, an electrochemical process, is responsible



for the deterioration of most ferrous metals.   When exposed to pollutants



in the atmosphere, the metallic surfaces form numerous tiny electrochemical



cells. Their reaction with water, even as a molecular layer on a surface



that appears dry,  provides an impetus force for corrosive action, and the



metal dissolves away.  Another corrosive mechanism involves removing



protective layers from materials surfaces.   For example, the green patina



on copper exposed to the atmosphere is attacked by H^S, which eventually



causes the surface to flake off and expose the metal  beneath to additional



damage.   Another,  more important example is the destruction of galvanized



coatings by the acid species.







     The most common effect of particle deposition on fabrics, painted



surfaces, and building materials is discoloration, occurring directly by



accumulation of the particles themselves or indirectly by other pollutants



absorbed by the particles. Cleaning discolored materials can be costly and



can further damage or shorten the useful life of the  object involved.
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B.2.2.2  Environmental factors—Damage from pollutants can occur through



synergistic interaction with natural factors such as moisture, particles,



temperature, sunlight, air movement, physical position, and biological



action.








     Without moisture, little if any atmospheric corrosion would occur



even in highly polluted environments.   Ironically, visibly wet surfaces



often reduce corrosion rates, probably from the dilution and washing away



of the corrosive material.  Corrosive agents, however, can accumulate at



the lower edge of a metallic object and accelerate corrosion there.   For



several metals there is a critical  atmospheric humidity that determines



the corrosion rate in polluted air.   It has been determined, for example,



that as relative humidity approaches 80 percent, the corrosive effects of



SOp proceed rapidly.








     In moist atmospheres, concentration of salt particles on the surface



of metals can greatly accelerate metal  corrosion.   In addition, heating



and cooling can speed up chemical reactions in metal deterioration.   For



example, at night, metal  objects often cool below the temperature of the



ambient air and, if the dew point is reached, moisture accumulates,  accel-



erating corrosion.  Freezing and thawing in the presence of moisture



speeds the deterioration of porous  materials such as concrete and building



stone.   Sunlight can also deteriorate certain materials, such as rubber



and painted surfaces.   Wind speed is significant in determining whether



solid and liquid agents impact on vertical  surfaces, settle on horizontal



surfaces, or produce abrasion.   Air movement can influence the volume of
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pollutant reaching the surface of a material and, subsequently, the rate



or even the type of reaction.







     Spatial position is an important variable in atmospheric corrosion.



In corrosion tests in which samples were mounted at 30 or 45 degrees from



the horizontal, the under surfaces often corroded more rapidly than the



upper surfaces.  The reason for this difference may have been that upper



surfaces were washed by rainfall and were less susceptible to lingering



dampness than were under surfaces.







     Biological action such as mildew and bacteria can affect materials of



natural origin, such as cotton, wood, and leather.  Lichens and other



plants affect the moisture level of the surface of materials on which they



grow.







     The order in which substances contact a surface is also significant.



For example, if copper is first exposed to ambient air, a thin oxide film



develops to help protect it against hydrogen sulfide.   But if the copper



is exposed to hydrogen sulfide before the protective coat forms, deteriora-



tion begins and can proceed to destruction.







B.2.2.3  Physical damage functions—A physical damage function is a mathe-



matical equation relating the damage of a given material to the pollutants



and environmental factors that caused the damage:  D = f(P, F, t).







     The damage (D) is expressed in terms appropriate to the pollutant/material



interaction.  For example, the corrosion of steel plate would be expressed
                                     372
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in units of thickness lost, but the soiling of paint would be stated in



units of reflectance.  The pollutant level (P) can be expressed in any



concentration unit.   Since materials damage usually takes some time to



develop, average or long-term pollutant levels are often used.   The effects



of other environmental factors (F) are often included in only a gross way



by specifying a type of environment (cold, wet, etc.).   However, meteoro-



logical parameters can be obtained and used with as much detail as are



pollution level data, if desired.   Relative humidity, rainfall, time of



wetness, sunlight, wind speed and direction, temperature, and other values



are available for many locations.   Additional  environmental  factors can be



approximated by more detailed geographical descriptions (e.g.,  New England/



coastal/industrial).    Time (t) is usually expressed in years.  The yearly



time scale makes economic comparisons easier and allows more averaging of



conditions in changeable climates.








B.2.3  Aesthetic Damage








     In many parts of the world,  air polluted  with sulfur oxide is silently



eating away irreplaceable works of art.   Some  of the finest  monuments of



antiquity and thousands of pieces of sculpture and carvings  on  historic



buildings such as cathedrals show vivid evidence of the insidious effects



of polluted atmospheres.   The marble frieze of the Parthenon in Athens,



Greece, is a good example:   a plaster cast made in 1802 shows relatively



minor damage during the first 2240 years,  but  a photograph of the same marble



frieze taken in 1938 is almost unrecognizable  because of rapid  deterioration



during the intervening 136 years  of increasing industrialization.
                                     373
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     Conservation scientists recognize that a number of environmental



agents hasten deterioration.  These include weathering (wind, rain, heat,



snow, and frost), traffic vibration, molds, lichens, and pigeon droppings.



However, sulfur compounds and other air pollutants, the unwanted byproducts



of the industrial age, are considered the major villains.







B.2.4  Economic Damage







     There are two basic approaches calculating the economic damage attributed



to an air pollutant:  comparative and analytic (Stankunas et al.  1978).



Neither approach is considered completely satisfactory.







     The comparative approach studies the lifetime maintenance costs for a



given material in use in several ambient environments.   For the method to



work, the environments should be as similar as possible, except for the



pollutant level.   The total materials damage costs for each of the locations



are used to calculate an economic damage function for the pollutant.



However, several  factors make the comparative approach difficult to apply.



It assumes, for example, that total materials damage costs can be determined



without specifying the type of damage.  The approach is also highly sensitive



to differences in the nonpollutant variables at each location, and it is



difficult to find locations that are suitably matched.   Environmental and



usage factors can differ so much that the whole mechanism of damage changes.



Another weakness in the comparative method is the need to examine many



environments to cancel random errors.  Approximations and simplified



assumptions can obscure the results.
                                     374
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     The analytic approach depends on laboratory- or field study-derived



physical damage functions and ambient air quality information.   First, the



materials and their specific interactions with the pollutants of interest



must be considered. The value of those materials and their use in society



must be assessed.   The exposure of the materials to pollutants and other



environmental factors must be determined, as well as the effects of repair,



replacement, protection, and substitution practices.  Finally, the appropriate



physical damage functions are used to quantify the damage caused by specific



pollutants.   The costs of that damage relative to the degree of pollution



are then calculated, and the total costs attributed to actual pollutant



levels are judged.   The weakness of the analytic approach is inherent in



its dependency on many complex variables, some of which are difficult to



assess in quantitative terms.








B.2.4.1  Choice of materials—Thousands of materials are exposed to sulfur



emissions from mobile sources.   Since a materials damage study cannot



account for all  damage to all materials, a scheme is needed to identify



those materials  whose damage has the greatest economic impact.   In general,



to warrant detailed study a material should both be affected by the pollutant



of interest and be economically important.








     Annual  production figures are of limited usefulness in determining



the economic impact of a given material.   Such figures do not take into



account the use for which the material is intended and do not include the



costs associated with that utilization.  If only materials with very high



annual  production were studied, materials with lower total production but
                                     375
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high loss rate due to pollutant damage would be missed.    This omission



would be particularly important if most of the turnover of the lower



production material arose from pollutant damage.







B.2.4.2  Value of materials—A material's value to society is difficult to



determine, though there are several publications that can be of help.



Retail/wholesale values of steel, for example, are noted in the American



Metal Market/Metal Working News; paint values are noted in the Kline Guide



to the Paint Industry.  Actual values of materials are available also



through the U.S. Government agencies that contribute to the Annual Consumer



Price Index.  However, the cost of the materials themselves is only a



small part of the costs of pollutant damage.







     Determining the cost of material becomes more complex when the cost



of labor is included.  Most studies simply apply a "labor factor" to the



overall cost of the material.  Since labor costs of production or installation



dominate total costs for most materials, any uncertainties or errors in



estimating a labor factor are greatly magnified in subsequent calculations.



Also, the labor factor gives no indication of the differences in value



that arise from differences in how the materials are used (e.g., assembly



line spray painting versus hand painting by a steeplejack).







B.2.4.3  Maintenance—A major cost item that has not been adequately



considered in most materials damage studies is maintenance.   Some of the



early studies completely ignored the fact that maintenance activity is



widely performed to mitigate the effects of materials damage.  More recent



studies have included the concept of maintenance, but only as it relates
                                     376
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to loss or degradation of materials.   Generally, it can be assumed that if



the costs of failure of a given component exceed the cost of preventive



measures, these measures will be taken.








     In some instances, maintenance may not be cost effective.   Uncoated



galvanized fencing, for instance, is less expensive to replace than it is



to maintain.  On the other hand, color-coated galvanized fencing has prepaid



maintenance value (as well as aesthetic value).   Unless the analytic



approach specifically accounts for the principal maintenance-controlling



factors, the damage cost estimate it generates is almost useless.








     In some cases, protection against air pollution damage may arise from



normal  maintenance, but it may not be the primary determinant of the



maintenance schedule.   For example, the protective coating of paint applied



to steel bridges, particularly to the roadway surface, will usually be



damaged by rock impact, salt, and other such factors long before the paint



can be  appreciably damaged by air pollution.   Similarly, a house may need



repainting because of peeling damage caused by moisture.  In both cases,



maintenance is required because of damage to the paint arising from factors



other than air pollution.   In essence, then,  air pollution is not always



the major determinant of the maintenance schedule or cost.








B.2.4.4  Relative 1ifetimes--The damage by a pollutant must be significant



relative to the normal lifetime of the material.  Children's shoes are



rarely  discarded because of SOp damage,  although the leather may have a



measurable damage function.   There are hundreds of similar examples.   To
                                     377
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assess damage costs, it must be shown that the pollutant has a direct



influence on the useful life of the material.   This concept is only recently



gaining general acceptance in materials damage estimates.







B.2.4.5  Exposure—A critical element in determining dollar losses due to



pollutant attack is the amount of material actually exposed to pollutants.



In the past, that factor has been calculated by determining the amount



produced during a period equal to the standard useful life of that material,



followed by the application of an "exposure factor."  The most serious



flaw in this methodology is the assumption that once a material is in



place it remains unchanged, except for deterioration. In some cases such



an assumption may be warranted, but in others  it totally ignores the



effects of maintenance operations.







     Galvanized steel is a good example.   Not  only has pollutant damage to



galvanized steel been well studied, but such damage is included in many



materials damage estimates.  For many years galvanized surfaces were not



coated because of poor paint adhesion.  During the last 10 years, however,



numerous paints and coatings have been introduced that not only adhere to



galvanized steels but also offer excellent pollutant resistance (J. E.



Kubanic, personal communication, 1978).  Where bare galvanized steels are



susceptible to pollutant attack, the coating of such materials (especially



for roofing and siding applications) has become common.   Therefore, although



galvanized products are still in extensive use, the amount of zinc actually



exposed to pollutants has greatly decreased—a factor not considered in



most materials damage estimates to date.
                                     378
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     It is important to note that air pollutant damage is basically a

surface phenomenon.  Once a material has been coated, the damage function

to be considered is no longer that of the original material, but that of

the coating.   Figure B-5 illustrates a hypothetical case where a material

of one susceptibility is coated with a material of different susceptibility

to pollutant attack.  The rate of damage of the original material is

changed to the rate of damage of the coating.   When the coating has deteriorated

to the point that it no longer provides protection, the rate of damage may

revert to or even exceed the original surface rate.  However, it is common

practice to repaint either before deterioration reaches ~10 percent or

well before serious damage to the underlying material occurs (Steel Structures

Painting Council 1977).
                                                        4—Time
               Figure B~5.   Hypothetical rate of damage:
               original material vs.  coating.
B.2.4.6  Social factors--The situation is further complicated for both the

comparative and analytic approaches by the social component of maintenance

schedules.   For instance, although a house may need repainting, the required
                                     379
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work might not be performed if the owner cannot afford it.   On the other



hand, a house not needing painting might be repainted because the owner



wishes to change the color.   It would be erroneous to compute a cost for



maintenance that was warranted but not performed.   Likewise, it would be



wrong to ascribe a maintenance cost to the effects of air pollution when



the reason for the cost-generating maintenance was something else.







B.2.4.7  Indirect costs—The indirect costs of materials damage have not



been documented but may be hypothesized.  For example, reduction in property



values in areas that are perceived as polluted can be a major cost item,



and obvious materials damage can play a major role in that perception.







B.2.5  Major Economic Studies







B.2.5.1  Introduction—Over the past 60 years many attempts have been made



to estimate the costs of air pollution in terms of damage to materials and



soiling.   Because of basic changes in estimation techniques, these earlier



studies are mainly of historical interest and will not be considered here.







B.2.5.2  Recent economic estimates—Recent work has improved estimates of



materials damage costs, but there are still major deficiencies.  Some of



the most serious problems are deeply rooted in the fundamental strategy of



the approaches used.







     The most comprehensive recent review of the economic effect of air



pollutants was assembled by Waddell (1974).  The portion of this review



devoted to the damage to materials was based on several studies using a
                                     380
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number of approaches and covering various parts of the problem area.

These studies are discussed briefly in the following sections.



B.2.5.3  Salmon:   General materials--In terms of the number of materials

covered, the study by Salmon (1970) is the most comprehensive attempted

thus far.  His study covered 32 materials and included a literature survey

and interviews with selected persons.   Costs were based on damaged properties

of the materials  or reduced serviceability.   The economic value of a

material exposed  to air pollution was assumed to be the product of annual

production in dollars multiplied by an average product life.   To this

value was applied an estimate of the net amount of deterioration occurring

as a result of a  fixed amount of air pollution in comparison with deterioration

in a nonpolluted  area.   The results, in terms of dollar cost for each of

32 materials, were ranked according to total annual economic loss.  The

major purpose of  this ranking was to show relative, rather than absolute,

values for air pollution damage.  Salmon listed the pollutants in order of

decreasing economic importance, along with the materials they damage:



          1.    Sulfur oxides:   metals, cotton, finishes, coatings,
               building stone, paints, paper, and leather

          2.    Ozone:   rubber, dyes, and paints

          3.    Nitrogen oxides:  dyes and paints

          4.    Carbon dioxide:  building stone

          5.    Particulates:  stone, clay, and glass
                                     381
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     Salmon estimated costs of soiling to be $100 billion a year,  a figure



based on the total area of the material  exposed,  a unit cost for cleaning



or repainting a surface, and the increased cost of cleaning or painting to



maintain a surface in a "clean" condition.   The standard used for "clean"



was assumed to be that found in a "normal" suburban residential  area.   On



the basis of the methods used and the assumptions made, Salmon's value for



total soiling costs is not considered valid.   Specifically, there is



considerable overlap between soiling and other forms of damage;  moreover,



there are serious questions regarding the validity of presumed costs based



on some arbitrary standard of cleanliness and willingness to pay for such



upkeep.







     To illustrate some of the problems in trying to use this estimate of



soiling cost, Salmon showed that over one-third of the total soiling cost,



or $35 billion, is for paint damage.  The figure is questionable,  since



the total value at the manufacturer's level of shipments of paints, varnishes,



and lacquers in 1968 was only $2.6 billion, or less than one-tenth of



Salmon's value for soiling damage to paint.







B.2.5.4  Robbins:   Electrical contacts--Robbins carried out a study in



1970 to determine whether air pollution causes economically important



damage to electrical contacts.  The categories of equipment covered included



switches, relays,  connectors, potentiometers, and commutators.  The information



for the study was collected through literature searches and discussions



with manufacturers.  The major cost categories covered were the direct
                                     382
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cost of plating contacts with precious metals and the indirect costs

associated with using air-cleaning equipment to provide switch gear with a

pollution-free atmosphere.  These costs are summarized as follows:
                    Plating contacts                   $20 million
                    Air cleaning                        25 million
                    Washing insulators                   4 million
                    Research and development by firms
                      affected by such damage            5 million
                    Costs of equipment failures         10 million
                       Total                           $64 million
     The author concluded that economic damage to electrical contacts was

not as serious as had been thought.   In any case, the principal finding of

the work was that SCL and H?S damage to low-voltage electrical contacts

was more costly than all other types of damage to electrical contacts

combined.   However, it is not clear if these costs were incurred for

prevention of pollution damage or for some other reason.



