ENVIRONMENTAL HEALTH SERIES
Air Pollution
EFFECTS OF THE RATIO
OF HYDROCARBON
TO OXIDES OF NITROGEN
IN IRRADIATED AOTO EXHAUST
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
-------
EFFECTS OF THE RATIO
OF HYDROCARBON
TO OXIDES OF NITROGEN
IN IRRADIATED AUTO EXHAUST
Merrill W. Korth
Engineering Research and Development
Laboratory of Engineering and Physical Sciences
Robert A. Taft Sanitary Engineering Center
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Division of Air Pollution
Cincinnati, Ohio 45226
October 1966
-------
The ENVIRONMENTAL HEALTH SERIES of reports was established
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Public Health Service Publication No. 999-AP-20
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FOREWORD
Vehicle exhaust is recognized as a. major air pollutant. This
problem has been under intensive study by government and private
research agencies for several years. Basic to these studies is the
determination of types and concentrations of pollutants contained in
vehicular exhaust, the photochemical reactions that occur when ex-
haust is discharged into the atmosphere, and the products responsible
for various air pollution effects.
Photochemical reactions are being studied in detail by the use
of "smog" chambers in which vehicular exhaust diluted with air is
irradiated to simulate the effects of sunlight in the atmosphere. This
is the second of a. series of reports describing irradiation chamber
tests conducted by the Division of Air Pollution of the Public Health
Service.* The work is performed by personnel of the Division's
Laboratory of Engineering and Physical Sciences at the Robert A.
Taft Sanitary Engineering Center at Cincinnati, Ohio.
Preliminary tests were conducted at the Center beginning in
February I960. The irradiation chamber tests completed between
that time and May 1961 are described in PHS Publication No. 999-
AP-5. The results of the series of tests conducted between May 1961
and November 1962 are presented in this report. This series investi-
gated the effects of varying the ratio of total hydrocarbons to oxides
of nitrogen in the exhaust products.
^Mention of commercial products used in this research does
not constitute endorsement by the Public Health Service.
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CONTENTS
Page
ABSTRACT vii
INTRODUCTION 1
TEST FACILITY AND PROCEDURES .... 1
TEST PARAMETERS 8
Major Independent Variables 8
Characteristics of Chamber Input . . 10
CHEMISTRY OF IRRADIATED EXHAUST ... 14
The NO NO2 Reaction Processes 14
NO Photoxidation 14
NO2 Formation Rate 14
CHEMICAL EFFECTS 18
Hydrocarbon Reactions .... . . . 18
Aldehydes 20
Oxidant Formation . 23
Percent NOX Reacted 25
Other Products 27
BIOLOGICAL EFFECTS 28
Eye Irritation 28
Plant Injury 30
ATMOSPHERIC EFFECTS . . 31
STATISTICAL ANALYSIS 33
SUMMARY OF RESULTS 35
ACKNOWLEDGMENTS 38
REFERENCES . ... 39
APPENDIX Detailed Test Data 43
Summary of Test Conditions and Run Numbers 44
Biological Data 45
Chemical Data 46
Chromatographic Data 47
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ABSTRACT
As a part of a series of investigations of the problem of vehicle
exhaust as an air pollutant, photochemical reactions are being studied
in detail by the use of large dynamic irradiation chambers. In these
studies auto exhaust, generated by test vehicles on a dynamometer, is
diluted with air and irradiated to simulate the effects of sunlight under
mixing conditions similar to those in the atmosphere. The irradiated
mixture is used to study chemical reactions and to evaluate plant
damage and human eye irritation.
In this second series of irradiation tests performed by the Public
Health Service, the ratio of total hydrocarbon (HC) to oxides of nitro-
gen (NOX) was varied between 1 - 1 / 2 and 24. Hydrocarbon concentra-
tions were varied from 3 ppm to 12 ppm total carbon; oxides of nitro-
gen concentrations were varied from 1/4 ppm to 2 ppm.
Greatest plant damage occurred when both the HC/NO ratios
and hydrocarbon concentrations were high. The levels of eye irrita-
tion were highest at the higher chamber hydrocarbon concentrations.
-ror a given hydrocarbon level, chemical reaction rates were highest
at the high HC/NOX ratios.
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INTRODUCTION
The growing air pollution problem resulting from automotive
emissions has resulted in legislation, in certain areas, directed
toward the reduction of gross hydrocarbon emissions. Although such
an approach is reasonable and expedient in view of the magnitude of
the problem, it was taken without complete knowledge of the effects
of such a reduction on atmospheric photochemical reactions. To
extend our knowledge of these reactions, we undertook a special
series of tests in the PHS chamber facility for irradiation of dilute
automotive exhaust. In these tests the ratios of total hydrocarbon
to oxides of nitrogen were controlled and varied over a range com-
parable to that found in the atmosphere.
Although the processes involved in photochemical smog are much
more variable in community atmospheres than in the laboratory, the
findings reported herein, representing one of the most closely con-
trolled experiments of this type completed to date, should aid materi-
ally in interpreting the effects of pollution control programs.
Air masses over urban areas continually undergo varying de-
grees of mixing of new pollutants with existing pollutants. The degree
of mixing depends on atmospheric turbulence and on the location and
movement of parcels of air with respect to pollutant sources. For
study of the atmospheric photochemical oxidation of dilute automotive
exhaust under conditions that simulate continuous uniform atmospheric
mixing of new with old pollutants, we have used a dynamic irradiation
system. In this dynamic system, dilute non-irradiated auto exhaust
is continually introduced into the irradiation chamber and dilute ir-
radiated exhaust is continually withdrawn.
TEST FACILITY AND PROCEDURES
The test facility is described in detail in earlier publica-
tions. ' ' The equipment consists of five major components:
a test vehicle operated on an automatically cycled chassis' dyna-
mometer to provide exhaust gases under simulated driving conditions,
a two-stage exhaust-transfer and dilution system to dilute the raw
exhaust gases to the specified concentrations, a dilution-air purifi-
cation system, dynamic irradiation chambers for the irradiation
of the dilute exhaust gases, and exposure facilities for evaluation
of plant damage and human eye irritation.
Several changes and improvements were made in the basic
irradiation facility before this test series was begun. A flywheel
was installed on the dynamometer to provide a source of stored
energy during deceleration in place of the slave engine used pre-
viously to simulate decelerations. The original hydraulic power
absorption unit was replaced with an eddy-current power absorption
unit capable of precise torque control. These modifications per-
-------
mitted the design and use of a vehicle cycle that was more reproduc-
ible and more realistic with respect to average driving conditions
than the cycle used in earlier tests. Figure 1 shows some of the
major parameters of the improved test cycle.
100
1 23456
TIME, minutes
Figure 1. Automatic cycle for test vehicles.
EFFECTS OF HC/NCv RATIOS
-------
In the irradiation chambers the original irradiation lamps were
replaced with 24 fluorescent sun lamps, 36 fluorescent blue lamps,
and 88 fluorescent black light lamps. This change increased the light
energy in the ultraviolet region of photochemical importance. In
addition, Tedlar PVF film was installed in place of Mylar for the
chamber windows. The combined effect of these modifications was an
improvement in the degree to which the light energy in the chamber
approximated the sunlight levels in the photoreactive region of 2900
to 3800 angstroms, Figure i. Measurement of the area under the
chamber light-energy curves indicates that the present level of light
intensity in the chamber is 35 percent higher than the previous level.
The present light distribution closely approximates the most recently
published sunlight data, 4 curve 2, in the region of 2900 to 3300
angstroms. The original sunlight distribution curve 1, based on
measurements made in Cleveland, Ohio, has been superseded by the
generally accepted curve 2, which was developed for the Los Angeles
area at a zenith angle of 20 degrees.
3000
3200 3400 3600
WAVELENGTH, angstrom units
3800
4000
Figure 2» Light intensity in irradiation chamber.
Test Facilities and Procedures
-------
The average irradiation time of a mixture passing through a
dynamic irradiation chamber depends on the volume of the chamber
and on flowrate. For the 335-cubic-foot chamber used in these ex-
periments, flowrates of Z.79 and 1.86 cubic feet per minute produce
irradiation times of 120 and 180 minutes, respectively.
Concentrations of the chemical constituents were monitored in
the exhaust gas mixture after dilution and in the irradiation chamber
before and during irradiation. Hydrocarbon in both the irradiated and
nonirradiated exhaust gas mixture after dilution was measured with
a flame ionization detector, which responds in ppm as total carbon
atoms. Nitric oxide and nitrogen dioxide were measured with a con-
tinuous-recording colorimetric instrument. Because of the time-
response characteristics of this instrument, a computer program was
applied to convert the instrument response to instantaneous values.
Carbon monoxide concentrations in the irradiated gases -were measured
by a longpath nondispersive infrared analyzer. Oxidant concentrations
were measured by a continuous-recording coulometric instrument with
a neutral potassium iodide solution. Corrections for NC>2 interference
•were applied to the oxidant data.
Direct analyses by flame-ionization gas chromatography were
made for the following aliphatic hydrocarbons: . ethane, ethylene,
acetylene, propane, propylene, n-butane, isobutane, and isopentane.