B.2.5.5  Fink:   Corrosion of metals--In 1971,  Fink and his associates

assessed the costs of air pollution-induced corrosion to metallic systems

and structures exposed to the outdoor atmosphere.  The study was based on

national shipment/value data for selected materials and articles and

assumed that 80 percent of these materials were in "polluted" areas.   Nine

categories of materials were identified as being both economically significant

and sensitive to air pollution damage.   The total cost was made up of two

components:  the extra amount of protection and maintenance needed in

"polluted" areas, and the cost due to shortened life from air pollution-

induced corrosion.


                                     383
-------
     The results of the study are summarized in Table B-13.   Note that the



first four items are principally galvanized structures and systems and



that they account for about 93 percent of the total  cost.   The incremental



costs of color-coated galvanized steel are not included in the estimate.



The principal criticisms of this study are that damage is  not related to



specific levels of air pollutants;  no attempt was made to  account for the



effects of relative humidity and its variations from one part of the



country to another; also, maintenance factors do not include substitution



of a paint surface for a bare galvanized one.







B.2.5.6  ITT:  Electrical components—In 1971, the ITT Electro-Physics



Laboratories studied the effects of air pollutants on electrical components.



The study was similar in approach to that of Robbins and evaluated damage



costs for semiconductors, integrated circuits, television  picture tubes,



connectors, transformers, relays, receiving tubes, and crystals.  Results



of this study indicated that particulate matter is more damaging to electrical



components than is SO^.
                                     384
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           Table B-13.    ANNUAL COST OF CORROSION BY AIR POLLUTION
                   DAMAGE OF EXTERNAL METAL STRUCTURES, 1970

Structural system
Outdoor metal work
Chain link fencing
Pole line hardware
Galvanized wire
and rope
Steel storage tanks
Bridges
Street light fixtures
Power transformers
Transmission towers
Total
Useful life
years
45
30/20
30
20
50/11
30
20
30
30
Cost basis
Maintenance
Maintenance
Replacement
Replacement
Maintenance
Maintenance
Maintenance
Maintenance
Maintenance
Cost,
$ million
914.0
166.0
161.0
112.0
46.3
30.4
11.9
7.5
1.5
1450.6
Percent
of total
63.0
11.5
11.1
7.7
3.2
2.1
0.8
0.5
0.1
100.0
Source:   Fink et al.  (1971).




     Total damage costs attributed to air pollution (including sulfur

compounds) were estimated to  be $15.5 million,  of which $2.3 million was

for damage prevention (e.g.,  protective atmospheres) and $13.2 million was

for maintenance (e.g.,  cleaning, repairing,  and replacement).



B.2.5.7  Spence and Haynie:   Paints—In 1972,  Spence and Haynie investigated

the deterioration of exterior paints by particulate matter and by the

combined effects of SOp and particulate matter.  The authors developed
                                     385
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costs for air pollution-induced paint damage principally on the basis  of



differences in service life between urban and rural  areas.   Of the $704



million estimated total damage costs, $540 million or over 75 percent  was



for household paint.   "Normal  service" life was based on Internal  Revenue



Service estimates.   Such lifetimes, it should be noted,  are often  based



more on depreciation schedules than on actual lifetimes.







B.2.5.8  Gillette:   SO  effects on general materials—In 1975, Gillette
           "     ~ ~ n ~' " A


presented the results of a study based on the same general  approach used



by Fink et al.,  except that he considered a broader range of materials and



limited his investigation to the effects of sulfur oxides.   Further,



Gillette used air quality data and concentration-response data for S0?,



considered the joint effects of humidity and SO,, at various locations  in



the country,  assumed that materials were distributed according to  population,



and considered the differences between indoor and outdoor exposures.







     Table B-14 tracks Gillette's estimated S02 damage costs for the years



1968-72.  Note that estimated damage costs dropped from $909 million in



1968 to $75 million in 1972.  The author further estimated that SO^ damage



costs were probably greater than $1 billion prior to 1968.   He also showed



that between 1968 and 1972 the estimated percentage of materials exposed



to levels exceeding the primary annual average standard (80 ug/m ) dropped



from 25 percent to 3 percent.







B.2.5.9  National estimate of materials damage costs—Waddell summarized



several studies to estimate nationwide costs of air pollution damage in



1970.  The studies he considered are listed in Table B-15.
                                     386
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    Table B-14.  ESTIMATED MATERIALS DAMAGE COSTS ATTRIBUTED TO AMBIENT S02
                 LEVELS BY REGIONS OF THE UNITED STATES, 1968-72
     Year
Northeast
Damage costs, $ x 106
    North
   Central     South
West
Nationwide
1968
1969
1970
1971
1972
649.8
430.3
278.4
46.7
33.9
212.5
193.2
102.3
42.1
29.8
23.8
12.2
7.3
8.8
6.3
23.1
13.1
8.6
10.5
5.0
909.2
648.8
396.6
108.1
75.0
Note:  Materials damage and S02 levels were calculated by Standard Metropolitan
       Statistical Areas (SMSAs).   In each SMSA, the air quality measured at
       the center city site was assumed to be representative of the air quality
       for the entire SMSA.

Source:  Gillette (1975).
            Table B-15.   ESTIMATES OF TOTAL COSTS FROM AIR POLLUTION
                             DAMAGE TO MATERIALS IN 1970

Source of
information
Muel ler-Stickney
Gillette
Material
category
Elastomers
General materials
Principal
pol lutants
Ozone
S02
Estimated cost,
$ billion
0.5
0.4
Salvin

Spence-Haynie

Salmon



    Total
        but principally
        metal  corrosion

        Textiles & dyes

        Paints

        Remainder of
        important mater-
        ials not accounted
        for above
                 N02, 03                0.2

                 Particulates,  S02      0.7

                 Various, but probably  0.4
                 mostly S02             	


                                        2.2
Source:   Waddell (1974).
                                     387
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     Waddell assumed that the Gillette study is more defensible than the Fink



study, that it does not significantly overlap the Spence-Haynie study,  and that



it includes damage to electrical  contacts and components.   If the materials



evaluated in these studies (zinc, paints, rubber, carbon and alloy steel, fibers,



cement and concrete, plastics, building brick, paper, leather, wood, and building



stone) plus those believed by Fink to be relatively unaffected by air pollution



(aluminum, copper, stainless steel, and lead) are subtracted from the Salmon study,



a total remainder from the Salmon study of $0.4 billion is obtained.  Using these



data and the assumptions outlined above, Waddell estimated 1970 air pollution



damage costs to be $2.2 billion.
                                     388
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Bibliography

Abe, H., Y. Ishii, and H. Kato.  Evaluation of atmospheric factors  by
  analyses of corrosion products and surface deposits on copper plates.
  Rail. Techno!. Res. Inst.  J_2(3): 170-174, 1971.

Adams, A.  A Study of Exposed Reinforced Concrete Facings.  Division of
  Building Research Technical Translation 993.   (Translated by D. A.
  Sinclair from Ann.  Inst. Tech. Batim. Trav.  Publics 159-160:377-388,
  1961.)  Ottawa, National Research Council of Canada.  1961.

Ailor, W. H., Jr.  Aluminum corrosion at urban and industrial locations.
  J. Struct.  Div. Proc.  Am. Soc. Civil Eng.  95:2141-2160, 1969.

The Aluminum Association, Inc.  Aluminum Statistical Review 1976.
  Washington, D.C.

American Iron and Steel  Institute, Annual Statistical Report  1977.
  Washington, D.C.

Barrett, L. B., and T.  E. Waddell.  Cost of Air  Pollution Damage:   A
  Status Report.  Research Triangle Park, N.C. National Environmental
  Research Center, U.S.  Environmental Protection Agency.  1973.  73 p.
  Publication No. AP-85.

Beloyn, N.  J.   A chamber study.  Fading of dyed  fabrics exposed to  air
  pollutants.  Text.  Chem. Color.  5:128/29-133/34, 1973.

Beloyn, N., and F. H. Haynie.  Soiling of building materials.  J. Air
  Pollut. Control Assoc.   25:399, 1975.

Berger, H.  W.,  M. Tyron,  E. J. Clark, and L. F.  Skoda.  Final Project
  Report on the Effects  of Atmospheric Contaminants on the Durability
  of Building Materials.  Washington, D.C., National Bureau of Standards.
  1970.  36 p.   NBS Report 10 504.

Bigos, J. Theory of Corrosion and Prevention of  Paint Failures.  Proceedings:
  Highway Research Board.  January 1954.

Boyd, W.  K.,  and F.  W.  Fink.   Corrosion of Metals in the Atmosphere.
  Columbus, Ohio, Battelle Laboratories.   1974.

Brown, L. S.   Evaluation of the Condition of the Lincoln Memorial
  Stonework.   Study conducted for the U.S.  Department of the  Interior,
  National  Park Service.   Alexandria, Va., Value Engineering  Laboratory.
  1971.  5 p.

Chandler, K.  A., and M.  B. Kilcullen.  Survey of corrosion and atmospheric
  pollution in and around Sheffield.  Br. Corros. J.  3:80-84, 1968.
                                  389
-------
Cowling, J. E. ,  and M. E. Roberts.  Paints, varnishes, enamels, and
  lacquers.  In:  Deterioration of Materials.  Causes and Preventive
  Techniques.  G.  A. Greathouse and C. J. Wessell (eds.).  New York,
  Reinhold Publishing Corporation.  1954.  p. 596-645.

Elliott, J. F. E., and A. G. Franks.  Design of telephone exchanges for
  corrosive atmospheres.  Systems Techno!.  6:39-48, 1969.

Fairchild Publications Inc.  American Metal Market/Metal Working News.
  New York. Undated.

Fairchild Publications Inc.  Metal Statistics.  New York.  1977.

Fink, F. W., F.  H.  Buttner,  and W. K.  Boyd.  Technical-Economic Evaluation
  of Air-Pollution Corrosion Costs on Metals in the United States.
  Prepared by Batelle Memorial Institute, Columbus, Ohio.  U.S. Environmental
  Protection Agency, Air Pollution Control Office.  Publication No.
  APTD-0654.  1971.

Fujii, T., and A.  Hirata.  Studies of the effects of air pollution on
  the fading of dyed fabrics.  Taiki Osen Ken Kyu (J. Jpn. Soc. Air
  Pollut.)  5:164, 1970.  (In Japanese.)

Fujii, T., and C.  Tsuda.  Studies on the effects of air pollution on
  the fading of dyed fabrics.  J. Jpn. Soc. Air Pollut.  6(1):162,
  1971.   (In Japanese.)

Gibbons, E. V.  The Corrosion Behavior of Some Architectural Metals in
  Canadian Atmospheres:  Summary of Ten-Year Results of Group I.
  Ottawa, National Research Council of Canada.   1972.  81 p.  Division
  of Building Research Technical Paper No. 328.

Gibbons, E. V.  The Corrosion Behavior of Some Architectural Metals in
  Canadian Atmospheres:  Summary of Ten-Year Results of Group II.
  Ottawa, National Research Council of Canada.   1972.  Division of
  Building Research Technical Paper No. 873.

Gillette, D. A., I. H. Blifford, Jr., and C. R. Fenster.  Measurements
  of aerosol size distributions and vertical fluxes of aerosols on land
  subject to wind erosion.   J. Appl. Meteorol.   V1/.977-987, 1972.

Gillette, D. G.   Sulfur dioxide and material damage.  J. Air Pollut.
  Control Assoc.  25(12):1238-1243, 1975.

Goodwin, J. E.,  W.  Sage, and G. P. Tilly.  Study of erosion by solid
  particles. Inst.  Mech. Eng. Proc.  184(15):279-292, 1969-1970.

Guttman, H.  Effects of atmospheric factors on the corrosion of rolled
  zinc.  In:  Metal Corrosion in the Atmosphere.  A symposium presented
  at the 70th Annual Meeting, American Society for Testing and Materials,
  Boston, Mass., June 1967.   Philadelphia, American Society for Testing
  & Materials.  1968.  p. 223-39.  ASTM Special Technical Publication
  No. 435.
                                  390
-------
Guttman, H. , and E. V. Gibbons.  Corrosion Behavior of Metal-Coated
  Panels at Eight Canadian Locations:  Summary of a Fourteen-Year
  Program.  Ottawa, National Research Council of Canada.   1971.  Division
  of Building Research. Technical Paper 354.

Haagen-Smit, A. J.  , M. F. Burnelle, and J. W. Haagen-Smit.  Ozone
  cracking in the Los Angeles area.  Rubber Chem. Techno!.  32:1134-1142,
  1959.

Hamada, M., R. Fujikawa, C. Itakura et al.  Durability of  Asphaltic
  Materials. Parts 1-5.  Ottawa, National Research Council of  Canada.
  1964.  57 p.  Division of Building Research Technical Translation
  1146.  (Translated by H. J. Kondo from Proc. Architecht.  Inst. Jpn.
  69:53-72, 1961.)

Haynie, F. H.   The Economics of Clean Air in Perspective.  Research
  Triangle Park, N.C., U.S. Environmental Protection Agency.   Undated.

Haynie, F. H.   Methodology for Determining Cost of Air Pollution Caused
  Material Damage.   Research Triangle Park, N.C., U.S. Environmental
  Protection Agency.   1973.  Unpublished preliminary draft.

Haynie, F. H., J. W.  Spence, and J. B.  Upham.  Effects of  Gaseous
  Pollutants on Materials--A Chamber Study.  Research Triangle  Park,
  N.C., U.S. Environmental Protection Agency.  1976.  Publication No.
  600-3-76-015.

Haynie, F. H., and J. B. Upham.  Effects of atmospheric sulfur  dioxide
  on the corrosion of zinc.  Mater. Prot. Perform.  9(8):35-40,  1970.

Haynie, F. H., and J. B. Upham.  Effects of atmospheric pollutants on
  corrosion behavior of steels.  Mater.  Prot. Perform.  JO:18-21, 1971.

Hermance, H.  W.  Combatting the effects of smog on wire-spring  relays.
  Bell Lab. Rec.   44:48-52, 1966.

Hershaft, A.,  J.  Morton, and G. Shea.  Assessment and Enhancement of
  the Utility of Air Pollution Dose-Effect Functions.  Council  on
  Environmental Quality.  1975.

Holbrow, G. L.   Atmospheric pollution.   Its measurement and some effects
  on paint.  J. Oil Colour Chem.  Assoc.   45:701-718, 1962.

Hosking, E. S.   Effects of Air Pollution on the Abrasion Resistance of
  Selected Fabrics.  M.S. Thesis.  Loma Linda University,  Los Angeles.
  1970.  61 p.

Hukui, S., and A. Yamamoto.  Studies on the corrosion of metallic
  materials by polluted air.  Netsu Kanri (Heat Management, Energy, and
  Pollution Control) 2T_(6):28-44, 1969.   (In Japanese.)

ITT Electro-Physics Laboratories, Inc.   A Survey and Economic Assessment
  of the Effects of Air Pollutants on Electrical Contacts.  Prepared
  for U.S. Environmental Protection Agency.  1971.
                                  391
-------
Judge, J.   Venice fights for life.  Nat. Geographic  J42:591-631, 1972.

Keane, J.  D.  Corrosion Resistant Zinc Paints.  May 1967.  Available
  from Steel Structures Painting Council.

Keane, J.  D.  Protective Coatings for Highway Structural Steel.  Highway
  Research Board.  1969.  Report 74B.

Keane, J.  D. Protective Coatings for Highway Structural Steel — Current
  Highway Practices.   Highway Research Board.  1969.

Keane, J.  D. et al.   Surface Profile for Anti-Corrosive Painting of
  Structural Steel (Literature Review).  Steel Structures Painting
  Council.  1974.

Keith, C.  H.,  and A.  B. Arons.   The growth of sea-salt particles by
  condensation of atmospheric water vapor.  J. Meteorol.  jj:173-184,
  1954.

Kline, Charles H. & Co., Inc.  The Kline Guide to the Paint  Industry.
  Fairfield, N.J. 1975.

Kubanick,  J. E. Market Development, Coatings Department, Mobay Chemical
  Corp., Pittsburgh,  Pa.  Personal communication.

Lightbody, A., M. E.  Roberts, and C.  J. Wessel.  Plastics and rubber.
  In:  Deterioration of Materials.  Causes and Preventive Techniques.
  G. A. Greathouse and C. J. Wessel (eds.).  New York, Reinhold Publishing
  Corporation.  1954.  p. 537-95.

Liu, B. C.,  and E. S.  H. Yu.  Physical and Economic Damage Functions
  for Air Pollutants  by Receptors.  Report prepared for Environmental
  Protection Agency by Midwest Research Institute, Kansas City.  1976.

McBurney,  J. W.  Effects of atmosphere on masonry and related materials.
  In: Symposium on Some Approaches to Durability in Structures.  Philadelphia,
  American Society for Testing and Materials.  1959. p. 45-56.  ASTM
  Special  Technical  Publication No. 236.

McLeod, W.,  and R. R.  Rogers.  Corrosion of metals by aqueous solutions
  of the atmospheric pollutant sulfurous acid.  Electrochem. Technol.
  6:231-235, 1968.

McLeod, W.,  and R. R.  Rogers.  The nature of corrosion of zinc by
  sulfurous acid at ordinary temperatures.  Corrosion 2jr.74-76, 1969.

Moore, D.  G.,  and A.  Potter.  Effect of Exposure Site on Weather Resistance
  of Porcelain Enamels Exposed for Three Years.  Washington, D.C. , U.S.
  Government Printing Office.  1962.   13 p.  National Bureau of Standards
  Monograph 44.

National Association of Corrosion Engineers.  Corrosion:  A  Devastating
  Problem That Is Costing U.S.  Industries $ Billion Each Year.  1976.


                                  392
-------
Nuessle, A. C.  Soil and stain resistance.  In:  Chemical After-treatment
  of Textiles.  H. F. Mark, N. S. Wooding, and S. M. Atlas  (eds.).  New
  York, Wiley-Interscience.   1971.  p. 465-505.

Pedace, E. A., and E. B. Sansone.  The relationship between "soiling
  index" and suspended participate matter concentrations.  J. Air
  Pollut.  Control Assoc.  22:348-351, 1972.

Robbins, R. C.  Inquiry into  the Economic Effects of Air Pollution on
  Electrical Contacts.   Stanford, Calif., Stanford Research Institute.
  EPA Publication No. PH 22-68-35.  1970.

Rushmer, M. A., and M.  D.  Burdick.  Weather Resistance of Porcelain
  Enamels. Effect of Exposure Site and Other Variables After Seven
  Years.  Washington, D.C., U.S.  Government Printing Office.  United
  States Department of Commerce,  National Bureau of Standards, Building
  Science Series 4.   1966.   16 p.

Sales and Marketing Management.   1977 Survey of Buying Power, Parts I &
  II.  New York.  Undated.

Salmon, R. L.   Systems Analysis of the Effects of Air Pollution on
  Materials. Final Report for Economic Effects Research Division,
  National Air Pollution Control  Administration.  Kansas City, Midwest
  Research Institute.  1970.  192 p.

Schaffer,  R. J.   The Weathering of Natural Building Stones.  London,
  His Majesty's Stationery Office.  1932.  149 p.

Seabright, L.  H., and R. J. Fabian.   The many faces of corrosion.
  Mater. Des.  Eng.  57(1):85-91,  1963.

Sehmel, G. A.   Particle resuspension from an asphalt road caused by car
  and truck traffic.   Atmos.  Environ.   7:291-309, 1973.

Simpson, J. W., and P.  J.  Horrobin (eds.).  The Weathering and Performance
  of Building Materials.  New York,  Wiley-Interscience.   1970.   286 p.

Slunder, C. J., and W.  K.  Boyd.   Zinc:  Its Corrosion Resistance.
  Columbus, Ohio, Battelle Memorial  Institute.   1971.

Spence, J. W., and F. H. Haynie.   Paint Technology and Air Pollution:
  A Survey and Economic Assessment.   Washington, D.C., U.S. Government
  Printing Office.  1972.   p.  20-24.

Stankunas, A., S.  Hoffman,  and J. Yocom.   Material Damage Costs from
  Sulfur Oxides.  Palo Alto,  Calif.,  Electric Power Research Institute.
  1978 (to be published).
                                  393
-------
Stedman, H. F.  Natural and artifical weathering performance of rigid
  polyvinyl chloride (PVC) and other plastic materials.  Iji:  Performance
  Concept in Buildings, Vol.  I:  Invited Papers.  Proceedings of a
  Symposium.  Washington, D.C., U.S. Government Printing Office.
  National Bureau of Standards Special Publication 361.  1972.

Steel Structures Painting Council.   Steel Structures Painting Manual,
  Vols. 1 and 2.  Pittsburgh, Pa. 1977.

Steel Structures Painting Council.   Standard Method of Evaluating
  Degree of Rusting on Painted Steel Surfaces.  Pittsburgh, Pa. 1970.

Sydberger, T.  Influence of Sulfur Pollution on the Atmospheric Corrosion
  of Steel.  Institutionen for Oorganisk Kemi, University of Goteborg
  (Sweden).  1976.

Tajiri, Y.  Effect of air pollution on metals.  Kuki Seijo  (Air Clean.
  J. Jpn.  Air Clean. Assoc.) U)(5):90-99, 1972.  (In Japanese.)

U.S. Bureau of the Census, Statistical Abstract of the United States.
  Washington, D.C. , U.S. Government Printing Office.  1976.

U.S. Bureau of the Census.  1972 Census of Manufactures—Special Report
  Series—Consumption of Selected Metal Mill Shapes and Forms.  Washington,
  D.C., U.S. Government Printing Office.  1977.

U.S. Treasury Department, Internal  Revenue Service.  Depreciation
  Guidelines and Rules.  Washington, D.C., U.S. Government  Printing
  Office.  1964.

Waddell, T. E.  The Economic Damages of Air Pollution.  Research Triangle
  Park, N.C.  U.S.  Environmental Protection Agency, Economic Analysis
  Branch.  1974.

Wessel, C. J.  Textiles and cordage.  In:  Deterioration of Materials.
  Causes and Preventive Techniques.   G. A. Greathouse and C. J. Wessel.
  (eds).  New York, Reinhold Publishing Corporation.  1954.

Wilson, J. G.  Exposed Concrete Finishes, Vol. 2.  New York, John Wiley
  and Sons, Inc. 1965.  p. 115-124.

Yamasaki, S., and Y. Yokoi.  Accelerated atmospheric corrosion  tests  in
  polluted air (2nd report).   Influence of dewing on mild steel in
  sulfur dioxide environment.  Boshoku Gijustu (Corrosion Eng.) 20(11/12):
  23-29, 1971.

Yocom, J., and N. Grappone.  The Effects of Power Plant Emissions on
  Materials. Palo Alto, Calif., Electric Power Research Institute.
  1976.
                                  394
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Yocom, J.  E.,  and R. 0. McCaldin.  Effects of air pollution on materials
  and the economy.   In:  Air Pollution, Vol. I (2nd ed.).  Air Pollution
  and Its Effects.   A.  C.  Stearn (ed.).  New York, Academic Press.
  1968.   p.  617-54.

Zeronian, S.  H.,  K.  W.  Alger, and S.  T. Omaye.  Reaction of fabrics
  made from synthetic fabrics to air contaminated with nitrogen dioxide,
  ozone, or sulfur dioxide.   ^n:  Proceedings of the Second International
  Clean Air Congress, Washington, D.C., December 1970.  H. M. Englund
  and W. T.  Beery (eds.).   New York,  Academic Press.  1971.
                                  395
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B.3  VISIBILITY AND CLIMATE







     High atmospheric concentrations of sulfates reduce visibility, and



the possibility that they play a role in climatic effects has also been



considered.   Mobile sources produce sulfates directly as well as indirectly,



in that the sulfur dioxide they emit can be oxidized to sulfates in the



atmosphere.   However, these sources account for only a small portion of



the total atmospheric sulfates, so small in fact that they would not in



themselves measurably reduce visibility or exert any effects on climate.



The following report defines relationships between sulfur-bearing compounds



and visibility reduction and also addresses the question of climatic



effects.  Visibility reduction will be explored in greater detail in a



separate, later report required under Section 169A of the 1977 Amendments



to the Clean Air Act.







B.3.1  Visibility







     Visibility in daylight is the greatest distance at which the unaided



eye can see a prominent dark object against the sky at the horizon.  This



distance is strongly affected by the number of very small particles in the



atmosphere.   These particles, which cannot be seen by the unaided eye,



produce light-scattering effects, thereby reducing visibility.  Paradoxically,



those particles which are large enough to be seen, such as dust from a



quarry or an unpaved road, do not usually reduce visibility on a regional



basis.  To examine the relationship between mobile emissions of sulfur-



bearing compounds and visibility, the following discussion will consider
                                   396
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ways to measure visibility, various factors that lower it, and how sulfur-



bearing compounds affect it.







     The most common source of visibility data are observations taken at



weather stations.  When visibility is reported at weather stations, it is



a composite value, called "prevailing visibility," for the greatest distance



visible around at least 180 degrees of the horizon, not just for a single



direction.   For example, if the horizon were divided into four sectors,



with visibilities of 3, 4, 5, and 8 miles, the prevailing visibility, or



just visibility, would be recorded as 5 miles.  Particularly low or variable



visibilities in a given sector or direction would be noted as additional



data.  Reporting of prevailing visibility has been a standard procedure in



the weather service since 1939.







     This reporting procedure, however, has certain limitations.   For



instance, since most visibility observations are taken at airports, usually



located outside of the downtown and industrial areas,  the prevailing



visibility observation may not accurately describe the visibility in more



polluted urban areas.   Also, many weather stations do  not have suitable



markers beyond 15 miles; greater visibilities are reported as 15+.   For



locations characterized by very clear, or clean, atmospheres such as in



remote areas, there frequently is a need for visibility markers at great



distances,  since objects can often be discerned at a distance of 100



miles.  In flat country, observation distances are inherently limited by



the curvature of the earth.   For instance, at sea the  horizon for an



observer who is 6 ft above the water is 5.2 km (slightly more than 3
                                   397
-------
miles).   Where there are no suitable distant visibility targets,  long-



range visibilities are usually estimated from the clarity of objects,



requiring very subjective evaluations.   Therefore,  the large and  valuable



body of meteorological observations must be utilized with care if the  data



are to establish relationships between air pollution and visibility.







     Visibility is reduced by light scattering,  which impedes the transmission



of light and weakens contrast.  The reduction of light in the atmosphere



by light scattering and by light absorption is termed "extinction."   Light



scattering is caused primarily by particles or aerosols, but even in their



absence, visibility would be limited by the scattering of light by air



molecules (so-called Rayleigh scattering).  (Note:   An aerosol is a  gas-



phase colloid consisting of small suspended particles uniformly dispersed



in a gas.)







     The particles that scatter light with greater effectiveness  range



primarily between 0.1 and 1.0 urn in diameter.  (A micrometer, or  micron,



is one-millionth of a meter, or a thousandth of a millimeter.)  Particles



forming aerosols in the atmosphere can be divided into three groups  according



to their method of formation.  The smallest particles, having a diameter



of about 0.04 urn or less, are produced mainly by gas-to-aerosol conversion



(e.g., sulfur dioxide to sulfates) or from the condensation of vaporized



materials (e.g., oils or metal vapors).  This size range is termed the



"nuclei" mode.  At the other extreme are the "coarse" aerosols with  particles



larger than 2 urn, which result from abrasive processes (e.g., grinding and



atomization) and include almost all of the natural  particulate matter in
                                   398
-------






















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399
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wind-blown dust and sea spray (Whitby 1978).  The third size range is the



"accumulation" mode, which includes particles from about 0.1 to 0.5 urn.



These particles result primarily from the coagulation of the smaller-sized



aerosols.  Such aerosols generally do not settle out by gravity and are



not removed efficiently from the atmosphere except by incorporation into



clouds and the subsequent rainout.  Studies show that they may persist in



the atmosphere for several days.  Of the three size classes, the accumulation



mode is mainly responsible for the reduction of visibility and the alteration



of solar/terrestial radiation.  Table B-16 lists the major atmospheric



aerosols of both natural and anthropogenic origin.







     Another cause of visibility reduction is the interaction of aerosol



particles (either natural or anthropogenic) with atmospheric water vapor.



It has been shown that a relative humidity (RH) range from 30 percent to



about 60 percent frequently has little or no effect on light scattering



(and, hence, visibility).  However, the light-scattering effects double by



the time the humidity reaches slightly above 80 percent.  The effect is



even more dramatic at near 88 percent RH, where light scattering increases



to four times the level measured in the dry air (30 percent RH).  This



effect arises in part from hygroscopicity of particulate materials.  As



the humidity increases, sulfate and other particles pick up water, thereby



increasing in size.  As they reach a size corresponding to the wavelength



of visible light and increase further to become fog droplets, their potential



to scatter light and thereby reduce visibility is maximized.  It may be



useful to note that the effect of RH may vary considerably depending on



the composition of the aerosol.
                                   400
-------
     Trijonis and Yuan (1978) noted the visibility effects of changes in



sulfur emissions from copper smelting.   During a 9-month strike in the



copper-smelting industry in Arizona in 1967-68, sulfate levels in the air



were 38 to 76 percent lower than seasonal averages at five sites within 70



miles of copper smelters.   Grand Canyon and Mesa Verde National Parks,



about 200 to 300 miles from the smelters, also experienced significant



drops in ambient sulfate levels.   During the strike, visibility reportedly



improved from 5 to 25 percent at locations within 50 miles of the operations.



Pollution potential from other sources appears to have been slightly



greater than usual during the 9-month period.   Since weather patterns were



about normal, Trijonis and Yuan concluded that weather was not a major



factor contributing to the improved visibility.








     Visibility can be measured by mechanical  means.  The most widely



deployed instrument in the meteorological services is the transmissometer,



which measures the transmitted light along a path of known length (usually



500 ft).   It utilizes an intense beam of carefully focused, pulsating



light which is measured by a photocell  receiver.   At selected light pulsation



frequencies, this instrument works satisfactorily both day and night.  In



usual practice, however, the instrument is designed and installed so as to



sense very low visibilities, such as are due to fog at airports.   As such,



the instrument may not be accurate enough for the higher light transmission



values necessary in air pollution evaluations.








     Telephotometers can be used to measure contrast differences over



distances much greater than those a transmissometer can measure directly.
                                   401
-------
The contrast of objects on the horizon can be measured.   Whereas the



measurement of a transmissometer is limited to the fixed path between the



light source and receptor (or reflector),  the measurement of a telephotometer



may be made in any direction from the point of observation.







     Photographic techniques to determine  visibility measure reductions in



contrast caused by haze.   They can operate over a shorter light path than



the transmissometers but usually are directed toward more distant visibility



targets (Steffens 1949).







     The integrating nephelometer (Char!son et al.  1969) is  increasingly



deployed for visibility measurements.   This instrument draws air into a



sample chamber, where it is illuminated by a pulsed flash lamp, and the



scattering of light is detected by a photomultiplier tube.   It is used



both in research and as a routine monitor  of the atmosphere's scattering



potential.







     Since the magnitude of scattering from a particle is a  function of



the wavelength of the incident light, it is possible to use  scattering



intensities at two or more wavelengths to  determine the average size



distribution of an aerosol.  Because the nephelometer samples only a small



volume of the atmosphere and senses only scattering effects, it can give



misleading results if it is not properly calibrated and if the concentra-



tions in the air are not relatively uniform.  Nevertheless,  it is the best



indicator of visibility currently available for routine use  in many air



pollution monitoring situations.
                                   402
-------
     More recently, laser transmissometer systems have been developed to



measure visibility over long distances.  Although these systems require



more refinement, the coherent nature of the light intrinsic to the laser



can permit quantitative detection of aerosol attenuation over longer



ranges.  Also, the use of laser light of different frequencies can assist



in determining what particle sizes are contributing to visibility reduction.








     Because of the importance of aerosols in visibility reduction and



other consequences of air pollution, EPA has supported a great deal of



research in this area.   EPA is currently testing and evaluating alternative



means of visibility measurement, and there is considerable debate over



which is the best visibility indicator.   Another line of research has



resulted in a "dichotomous"  mass sampler, which collects ambient air



samples in two size fractions.   One is termed the "fine fraction," containing



particles less than 3.5 pm.   The other,  the "coarse fraction," contains



particles ranging from 3.5 to 15 (jm in diameter.   This instrument has been



extensively used in recent aerosol  research studies (Stevens et al.  1978).








     The studies of the size distribution of aerosols have been further



extended by the collection of enough material  in the various size ranges



to permit chemical  analysis  by mass spectrometry, X-ray fluorescence,



laser-induced Raman spectroscopy,  and other advanced techniques.   These



complicated procedures require careful material collection and handling



methods.  A body of data is just now becoming available with sufficient



geographical, seasonal, and source information to permit some generali-



zations to be made.
                                   403
-------
     First, most of the sulfur occurs in the "fine" particulate matter



(i.e., the "accumulation" and "nuclei" modes).   Further, in some areas,



sulfur as sulfate can account for much of the mass of this fine material.