These analyses were made every ZO to 30 minutes during the experi-
ment with a IZ-foot-long silica gel column used at room temperature
for separation of the components. The sample was obtained from an
aluminum line, through which a portion of the contents of the irradia-
tion chamber was drawn continuously during each experiment. Direct
analyses also were made for the following aromatic hydrocarbons:
benzene, toluene, ethylbenzene, m- and p-xylene, n-propylbenzene,
3- and 4-ethyltoluene, 1, 3, 5-trimethylbenzene and sec. and tert.
butylbenzene, (reported as 1, 3, 5-trimethylbenzene), 1, Z, 4-trimethyl-
benzene, and styrene and Z-ethyltoluene. Analyses for aromatic
hydrocarbons were made with a 15-foot-long column consisting of
5 percent 1,2,3-tris (Z-cyanoethoxy) propane on 50- to 60-mesh C-ZZ
V R
firebrick at 50°C. Propadiene, four- and five-carbon olefins,
n-pentane, and Z-methylpentane were present in very low concentra-
tions; these components were analyzed after a concentration step on
a combination column containing a 6-foot length of bis-Z (Z-methoxy-
ethyl) adipate and a Zl-foot length of dibutyl maleate on C-ZZ firebrick,
operated at 40°C. Although all of the components listed could be
analyzed at chamber concentrations of 1Z ppm carbon, a number of
the less abundant hydrocarbons could not be determined quantitatively
at 6 and particularly at 3 ppm carbon. All gas chromatographic an-
alyses for hydrocarbons were made with flame ionization detectors.
During a few of the last experiments in this series, organic nitrates
and diketones were analyzed by electron-capture gas chromotography.
The spectrophotometric methods for formaldehyde by the chromo-
tropic acid method, 10- U acrolein by the 4-hexylresorcinol method, 12
and total aliphatic aldehydes by the 3-methyl-2-benzothiazolone hydra-
zone method13- 14 were used in previous irradiation studies. 2> 15
4 EFFECTS OF HC/NOX RATIOS
-------
Four-carbon and higher olefins were analyzed by the dime thy lamino-
benzaldehyde procedure also discussed previously. The bubbler
containing the reagent for the olefin analysis was in series with and
followed the bubbler containing the water used to collect formalde-
hyde from the sample stream. Nitric oxide was analyzed with bubbler
samples after permanganate oxidation, and nitrogen dioxide was
analyzed directly by the Saltzman procedure. Oxidant was deter-
mined by the 1 percent neutral potassium iodide procedure. 18
Samples were collected either in 10 or 20 ml of collecting solu-
tion contained in a "smog" type fritted-glass bubbler. The flowrates
were kept low to insure maximum collection efficiency. Nitrogen
dioxide was collected at flowrates as low as 200 cc per minute.
Most of the samples were drawn through the bubblers at flowrates
between 400 and 1000 cc per minute. Materials such as Tygon,
Nalgon, rubber, and polyethylene were not incorporated into sam-
pling lines to preclude losses of the more reactive substances.
Teflon tubing proved satisfactory, as did glass, aluminum, and stain-
less steel tubing after tho'rough conditioning.
To obtain a test fuel having characteristics similar to the fuels
used in the previous irradiation chamber studies, we blended two
fuels prepared by the Western Oil and Gas Association in equal pro-
portions. Analysis of the fuel is given in Table 1.
Table 1. PHYSICAL AND CHEMICAL PROPERTIES OF TEST FUEL
Properties
API gravity, degrees 56."6
Reid vapor pressure, Ib/in. ^ 9. 35
Distillation, °F
Initial / 95
End point ' 402
Research octane number, F-l ' 100. 3
Motor octane number, F-2 ' 89. 2
Sulfur (total), weight % 0.031
Bromine no. (electrometric), g/lOOg 37.0
Tetraethyl lead, ml/gal 1.25
Fluorescent indicator analysis (as received),
volume %
Saturates 46
Olefins 16
Aromatics 38
For the plant-damage evaluations, plants that develop distinct
types of physical injury were selected to indicate the effects of the
various phytotoxicants in irradiated auto exhaust:
1. Pinto bean primary (Phaseolus vulgaris, L. , var. pinto)
2. Pinto bean trifoliate (Phaseolus vulgaris, L. , var. pinto)
3. Young pinto bean (Phaseolus vulgaris, L. , var. pinto)
4. Tobacco wrapper C. (Nicotiana tabacum, L. , var. Bel. C)
5. Tobacco Smyrna (Nicotiana tabacum, L. , var. Smyrna)
6. Petunia (Petunia hybrida, Vilm. , var. Celestial Rose)
Test Facilities and Procedures 5
-------
The plants were selected at specific stages of growth, rather than at
chronological age from planting or emergence, so that some of the
variability resulting from differences in environmental conditions
could be avoided. Individual plants were selected for exposure on the
following bases: (1) pinto bean (primary) after the first trifoliate leaf
appeared and had been debudded so that only the primary leaves were
present, (2) pinto bean (trifoliate) when the first trifoliate expanded
and began to develop the characteristics of a mature leaf, (3) young
pinto bean when the plants had fairly young primary leaves, about one-
quarter the size of a mature leaf, and one unfolding trifoliate bud,
(4) both tobacco varieties when the plants had 8 to 12 leaves, and (5)
petunias when the plant had one stock and four to six middle-aged
leaves, prior to bud development. These stages of growth were
easily identified and appeared to yield tissue of fairly uniform sus-
ceptibility to irradiated auto exhaust.
All plants were grown under closely controlled greenhouse con-
ditions. For uniform exposure, the plants were placed on a rotating
table in a small exposure chamber, Figure 3, lighted by deluxe
warm-white fluorescent lamps at approximately 1800 foot-candles.
The 4-hour exposure of plants to irradiated auto exhaust usually be-
gan within 15 minutes after the beginning of irradiation in the irradia-
tion chamber.
Figure 3. Plant-exposure chamber.
EFFECTS OF HC/NOX RATIOS
-------
Microscopic examinations of the internal cell structure were
made several times during the first few days after exposure to identify
the phytotoxicants by the type of cell injury. The external leaf
damage was estimated the third day after exposure and expressed in
terms of an injury index on a scale of 0, 1, 2, 3, and 4, where 4
indicates total injury of the sensitive tissue.
Irritation of human eyes by the irradiated dilute exhaust was
measured on ten volunteer panelists in the exposure facility illustrated
in Figure 4. Five of the ten panelists were exposed simultaneously
in five exposure booths housed in an air-conditioned enclosure.
Figure 4. Eye-exposure booth.
Test Facilities and Procedures
-------
The test atmosphere was delivered to panelists through a glass mani-
fold connected to flexible plastic goggle-type masks with Teflon tubing.
Each panelist wore a respirator with activated charcoal filters to
separate any odor response from the eye irritation response. The
goggle-type masks were chosen instead of the open-helmet type as a
result of a series of experiments in which the distribution of gas
within the masks was studied by use of probes and a flame ionization
analyzer.
Each panelist reported the degree of irritation on a scale of
0 to 3 (none, light, medium, and heavy) every 30 seconds. The index
number for each run was determined by adding the highest response
numbers reported twice in succession by each panelist. This pro-
cedure was intended to eliminate spurious single responses by panel-
ists.
TEST PARAMETERS
Major Independent Variables
The effects of dilute irradiated exhaust mixtures on chemical
reactivity, eye irritation, and vegetation injury were studied in terms
of two independent variables:
1. The initial hydrocarbon (HC) concentrations were set at
3, 6, and 12 ppm carbon.
2. Initial oxides of nitrogen (NOX) concentrations were estab-
lished at 1/4, 1/2, 1. and 2 ppm.
These ranges of concentrations, shown in Table 2, established the
HC/NOX ratios for this study at 1-1/2, 3, 6, 12, and 24. All tests
were duplicated except for those at HC/NOX ratios of 1-1/2 and 24,
which were single tests undertaken to complete the test design matrix.
Table 2. PARAMETERS ESTABLISHED BY TEST DESIGN
Number of tests at
HC concentration,
ppm carbon
3
3
3
3
6
6
6
12
12
12
NOX concentration,
ppm
1/4
1/2
1
2
1/2
1
2
1/2
1
2
HC/NOX
ratio
12
6
3
1- l/2b
12
6
3
24^
12
6
120-min
AITa
2
2
3
1
3
2
2
1
2
2
180-min
AITa
1
1
1
1
1
1
1
aAIT: Average irradiation time.
"Single tests; all others duplicated.
EFFECTS OF HC/NOX RATIOS
-------
The concentrations and ratios in this study were intended to be
comparable with those in a community atmosphere under severe
photochemical conditions; therefore, data obtained by the Continuous
Air Monitoring Program (CAMP) of the Public Health Service in the
Los Angeles area during August and September 1962 were analyzed
to determine comparability. Data for 5 days during which severe
eye irritation occurred were evaluated to determine the total HC
and NOX concentrations in the atmosphere immediately before the
beginning of the photochemical reaction. The highest daily atmos-
pheric oxidant concentrations occured after the reaction "was "well
under way. These data are presented in Table 3.