Depending upon the situation, the bulk of the remaining mass of material



in this optically active range may be nitrate (N03) or organics.  A complete



description of the specific molecular forms containing sulfate and nitrate



ions is not yet available.   However, discussions of the various species of



sulfur have been described by Charlson et al.  (1978). Knowledge of the



specific sulfur compounds and of their distribution and conversion rates



would enable much more precise determination of their effect on visibility.



Compounds in the atmosphere known to reduce visibility are ammonium sulfate,



sulfuric acid mist, and ammonium acid sulfate.







     A Los Angeles study relating aerosol composition to light-scattering



measurements (White and Roberts 1977) indicated that sulfates and nitrates



always dominate the scattering but that one may be more important than the



other, depending on the location of measurement.  Whether these relationships



hold in other geographic areas, at different pollution concentrations,



with different aerosol compositions, and with different meteorological



conditions remains to be seen.  Extrapolations from a study site to another



geographic area should be done with caution.  However, most available



studies indicate that sulfates should be considered a primary cause of



visibility reduction (Trijonis and Yuan 1978; Leaderer  1978).  The added



contribution from nitrates seems to vary according to relative humidity.
                                   404
-------
     Data taken in controlled laboratory experiments can systematically be



used to investigate the physical/chemical mechanisms that lead to results



observed in the ambient atmosphere.  EPA sponsored a study of such mechanisms,



entitled "A Methodology for Determining the Effects of Fuels and Additives



on Atmospheric Visibility" (Kochmond et al. 1975).  Automobile exhaust



with incremental hydrocarbon and diluted with ambient air was introduced



into a large smog chamber and irradiated with simulated sunlight.  Visibility,



expressed in terms of nephelometer light-scattering values,  was measured



after various times of irradiation.  Variables in addition to irradiation



time were humidity, amount of sulfur dioxide, and the amount of particulate



matter.  Early in the test period, it was observed that the ambient air



introduced to dilute exhaust emissions exerted marked and variable influences



on visibility measurements.   This effect was due to shifts in the background



concentration of visibility-reducing aerosols.  Filtered air was therefore



substituted to enable strict control of the experimental values.







     The results of these tests demonstrated the contribution of a number



of factors to the visibility-reducing effects of automobile exhaust.



While the ratio of HC/NO emissions was important, it was shown that visibility



reduction was also correlated with S0? and relative humidity (RH).   Under



the controlled conditions of the test, the effects of these two factors,



which were interactive, increased with irradiation time.  As shown in



Figure B-6, when RH was low (35 percent), the exhaust emission's effect on



visibility changed little over the course of the irradiation period.   At



the other extreme, when the RH was raised to 80 percent and the air-



exhaust mixture was supplemented with additional SO,, (0.9 ppm), visibility



fell from an initial value of about 50 km to less than 4 km within 22 hr.
                                   405
-------
     Analysis of data from tests of different fuels indicated that the



sulfur content of gasoline was directly related to emissions which led to



the formation of light-scattering aerosols.   Thus, at a given ratio of



HC/NO emissions, fuels with high sulfur content had the most marked effects



on visibility in this chamber study.







     Although laboratory data provide important information on specific



mechanisms of aerosol formation and its effect on light scattering, it is



necessary to obtain information on the effects of ambient aerosol formation



on visibility.   Many visibility studies have centered on the Southwestern



United States.   However, these studies may not be applicable to other



geographic locations.  When considering light-scattering effects in the



atmosphere, it should be noted that visibility may not be strongly related



to the total mass of suspended particulate material.   Those particles



having characteristic dimensions near the wavelength of visible light are



more effective in light scattering, and the proportion of these particles



to the total particulate mass will vary with time and place.  Therefore,



arbitrary correlations between visibility and total suspended particle



mass are not likely to be constant when different regions or seasons are



compared.  Relationships between visibility and particle mass have been



shown to have an accuracy of plus or minus a factor of two.
                                   406
-------
-Q
CO
No.
  4 D-
                                                                  RH
-D  Auto exhaust + filtered air (200:1)
 10 O	-O Auto exhaust + filtered air (200:1)
 11 A	A Auto exhaust-(-filtered air (200:1)
 12 O	O Auto exhaust -f- filtered air (200:1)  -f 0.9 ppm S02 80% CarA
                                                                 35% Car A
                                                                 80% CarA
                                                     0.8ppmS02  35% CarA
                                                                                f
                                                                                g;
                                                                                r-f
        0    2
                   6     8   10    12    14   16   18   20    22
                              Irradiation time,hr
           Figure  B-6.   Effect of relative  humidity and added
           SO   on  test results.
                                   407
-------
     There is also concern with transport of sulfates into relatively

unpolluted areas from long distances.   Impairment in visibility in these

areas could occur by transport of urban and other industrial pollutants

from 200 or more miles away, and these effects may equal or exceed effects

from closer pollutant emissions (Ursenbach 1978).  In addition, a review

by Wilson et al. (1977) showed that sulfur transported from the United

Kingdom arrived in Scandinavia as sulfates.



     The effects of reduction of visibility can be described in social as

well as economic terms.  People often respond emotionally to visible

pollution.  For instance, not being able to see a familiar landmark raises

such questions as:  "Is the air unhealthy?  Are we damaging the environment?"

The reactions to seeing smog effects are much the same as to seeing a

dirty river that once was crystal clear.



     The economic effects of reduced visibility are primarily felt in the

transportation and real estate enterprises.  The ability of an area to
                                   »
attract and keep residents, an important factor in real estate values, can

be impaired considerably by obvious pollution.  Low visibilities can slow

transportation systems and reduce capacity, although these effects are

mostly confined to the very lowest visibilities characteristic of heavy

fog.
                                   408
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B.3.2  Climate







     Pollutants released to the atmosphere alter the environment in ways



other than visibility reduction.   Importantly, they may lead to slow and



subtle changes in atmosphere composition and, possibly, climate.







     Climate has been defined as  the long-term manifestations of weather



at a given location over a specified period, usually several decades;



current discussions of climate usually use the reference period 1940 to



1970.  Weather manifestations may be specified as averages (i.e., of



temperatures, rainfall,  wind speeds, etc.) or as frequencies (i.e., hurricane



occurrence, maximum temperature over 100°F [36°C], etc.).







     Climate exerts a major influence on many aspects of society, including



architecture and agriculture.   Climate factors such as temperature and



precipitation must be considered  both in design of buildings and in crop



selection.  Some acts of man may  increase the impact of climatic trends.



For example, the recent  drought in Northwest Africa may have been exacerbated



by overgrazing the land  during periods of above-average rainfall.







     Societal responses  to long-term climate changes have not been explored



fully, but it is obvious that any major shift in food production capability



of a large area would be socially disruptive, as was proven by the Dust



Bowl of the 1930's.  Recently, much attention on an international scale



has been devoted to both the effects of long-term climate changes on



society and, conversely, society's influence on long-term climate changes.
                                   409
-------
These issues were addressed at the 1972 United Nations Conference on the



Human Environment.   The second of these issues is of present concern--the



effects of air pollution on climate.







     Climate change attributable to air pollution may be effected in a



number of ways.  The release of gases and production of aerosols could



significantly alter the atmosphere's composition (hence, heat-absorption



characteristics) to bring about a change in the earth's radiation balance.



Shifts in this balance would be associated with temperature change.   Cloud



formation could also be affected.  Changes in cloud cover could alter



albedo (reflection of sunlight), another important factor in maintaining



the earth's radiation balance.  Changes in the location, frequency,  and



amount of precipitation might also occur.







     So far as is known, only sulfur compounds in solid phase (i.e.,



sulfates) are involved in processes affecting climate.  In fact, for all



practical purposes, this discussion can be limited to sulfate particles.



These particles can absorb sunlight and water from the atmosphere, and



they can also affect cloud condensation nuclei (CCN), which are critical



in the rainfall process.  Many reports have correlated particulate matter



with potential climate change.  Natural events such as the explosive



injection of volcanic material into the atmosphere verify this correlation-



Krakatoa in 1883, Katmai in Alaska in 1912, and, more recently, Bali's Mt.



Agung in 1963.  These eruptions showed the capacity of volcanic material



to scatter incoming solar radiation.   At the time of Agung, monitoring



systems had progressed to the point that the spread-and-time history of
                                   410
-------
the aerosol could be documented with the aid of laser systems.   An analysis



of upper-air temperatures in the Southern Hemisphere detected a major



warming attributed to the absorption of radiation by the aerosol.   Little



surface temperature or rainfall effects have been identified directly with



these events.   In general, however, the large variability of weather



obscures all but the most dramatic effects.







     On a global scale, meteorological observations linking air pollution



to climate changes are lacking.  Over cities, the reduction of received



radiation can be ascribed definitely to the increase of fine aerosols.



Cloudiness appears to be increased by 5 to 10 percent.   Fog develops about



twice as often over urban areas as over the countryside, and the duration



is lengthened by an abundance of hygroscopic compounds.   Thunderstorms may



be enhanced, and precipitation appears to be increased over and especially



downwind of cities.   The effects of pollutants on precipitation have yet



to be separated from the effects of thermal  energy over urban areas.   In



studies of the correlates of air pollution and local or regional climatic



processes, a role for mobile source emissions has not been defined.
                                   411
-------
Bibliography

   Air Quality Data - 1975 Annual Statistics—Including Summaries with
     Reference to Standards.   U.S. Environmental Protection Agency.
     Research Triangle Park,  N.C.  Publication No. EPA 450/2-77-002.
     1974.

   Aitken, J.  Collected Scientific Papers of John Aitken, L.L.D., F.R.S.
     C. G. Knott (ed.).   London, Cambridge University Press.  1923.  591
     P-

   Alkezweeny, A. J., and D.  R. Drewes.  Airborne measurements of pollutants
     over urban and rural sites.  J. Appl. Meteorol. J_6:561-563, 1977.

   Alkezweeny, A. J., and D.  C. Powell.  Estimation of transformation rate
     of S02 to S04 from atmospheric concentration data.  Atmos. Environ.
     H:179-182, 1977.

   Altshuller, A. P.  Atmospheric sulfur dioxide and sulfate.  Distribution
     of concentration at urban and nonurban sites in the United States.
     Environ. Sci. Techno!. 7:709-712, 1973.

   Altshuller, A. P.  Characteristics of the chemical composition of the
     fine particulate fraction in the atmosphere.  Unpublished paper.  May
     1976.

   Altshuller, A. P., and J.  J. Bufalini.  Photochemical aspects of air
     pollution:  A review.   Environ. Sci. Techno!. 5:39-64, 1971.

   Atwater, M. A.  Planetary albedo changes due to aerosols.  Science
     ]_70: 64-66, 1970.

   Atwater, M. A.  Urbanization and pollutant effects on the thermal
     structure in four climatic regimes.  J. App!. Meteorol. 16:888-895,
     1977.

   Auer,  A. H., Jr.  The evolution of visibility deterioration and aerosol
     spectra in the St.  Louis urban plume.  J. Air Pollut. Control Assoc.
     27:1188-1191, 1977.

   Azarniouch, M. K., A. J. Bobkowicz, N. E. Cooke et al.  Growth of a
     sulfuric acid droplet exposed to water vapor.  Can. J. Chem. Eng.
     51:590-595, 1973.

   Barnes, R. A., and A. E. J. Eggleton.  The transport of atmospheric
     pollutants across the North Sea and English Channel.  Atmos. Environ.
     11:879-892, 1977.

   Barone, J., et al.  Visibility reduction characteristics of three
     cities  in California.    To be submitted to Atmospheric Environment.
                                   412
-------
Barrett, L. B. ,  and T. E. Waddell.  Cost cf Air Pollution Damage:  A
  Status Report.  National Environmental Research Center, Environmental
  Protection Agency.  Research Triangle Park, N.C.  Publication No.
  AP-85.  1973.   73 p.

Beilke, S., and H.  W. Georgii.  Investigation on the incorporation of
  sulfur-dioxide into fog- and rain-droplets.  Tellus 20:435-442.

Beilke, S., and G.  Gravenhorst.  Heterogeneous S02-oxidation in the
  droplet phase.  Atmos.  Environ.  Vol. 12, in press.  1978.

Beloin, N.  J.   A chamber study.  Fading of dyed fabrics exposed to air
  pollutants.   Text. Chem. Color.  5:128/29-133/34,  1973.

Berger, H.  W., M.  Tryon,  E.  J. Clark et al.  Final  Project Report on
  the Effects of Atmospheric Contaminants on the Durability of Building
  Materials.   NBS Report 10 504 for the National Air Pollution Control
  Administration.   National  Bureau of Standards.  Washington, D.C.
  1970.  36 p.

Bergstrom,  R.  W.,  and J.  T.  Peterson.   Comparison of predicted and
  observed solar radiation in an urban area.   J. Appl.  Meteorol. 16:1107-
  1116, 1977.

Bernstein,  D., M.  T. Kleinman, T.  J. Kneip et al.   A high-volume sampler
  for the determination of particle size distributions in ambient air.
  J. Air Pollut. Control  Assoc. 26:1069-1072, 1976.

Bigg, E. K.  Size distributions of stratospheric aerosols and their
  variations with altitude and time.  J. Atmos. Sci. 3j:1080-1086,
  1976.

Bigg, E. K.  Some properties of the aerosol at Mauna Loa Observatory.
  J. Appl.  Meteorol. 16:262-267, 1977.

Bigg, E. K., S.  C.  Mossop, R.  T. Meade et al.  The measurement of ice
  nucleus concentrations  by means of Millipore filters.   J. Appl.
  Meteorol. 2:266-269, 1963.

Bodhaine, B.  A., and B.  G. Mendonca.  Preliminary four wavelength
  nephelometer measurements at Mauna Loa Observatory.   Geophys. Res.
  Lett. 1:119-122,  1974.

Bohlau, V.  (ed.).   Aerosole in Physik, Medizin und Technik:  Proc. of
  Conf., Bad Soden, October 17-18, 1973.  Gesellschaft fur Aerosol-
  forschung.   Bad Soden,  West Germany.  1973.  165 p.

Bo!in, B.,  L.  Granat, L.  Ingelstam et al.   Air Pollution Across National
  Boundaries.   The Impact on the Environment of Sulfur in Air and
  Precipitation.  Royal Ministry for Foreign Affairs,  Royal Ministry of
  Agriculture.  Stockholm, P.  A. Norstedt & Soner.  1971.   96 p.

Bolin, B. ,  G.  Witt, and R. J.  Charlson.  Stockholm  tropospheric aerosol
  seminar:   Measurement of regional to global scale pollution by airborne
  particles.   Bull. Am.  Meteorol.  Soc. 55:228-231,  1974.

                                413
-------
Bracewell, J.  M.,  and D.  Gall.   The catalytic oxidation of sulphur
  dioxide in solution at concentrations occurring in fog droplets.  In:
  Air Pollution:   Proc.  of Symp.  on the Physico-chemical Transformation
  of Sulphur Compounds in the Atmosphere and the Formation of Acid
  Smogs, Mainz, June 8-9, 1967.   Paris Organization for Economic Co-
  operation and Development.  1967.  p. 17-26.

Bricard, J., G. J. Madelaine, and D. Vigla.  The formation and evolution
  of aerosols generated through the action of ultraviolet and solar
  radiation.  In:   Proc.  of 7th Int'l. Conf. on Condensation and Ice
  Nuclei.  Prague and Vienna, Sept. 18-24, 1969.  Prague, Academia.

Brimblecombe, P.   London air pollution, 1500-1900.   Atmos. Environ.
  V[: H57-1162, 1977.

Brock, J. R.  Condensational growth of atmospheric aerosols.  J. Colloid.
  Interface Sci.  39:32-36, 1972.

Brosset, C., K. Andreasson, and M.  Perm.  The nature and possible
  origin of acid particles observed at the Swedish West Coast.  Atmos.
  Environ. 9:631-642, 1975.

Bryson, R.  Climatic modification by air pollution.  In:  Proc. of
  First Int'l.   Conf. on Environmental Future, Finland, June 27-July 3,
  1971.  N.  Polunin (ed.).  London, The Macmillan Press.  1972.  p.
  134-174.

Bryson, R. A.   "All other factors being constant..."  A reconciliation
  of several theories of climatic change.  Weatherwise 2_]_:56-61, 1968.