Table 3. ATMOSPHERIC DATA FROM LOS ANGELES CAMP STATION
Date
8/7/62
8/8/6Z
8/9/62
8/14/62
9/20/62
HC concentration,
ppmC
3.2
8. 0
3. 0
5.0
7. 0
NOX concentration,
ppm
0. 32
0. 59
0. 32
0.45
0. 62
HC/NOX
ratio
10. 0
13. 5
9.4
11.1
11.3
Maximum daily
oxidant cone. , pphm
25
30
16
45
30
Total HC concentrations were corrected for background levels by
subtraction of the lowest value shown between midnight and the time
of the peak HC concentration. This correction is minimal, a sub-
traction of Z to 3 ppm of what is presumed to be largely methane from
the total HC concentrations measured in the morning before the
photochemical reaction began. Even this small correction, however,
helps to relate the hydrocarbon composition of the experimental auto
exhaust more nearly to that of the atmosphere. Gas chromatographic
analyses were not available on these dates to permit a more detailed
correction procedure. Oxidant values were corrected for interference
of NO2 and SO2. The atmospheric HC levels, NOX levels, and HC/NOX
ratios fall within the extremes of the test values used in this study.
Findings of the previous test series ' indicated no significant
effects as average irradiation time increased from 85 minutes to 1ZO
minutes. The present series was conducted primarily at an average
irradiation time of 120 minutes. There is some evidence, however,
that irradiation periods exceeding 120 minutes are important for
static chamber operation. Hence the average irradiation time was
extended to 180 minutes in several exploratory tests, but not enough
observations were made to justify statistical evaluation. Observations
and conclusions presented in this paper, therefore, are based pri-
marily on the more complete data for the 120-minute average irradia-
tion time.
Initial HC concentrations were established above the background
level observed in the dilution air. Chromatographic analysis of this
background level indicated that the total concentration is about 1. 5
ppmC, of which 93 percent is methane.
Test Parameters 9
-------
The statistical significance of the changes in each level of the
response variable over the condition of the experiment was determined
by an analysis of variance; results are reported under Statistical
Analysis .
Characteristics of Chamber Input
The gas chromatographic analyses demonstrate that the detailed
HC composition before irradiation was essentially constant for runs
at the same total HC level and for each of the three HC levels used.
Results of gas chromatographic analyses of auto exhaust samples
having HC contents at one of the three concentrations normalized to
the ethylene concentration are shown in Table 4. The HC concentra-
tions used to obtain these ratios are based on average values from
six to eight tests run at each concentration. The ranges of concen-
trations reported "were not obtained by diluting an individual sample
but are the results of individual tests at each concentration level and
ratio. Table 4 shows that the detailed HC composition varies negli-
gibly as the total HC level is varied. The standard deviations in per-
cent associated with the average concentrations of various hydro-
carbons are given in Table 5 to indicate the reproducibility of the en-
tire test procedure including the gas chromatographic measurements.
The standard deviations increased slightly "with decreasing concentra-
tion. Figure 5 shows individual concentrations of several hydrocar-
bons versus total HC concentration determined with a flame ioniza-
tion analyzer (as ppmC). The averages and standard deviations were
obtained from six to eight tests -at each of the three concentrations.
Table 4. RATIO OF CONCENTRATIONS OF VARIOUS HYDROCARBONS TO ETHYLENE
Nominal
carbon, ppm
11. 2
6. 2
3. 0
average
a
C2H6 C2H4 C2H2 n-C4H10 C3H6
0.
0.
0.
0.
to.
12 1.
12 1.
12 1.
12 1.
000
.00
00
00
00
1. 18
1. 15
1. 17
1. 17
to. 015
0.20
0. 20
0. 19
0.20
tO. 005
0.
0.
0.
26
28
32
0.29
to.
03
C&H6
0.
0.
0.
0.
10.
23
25
25
24
01
C7H8
0.47
0. 52
0. 52
0. 50
tO. 03
m - and c -
xylene
0. 39
0. 39
0.47
0.42
tO. 045
Table 5. REPRODUCIBILITY IN GAS CHROMATOGRAPHIC MEASUREMENTS OF
INITIAL HYDROCARBON CONCENTRATIONS
Initial Ethyl- Acetyl- Propyl- n- r-andp-
carbon, ppm Ethane ene ene ene Butane Benzene Toluene Xylene Average
11.2
6. 1
3. 0
average
10
4
20
11
9
10
14
11
8
7
16
10
10
5
7
7
6
9
15
10
7
12
10
10
10
16
9
12
4
8
13
8
8
9
13
10
10 EFFECTS OF HC/NO RATIOS
-------
The extensions of each point in both directions show the one-sigma
value for that point. Deviations are minimal, and the individual HC
concentrations vary linearly with total HC concentration. These
plots show that no significant changes occur in the detailed HC com-
position with variations in total HC level.
(ONE SIGMA SHOWN FOR FIA AND GAS
CHROMATOGRAPHIC HYDROCARBON
VALUES)
0.10 0-20 0.30
INITIAL CONCENTRATION OF HYDROCARBON, ppm by volume
Figure 5. Relationship of individual HC concentrations to total HC concen-
trations determined by flame ionization analyzer.
This consistency also is evident for a single component con-
sidered in more detail. On the assumption that n-butane is a non-
reactive substance and should remain constant throughout the course of
a run, standard deviations were calculated by averaging all measure-
ments made from immediately before irradiation until the end of the
run. Table 6 shows the average concentration at each experimental
condition, the average standard deviation, and the percent deviation.
All values are averaged from data for at least two runs unless other-
wise noted. The over-all average standard deviation of 7 percent is
approximately twice the value considered to be a reasonable error in
the instrumental reproducibility and in the measurement of peak areas
with a standard butane mixture. Minor variations in the composition
of the chamber input and in sampling lines probably account for the
larger over-all error shown in analysis of the chamber contents.
In two experiments the chamber was charged with the charcoal-
filtered air only. Analyses were performed for hydrocarbons and
for the various products normally measured. Hydrocarbon contami-
nants in the air were present at very low levels. The background
Test Parameters
11
-------
Table 6. REPRODUCIBILITY IN GAS CHROMATOGRAPHIC MEASUREMENTS OF n-BUTANE
Standard deviation of concentration within run
HC concen-
tration, ppn
12
fa
3
12
6
3
Avg
-iC 12/1_
0. 066
0. 037
0. 020
Standard
5
7
10
7
HC/NOX
fa/ 1
0. 068
0. 038
0. 025
Deviation,
S
6
a
k
ratio
3/1 3/Z
0. 036
0.022 0.015
%
7
5 7
6 7
HC/NOX ratio
12/1 6/1 i/J_
0. 003 0. 004
0.0025 0.002 0.003
0.002 0.002 0.001
Avg
7
7
8
7
3/2
0. 001
levels of ethane, ethylene, acetylene, and n-butane averaged 0.008,
0. 004, 0. 002, and 0. 006 ppm, respectively. Other hydrocarbons
•were present at or below their detection limits. Only for ethane was
the level significant as compared to its level when the chamber was
charged with diluted auto exhaust (approximately 10%). Correction
for background ethane was made where necessary in the computations.
The products formed from this low background of hydrocarbons were
barely detectable.
A few analyses with the electron-capture detector showed that
no electron-capturing products, such as organic nitrates or dicarbonyl
compounds were present before irradiation, within the limits of de-
tection of this instrument. Values obtained by wet chemical analyses
for aldehydes were always below 0. 1 ppm, and the aldehydes probably
did not contribute any significant amount to the carbon balance before
irradiation.
At the nominal 12-ppm carbon concentration a fairly complete
analysis for HC content of the mixture was possible. This analysis,
shown in Table 7, accounts for most of the carbon measured by the
flame-ionization analyzer. Results in Table 7 are considered typical
of the analysis at all concentrations in view of the high degree of con-
sistency previously seen at all carbon concentrations for a wide var-
iety of compounds (Tables 4, 5, and 6, Figure 5). These computations
account for 92 percent of the carbon present, as determined by the
flame-ionization analyzer. Since the flame-ionization analyzer does
not respond equally to various classes of hydrocarbons, the two meth-
ods of measurement should not be expected to give exactly the same
total concentrations. The average carbon number for the aromatics
is 7. 8, which is typical of a gasoline fraction, and their distribution
is similar to that of gasoline. The distribution of aliphatic hydro-
carbons is strongly affected by the combustion process, as would
be expected, with the composition passing through a minimum con-
centration for the three-carbon hydrocarbons. The values for the
intermediate-range aliphatic hydrocarbons may be slightly low owing
to recurrent occasional minor leaks in some of the valves of the
trapping apparatus used for concentration of these hydrocarbons
12 EFFECTS OF HC/NOX RATIOS
-------
The total concentration of six-carbon and higher olefins, five-carbon
and higher diolefins, and four-carbon and higher acetylenes, naph-
thenes, and polar substances with any response on the flame-ioniza-
tion detector should be less than 1 ppm carbon. If it is assumed that
the average molecule for this group of substances has six carbon
atoms, the maximum volume concentration of these higher-molecular-
weight materials or polar substances would be approximately 0. 15
ppm at the 12-carbon-ppm level in this system.
The concentrations for methane and for six-carbon and higher
aliphatic hydrocarbons were estimated from the work of Hum and
1 Q
coworkers on auto exhaust. Since similar fuels were used in both
investigations, a close similarity in detailed compostion is assumed
for computation of relative concentrations of hydrocarbon classes
not directly analyzed in this work.
Table 7. AVERAGE COMPOSITION OF CHAMBER AIR BEFORE IRRADIATION
(at 11.2 ppm carbon concentration}
Compound
Benzene
Toluene
Ethylbenzene
" - and L<-Xylene
o-Xylene
<• -Propylbenzene
3, 4-Ethyltoluene
1, 3, 5-Trimethylbenzene
+ sec and tert butylbenzene
1, 2, 4-T rimethylbenzene
Styrene + 2-ethyltoluene
Total aromatics
Ethane
Ethylene
Acetylene
Propane
Propylene
Propadiene
Isobutane
n-Butane
Butene-1 and isobutene
Transbutene-2
cis-Butene-2
Butadiene
Methyl acetylene
n -Pentane
Isopentane
IrPentene
2-Methylbutene- 1
Z-Methylbutene-2
Transpentene-2
2-Methylpentane
Total C^-Cs + 2-Methylpentane
Total aromatics
Estimated methane
Cjjj + paraffin
Total
Concentration,
ppm
0.073
0. 147
0. 041
0. 120
0. 050
0. 013
0. 055
0. 020
0. 070
0. 02
0. 609
0. 040
0. 304
0. 358
0. 004
0. 079
0. 006
0.009
0. 067
0. 032
0. 006
0. 006
0. 017
0. 010
0. 021
0. 078
0. 005
0.013
0. 022
0. 015
0. 042
1. 134
0. 609
0. 3
0. 33
2. 37
Ppm of Ppm by
carbon carbon number
0.438 0.073
1. 029 0. 147
0.328, 0.211
0. 960)
0. 40o)
0. 117
0.495 0. 178
0. 200
0. 630
0. 150
4. 747 Avg carbon no. 7. 8
0. 080)
0.608) 0.702
0. 716)
0.012)
0.237) 0.089
o. oia)
0.036
0.268
0. 128 0. 147
0. 024
0. 024
0. 068
0. 030
0. 105
0. 390
0.025 0.154
0.065
0. 110
0. 075
0. 252
3, 271 Avg carbon no.
2. 9
4.747
0.3
2. 0
10. 3 ppm out of 11. 2, or 92%
aAssuming Hum's ratio of 2. 5 x concentration of C% through €5 paraffins (0. 89 x
2.5 = 2. 23) less measured value of 2-methylpentane (2. 2j - 0. 2^} 2. 0).
Test Parameters
13
-------
CHEMISTRY OF IRRADIATED EXHAUST
The NO-NOQ Reaction Processes
As demonstrated in this and earlier studies, 1( ' the general
NO-NO2 reaction system provides an important index for character-
izing the atmospheric photochemical air pollution complex, in terms
of both the rates of the over-all air pollution reaction and the degree
to which the reactions proceed. This complex chemical reaction sys-
tem consists of two over-all competing photochemical reaction se-
quences: (1) the photooxidation of NO in the presence of specific
organic compounds under ultraviolet radiation below 4000 angstroms
to produce NC>2 with the subsequent formation of ozone, and (2) the
reaction between NO? and the free-radical species produced in the
photooxidation of NO to form compounds such as alkyl nitrates and
peroxyacyl nitrates with the subsequent reduction of NOX (nitric ox-
ide plus nitrogen dioxide) in the system. Since the data indicate that
the chemical, physical, and biological effects can be generally cor-
related with measurements of the rates of photoxidation of NO, the
reduction of total NOX in the system, and the formation of ozone at
equilibrium conditions, the over-all photochemical air pollution sys-
tem can be characterized in terms of these parameters
NO Photoxidation
Variations both in the concentrations and ratios of HC and NOX
produce distinct differences in the general atmospheric photochemical
air pollution systems, as shown in Figure 6.
The over-all reactions, as characterized by the NO^ formation
rate, the percent of the total NOx reacting, and oxidant formation,
tend to be slower and less complete as the HC/NOX ratio is decreased
from 24 to 1-1/2. The various systems studied differ significantly.
At ratios of 3 and less, equilibrium is reached with free NO existing
and zero reduction of the total NO in the system. Increasing the
ratios above 3 results in both increasing NO2 formation rates (in-
crease in the initial slope for the NO2 reaction) and increasing total
NOX reacting in the system at equilibrium. Oxidant level at equili-
brium generally exhibits the same characteristics. As would be
expected, at HC/NOX ratios of 3 and less, where free NO exists in
the system, no equilibrium oxidant concentration is found. At ratios
above 3 oxidant level at equilibrium increases as the ratio increases
to 24.
NOo Formation Rate
The effect of the initial HC and NOX concentrations on the over-
all NO-NO2 reaction sequence is indicated by the variations in the
rate of NO photooxidation. Within the limits of this study, variation
of HC concentration produces the greatest single effect on NO photo-
oxidation as measured by NO2 formation rate; Figure 7, Table 8.
Increases in HC concentration produce an increase in NOp formation
rate consistently for each NOX level studied; the increase is greatest
at the 1-ppm NOX level.
14 EFFECTS OF HC/NOX RATIOS
-------
HYDRO- OXIDES OF
CARBON, ppmC NITROGEN, ppm .
2.00
1.60
o K2°
.40
2.00
1.60
|l.20
3 .. .80
Z .40
S ?
ujl.60
Z 1.20
6 8 .80
.40
2.00
1.60
12 '-2°
.80
40
0
1/4
NO DATA
-
HC/NOX = 12
•v .,«r.tT.
.\_l' , 1 i i
NO DATA
-
NO DATA
i i i i i
1/2
NO DATA
LEGEND:
: NITROGEN
DIOXIDE
NITRIC OXIDE
OXIDANT
HC/NOX = 6
XI' -•-=-:
HC/NOX = 12
X^->"-~" —
HC/NO* = 24
& „-- ?
:-\*-*T -••-•;•••;
1
HC/NOX = 0
-
HC/NOX = 3
••""
•HC/NOX = 6
:/ V^
HC/NOX=12
Kx-r - -
,'V . : : r
0 120 240 3600 120 240 360 0 120 240 360 0 120 240 360
TIME, minutes
Figure 6. Reactions of NO, NO2/ and oxidant in various photochemical
systems.
The effect of initial NOX concentration on NO£ formation rate
varies depending on the HC concentration at which the measurements
are made; Figure 7, Table 8. For the 12-ppmC HC level, increase
in NOX concentration from 1/2 ppm through 2 ppm results in the NC>2
formation rate initially increasing, passing through a maximum at
about the 1-ppm level, and decreasing as the NOX concentration
approaches the 2-ppm level, This peaking effect becomes less pro-
nounced with decreasing HC level at which the variation in NOX con-
centration is measured. At the 3-ppmC HC level no significant change
in NO^ formation rate is noted with change in NO concentration.
The data in Table 8 indicate that the- 180-minute average ir-
radiation time follows the same general pattern as the IZO-minute
•irradiation time with respect to the effects of HC and NOX concen-
trations. Not enough tests were made in this exploratory phase of
the study to allow the determination of statistical significance in the
results, but the over-all effect appears to be a somewhat lower
level of NOT formation rate for the longer average irradiation time.
Chemistry of Irradiated Exhaust
15
-------
0 1/2 1 1-1/2 2
OXIDES OF NITROGEN, ppm
0 3 6 9 12
HYDROCARBON, ppmC
HC/NOX = 12 2.5
HC/NOX = 24
1/2 1 1-1/2
OXIDES OF NITROGEN, ppm
Figure 7. Average NG>2 formation rate versus HC and NO concentrations.
Table 8. CHEMICAL RESPONSE DATA
Average
Irradiation
Time,
mm
120
180
Test conditions
Nominal
concentration
HC,
ppmC
12
12
12
6
6
6
3
3
3
3
0
12
12
6
6
6
3
3
NOX,
ppm
2
1
1/2
2
1
1/2
2
1
1/2
1/4
1
2
1
2
1
1/2
1
1/2
Mean
concentration
HC,
ppmC
11.2
11.1
11.7
6. 2
5.8
6. 0
2.8
2. 8
3. 3
2. 8
0
11.3
12. 0
6. 6
6. 3
6. 1
3. 0
3.2
NOX,
ppm
2.00
0.73
0. 65
2. 10
1. 02
0. 44
2. 14
1. 03
0. 51
0. 34
0. 97
1. 86
1. 05
1.96
0. 92
0.47
1.20
0.47
Response
NO2 forma- NOX reacted Corrected
tion rate oxidant
Mean,
pphm/min
1.85
2.50
1.97
0. 95
1. 47
1. 30
0. 56
0. 60
0. 79
0. 79
0. 15
1. 40
1.56
0. 69
1. 00
1. 31
0. 61
0.70
Mean.