Bryson, R. A.   A perspective on climatic change.  Climate responds
  rapidly and significantly to small changes of the independent variables.
  Science ]84:753-760, 1974.

Bryson, R. A.,  and D. A.  Baerreis.   Possibilities of major climatic
  modification and their implications:  Northwest India, a case for
  study.  Bull. Am. Meteorol. Soc.  48:136-142, 1967.

Budyko, M. I.   The effect of solar radiation variations on the climate
  of the earth.  Tellus 2_1:611-619, 1969.

Bufalini, M.  Oxidation of sulfur dioxide in polluted atmospheres—A
  review.  Environ. Sci.  Technol. 5:685-700, 1971.

Butcher, S.  S., and R. J. Charlson.  An Introduction to Air Chemistry.
  New York,  Academic Press.  1972.   241 p.

Cadle, R. D.  Particles in the Atmosphere and Space.  New York, Reinhold
  Publishing Corp.  1966.  226 p.

Cadle, R. D.  The Measurement of Airborne Particles.  New York, John
  Wiley & Sons, Inc. 1975.  342 p.
                                414
-------
Cadle, R. D., C. S. Kiang, and J.-F. Louis.  The global  scale  dispersion
  of the eruption clouds from major eruptions.  J. Geophys.  Res. 8h3125-
  3132,  1976.

Cadle, R. D. , and P. L. Magill.  Chemistry of contaminated atmospheres.
  In:  Mr Pollution Handbook.  P. L. Magill, F. R. Holden,  and  C.
  Ackley (eds.).  New York, McGraw-Hill Book Company,  Inc.,  1956.

Carlson, T.  N., and R. S. Caverly.  Radioative characteristics of
  Saharan dust at solar wavelengths.  J. Geophys.  Res. 82:3141-3152,
  1977.

Carlson, T.  N., and B. M. Prospero.  The large-scale movement  of Saharan
  air outbreaks over the northern equatorial Atlantic.   J. Appl. Meteorol.
  Vh 283-297, 1972.

Cass, G. R.  The relationship between sulfate air  quality and  visibility
  at Los Angeles, EQL Memo #18.  Pasadena, California  Institute  of
  Technology.  1976.

Cassatt, W.  A., and R. S. Maddock (eds.).  Aerosol measurements.  J.n:
  Proc. of a Seminar on Aerosol Measurements, May  7, 1974, sponsored by
  The National Bureau of Standards and The Food and Drug Administration.
  National Bureau of Standards Special Publication 412.  Washington,
  D.C., U.S. Government Printing Office.  1974.  182 p.

Changnon, S. A., Jr., F.  A. Huff, and R. G. Semonin.   Metromex:  An
  investigation of inadvertent weather modification.   Bull.  Am.  Meteorol.
  Soc.  52:958-967, 1971.

Charlson, R. J.   Atmospheric visibility related to aerosol mass  concentration.
  A review.  Environ.  Sci.  Techno!. 3:913-918, 1969.

Charlson, R. J. , N. C. Ahlquist, and H.  Horvath.  On the generality of
  correlation of atmospheric aerosol mass concentration  and  light
  scatter.    Atmos. Environ. 2:455-464, 1968.

Charlson, R. J. , N. C. Ahlquist, H. Selvidge et al. Monitoring of
  atmospheric aerosol parameters with the integrating  nephelometer.  J.
  Air Pollut. Control Assoc.  Jj9:937-942, 1969.

Charlson, R. J., D. S. Covert, Y. Tokiwa et al.  Multi-wavelength
  nephelometer measurements in Los Angeles smog aerosol.  III.   Comparison
  to light extinction by N02.   In:  Aerosols and Atmospheric Chemistry.
  G. M. Hidy (ed.).  Proc.  of the American Chemical Society, Los Angeles,
  March 28-April 2, 1971.  New York, Academic Press.   1972.  p.  333-338.

Charlson, R. J., H. Harrison,  and G. Witt.  Aerosol concentrations:
  Effect on  planetary temperatures.  Science 175:95-96,  1972.

Charlson, R. J., and M. J.  Pilat.  Climate:  The influence of  aerosols.
  J. Appl.  Meteorol. 8:1001-1002, 1969.
                                415
-------
Charlson, R. J.,  and M. J. Pilat.  Reply [to S. H. Schneider on climate].
  J.  Appl. Meteorol. K): 841-842, 1971.

Charlson, R. J.,  W. M.  Porch, A. P. Waggoner et al.   Background aerosol
  light scattering characteristics:  Nephelometric observations at
  Mauna Loa Observatory compared with results at other remote locations.
  Tell us 26:345-360, 1974.

Charlson, R. J.,  A. H.  Vanderpol, D. S. Covert et al.  H2S04/(NH4)2S04
  background aerosol:  Optical detection in St. Louis region.  Atmos.
  Environ. 8:1257-1267, 1974.

Charlson, R. J.,  A. H.  Vanderpol, D. S. Covert et al.  Sulfuric acid-
  ammonium sulfate aerosol:  Optical detection in the St. Louis region.
  Science J84:156-158,  1974.

Charlson, R. J.  et al.   Chemical properties of tropospheric aerosols.
  Atmos. Environ.   12.: 39-53, 1978.

Chylek, P., and J. A. Coakley, Jr.  Aerosols and climate.  Science
  183:75-77, 1974.

Clark, W. E.  Measurements of Aerosols Produced by the Photochemical
  Oxidation of Sulfur-Dioxide in Air.  Ph.D. Thesis, University of
  Minnesota.  Minneapolis, Minnesota.  1972.  152 p.

Clark, W. E., and K. T. Whitby.  Concentration and size distribution
  measurements of atmospheric aerosols and a test of the theory of
  self-preserving size distributions.  J. Atmos. Sci. 24:677-687, 1967.

Clark, W. E., and K. T. Whitby.  Measurements of aerosols produced by
  the photochemical oxidation of S02 in air.  J. Colloid Interface Sci.
  5_h 477-490, 1975.

Cobb, W. E.  Oceanic aerosol levels deduced from measurements of the
  electrical conductivity of the atmosphere.  J. Atmos. Sci. 30:101-106,
  1973.

Cobb, W. E., and H. J.  Wells.  The electrical conductivity of oceanic
  air and its correlation to global atmospheric pollution.  J. Atmos.
  Sci. 27:814-819, 1970.

Cooke, D. D., and M. Kerker.  Response calculations for light-scattering
  aerosol particle counters.  Appl. Opt. 14:734-739, 1975.

Cooper, D. W., R.  L. Byers, and J. W. Davis.  Measurements of laser
  light backscattering vs. humidity for salt aerosols.  Environ. Sci.
  Techno!. 7:142-146,  1973.

Covert, D. S.  The Relationship Between Chemical Composition, Relative
  Humidity and Light Scattering by Aerosols.  M.S. Thesis, University
  of Washington.   Seattle, Washington.  (On file at University of
  Washington Library.) 1971.
                                416
-------
Covert, D. S.  A Study of the Relationship of Chemical Composition  and
  Humidity to Light Scattering by Aerosols.  Ph.D. Thesis, University
  of Washington.  Seattle, Washington.  (University Microfilms, Ann
  Arbor, Mich.)  1974.  167 p.

Covert, D. S., et al.  A study of the relationship of chemical composition
  and humidity to light scattering by aerosols.  J. Appl. Meteorol.
  U_:968-976, 1972.

Cox, R. A., and S.  A. Penkett.  Aerosol formation from sulphur dioxide
  in the presence of ozone and olefinic hydrocarbons.  J. Chem. Soc.
  68:1735-1753, 1972.

Cronn, D.  R. , R. J.  Charlson, R. L. Knights et al.  A survey of the
  molecular nature of primary and secondary components of particles in
  urban air by high-resolution mass spectrometry.  Atmos. Environ.
  11:929-937, 1977.

Dahl, E.,  and 0. Skre.  An investigation of the effects of acid precipitation
  on land productivity.   In:   Konferens om Avsvavling, Stockholm, Nov.
  11, 1969.   Helsinki, Nordforsk Miljovardssekretariatet.  (In Norwegian.)
  1971.  p.  27-40.

Dana, M.,  J.  M.  Hales, C.  E.  Hane et al.  Some references pertinent to
  the field of precipitation chemistry.  In:  Appendix B of Precipitation
  Scavenging of Inorganic Pollutants from Metropolitan Sources.  Prepared
  by Battelle-Pacific Northwest Laboratories, Richland, Wash.  U.S.
  Environmental  Protection Agency.   Research Triangle Park, N.C.
  Report No.  EPA-650/3-74-005.  1974.

DeLuisi, J.  J.,  J.  E. Bonelli, and C.  E. Shelden.  Spectral absorption
  of solar radiation by the Denver brown (pollution) cloud.  Atmos.
  Environ. V[: 829-836, 1977.

DeLuisi, J.  J.,  P.  M. Furukawa, D.  A.  Gillette et al.  Results of a
  comprehensive atmospheric aerosol-radiation experiment in the South-
  western  United States, Part I:  Size distribution, extinction optical
  depth and vertical profiles of aerosols suspended in the atmosphere.
  J. Appl. Meteorol. ]_5:441-454, 1976.

DeLuisi, J.  J. ,  P.  M. Furukawa, D.  A.  Gillette et al.  Results of a
  comprehensive atmospheric aerosol-radiation experiment in the South-
  western  United States, Part II:   Radiation flux measurements and
  theoretical interpretation.  J.  Appl. Meteorol. ]_5:455-463, 1976.

Dochinger, L.  S., and T. A.  Seliga (eds.).   Proc. 1st Int'l Symp. on
  Acid Precipitation and the Forest Ecosystem.   Upper Darby, Pa. ,
  Forest Service, U.S. Department of Agriculture.  USDA Forest Service
  General  Technical  Report NE-23.   1976.  1074 p.

Dzubay, T. G., and R. K. Stevens.   Ambient air analysis with dichotomous
  sampler and X-ray fluorescence spectrometer.   Environ. Sci. Techno!.
  9:663-668,  1975.
                                417
-------
Dzubay, T.  G., and R. K. Stevens.  The characterization of atmospheric
  aerosol by physical and chemical methods.  Presented at the 171st
  National  Meeting of the American Chemical Society, New York, N.Y.,
  April 4-9, 1976.  Preprint in vol.  16, no. 1.  Available through  the
  ACS Environmental Chemists Division.

Dzubay, T.  G., R. K.  Stevens, and C.  M. Peterson.  Application of the
  dichotomous sampler to the characterization of ambient aerosols.   In:
  X-Ray Fluorescence Analysis of Environmental Samples.  T. G. Dzubay
  (ed.).  Ann Arbor, Mich., Ann Arbor Science Publishers, Inc.  1977.
  p. 95-106.

Eagan, R. C. ,  P. V. Hobbs, and L. F.  Radke.  Particle emissions from a
  large kraft paper mill and their effects on the microstructure of
  warm clouds.  J. Appl. Meteorol. T3:535-552, 1974.

Eggleton, A. E.  J., and R. A. Cox.  Homogeneous oxidation of sulphur
  compounds in the atmosphere.   Atmos.  Environ.  January, 1978.

Ellis, H. T.,  and R.  F. Pueschel.  Solar radiation:  Absence of air
  pollution trends at Mauna Loa.   Science 172:845-846, 1971.

Elterman, L.,  R. B. Toolin, and J. D. Essex.  Stratospheric aerosol
  measurements with implications for global climate.  Appl. Opt. 12:330-337,
  1973.

Energy and Climate.  Washington,  D.C., Geophysics Study Committee,
  National  Academy of Sciences.  1977.

Engelmann,  R.  J., and W. G. N.  Slinn.  Precipitation scavenging.  In:
  Proc. of Symp., Richland, Wash., June 2-4, 1970.  Oak Ridge, Tenn. ,
  USAEC Division of Technical Information Extension.  1970.  499 p.

Ensor, D. S. ,  R. J. Charlson, N.  C. Ahlquist et al.  Multiwavelength
  nephelometer measurements in Los Angeles smog aerosol.  Comparison of
  calculated and measured light scattering.  In:  Aerosols and Atmospheric
  Chemistry.  G. M. Hidy (ed.).  Proc.  of the American Chemical Society,
  Los Angeles, Calif., March 28-April 2, 1971.  New York, Academic
  Press.  1972.   p. 315-324.

Ensor, D. S.,  and M.  J. Pilat.   Calculation of smoke plume opacity  from
  particulate air pollutant properties.  J. Air Pollut. Control Assoc.
  2T.:496-501,  1971.

Ensor, D. S.,  W. M. Porch, M. J.  Pilat et al.   Influence of the atmospheric
  aerosol on albedo.   J. Appl.  Meteorol. 1_0:1303-1306, 1971.

Erikson, E.  The yearly circulation of sulfur in nature.  J. Geophys.
  Res. 68:4001-4008, 1963.

Evans, G. R.,  and A.  F. Roddy.   The condensation nuclei formed in
  polluted air by ultraviolet radiation whose wavelengths are  longer
  than 2900 A.  Jn:  Proc. 7th Int'l Conf. on Condensation and Ice
  Nuclei, Prague and Vienna, Sept. 18-24, 1969.  Prague, Academia.
  1969.  p. 369-373.

                                418
-------
Fernald, F. G., and B. G. Schuster.  Wintertime  1973 airborne  lidar
  measurements of stratospheric aerosols.  J. Geophys. Res. 82:433-437,
  1977.

Fiocco, G., G. Grams, and A. Mugnai.  Energy exchange and temperature
  of aerosols in the earth's atmosphere  (0-60 km).  J. Atmos.  Sci.
  33:2415-2424, 1976.

Fletcher, N. H.  The Physics of Rainclouds.  Cambridge, England, University
  Press.  1962.

Flowers, E. C., R. A. McCormick, and K.  R. Kurfis.  Atmospheric  turbidity
  over the United States.  J. Appl. Meteorol. 8:955-962, 1969.

Flyger, H., K. Hansen, W. J. Megaw et al.  The background level  of the
  summer tropospheric aerosol over Greenland and the North Atlantic
  Ocean.  J. Appl. Meteorol. T2:161-174,  1973.

Flyger, H., N. Z.  Heidam, K. Hansen et al.  The background level of the
  summer tropospheric aerosol, sulfur dioxide and ozone over Greenland
  and the North Atlantic Ocean.  J. Aerosol Sci. 7:103-140, 1976.

Friedlander, S. K.  Theoretical considerations for the particle  size
  spectrum of the stratospheric aerosol.  Am. Meteorol. Soc. J.  Meteorol.
  |8:753-759, 1961.

Friend, J. P.  The global sulfur cycle.   In:  Chemistry of the Lower
  Atmosphere.  S.  E. Rasool (ed.).  Plenum Press, New York. 1973. p.
  177-201.

Fuchs, N. A.  The Mechanics of Aerosols.  New York, Pergamon Press.
  1964.  408 p.

Fujiwara, M. , T.  Itabe, and M. Hirono.    Sudden increase of strato-
  spheric aerosol  content after the eruption of Fuego volcano:   Lidar
  observations in Fukuoka.   Rep. Ionosphere Space Res. Jpn. 29:74-78,
  1975.

Garland, J. A., J. R. Branson, and L. C.  Cox.  A study of the contribution
  of pollution to visibility in a radiation fog.  Atmos. Environ.
  7:1079-1092, 1973.

Gartrell, G., Jr., and S. K. Friedlander.  Relating particulate  pollution
  to sources:  The 1972 California aerosol characterization study.
  Atmos. Environ.  9:279-299, 1975.

Gerhard, E., and H.  F. Johnstone.   Photochemical oxidation of sulfur
  dioxide in air.   Ind. Eng. Chem. 47:972-976, 1955.

Gibbs, J.  Light scattering from particles of different shapes.  J.
  Geophys. Res.  83:501-502, 1978.

Gillette, D. A.,  I.  H. Blifford, Jr., and C. R. Fenster.  Measurements
  of aerosol size distributions and vertical fluxes of aerosols  on land
  subject to wind erosion.   J. Appl. Meteorol. JJ:977-987, 1972.

                                419
-------
Gladney, E. S., W. H. Zoller, A. G. Jones et al.   Composition and size
  distributions of atmospheric particulate matter in the Boston area.
  Environ. Sci. Technol. 8:551-557, 1974.

Glazier, J., J. L. Monteith, and M. H. Unsworth.   Effects of aerosol on
  the local heat budget of the lower atmosphere.   Q. J. Roy. Meteorol.
  Soc. |02:95-102, 1976.

Gras, J. L.  Southern hemisphere mid-latitude stratospheric aerosol
  after the 1974 Fuego eruption.  Geophys. Res. Lett. 3:533-536, 1976.