%
35
56
65
4
42
58
0
0
23
46
0
8
66
0
13
61
0
36
Mean,
pphm
7
43
52
0
19
36
0
0
23
31
0
4
53
0
10
41
0
25
16
EFFECTS OF HC/NOV RATIOS
-------
This effect is consistent with results from the static chamber tests
of fuel effects. 21 As indicated in Table 9, increase in average ir-
radiation time from 120 minutes to its upper limit, i.e. , static
irradiation, yields a consistent reduction of NC>2 formation rate.
This finding is also consistent with results of the first series of PHS
irradiation chamber studies, which indicated no significant effect on
NO2 formation rate at the lower average irradiation times, i.e. , 85-
minutes and 120-minutes. These shorter irradiation times appear
to be the lower limit of the effect of average irradiation time on NO2
formation rate.
Table 9. EFFECT OF AVERAGE IRRADIATION TIME
ON NO2 FORMATION RATE
Mean
concentrations3-
HC,
ppmC
12.9
4. 6
NOX,
ppm
1. 01
0. 97
Mean NO2 formation
pphm/min
120-minb
AIT
2. 65
1. 10
180-minb
AIT
1. 66
0. 84
rates,
Statica
AIT
1.59
0. 61
aData obtained from Reference Zl.
bData from Table 8 extrapolated to the HC and NOX
concentrations indicated.
Comparison of the data from the first PHS study on photoxida-
tion of exhaust products indicates that the NO formation rate at 12
ppmC HC and 1 ppm NO was lower in the original study. With
identical fuel at 120-minute average irradiation time, the value •was
1. 5 pphm per minute; in the present tests, 2. 5 pphm per minute.
These results are not inconsistent, however, because the light in-
tensity in the earlier tests was approximately 35 percent lower than
in the present series. Based on the work of Tuesday^ concerning
the effect of light intensity on NO2 formation for a system of 10 ppm
trans-butene-2 and 4.2 ppm nitric oxide, a correction factor •was
applied to the NO-> formation rate developed in the original study.
Application of this factor resulted in a value of 2. 3 pphm per minute,
which agrees well with the level observed in the present series. Use
of this correction factor assumes that the effect of light intensity on
irradiated auto exhaust would be the same as that found for the
butene-2 NO system. Unpublished work by Tuesday with other
systems indicates that this assumption is reasonable at the concentra-
tions studied.
Chemistry of Irradiated Exhaust 17
-------
CHEMICAL EFFECTS
Hydrocarbon Reactions
The rates of reaction of six of the more abundant hydrocarbons,
analyzed by gas chromatography, are given in Table 10. The percent
decrease in concentration of each hydrocarbon is computed from the
difference between the average initial concentration (computed from
several analyses made immediately before irradiation begins) and the
average concentration at dynamic equilibrium (computed from several
analyses made after about two average irradiation times — about 4
hours for an average irradiation time of 120 minutes). The percent
decreases are listed as functions of both total carbon levels and total
HC/NOX ratios.
Table 10. PERCENT DECREASE IN HYDROCARBON CONCENTRATION
DURING IRRADIATIONa
Hydrocarbon,
ppmC
11
6
3
Average
12
6
3
Average
12
6
3
Average
Ratio, HC/NO
12/1
38
40
36
39
17
31
25
24
m -
40
47
44
44
6/1
Ethylene
24
27
30
27
Toluene
12
15
22
16
X
3/1
25
20
22
12
12
Ratio, HC/NO
12/i
77
76
76
15
20
23
19
and P-Xylene
34
37
38
36
35
35
24
34
29
I 6/1
Propylene
56
61
64
60
Ethylbenzene
13
17
17
16
o -Xylene
25
25
34
26
X
3/1
52
57
55
16
16
28
28
Percent decreases computed from differences between the average concen-
tration immediately before irradiation began and the average concentration
at dynamic equilibrium.
The percent decreases given in Table 10 for the six hydrocar-
bons listed occur in the same relative order as that previously re-
ported in dynamic irradiation experiments. The absolute values
average somewhat higher for the current tests. The present data
confirm the previously reported results on the reactivity of aroma-
tics in irradiated exhaust. 14 Toluene and ethylbenzene are somewhat
less reactive than ethylene, while the combined m - andp-xylene are
somewhat more reactive than ethylene. Less extensive data for 3-
ethyltoluene and 4-ethyltoluene indicated an average decrease of 45
percent during irradiation. Analyses for 1, 3, 5-trimethylbenzene
and 1, 2, 4-trimethylbenzene were, limited to the 12-carbon-ppm level'
these trimethylbenzenes decreased by over 60 percent during the ir-
radiation, ^ and thus are consumed to the same extent as propylene
18 EFFECTS OF HC/NO RATIOS
-------
A number of the hydrocarbons analyzed showed little or no
decrease in concentration during the irradiations. The average per-
cent decrease and standard deviations in percent were as follows:
ethane, -2 t 9; acetylene, -1 1 5; n-butane, -8 t 6; isobutane, -6+9;
and benzene, -4 + 6. These values show that no significant changes
in the concentrations of ethane, acetylene, or benzene occurred
during irradiation. The butanes may have reacted very slightly.
These results agree essentially with those obtained previously in a
dynamic irradiation system. '•-'
None of the less abundant four- and five-carbon olefins analyzed
after the concentration step are listed in Table 10. The gas chromato-
graphic data obtained are considered reliable enough to use for deter-
mining initial loadings, as in Table 7. So few analyses could be made
during irradiation that the values for percent decrease in concentra-
tion are considered less reliable than values for those hydrocarbons
determined by direct sampling and analysis. The average over-all
decrease in the four- and five-carbon olefins was about 85 percent.
The percent decreases in 1-alkenes and internally double-bonded
alkenes generally agreed "with the percent reductions previously re-
ported (75% and 95-100%) for these two classes of olefins. 15
The scatter in the values for initial olefin concentrations de-
termined by the colorimetric olefin procedure is appreciably larger
than that in the values obtained by gas chromatography (Figure 8).
The over-all results appear to vary linearly with total carbon loading.
The percentage debreases in four-carbon and higher olefins during the
0.20 0.40 0.60 0.80 1.00 1.20 1.40
INITIAL OLEFIN CONCENTRATION (BY COLORIMETRY), ^a/liwr
Figure 8. Relationship of olefin concentrations (colorimetry) to total
HC concentrations (flame ionization analyzer) .
Chemical Effects
19
-------
irradiations were more consistent. The decrease for all experiments
averaged 85 percent with one standard deviation being t 5 percent.
This result agreed substantially with the percent decreases deter-
mined by this procedure in previous dynamic irradiation experi-
ments.
15
Average irradiation times of 120 and 180 minutes show no sig-
nificant effects for ethylene, propylene, toluene, ethylbenzene,
and m -xylene and p-xylene. At the three nominal total concentrations,
12, 6, and 3 carbon ppm, the average differences in percent decrease
at the two average irradiation times are 2, 2, and 0 percent, respec-
tively. Similarly, no significant differences were found for olefins
or aromatics considered separately with respect to the effect of
average irradiation time.
If the effect of reducing initial HC concentration is considered
at constant NOX level, a marked decrease in percent HC reacted is
apparent for the two olefins. For example, at an NOX level of 1 ppm,
a fourfold reduction in initial HC concentration reduced the percent
ethylene reacted from 38+3 percent to 20 t 5 percent, and the per-
cent propylene reacted from 77 I 3 percent to 57 1 5 percent. For
the four aromatic hydrocarbons, however, varying the initial HC
concentration at constant NOX level yielded no significant effects.
Since the percent decrease is a normalized rate, ^ , the actual
rate of reaction for the same percent decrease in HC concentration
is 4 times greater at 12 carbon ppm than at 3 carbon ppm. That is,
the essentially constant percent reduction in concentration of aroma-
tics with irradiation over a fourfold initial concentration range in-
dicates that the rate of reaction of the aromatics is approximately
a. linear function of their initial concentrations. Since for olefins the
percent consumed or normalized rate decreases with decreasing in-
itial olefin concentration, the rate of reaction shows greater than a
first-power relation to initial olefin concentration.
A marked effect on percent decrease in concentration of the
hydrocarbons listed in Table 10 during irradiation occurs when the
ratio is varied at constant HC level. A fourfold decrease in ratio,
that is, a fourfold increase in NOX, causes a 50 to 100 percent reduc-
tion in percent of HC reacted for ethylene, propylene, toluene, and
ethylbenzene, and lesser reductions for the xylenes. These values
show that an increase in NOX inhibits the rate of consumption of these
hydrocarbons.
Aldehydes
Formaldehyde, acrolein, and total aliphatic aldehydes were
measured immediately before irradiation and during irradiation until
dynamic equilibrium -was nearly attained. The aldehyde concentra-
tions reported in this investigation are net values obtained by sub-
tracting the concentrations measured before irradiation from those
measured near dynamic equilibrium. The aldehyde measured before
irradiation was produced by incomplete combustion in the automobile.
The various aldehydes produced by incomplete combustion constituted
20 EFFECTS OF HC/NOX RATIOS
-------
10 to 20 percent of the total aldehyde measured near dynamic equili-
brium. For example, at 12 carbon ppm, the formaldehyde concentra-
tions immediately before irradiation averaged 0. 06 ± 0. 01 ppm,
whereas at equilibrium the concentrations ranged from 0. 3 to 0. 4
ppm. The formaldehyde, acrolein, and total aliphatic aldehydes
present before irradiation under the other experimental conditions
were in approximately the same relative proportion to the gross con-
centrations.
The average concentrations of formaldehyde and total aliphatic
aldehydes obtained from a number of experiments at each of the three
concentrations are plotted in Figure 9 versus the total HC measured
as ppmC by a flame-ionization analyzer. The standard deviations in
the aldehyde and the HC values are indicated for each point. The
yields of formaldehyde and total aliphatic aldehyde clearly are linear
16.0 —
H.O —
12.C —
10.0 —
.
<
O
2
O
FORMALDEHYDE (ONE SIGMA
SHOWN FOR FIA AND
FORMADEHYDE VALUES)
TOTAL. ALIPHATIC ALDEHYDES
(ONE SIGMA SHOWN FOR FIA
AND ALDEHYDE VALUES)
0.10
0.20 0.30 0.40 0.50
CONCENTRATION OF ALDEHYDES, ppm by volume
0.60
0.70
Figure 9. Relationship of aldehyde concentrations to total HC concentra-
tions (flame ionization analyzer) .
Chemical Effects
21
-------
functions of the total HC concentration. This result does not imply
that the aldehydes are produced from all of the hydrocarbons. Almost
all of the aldehydes produced should result from the photooxidation
of the olefinic and aromatic hydrocarbons, with very small yields,
if any, from the paraffinic and acetylenic hydrocarbons.
The net concentrations of formaldehyde, acrolein, and total
aliphatic aldehydes (calculated as formaldehyde) produced by photo-
oxidation of the hydrocarbons and by subsequent secondary reactions
are given in Table 11. Aldehyde yields show no significant increase
when average irradiation time is increased from 120 to 180 minutes.
The slight apparent average increase in aldehyde yield indicated in
the tabular data can be accounted for by the 5 to 1 0 percent higher
average HC levels at the 180-minute average irradiation time.
Table 11. CONCENTRATIONS OF FORMALDEHYDE, ACROLEIN, AND TOTAL
ALIPHATIC ALDEHYDES PRODUCED DURING IRRADIATION
Aldehyde
Formaldehyde
Acrole in
Total aliphatic
aldehydes
Carbon,
concentration,
ppm
11.
11.
6.
6.
2.
3.
11.
11.
6.
6.
11.
11.
6.
6.
2.
3.
Z t
b 1
0 +
3 t
9 ±
1
2 t
6 i
o +_
3 t
2 i
b +
o i
3 1
9 1
1
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
4
4
4
2
3
.4
4
.4
.2
4
4
4
2
3
AIT,
min
120
180
120
180
120
180
120
180
120
180
120
180
120
180
120
180
Nominal HC/NOX ratio
24 12
0.32 0.
0.
0.
0.
0.
0.029 0.
0.
0.
0.46 0.
0.
0.
0.
0.
32
36
17.
20
10
031
034
024
45
50
25
35
17
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
6
29
40
20
17
10
10
028
020
026
50
55
34
26
19
18
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
3 1.5
17
15
08 0. 06
09
022
024
26
28
15 0. 12
15
The average formaldehyde concentration was about 60 percent
of the toal aliphatic aldehyde computed as formaldehyde. As dis-
cussed in detail elsewhere, the 3-methyl-2-benzothiazolone pro-
cedure is more sensitive to formaldehyde than to other aldehydes.
For photochemical-smog-type reactions, a factor of 1.25 t 0. 10 is
applicable. If this factor is applied to the data, the aldehyde concen-
trations expressed as an average aldehyde would be 25 percent higher
than those listed in Table 11. Also the formaldehyde would constitute
only about 50 percent of the toal aldehydes expressed as an average
aldehyde. The average acrolein concentration is about 10 to 12 per-
cent of the average formaldehyde concentration, and acrolein would
constitute about 5 percent of the total aliphatic aldehydes.
22 EFFECTS OF HC/NOX RATIOS
-------
The concentrations of acrolein reported are the maximum con-
centrations. Unlike the values for formaldehyde and total aldehydes,
however, the maximum values for acrolein occurred after only about
one and a half average irradiation times. Subsequently, the acrolein
concentrations decreased, so that after two to three average irradia-
tion times they averaged 25 percent less than the maximum concen-
tration. The formaldehyde concentrations did not tend to decrease
during irradiation. In about one-third of the experiments, the con-
centrations of total aldehydes did decrease after two average irradia-
tion times. The decrease •was slight, averaging about 5 percent for
all of the experiments. Since formaldehyde makes up half of the
total aldehydes, concentrations of the higher aldehydes that make up
the other half may have decreased as much as 10 percent. Since acro-
lein constitutes only 5 percent of total aldehydes or about 10 percent
of the higher aldehydes, the decrease in acrolein accounts for only
about 2 percent of a 10 percent decrease.
These results for the reactions of the aldehydes are qualitatively
reasonable. Formaldehyde is produced from almost all olefins and
aromatics, including those that react rapidly and those that react
slowly. In addition, many higher aldehydes that photooxidize produce
some formaldehyde. Although formaldehyde slowly disappears by
photooxidation, it is being produced also. The higher aldehydes
are mostly produced from hydrocarbons that are largely consumed
early in the irradiation; as a result, a net loss of higher aldehydes
might be expected. Acrolein probably is produced in significant
amounts only from a single hydrocarbon, 1, 3-butadiene, which
rapidly reaches its low equilibrium concentration with irradiation.
Acrolein is being produced from this small equilibrium level of 1,3-
butadiene much less rapidly than the acrolein is being consumed by
photooxidation. Hence, acrolein disappears at an appreciable rate
during the later stages of the irradiation.
The aldehyde yields vary with HC/NO ratio at constant HC
level. This effect is obvious when the averaged data at each concen-
tration level for formaldehyde and total aliphatic aldehydes are plotted
against ratio (Figures 10 and 11). At the highest concentration a
range of actual ratios between 22 and 6 is covered. At ratios over
12 the aldehyde yield increases slightly and then levels off. At ratios
below 6 the yield definitely decreases. The decreases in concentra-
tions of formaldehyde and aliphatic aldehydes occur consistently at
ratios below 6 in all four of the curves for which experimental data
are available.
Oxidant Formation
A plot of the mean value for oxidant at equilibrium against
initial concentrations of HC and NOX, Figure 12, and values given in
Table 8 indicate that the formation of oxidant is strongly influenced
by the HC/NOX ratio, consistently decreasing with decreasing HC/NOX
ratio when measured at a constant level of either HC or NDX. This
trend is further established by one additional oxidant value at 31 pphm
Chemical Effects 23
-------
2 0.30
6 pprnC
3 ppmC
I
I
J L
2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0
INITIAL HC/NOX RATIO
Figure 10. Average aliphatic aldehyde concentrations versus HC/NOX ratio.
i i i i—i—i—r
12ppmC
D6 ppmC
3 ppmC
] I
I I
J I
2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0
INITIAL HC/NOX RATIO
Figure 11. Average formaldehyde concentrations versus HC/NOX ratio.
EFFECTS OF HC/NOX RATIOS
-------
= 6ppniC
1C = 12 ppmC
"01/2 T 1-1/2
OXIDES OF NITROGEN, ppm
2 ppm
9 12
HYDROCARBON, ppmC
HC/NOX = 12
HC/NO
0 1/4 1/2 1 1-1/2
OXIDES OF NITROGEN, ppm
Figure 12. Oxidant concentrations at equilibrium versus HC and NOX
concentrations ( 120-min Al T) .
for the 12:1 HC/NOX ratio at
The
3 ppmC HC and 1/4 ppm NOX.
ratio also is reflected in the individual effects of
-A.
HC and NO concentrations on oxidant formation: oxidant concentra-
tion increases with increasing HC and decreasing NOX -concentrations,
when measured at constant NOX and HC levels, respectively. The
data in Table 8 indicate no effect of increased irradiation time.
Appreciable oxidant concentrations will exist at HC levels below
3 ppmC and NOX levels below 1/2 ppm, if the HC/NOX ratio is 6 or
higher. Within the concentration range studied, HC/NOX ratios
below 3 produced no free oxidant in the system. Oxidant concentra-
tion should approach zero as NOX level approaches zero, and the test
data indicate that oxidant concentration increases as NOX decreases
to 1/2 ppm levels; therefore, a peak in oxidant formation must occur
at NOX concentrations below 1/2 ppm (below 1/4 ppm at 3 carbon
ppm). Additional work in this concentration range is required to
establish this relationship.