Green, H.  L. , and W.  R. Lane.  Particulate clouds:  Dusts, smokes and
  mists; Their physics and physical chemistry and industrial and environmental
  aspects.  New York, D. Van Nostrand Co.  1957.   452 p.

Hagen, L'. J. , and N.  P. Woodruff.  Air pollution from duststorms in  the
  Great Plains.  Atmos. Environ. 7:323-332, 1973.

Hall, J. S., M. Jerzykiewicz, and L. Riley.  Extinction measurements
  for sensitive assessment of air quality, 1975.   J. Air Pollut. Control
  Assoc. 25:1045-1048, 1975.

Hall, T. C. , Jr.  Photochemical Studies of Nitrogen-Dioxide and Sulfur-
  Dioxide.  Ph.D.  Thesis, University of California.  Los Angeles,
  California.  1954.

Halter, B., and E. Robinson.  Nuclei concentrations over the extreme
  Eastern  Pacific Ocean.  J. Geophys. Res. 82:991-994, 1977.

Hanel, G.  New results concerning the dependence of visibility on
  relative humidity and their significance in a model for visibility
  forecast.  Beitr. Phys. Atmos. 44:137-167, 1971.

Hanel, G.  Computation of the extinction of visible radiation by atmospheric
  aerosol particles as a function of the relative humidity, based upon
  measured properties.  Aerosol Sci. 3:377-386, 1972.

Hanel, G.  The ratio of the extinction coefficient to the mass of
  atmospheric aerosol particles as a function of the relative humidity.
  Aerosol Sci. 3:455-460, 1972.

Harrison,  P. R., W. R. Matson, and J. W. Winchester.  Time variations
  of  lead, copper and cadmium concentrations in aerosols in Ann Arbor,
  Michigan.  Atmos. Environ. 5:613-619, 1971.

Heinsohn,  R. J., C. Birnie, Jr., and T. A. Cuscino.  Fugitive Dust from
  Vehicles Using Unpaved Roads.  Center for Air Environment Studies
  (CAES) Publication No. 419-75.  University Park, Pa., The Pennsylvania
  State University.  1975.  29 p.

Heisler, S. L., and S. K. Friedlander.  Gas-to-particle conversion in
  photochemical smog:  Aerosol growth laws and mechanisms for organics.
  Atmos. Environ.  11:157-168, 1977.
                                420
-------
Henry, R. C.  The application of the  linear  system  theory  of  visual
  acuity to visibility reduction by aerosols.  Atmos.  Environ.  11:697-701,
  1977.

Herman, B. M., and S. R. Browning.  The effect of aerosols on earth-
  atmosphere albedo.  J. Atmos. Sci.  32:1430-1445,  1975.

Herman, B. M., S. R. Browning, and R. Rabinoff.  The  change in earth-
  atmosphere albedo and radiational equilibrium temperatures  due  to
  stratospheric pollution.  J. Appl.  Meteorol. JJ5:1057-1067,  1976.

Hidy, G. M. (ed.).  Aerosols and Atmospheric Chemistry.  Proc.  of the
  American Chemical Society, Los Angeles, Calif., March 28-April  2,
  1971.  New York, Academic Press.  1972.  348 p.

Hidy, G. M.  Some aspects of airborne particles and radiation in  the
  atmosphere.  In:  Radiation Research.  Biomedical,  Chemical,  and
  Physical Perspectives.  0. F. Nygaard, H.  I. Adler,  and  W.  K. Sinclair
  (eds.).  Proc.  5th Int'l. Cong, of  Radiation Research, Seattle,
  Washington, July 14-20, 1974.  New  York, Academic Press.  1975.  p.
  1286-1298.

Hidy, G. M., B.  Appel, R. J. Charlson et al. Characterization of  Aerosols
  in California (ACHEX).  Final Report, vol. I-IV.  Submitted to  the
  Air Resources Board, State of California,  Sept. 30,  1974.

Hidy, G. M., B.  R. Appel, R. J. Charlson et  al.  Summary of the California
  aerosol characterization experiment.  J. Air Pollut. Control  Assoc.
  25:1106-1114,  1975.

Hidy, G. M., and J.  R.  Brock.   The Dynamic of Aerocolloidal Systems.
  New York, Pergamon Press.  1970.

Hidy, G. M., and J.  R.  Brock.   An assessment of the global  sources of
  tropospheric aerosols.  In:   Proc.  2nd Int'l. Clean  Air  Congress.  H.
  M. Englund and W.  T.  Beery (eds.).  New York, Academic Press.   1971.
  p. 1088-1097.

Higgins, I. T. T. , et al.  Airborne Particles.  Washington, D.C.,
  National Academy of Sciences.  1977.

Hindman, E. E. ,  II.   Aerosol particle workshop in a coastal environment.
  Bull. Am. Meteorol. Soc. 58:592-595, 1977.

Hindman, E. E. ,  II, P.  V. Hobbs, and  L. F. Radke.   Cloud condensation
  nuclei from a paper mill.  Part I:  Measured effects on  clouds.  J.
  Appl. Meteorol. 1^:745-752,  1977.

Hirono, M., M. Fujiwara, and T. Itabe.  Behavior of the stratospheric
  aerosols inferred from laser radar  and small ion  radiosonde observations.
  J. Geophys. Res. 8J:1593-1600, 1976.

Ho, W., G. M. Hidy, and R. M.  Govan.  Microwave measurements  of the
  liquid water content of atmospheric aerosols.  J. Appl.  Meteorol.
  13:871-879, 1974.

                                421
-------
Hobbs, P.  V.  Comparison of ice nucleus concentrations measured with an
  acoustical counter and Millipore filters.  J. Appl. Meteorol. 9:828-829,
  1970.

Hobbs, P.  V., and J. P. Locatell.   Ice nuclei from a natural forest
  fire.   J. Appl. Meteorol. 8:833-834, 1969.

Hobbs, P.  V., and L. F. Radke.  Cloud condensation nuclei from a simulated
  forest fire.   Science ]63:279-280, 1967.

Hobbs, P.V., L.  F.  Radke, and S. E.  Shumway.  Cloud condensation nuclei
  from industrial sources and their apparent influence on precipitation
  in Washington State.   J.  Atmos.  Sci. 27:81-89, 1970.

Hodge, P.  W.  Large decrease in the clean air transmission of the air
  1.7 km above Los Angeles.  Nature 229:549, 1971.

Hodge, P.  W., N.  Laulainen, and R.  J.  Charlson.  Astronomy and air
  pollution.  Science 218:1123-1124, 1972.

Hofmann, D. J.,  and J.  M. Rosen.  Balloon observations of the time
  development of the stratospheric aerosol event of 1974-1975.  J.
  Geophys.  Res.  82:1435-1440, 1977.

Hofmann, D. J.,  J.  M.  Rosen, and J.  M. Kiernan.  Stratospheric aerosol
  measurements IV:   Global  time variations of the aerosol burden and
  source considerations.  J. Atmos.  Sci.  33:1782-1788, 1976.

Hofmann, D. J.,  J.  M.  Rosen, T.  J.  Pepin et al.  Stratospheric aerosol
  measurements I:  Time variations at northern midlatitudes.  J. Atmos.
  Sci. 32:1446-1456, 1975.

Hogan, A.  W.  Antarctic aerosols.   J.  Appl. Meteorol. 1_4:550-559, 1975.

Hogan, A.  W.  Aerosols of the trade wind region.  J. Appl. Meteorol.
  15:611-618, 1976.

Holland, A. C.,  and G.  Gagne.  The scattering of polarized light by
  polydisperse systems of irregular particles.  Appl. Opt. 9:1118-1121,
  1970.

Holzworth,  G.  C.   Some effects of air pollution on visibility in the
  near cities.   In:   Public Health Service, Robert A. Taft Sanitary
  Engineering Center Symp., Air over Cities, Cincinnati, Ohio.  Nov.
  6-7, 1961.  SEC Technical Report A62-5.  Washington, D.C., U.S.
  Government Printing Office.  1962.  p.  69-88.

Horvath, H.  On the brown color of atmospheric haze.  Atmos. Environ.
  5:333-344, 1971.

Horvath, H., and K.  E.  Noll.  The relationship between atmospheric
  light scattering coefficient and visibility.  Atmos. Environ. 3:543-550,
  1969.
                                422
-------
Houghton, H. G.  On the physics of clouds and precipitation.   In:
  Compendium of Meteorology.  T. F. Malone (ed.).  Boston, Mass.,
  American Meteorological Society.

Huff, F. A., and S. A. Changnon.  Precipitation modification by major
  urban areas.  Bull. Am. Meteorol. Soc. 54:1220-1232, 1973.

Husar, R. B.  Coagulation of Knudsen Aerosols.  Ph.D. Thesis,  University
  of Minnesota.  Minneapolis, Minnesota.  1971.  212 p.

Husar, R. B., N. V. Gillani, J. D.  Husar et al.  A study of long range
  transport from visibility observations, trajectory analysis  and  local
  air pollution monitoring data.  Presented at the 7th Int'l.  Technical
  Meeting on Air Pollution Modeling and Its Application, NATO  Committee
  on the Challenges of Modern Society, Airlie, Va. , Sept. 7-10, 1976.

Husar, R. B., D. E. Patterson, D. L. Blumenthal et al. Three-dimensional
  distribution of air pollutants in the Los Angeles basin.  J. Appl.
  Meteorol. J6:1089-1096, 1977.

Husar, R. B. , and W. R.  Shu.  Thermal analyses of the Los Angeles  smog
  aerosol.   J. Appl. Meteorol. ]4:1558-1565, 1975.

Husar, R. B., K. T. Whitby, and B.  Y. H. Liu.  Physical mechanisms
  governing the dynamics of Los Angeles smog aerosol.  J. Colloid
  Interface Sci. 39:211-224, 1972.

Husar, R. B., and W. H.  White.  On the color of the Los Angeles smog.
  Atmos. Environ.  J_0:199-204, 1976.

Huschke, R. E. (ed.).  Glossary of Meteorology.  Boston, American
  Meteorological Society.  1959.  p. 13, 613.

Idso, S. B., and A. J. Brazel.  Planetary radiation balance as a function
  of atmospheric dust:  Climatological consequences.   Science  198:731-733,
  1977.

Inadvertent Climate Modification.  Report of the Study of Man's Impact
  on Climate (SMIC).  Cambridge, The MIT Press.  1971.  308 p.

International Conference on Environmental Sensing and Assessment.  Las
  Vegas, Sept. 14-19, 1975.   New York, Institute of Electrical and
  Electronics Engineers.  1976.

International Symposium on Sulfur in the Atmosphere,  Dubrovnik, Yugoslavia,
  Sept.  1977.   Atmos. Environ., vol. 11 (1977) and vol. 12 (1978).

Jaenicke, R., C. Junge,  and H. J. Kanter.  Messungen der Aerosolgrossen-
  verteilung uber dem Atlantik.  "Meteor" Forschungsergebnisse, Reihe B
  7:1-54, 1971.

Jiusto,  J.  E.   Aerosol and cloud microphysics measurements in  Hawaii.
  Tellus 19:359-368, 1973.
                                423
-------
Jonsson, B., and R. Sundberg.  Has the Acidification by Atmospheric
  Pollution Caused a Growth Reduction in Swedish Forests?  A Comparison
  of Growth between Regions with Different Soil Properties.  Research
  Note 20.   Stockholm, Royal College of Forestry, Department of Forest
  Yield Research.  (In Swedish with summary in English.)

Joseph, J.  H.,  and A.  Manes.  Secular and seasonal variations of atmospheric
  turbidity at Jerusalem.  J. Appl. Meteorol. K):453-462,  1971.

Junge, C.   The size distribution and aging of natural aerosols as
  determined from electric and optical data on the atmosphere.  Am.
  Meteorol. Soc.  J. Meteorol. 1_2:13-25, 1955.

Junge, C.  E.  Nuclei of atmospheric condensation.  In:  Compendium of
  Meteorology.   T. F.  Malone (ed.).  Boston, American Meteorological
  Society.   1951.  p.  182-191.

Junge, C.  E.  The chemical composition of atmospheric aerosols, 1:^
  Measurements at Round Hill Field Station, June-July 1953.  J. Meteorol.
  11:323-333, 1954.

Junge, C.  £.  Vertical profiles of condensation nuclei in  the stratosphere.
  Am. Meteorol.  Soc.  J. Meteorol. ]8:501-509, 1961.

Junge, C.  E.  Air Chemistry and Radioactivity.  New York,  Academic
  Press.  1963.   382 p.

Junge, C.  E.  Our knowledge of the physico-chemistry of aerosols in the
  undisturbed marine environment.  J. Geophys. Res. 77:5183-5200, 1972.

Junge, C.  E., and T. G. Ryan.  Study of the S02 oxidation  in solution
  and its role in atmospheric chemistry.  Q. J. Roy. Meteorol. Soc.
  84:46-56, 1958.

Kadowaki, S.  Size distribution and chemical composition of atmospheric
  particulate nitrate in the Nagoya area.  Atmos. Environ. 11:671-675,
  1977.

Karuhn, R.  F.   The Development of a New Acoustic Particle  Counter for
  Particle Size Analysis.  In:  Particle Technology 1973.  Proc. 1st
  Int'l. Conf.  on Particle Technology, Chicago, Aug. 21-24, 1973.
  Chicago,  IIT Research Institute.  1973.

Keith, C.  H., and A. B. Arons.  The growth of sea-salt particles by
  condensation of atmospheric water vapor.  J. Meteorol. 11:173-184,
  1954.

Kiang, C.  S., and P. Middleton.  Formation of secondary sulfuric acid
  aerosols in urban atmosphere.  Geophys. Res. Lett. 4:17-20, 1977.

Klein, W.  M., H. S. Parker, and J. G. Severson, Jr.  Sulfur and biological
  systems—Report of a workshop.  Palo Alto, Calif., Electric Power
  Research Institute.   (Manuscript) 1977.  277 p.
                                424
-------
Kochmond, W. C.,  and E. J. Mack.  The vertical distribution of cloud
  and Aitken nuclei downwind of urban pollution sources.  J. Appl.
  Meteorol. JJ:141-148, 1972.

Kochmond, W. C.,  J. Y.  Yang, and J. A. Davis.  A methodology for  determining
  the effects of fuels and additives on atmospheric visibility.   Springfielu,
  Va. ,  NTIS.  1975.

Kondratyev, K.  Ya.   The complete atmospheric energetics experiments.
  Global Atmospheric Research Programme (GARP) Publication Ser. No. 12.
  Geneva, World Meteorological Organization.  1973.  43 p.

Korshover, J.   Climatology of stagnating anticyclones east of the  Rocky
  Mountains, 1976.   NOAA Techical Memo ERL ARL-55.  1976.

Koschmieder, H.  Theorie der horizontalen Sichtweite II:  Kontrast und
  Sichtweite.   Beitr.  Phys. Freien Atmos.  ]_2:171-181, 1925.

Landsberg, H.  E.   The climate of towns.   In:  Man's Role  in Changing
  the Face of the Earth.   W. L.  Thomas,  Jr.  (ed.). Chicago, University
  of Chicago Press.  1956.  p. 584-606.

Larson, T. V.,  and H.  Harrison.   Acidic sulfate aerosols:  Formation
  from  heterogeneous oxidation by 03 in clouds.   Atmos.  Environ.  11:1133-1141
  1977.

Leaderer, B. P.  Summary of the New York summer aerosol  study.   J.  Air
  Pollut. Control Assoc.  28(4):321-327,  1978.

Lee, R. E., Jr.  The size of suspended particulate matter in air.
  Science V78:567-575,  1972.

Likens, G. E.,  and F.  H.  Bormann.   Acid rain.  A serious  regional
  environmental problem.   Science 184:1176-1179, 1974.

Lin, C., M.  Baker,  and R.  J. Charlson.  Absorption coefficient of
  atmospheric aerosol:   A method for measurement.   Appl. Opt.  12:1356-1363,
  1973.

Lindberg, J. D.,  and L. S. Laude.   Measurement of the absorption  coefficient
  of atmospheric  dust.   Appl. Opt.  ]_3:1923-1927, 1974.

Liu, B. Y. H.  (ed.).   Fine Particles.   Aerosol Generation, Measurement,
  Sampling, and Analysis.   Proceedings of symposium sponsored by  the
  U.S.  Environmental  Protection Agency,  Minneapolis, Minn., May 28-30,
  1975.  New York,  Academic Press.   1976.   837 p.