Percent NO^ Reacted
Percent of NOX reacted at equilibrium generally parallels the
trends exhibited by oxidant formation concerning the effects produced
by the HC/NOX ratio, initial HC concentration, and initial NOX con-
Chemical Effects
25
-------
HC = 12 ppmC
rHC = 6 ppmC
-HC = 3 ppmC
01/41/2 1 H/2 ~2
OXIDES OF NITROGEN, ppm
•HC/NOX = 3
1/4
1/2 1 1-1/2
OXIDES OF NITROGEN, ppm
Figure 13. Percent total NOX reacted versus HC and NO concentrations
(120-min AIT).
centration, Figure 13, Table 8. Again the data indicate that the HC/
NOX ratio exerts the greatest effect on the percent NOX reacted within
the system. The plot shows a consistent increase in percent NOX re-
acted at equilibrium with increasing HC/NOX ratio, ranging from a
low of zero reaction at a ratio of 3 to 65 percent reaction at a ratio of
24. This trend is reflected in the decrease in percent NOX reacted
with decreasing initial HC concentration and in the increase in per-
cent NCv reacted with decreasing initial NO,, concentration.
.X. o X
Within the limits of this study, a maximum is indicated in the
total NOX reacted at equilibrium as the over-all concentrations of HC
and NOX are increased at constant HC/NOX ratios. This maximum
occurs at approximately the 6-ppmC HC level at a ratio of 6 (where
sufficient data are available to determine such a. trend), decreasing
•with either increase or decrease in HC concentration. The initial
irradiation study confirms this trend, in that the percent of NO
reacted at a HC concentration of 12 ppmC for the HC/NO ratio of
12 corresponded to values obtained in the present study, and decreased
as the over-all concentration was increased to the 33-ppmC HC level.
26
EFFECTS OF HC/NOX RATIOS
-------
Other Products
Toward the end of this series of tests an electron-capture de-
tector was acquired and put into operation. For use with this detector
a 21-foot, 1/8-inch-OD column was packed with 5 percent 1,2,3-tris
(L-cyanoethoxyl)-propane on Chromosorb-W and operated at 75°C.
Since the detector was not sensitive to the hydrocarbon components of
the system, analysis for the organic nitrates was possible. Figure 14
shows the variations of the organic nitrates with time for a single
chamber run at an HC concentration of 3 ppmC and an HC/NOX ratio
of 3. Since this analysis was not quantitated, the results are reliable
only on an area basis. The interesting features are the initial in-
crease in concentration beginning at zero time for the alkyl nitrates
(except propyl nitrate), and the continued increase during the irradia-
tion period with a plateau usually near dynamic equilibrium. The ir-
radiation also produced biacetyl, which started to form only after the
irradiation had proceeded for some time, rapidly reached a maximum,
and then decreased in concentration. Biacetyl was found in all analy-
ses.
1300
1400
1300
| 1200
ti
E
•• 1100
i
0° 1000
900
800 —
700
10/11/62:
HC = 3 ppmC
NO = 1 ppm
Sample volume = 3 cc
•METHYL
NITRATE
— 700
UNKNOWN
^^»
BIACETYL —
UNKNOWN
ISO PROPYL NITRATE .ETHYL NITRATE —
PROPYL NITRATE
800
600
500 E
a
z
400
300
u
OIL
UJ
5
_i
<
200
100
100 200
IRRADIATION TIME, minutes
300
Figure 14. Variations of organic nitrate concentrations as measured by
electron -capture detector.
Chemical Effects
-------
Biacetyl may be formed in the irradiation by the recombination
of acetyl radicals, although this appears to be an unfavored process.
The disappearance of biacetyl is to be expected, since biacetyl readily
undergoes photolysis in the presence of visible and ultraviolet radia-
tion.
The extreme sensitivity of the gas chromatographic analytical
method is indicated in Figure 14. Results from these analyses were
compared with those obtained by flame ionization on a similar column
used for aromatic hydrocarbon analysis. Comparison indicated no
significant overlap or interference of the hydrocarbons in the electron-
capture analysis, nor conversely of the organic nitrates and biacetyl
in the aromatic hydrocarbon analysis with the flame-ionization de-
tector.
BIOLOGICAL EFFECTS
Eye Irritation
A plot of eye irritation versus the two independent variables,
initial concentrations of NOX and HC, is shown in Figure 15; values
are presented in Table 12. Within the concentration ranges of this
study, the data indicate that HC concentration produces the greatest
single effect on the production of materials causing eye irritation.
Increase in HC level produces an increase in eye irritation, which is
consistent at each NOX level studied.
When NOX concentration is increased above 1/2 ppm, eye irri-
tation initially increases to a maximum at 1 ppm and decreases as
the NOX level reaches 2 ppm. This effect is consistent for each HC
concentration at which effect of the variation in NOX concentration
was measured. It is significant that eye irritation occurs at HC/NOX
ratios of 3 and lower, in contrast to the zero responses for both
oxidant concentration and percent of NOX reacted in the system at
these lower ratios.
Earlier measurements of eye irritation from irradiated auto
exhaust" in general confirm these findings. The data reported here
indicate a decrease in eye irritation with decreasing HC concentra-
tions measured at constant NOX levels and a peaking of eye irritation
at an NOX concentration of approximately 1 ppm, measured at con-
stant HC concentrations.
The effect of increasing average irradiation time from 120
minutes to 180 minutes is even less definitive for eye irritation
than for NC>2 formation rate, oxidant formation, and percent of NOX
reacted in the system. Eye irritation is a highly subjective measure-
ment, and as such is most variable. The data indicate that eye ir-
ritation responses follow the same general pattern for the 180-minute
and the 120-minute average irradiation times.
28 EFFECTS OF HC/NOX RATIOS
-------
Table \Z. BIOLOGICAL RESPONSE DATA (120-min AIT)
Test conditions
Nominal
concentration
HC,
ppmC
12
12
12
6
6
6
3
3
3
3
0
NOX,
ppm
2
1
1/2
2
1
1/2
2
1
1/2
1/4
1
Mean
concentration
HC,
ppmC
11.2
11.1
11.7
6. 2
5.8
6. 0
2.8
2. 8
3. 3
Z.U
0
NOX,
ppm
2. 0
0. 73
0. 65
2. 10
1. 02
0. 44
2. 14
1. 03
0. 51
0. 34
0. 97
Response
Eye
irritation
Mean
indexa
5.5
10.2
7
2
7. 5
5. 7
1
5.4
3. 2
3. 3
6
Mean plant injury"
Young
pinto
bean
0
3. 5
3. 0
0
1. 0
2. 0
0
0
0. 1
0. 4
0
Tobacco
wrappe r
0
0. 1
0. 2
0
0
0. 3
0
0
0
0. 5
0
Petunia
0
3. 0
2.0
0
1. 3
2. 6
0
0
1. 2
1. 1
0
aPanelists reported irritation response on scale of 0 (none) to 3 (heavy); index
determined by adding nighest response numbers reported twice by each of
ten panelists.
On a scale of 0 to 4; 4 maximum damage.
'0 1/2 1 H/2 2
OXIDES OF NITROGEN, ppm
X10
S
il0.2
0 3 6 9 12
HYDROCARBON, ppmC
HC/NOX = 12
24 XlO.2
1/2 I H/2
OXIDES OF NITROGEN, ppm
Figure 15. Eye-irritation responses versus HC and NOX concentrations.
Biological Effects
-------
Plant Injury
Microscopic examination of plant tissues and observation of
injury patterns indicate that the irradiated exhaust contains at least
three distinct phytotoxicants that produce the sequence of anatomical
and morphological changes observed. '
The first toxicant causes glazing and silvering of the lower sur-
face of young primary leaves of the pinto bean used as the indicator.
These symptoms are similar to the injury developed under field con-
ditions in the Los Angeles area2^ and to the symptoms develped on
young pinto bean plants exposed to peroxyacetyl nitrate.
The injury pattern of the second toxicant exhibits itself as de-
hydrated, bleached sunken spots on the upper surfaces of middle-
aged leaves and tends to be random on the leaf surface. The middle-
aged leaves of tobacco wrapper C are used to indicate this type of
toxicant. The symptoms are similar to tobacco-fleck type of injury,
which is known to be caused by ozone and •which is common in the
northeast area of the United States. ' In this type of injury, only
the palisade cell is typically affected.
The injury pattern of the third toxicant also involves the palisade
cells but occurs on younger leaves than is typical of the ozone-type
injury. Initially a water-logged appearance develops on the upper
surface of the leaf; later the injured tissue becomes reddish brown and
finally develops a tan or bronze color, depending on the environmental
conditions in which the plants are grown. This type of injury develops
(1) near the tip of the very young petunia leaf, (2) more toward the
base on slightly older leaves, and (3) at the base of the newly expanded
leaf, Petunia also responds to all types of toxicants and as used here
reflects the total phytotoxic development, regardless of type.