Liu, B. Y. H. ,  and D.  Y.  H. Pui.  Electrical behavior of aerosols.
  Presented at the 82nd National Meeting of American Institute of
  Chemical Engineers,  Atlantic City, August 1976.

Lodge,  J. P.,  Jr.,  and E.  R. Frank.  Chemical identification of some
  atmospheric components in the Aitken nucleus size range.  J.  Rech.
  Atmos. 2:139-140, 1966.


                                425
-------
Loo, B.  W.,  J.  M. Jaklevic, and F. S. Goulding.  Dichotomous virtual
  impactors  for large scale monitoring of airborne participate matter.
  In:   Fine  Particles.  Aerosol Generation, Measurement, Sampling, and
  Analysis.   B. Y. H. Liu (ed.).  Proceedings of symposium sponsored by
  the U.S.  Environmental Protection Agency, Minneapolis, Minn., May
  28-30, 1975.   New York, Academic Press.  1976.  p. 311-350.

Ludwig,  J.  H.,  G. B.  Morgan, and T.  B. McMullen.  Trends in urban air
  quality.    In:  Man's Impact on the Climate.  W. H. Matthews, W. W.
  Kellogg,  and G. 0.  Robinson (eds.).  Cambridge, The MIT Press.  1971.
  p. 321-338.

Lyons, W.  A.,  and R.  B. Husar.  SMS/GOES visible images detect a synoptic-
  scale air pollution episode.  Mon. Weather Rev. 1_04:1623-1626, 1976.

Lyons, W.  A.,  and S.  R. Pease.  Detection of particulate air pollution
  plumes from major point sources using ERTS-1 imagery.  Bull. Am.
  Meteorol.  Soc. 54:1163-1170, 1973.

McCormick,  R.  A., and J. H. Ludwig.   Climate modification by atmospheric
  aerosols.   Science 1_56:1358-1360, 1967.

Machta,  L.   Mauna Loa and global trends in air quality.  Bull. Am.
  Meteorol.  Soc. 53:402-420, 1972.

McWilliams,  S.   Atmospheric Turbidity at Valentia Observatory.  Technical
  Note No.  36.   Dublin, Ireland, Department of Transport and Power,
  Meteorological Service.

Malm, W. C., E. G. Walther, and R. A. Cudney.  The effects of water
  vapor, ozone and aerosol on atmospheric turbidity.  J. Appl. Meteorol.
  l_6:268-274,  1977.

Martens, C.  S., and R. C. Harriss.  Chemistry of aerosols, cloud droplets,
  and rain in the Puerto Rican marine atmosphere.  J. Geophys. Res.
  78:949-957,  1973.

Matthews,  W.  H. (ed.).  Man's Impact on the Global Environment, Assessment
  and Recommendations for Action.  Cambridge, The MIT Press.  1970.

Matthews,  W.  H., W. W. Kellogg, and G. D. Robinson (eds.).  Inadvertent
  Climate Modification.  Report of the Study of Man's Impact on Climate
  (SMIC).   Cambridge, The MIT Press.  1971.

Mekler,  Yu., H. Quenzel, G. Ohring et al. Relative atmospheric aerosol
  content from ERTS observations.  J. Geophys. Res. 82:967-970, 1977.

Middleton,  W.  E. K.  Visibility in meteorology.  In:  Compendium of
  Meteorology.   T. F. Malone (ed.).  Boston, American Meteorological
  Society.   1951.  p. 91-97.

Middleton,  W.  E. K.  Vision Through the Atmosphere.  Toronto, University
  of Toronto Press.  1952.  250 p.
                                426
-------
Miller, J. M. (ed.)-  Geophysical Monitoring  for  Climatic  Change,  No.
  1, Summary Report  1972.  Boulder, Colo., NOAA.   1974.

Miller, J. M. (ed.).  Geophysical Monitoring  for  Climatic  Change,  No.
  2, Summary Report  1973.  Boulder, Colo., NOAA.   1974.

Miller, J. M. (ed.).  Geophysical Monitoring  for  Climatic  Change,  No.
  3, Summary Report  1974.  Boulder, Colo., NOAA.   1975.

Miller, M. S., S. K. Friedlander, and G. M. Hidy.  A  chemical  element
  balance for the Pasadena aerosol.  In:  Aerosols and Atmospheric
  Chemistry.  G. M.  Hidy (ed.).  Proc. of the American Chemical  Society,
  Los Angeles, March 28-April 2, 1971.  New York, Academic  Press.
  1972.  p.  301-312.

Misaki, M., M.  Ikegami, and I. Kanazawa.  Atmospheric electrical conductivity
  measurement in the Pacific Ocean, exploring the background  level  of
  global pollution.  J. Meteorol. Soc. Jpn. 50:497-500,  1972.

Misaki, M., and T.  Takeuti.  The extension of air pollution from land
  over ocean as revealed in the variation of atmospheric electric
  conductivity.   J. Meteorol. Soc.  Jpn. 48:263-269, 1970.

Mitchell, J. M., Jr.  Summary of the problem of air pollution  effects
  on climate.   Iri:  Man's Impact on the Climate.  W. H. Matthews,  W.
  W. Kellogg, and G. 0. Robinson (eds.).  Cambridge,  The MIT  Press.
  1971.  p.  167-175.

Mitchell, J. M., Jr.  The effect of atmospheric aerosols on climate
  with special  reference to temperature near the earth's surface.   J.
  Appl. Meteorol.  K):703-714, 1971.

Mitchell, J. M., Jr.  The effect of atmospheric particles on  radiation
  and temperature.   In:  Man's Impact on the Climate.  W. H. Matthews,
  W. W. Kellogg, and G. 0.  Robinson (eds.).  Cambridge, The MIT Press.
  1971.  p.  295-301.

Monitoring and Air Quality Trends Report, 1973.   U.S. Environmental
  Protection Agency.  Research Triangle Park, N.C.  Publication No.
  EPA-450/1-74-007.   1974.

Monitoring and Air Quality Trends Report, 1974.   U.S. Environmental
  Protection Agency.  Research Triangle Park, N.C.  Publication No.
  EPA-450/1-76-001.   1976.

Mossop, S. C.  Comparisons between concentration of ice crystals in
  cloud and the concentration of ice nuclei.   J. Rech. Atmos.  3:119-124,
  1968.

Moyers, J. L.  The Identification and Analysis of Urban Air Quality
  Patterns.   Final  Report, University of Arizona.  Palo Alto,  Calif.,
  Electric Power Research Institute.  1977.
                                427
-------
Munn, R. E. , and B. Bolin.  Global air pollution—Meteorological aspects.
  A survey.  Atmos. Environ. 5:363-402, 1971.

Noll, K. E. , P. K. Mueller, and M. Imada.  Visibility and aerosol
  concentration in urban air.  Atmos. Environ. 2:465-475, 1968.

Nomoto, S.   Visibility and air pollution.  (Unpublished notes.)  1975.

Novakov, T., S. G. Chang, and A. B. Marker.  Sulfates as pollution
  particulates:  Catalytic formation on carbon (soot) particles.
  Science ^86:259-261, 1974.

Nyberg, A.   On air-borne transport of sulfur over the North Atlantic.
  J. Roy. Meteorol. Soc. J_03:607-615, 1977.

Oden, S.  The Acidification of Air and Precipitation and Its Consequences
  on the Natural Environment.  Uppsala, Sweden, The State National
  Science Research Council.  (APTIC Translation TR-1172.)  1968.

Ogden, T. L.  The effect of rainfall on a  large steelworks.  J. Appl.
  Meteorol. 8:585-591, 1969.

Oliver, R.  C.  On the response of hemispheric mean temperature to
  stratospheric dust:  An empirical approach.  J. Appl. Meteorol.
  J_5: 933-950, 1976.

Orr, C. , Jr., F. K. Hurd, and W. J. Corbett.  Aerosol size and relative
  humidity.  J. Colloid Interface Sci. 13:472-482, 1958.

Particulate Technology 1973.  Proc. 1st Int'l. Conf. on Particle Technology,
  Chicago,  Aug. 21-24, 1973.  Chicago, IIT Research Institute.  1973.
  328 p.

Paterson, M. P.  The Atmospheric Transport of Natural and Man-Made
  Substances.  Ph.D. Thesis, University of London.  London, England.
  1975.

Patterson,  E. M., and D. A. Gillette.  Measurements of visibility vs.
  mass-concentration per airborne soil particles.  Atmos. Environ.
  Vh 193-196, 1977.

Patterson,  E. M., D. A. Gillette, and G. W. Grams.  The relation between
  visibility and the size-number distribution of airborne soil particles.
  J. Appl.  Meteorol. 15:470-478, 1976.

Patterson,  E. M., D. A. Gillette, and B. H. Stockton.  Complex index  of
  refraction between 300 and 700 nm for Saharan aerosols.  J. Geophys.
  Res. 82:3153-3160, 1977.

Patterson,  R. K., and J. Wagman.  Mass and composition of an urban
  aerosol as a function of size for several visibility levels.  J.
  Aerosol Sci. 8:191-201, 1977.
                                428
-------
Redder, M. A.  The correlation of Aitken nucleus characteristics with
  mass concentration in atmospheric aerosol.  Atmos. Environ. 6:735-742,
  1972.

Penkett, S. A.  Oxidation of S02 and other atmospheric gases by ozone
  in aqueous solution.   Nature (Phys. Sci.) 240:105-106,  1972.

Penkett, S. A. , and J.  A.  Garland.  Oxidation of sulphur  dioxide in
  artificial fogs by ozone.  Tellus 26(1-2):284-290, 1974.

Peterson, J. T.   The Climate of Cities:  A Survey of Recent Literature.
  Raleigh, N.C., National  Air Pollution Control Administration.  1969.

Pinnick, R. G., J.  M. Rosen, and D. J.  Hofmann.  Stratospheric aerosol
  measurements III:  Optical model calculations.  J. Atmos. Sci. 33:304-314,
  1976.

Podzimek, J., W.  A. Sedlacek, and J.  B. Haberl.  Aircraft Measurements
  of Aitken Nuclei  in the Lower Stratosphere.  Technical  report to the
  Office of Naval Research and to the U.S.  Department of Transportation,
  CIAP, from the Graduate Center for Cloud Physics Research.  University
  of Missouri, Rolla Rolla, Mo.   1975.

Robinson, E.  Effect on the physical  properties of the atmosphere.  In:
  Air Pollution, vol. I:  Air Pollution and Its Effects.  A. C. Stern
  (ed.).  New York, Academic Press.  1968.   p. 349-400.

Robinson, E. , and R.  C.  Robbins.   Sources,  Abundance, and Fate of
  Gaseous Atmospheric Pollutants.   Prepared for the American Petroleum
  Institute by the  Stanford Research Institute.  SRI Project PR-6755.
  Menlo Park, Calif., Stanford Research Institute, 1968.  123 p.

Robinson, G. D.   Scattering and Absorptive Properties of Atmospheric
  Particles Deduced from Routine Records of Solar Radiation.  Final
  Report to NOAA from Center for the Environment and Man, Hartford,
  Conn.  1974.  45  p.

Rodhe,  H., and J. Grande!!.  On the removal time of aerosol particles
  from the atmosphere by precipitation scavenging.  Tellus 24:442-454,
  1972.

Roosen, R.  G., R. J.  Angione, and C.  H. Klemcke.  Worldwide variations
  in atmospheric transmission:   1.  Baseline results from Smithsonian
  observations.   Bull.  Am.  Meteorol.  Soc.  54:307-316, 1973.

Rosen,  J. M., D.  J. Hofmann, and J. Laby.   Stratospheric aerosol measurements
  II:   The worldwide distribution.  J.  Atmos. Sci. 32:1457-1462, 1975.

Russell, P. B.,  and G.  W.  Grams.   Application of soil dust optical
  properties in analytical  models of climate change.  J. Appl. Meteorol.
  T4:1037-1043,  1975.

Russell, P. B.,  and R.  D.  Hake,  Jr.  The post-Fuego stratospheric
  aerosol:   Lidar measurements,  with radiative and thermal implications.
  J. Atmos. Sci.  34:163-177, 1977.

                                429
-------
Russell, P.  B.,  W.  Viezee, R.  D.  Hake, Jr. et al.  Lidar observations
  of the stratospheric aerosol:   California, October 1972 to March
  1974.   Q.  J.  Roy.  Meteorol.  Soc.  1J32:675-695, 1976.

Samson,  P. J.,  G. Neighmond, and A. J. Yencha.  The transport of suspended
  particulates  as a function of wind direction and atmospheric conditions.
  J. Air Pollut. Control Assoc.  25:1232-1237, 1975.

Samson,  P. J.,  and K.  W. Ragland.   Ozone and visibility reduction in
  the Midwest:   Evidence for large-scale transport.  J. Appl. Meteorol.
  16:1101-1106,  1977.

Samuels, H.  J.,  S.  Twiss, and E.  W. Wong.  Visibility, Light Scattering
  and Mass Concentration of Particulate Matter.  Report of the California
  Tri-City Aerosol  Sampling Project.  Sacramento, State of California
  Air Resources  Board.  1973.   60 p.

Schaefer, V. J.   The inadvertent modification of the atmosphere by air
  pollution.  Bull.  Am. Meteorol.  Soc. 50:199-206, 1969.

Schaefer, V. J.   The Air Quality Patterns of Aerosols on the Global
  Scale.  Part 1 and Part 2.  Final Report prepared for the National
  Science Foundation.   ASRC-SUNY Publication No. 406.  Albany, Atmospheric
  Sciences Research Center, State University of New York.  1976.  110
  p. and 262 p.

Schneider, S. H.  A comment on "Climate:  The influence of aerosols."
  J. Appl. Meteorol. JO:840-841,  1971.

Schnell, R.  C.,  C.  C.  Van Valin,  and R. F. Pueschel.  1976.  Atmospheric
  ice nuclei:  No detectable effects from a coal-fixed powerplant
  plume.  Geophys.  Res. Lett.  3:657-660, 1976.

Sehmel,  G. A.  Particle resuspension from an asphalt road caused by car
  and truck traffic.  Atmos. Environ. 7:291-309, 1973.

Selezneva, E. S.  Atmospheric Aerosols.  Leningrad, Gidometeorologi-
  cheskoi Izdatel'.   1966.

Semonin, R.  G.   Urban-induced weather modification.  In:  1974 Earth
  Environment and Resources Conference Digest of Technical Papers.  New
  York,  Lewis Winner.   1974.  p.  40-41.

Shaw, G. E.   Properties of the background global aerosol and their
  effects on climate.   Science 192:1334-1336, 1976.

Shriner, D.  S.   Effects of Simulated Rain Acidified with Sulfuric Acid
  on Host-Parasite Interactions.   Ph.D. Thesis, North Carolina State
  University.  Raleigh,  N.C.   1974.  85 p.

Sidebottom,  H.  W., C.  C. Badcock, G. E. Jackson et al.  Photooxidation
  of sulfur dioxide.  Environ. Sci. Techno!. 6:72-79, 1972.
                                430
-------
Simmons, W. A., and W. Young.  Correlation of the  Integrating
  Nephelometer to High Volume Air Sampler.  Boston, Commonwealth  of
  Massachusetts Department of Public Health, Bureau of Air Use  Manage-*
  ment.  1970.  6 p.  (Available from Commonwealth of Massachusetts,
  Department of Environmental Quality Engineering  Division of Air
  Quality Control, 600 Washington Street, Boston,  MA 02111.)
SI inn, W. G. N., and J. M. Hales.
  thermophoresis as a mechanism of
  Atmos. Sci. 28:1465-1471, 1971.
                     A reevaluation of the role of
                     in- and belowcloud scavenging.  J.
Smith, F. B.  The turbulent spread of a falling cluster.   In:  Advances
  in Geophysics, vol. 6.  H. E. Landsberg and J. Van Mieghem  (eds.).
  New York, Academic Press.  1959.  p. 193-210.

Squires, P.  The microstructure and colloidal stability of warm  clouds.
  Part I.  The relation between structure and stability.  Tellus
  U): 256-261, 1958.

Squires, P.  An estimate of the anthropogenic production of cloud
  nuclei.  J. Rech.  Atmos. 2:297-307, 1966.

Stern, A. C., H. C.  Wohlers, R. W. Boubel et al.  Fundamentals of Air
  Pollution.  Academic Press,  New York.  1973.  p. 307-316.

Stevens, R. K.  et al.  Sampling and analysis of atmospheric sulfates
  and related species.   Atmos.  Environ.  J_2: 55-68, 1978.


Stevens, R. K. ,  A.  R. McFarland, and J.  B.  Wedding.  Comparison  of the
  Virtual Dichotomous Sampler with the Hi-Volume Sampler.  Presented at
  the 171st National Meeting of the American Chemical Society, New
  York, April 4-9,  1976.  Preprint in vol.  16, no. 1.  Available
  through the ACS Environmental Chemists Division. 1976.

Stevenson, H. J. R., D.  E. Sanderson, and A.  P. Altshuller.   Formation
  of photochemical
  1965.
     aerosols.   Air Water Pollut. Int. J. 9:367-375,
Storeb, P. B.
  bomb debris.

Strutt, J. W.
  particles.
 Formation of radioactivity size distributions in nuclear
  J.  Aerosol Sci.   5:557-577, 1974.

(Lord Rayleigh).   On the scattering of light by small
Phil.  Mag.  4]_: 447-454, 1971.
Sverdrup, G. M.,  and K. T. Whitby.  On the Variation of the Aerosol
  Volume to Light Scattering Coefficient.  Particle Technology
  Laboratory Publication No. 273.  Minneapolis, Mechanical Engineering
  Dept., University of Minnesota.  1976.

Sverdrup, G. M.,  K. T.  Whitby, and W. E. Clark.  Characterization of
  California aerosols--!!.  Aerosol size distribution measurements  in
  the Mojave Desert.  Atrnos. Environ. 9:483-494, 1975,
                                431
-------
Tanner, R. L.,  R. Cederwall, R. Garber et al.   Separation and analysis
  qf aerosol sulfate species at ambient concentrations.  Atmos. Environ.
  11:955-966, 1977.

Tanner, R. L.,  and W. H. Marlow.  Size discrimination and chemical
  composition of ambient airborne sulfate particles by diffusion sampling.
  Atmos. Environ. JJ:1143-1150, 1977.

Telford, J. W.   Freezing nuclei from industrial processes.  J. Meteorol.
  J7:676-681, 1960.

Timbrel 1, V.  An aerosol spectrometer and its applications.   In:
  Assessment of Airborne Particles.  Fundamentals, Applications, and
  Implications to Inhalation Toxicity.  T. T.  Mercer, P. E. Morrow, and
  W. Stober (eds.).  A  Proceedings Publication of the Third Rochester
  International Conference on Environmental Toxicity.  Springfield,
  111., Charles C. Thomas.  1972.  p. 290-330.

Toon, 0. B., J. B. Pollack, and B. N. Khare.  The optical constants of
  several aerosol species:  Ammonium sulfate, aluminum oxide  and sodium
  chloride.  J. Geophys. Res.  8].: 5733-5748, 1976.

Trijonis, D., and K. Yuan.  Visibility in the Southwest.  TSC-PD-B562-1.
  Santa Monica, Calif., Technology Service Corp. 1977.

Trijonis, D., and K. Yuan.  Visibility in the Northeast:  Long-Term
  Visibility Trends and Visibility/Pollutant Relationships.   Preliminary
  draft prepared for U.S. Environmental Protection Agency.  March 1978.

Twomey, S.  The influence of droplet concentration on rain formulation
  and stability in clouds.  Bull. Observ. Puy Dome 2:33-41, 1959.

Twomey, S.  The nuclei  of natural cloud formation.  Part II.  The
  supersaturation in natural clouds and the variation of cloud droplet
  concentration.  Geofis. Pura Appl.  43:243-249, 1959.

Twomey, S., and P. Squires.  The influence of cloud nucleus population
  on the microstructure and stability of convective clouds.   Tellus
  JJ:408-411, 1959.

Twomey, S., and J. Warner.  Comparison of measurements of cloud droplets
  and cloud nuclei.  J. Atmos. Sci. 24:702-703, 1967.

Uchino, 0., and M. Hirono.  On stratospheric aerosol size distributions
  from  recent optical radar observations.  Rep. Ionosphere Space Res.
  Jpn.   27:69-73, 1975.

Urone,   P., W. H. Schroeder, and S. R. Miller.   Reactions of sulfur
  dioxide in air.  In:  Proc.  2nd Int'l. Clean Air Congress,  Washington,
  D.C., Dec. 6-11, 1970, sponsored by The International Union of Air
  Pollution Prevention  Associations.   H. M. Englund and W. T. Beery
  (ed.).  New York, Academic Press.  1971.  p. 370-375.
                                432
-------
Ursenbach, W.  Personal communication,  1978.

U.S. Department of Health, Education, and Welfare.   Air  Quality  Criteria
  for Particulate Matter.  National Air  Pollution  Control  Administration
  Publication No. AP-49.  Washington, D.C., U.S. Government  Printing
  Office.  1969.  211 p.

Vandergrift, A. E.,  L. J. Shannon, E. E. Sallee  et al.   Particulate air
  pollution  in the United States.  J. Air Pollut.  Control  Assoc.  21_:321-328,
  1971.

Vanderpol, A. H., F. D. Carsey, D. S. Covert et  al.  Aerosol  chemical
  parameters and air mass character in the St. Louis region.   Science
  190:570, 1973.

Viskanta, R., R. W.  Bergstrom, and R. 0. Johnson.   Radiative  transfer
  in a polluted urban planetary boundary layer.  J.  Atmos. Sci.   34:1091-1103
  1977.

Vohra, K. G.  , K. N.  Vasudevan, and P. V. N. Nair.   Mechanisms  of nucleus-
  forming reactions  in the atmosphere.  J. Geophys.  Res. 75:2951-2960,
  1970.

Volz, F. E.   Turbidity at Uppsala from 1909 to 1922 from Sjostrom's
  solar radiation measurements.  Meddelanden Ser.  B, no. 28.   Stockholm,
  Sver. Meteorol. Hydro!. Inst. 1968.

Volz, F. E.   Economical multispectral sun photometer for measurements
  of aerosol  extinction from 0.44 urn to  1.6 pm and  precipitable  water.
  Appl. Opt.  J3:1732-1733, 1974.

Volz, F. E.   Burden of volcanic dust and nuclear debris after  injection
  into the stratosphere at 40°-58°.  J.  Geophys. Res. 80:2649-2652,
  1975.

Volz, F. E.   Distribution of turbidity after the Katmai eruption in
  Alaska.  J. Geophys. Res.  80:2643-2648, 1975.

Waggoner, A.  P., and R. J. Charlson.   Simulating the color of  polluted
  air.   Appl. Opt. JO:957-958, 1971.

Waggoner, A.  P., and R. J. Charlson.   Optical and  Chemical Characteristics
  of Aerosols.   Presented at Symposium on Geophysical Monitoring for
  Climatic Change, CSIRO, Aspendale, Australia.  1975.

Waggoner, A.  P., and R. J. Charlson.   Measurements  of aerosol  optical
  parameters.  In:  Fine Particles.  Aerosol Generation, Measurement,
  Sampling,  and Analysis.  B. Y. H. Liu  (ed.).   Proc. of Symp. sponsored
  by the U.S. Environmental  Protection Agency, Minneapolis, Minn., May
  28-30, 1975.   New York, Academic Press.  1976.   p. 511-533.

Waggoner, A.  P., and R. J. Charlson.   Aerosol Characteristics  and
  Visibility.  U.S.  Environmental Protection Agency.  Research Triangle
  Park, N.C.   Publication No. EPA-600/3-77-072.  1977.


                                433
-------
Waggoner, A. P., and R. J. Charlson.  Aerosol Characteristics and
  Visibility.  U.S. Environmental Protection Agency.  Research Triangle
  Park, N.C.  Publication No. EPA-600/3-77-072.  1977.

Waggoner, A. P., A. H. Vanderpol, R. J. Charlson et al.   Sulphate-light
  scattering ratio of an index of the role of sulphur in tropospheric
  optics.  Nature 261:120-122, 1976.

Wagman, J., R.  E. Lee, Jr., and C. J. Axt.  Influence of some atmospheric
  variables on the concentration and particle size distribution of
  sulfate in urban air.  Atmos.  Environ. 1:479-489, 1967.

Wang, W-C., and G. A. Domoto.  The radiative effect of aerosol in the
  earth's atmosphere.  J. Appl.  Meteorol. ]_3:521-534, 1974.

Warner, J.  A reduction in rainfall associated with smoke  from sugarcane
  fires—An inadvertent weather modification?  J. Appl.  Meteorol.
  7:247-251, 1968.

Warner, J.  The microstructure of cumulus cloud.  Part II.  The effect
  on droplet size distribution of the cloud nucleus spectrum and updraft
  velocity.  J. Atmos. Sci.  26:1272-1282, 1969.

Warner, J., and S. Twomey.  The production of cloud nuclei by cane
  fires and the effect on cloud droplet concentration.  J. Atmos. Sci.
  24:704-706, 1967.

Watkins, J. A.  (ed.).  Geophysical Monitoring for Climatic Change, No.
  4, Summary Report 1975.  Boulder, Colo., NOAA.  1976.

Weiss, R. E. et al.  Sulfate aerosol:   Its geographical extent in the
  midwestern and southern United States.  Science 195:979-981, 1977.

Welch, R. , and W. Zdunkowski.  A radiation model of the polluted atmospheric
  boundary layer.  J. Atmos. Sci. 33:2170-2184,  1976.

Wesolowski, J.  J., A. Alcocer, and B. R. Appel.  The Validation of the
  Lundgren Impactor.  AIHL Report No. 138-B.  Berkeley, Laboratory
  Services Branch, California State Department of Health.  1975.

Whitby, K. T.  Second International Workshop on  Cloud and  Ice Nuclei,
  Fort Collins, Colo., Aug. 5-19, 1970.  Particle Technology Laboratory
  Report No. 173.  University of Minnesota, Minneapolis, Environmental
  Division, Mechanical Engineering Department.   1973.

Whitby, K. T. Modeling of multimodal aerosol distributions.  In:
  Aerosole in Naturwissenschaft, Medizin und Technik.  V.  Bohlau (ed.).
  Proc. of Conf. held in Bad Soden, Oct. 16-19,  1974.  Bad Soden,
  Gesellschaft fur Aerosolforschung.  1974.
                                  434
-------
Wilkins, E. T.  Air pollution aspects  of  the  London  fog  of  December
  1952.  Q. J. Roy. Meteorol. Soc. 80:267-278,  1954.

Willeke, K. , and J. E. Brockmann.  Extinction coefficients  for multimodal
  atmospheric particle size distributions.  Atmos. Environ.  11:995-999,
  1977.

Willeke, K., and B. Y. H. Liu.  Single particle  optical  counter:
  Principle and application.  In:  Fine Particles.   Aerosol  Generation,
  Measurement, Sampling, and Analysis.  B. Y. H.  Liu (ed.).   Proc.  of
  Symp. sponsored by the U.S. Environmental Protection Agency,  Minneapolis,
  Minn., May 28-30, 1975.  New York, Academic Press.   1976.   p.  697-729.

Willeke, K., and K. T. Whitby.  Atmospheric aerosols:  Size  distribution
  interpretation.  J. Air Pollut. Control Assoc.  25:529-534,  1975.

Willeke, K., K.  J.  Whitby, W. E. Clark et al.  Size  distributions  of
  Denver aerosols--A comparison of two sites.  Atmos.  Environ.  8:609-633,
  1974.

Wilson, W.   E., et al.  Sulfates in the Atmosphere.   U.S.  Environmental
  Protection Agency.  Research Triangle Park, N.C.   Publication No.
  EPA-600/7-77-021.  1977.

Wilson, W.   E. , Jr., E. L. Merryman, and A. Levy.  A  Literature  Survey
  of Aerosol Formation and Visibility  Reduction  in Photochemical Smog.
  Research  report for  the American Petroleum Institute.  Columbus,
  Battelle Memorial Institute.  1969.  41 p.

Wilson, W.   E., Jr., E. L. Merryman, and A. Levy.  Aerosol formation  in
  photochemical  smog.  1. Effect of stirring.  J. Air Pollut.  Control
  Assoc. 21.:128-132, 1971.

Winchester, J.  W.  Trace metal associations in urban airborne particulates.
  Bull. Am. Meteorol. Soc. 54:94-97, 1973.

Winchester, J.  W.,  T, B.  Johanson, and R. E. Grieken.  Marine influences
  on aerosol composition in the coastal zone.  J. Rech.  Atmos.  8(3-4):761-776,
  1974.

Winkler, P.  The growth of atmospheric aerosol particles  as  a function
  of the relative humidity.   II. An improved concept of  mixed nuclei.
  J. Aerosol Sci. 4:373-387, 1973.

Winkler, P. , and C. Junge.  The growth of atmospheric aerosol particles
  as a function of the relative humidity.  Part  I. Method and measurement
  at different locations.  J. Rech. Atmos. 6:617-638,  1972.

Woodcock, A. H., and D. C. Blanchard.  Tests of  the  salt-nuclei  hypothesis
  of rain formation.  Tellus 7:437-448, 1955.
                                  435
-------
Yamamoto, G., and M. Tanaka.  Increase of global albedo due to air
  pollution.  J. Atmos. Sci. 29:1405-1412, 1972.

Yamamoto, K.  The Relationship Between Relative Humidity and Mass of
  Deliquescent Aerosols.  Master's Thesis, Washington University.  St.
  Louis, Mo.  1975.

Yudine, M. I.  Physical considerations on heavy particle diffusion.
  Adv. Geophys.  6:185-191,  1959.

Zdunkowski, W. G., R. M. Welch, and 0. Paegle.  One-dimensional  numerical
  simulation of the effects of air pollution on the planetary boundary
  layer.  J. Atmos.  Sci. 33:2399-2414, 1976.
                                  436
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                                    .,!>;,iCAi. R
   EPA-600/9-78-028

   EMISSION"OF'SULFUR-BEARING COMPOUNDS  FROM  MOTOR
            VEHICLE AND AIRCRAFT  ENGINES
                A Report To Congress
          |j RtPOHT UA Ft
          |   August 1978

          JG PERFORMING O R G AN , 7. ATI ON CODE
7 AUTHOR'S'
   James M. Kawecki
                                                          8. PERFORMING ORGANISATION REPORT M'
9 PERFORMING ORGANIZATION NAME AND ADDRESS
   Biospherics, Inc.
   Rockville, MD
           10 PROGRAM ELEMENT NO

             1AD712
           11. CONTRACT/GRANT NO.

             68-02-2926
 12. SPONSORING AGENCY NAME AND ADDRESS
   Environmental Sciences  Research  Laboratory -  RTP, NC
   Office of Research and  Development
   U.S. Environmental Protection  Agency
   Research Triangle Park,  NC   27711
           13. TYPE OF REPORT AND PERIOD COVERED
             Report To Congress
           14. SPONSORING AGENCY CODE
             EPA/600/09
15. SUPPLEMENTARY NOTES
 16. ABSTRACT
    This  report was generated in response to §403(g) of The Clean Air Act  as  amended
    August,  1977.   The report covers (1) a review of emission  factors for  H2S04,  S02,
    sulfate, H2$,  and carbonyl sulfide from motor vehicles, motor vehicle  engines and
    aircraft engines; (2)  a review of the known effects on health and welfare of  these
    compounds;  (3)  the status on technology to control such emissions;  and  (4)  an
    analysis of the costs  of control weighed against the social benefits of such
    control.  Available emission factors for these pollutants were converted  to ambient
    air concentrations by  using dispersion and stochastic models.  The  predicted  ambient
    air concentrations were compared to concentrations of these pollutants  known  to
    cause adverse  health or welfare effects.  Results of this comparison suggest  that
    benefits of any control are likely to be small.  Except for 3-way catalytic
    control  technology, cost data for fuel desulfurization and vehicle  on-board
    control  technology suggest an extremely large economic impact.  Consequently,
    specific controls of sulfur-bearing compounds from mobile sources are  not
    recommended.
17
                               KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
    *Air pollution
    *Sulfur inorganic compounds
    *Sulfur organic compounds
    ^Emission
    *Motor vehicles
    *Motor vehicle engines
    *Aircraft engines
    ^Economic analysis	
IS DI3TRIBU"!
            . £ TATEMENT
                                             b.IDENTIFIERS/OPEN ENDED TERMS
    RELEASE TO PUBLIC
SECURITY CLASS ,' / Ins Repot t/
_UNCLASSIFIED
SECURITY CLA-;S  -,/.v ;M!,"''  ~
  UNCLASSIFIED
                          COSATI I ic!d/Oroup
                              13B
                              07B
                              07C
                              13F
                              QIC
                              05C
21 NO OF PAGES

     453	
22 PRICE.
EFA Form
                                           437
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