The results of the plant exposures to dilute irradiated auto ex-
haust gases are shown in Table 13 A, B, C. The data, Table 13 A, C,
for injury of the lower-surface glazing type (young pinto bean) and for
the total injury response (petunia) indicate a decrease in severity of
injury as the HC/NOX ratio decreases to 3, at which level no injury
is observed. Increase in HC concentration produces an increase in
severity of injury for all conditions except the 12 ppmC HC and 1/2
ppm NOX concentrations for the general injury, Table 13 C. This
would be expected, since the generalized type of injury appears to be
produced by several phytotoxicants while the under-surface glazing
type appears to be specific for one phytotoxicant. The severity of
these two types of plant injury generally follows the trends indicated
by the percent of total NOX reacting in the system. Since some plant
damage has been attributed to compounds formed from reactions be-
tween free radicals and NO2 produced in the ph'otooxidation process,
this correlation is expected.
The ozone-type damage, Table 13 B, as might be expected,
appears to be related to the oxidant concentration in the system.
Further, no injury of this type was observed at oxidant levels below
30 pphm.
30 EFFECTS OF HC/NOX RATIOS
-------
Table 13. PLANT INJURY RESPONSE DATAa
HC,
ppmC 1/4
0
3 0.4
6
12
I/
0.
2.
3.
NOX,
2
1
0
0
ppm
1
0
0
3. 5
2
0
0
Young pinto bean: lower-surface-glazing type injury
0 0
3 0.5 0 0 0
6 0. 3 0 0
12 0.2 0.10
Tobacco wrapper: upper-surface type injury to
middle-aged leaves (ozone)
0
3
6
12
C
1.1 1.2
2. 6
2. 0
Petunia: total injury
0
0 0
1.3 0
3. 0 0
(all phytotoxicants)
aOn a. scale of 0 to 4; 4 maximum damage.
ATMOSPHERIC EFFECTS
While the effects of variations in initial HC concentration,
initial NOX concentration, and HC/NOX ratio on the response variables
cannot be extrapolated directly to atmospheric effects, sound judgment
allows an extension of the more definitive effects, within the limita-
tions of the experimental design. Differences of initial concentrations,
variability of the concentrations during irradiation, levels and varia-
bility of irradiation intensity, and rate of ventilation of a given air
mass all can produce significant differences between the experimen-
tal work performed under controlled laboratory conditions and
community atmospheric conditions. Within these limitations, ex-
tensions of the chamber work to atmospheric conditions will give
some indication of the effects of HC reduction on the atmospheric
response variables.
Reduction in atmospheric HC concentration should result in a
reduction of oxidant formed and a reduction in eye irritation produced
by the atmospheric photochemical NO-NO2 reaction system. At HC/
NOX ratios below 3, no oxidant should be produced and free NO should
exist in the atmosphere. Experimental data on eye irritation, how-
ever, indicate that lower but significant eye irritation levels will
exist, particularly at the low concentration ranges of both initial
HC and NOX-
"Atmospheric Effects 31
-------
Data on plant injury generally indicate the same over-all trends.
Reduction in atmospheric HC concentration should reduce the severity
of lower-surf ace glazing and the total phytotoxicant injury (young
pinto bean and petunia), to the HC/NOX ratio of 3, at which level no
injury is produced for the response conditions investigated. For the
upper-surface type of injury to middle-aged leaves (tobacco wrapper)
no injury should be produced at oxidant concentrations below 30 pphm,
since this type of plant injury appears to be oxidant-dependent.
The reduction of NOX concentrations to 1/2 ppm at HC levels
of 6 and 12 ppmC and to 1/4 ppm at 3 ppmC does not appear to reduce
the amount of HC consumption, the amount of oxidant or aldehyde
formed, or the degree of plant damage. Although the levels of
chemical and biological activity should decrease to zero at zero NOX
concentrations, it appears that a maximum occurs at NOX concen-
trations below those used in the present study. If so, a very large
percentage decrease in NOX may be necessary to produce an appreci-
able effect. More recent studies do not include plant-damage measure-
ments but tend to confirm the chemical results. '•
Schuck and coworkers^l used the atmospheric flame-ionization
and NOX analyzer measurements recently available and compared
these levels with the oxidant levels and smog days reported during
the same period of time. Their curves for oxidant versus NOX were
of the same general shape as those in the present study. Oxidant
levels reached a maximum at 0. 15 ppm NOX. Furthermore, the number
of smog days also reached a maximum at about 0. 15 ppm NOX. This
work by Schuck and others-^ was preliminary and involved many as-
sumptions about reactive hydrocarbons, meteorological parameters,
and pollutant charging conditions. The results also were not subject
to statistical evaluation. The difference between a maximum at 1 ppm
NOX for eye irritation in the present study and 0. 15 ppm NOX with
atmospheric data represents a large variation in results. The differ-
ence may be attributed to many factors, including the wide difference
in the eye irritation measures used, the difference between a stirred
dynamic flow reactor and the actual atmospheric conditions, differ-
ences in reactive HC concentrations, statistical considerations, etc.
Only further experimental work can resolve just at what point eye
irritation and other effects should maximize with variations in NOX
concentration in polluted atmospheres.
There has been some concern about the effects of a. reduction of
gross atmospheric HC concentration on the average and the instan-
taneous NO£ concentrations in the atmosphere. To explore this
phenomenon, average NO2 concentrations were developed from the
initial data by integration over the first 4 hours and over the first
10 hours after the start of irradiation, Figures 16 and 17. These
average NO£ concentrations were calculated by integrating the con-
centration with respect to time for the time interval shown and ex-
pressing this integral in terms of unit time to establish the average
NO£ concentration. These data indicate a general reduction of average
NO2 concentration with decreasing atmospheric HC concentrations,
except for NOX concentrations in the region of 1 ppm and below. For
this range the trend indicates that a reduction in concentration of
32 EFFECTS OF HC/NOX RATIOS
-------
atmospheric HC could initially produce an increase in average NO2
concentrations. With continued reduction, however, an over-all
decrease for both time periods studied is indicated.
STATISTICAL ANALYSIS
The effects on six response variables due to changes in the initial
concentrations of HC and NOX were evaluated statistically. Replicate
tests were conducted for each of the nine combinations of HC and NOX
concentrations resulting from the three levels of each pollutant, ex-
cept at the upper and lower extremes of HC/NOX ratio, where only
one test was run at each extreme (Table 2). The statistical signifi-
cance of changes in the level of each response variable over the con-
ditions of the experiment was determined by an analysis of variance.
The statistical model wa's a two-way classification, in which the main
effects of HC and NOX concentrations and the interactions between
them (HC/NOX ratio) were evaluated. Results are shown in Table 14.
01/41/2 1 1-1/2
OXIDES OF NITROGEN,
I J
100
54.2
108.5
NOX = 2 ppm
NOX = 1 ppm
NOX = 1/2 ppm
41.0
03 6 9 12
HYDROCARBON, ppmC
108.5
1-1/2
Figure 16. Average NC>2 cor
(first 4 hours; 120-min AIT).
Statistical Analysis
OXIDES OF NITROGEN, ppm
NOo concentration versus HC and NOX concentrations
;„ Am
33
-------
HC = 12 ppmC
HC=6ppmC^
•" HC = 3 ppmC V'
36.4
0 1/41/2 1 1-1/2 2
OXIDES OF NITROGEN, ppm
1/2 1 1-1/2
OXIDES OF NITROGEN, ppm
Figure 17. Average NC>2 concentration versus HC and NOX concentrations
(first 10 hours; 120-min AIT).
Table 14. RESULTS OF STATISTICAL ANALYSIS
Due to
HC change
Due to
NOX change
Interaction
(HC/NOX)
N©2 formation rate
Oxidant
Percent NOX reacting
Eye irritation
Average NO2 exposure
(0 to 4 hours)
Average NO2 exposure
(0 to 10 hours)
Blank Difference in level of response variable
* Difference -'- 1 1 -f --1-1
** Difference in level of
Dierence in evel o response variable not significant.
Difference in level of response variable significant at 5% level.
Difference in level of response variable significant at 1% level.
34
EFFECTS OF HC/NO RATIOS
-------
SUMMARY OF RESULTS
The concentrations of individual hydrocarbons in the diluted
auto exhaust were well within the concentrations reported for the
same hydrocarbons in Los Angeles. Ethylene concentrations before
irradiation averaged from 0. 31 ppm at the highest total HC concentra-
tion (1Z pprnC) to 0. 08 ppm at the lowest concentration (3 ppmC).
The average initial concentrations of several other hydrocarbons at
the highest and lowest total carbon concentrations were as follows:
acetylene, 0. 36 and 0. 10 ppm; propylene, 0. 08 and 0. 023 ppm;
benzene, 0. 07 and 0. 02 ppm; toluene, 0. 15 and 0. 04 ppm; and xylenes,
0. 17 and 0.05 ppm. The atmospheric levels of these substances re-
ported in Los Angeles either by Neligan during I96032 or Altshuller
and Bellar in 196133 fall into this range of values. The concentrations
of formaldehyde and total aliphatic aldehydes produced at 6 and 3 ppmC
are also within the range of atmospheric concentrations reported for
Los Angeles during I960 and 1961.33'34
The effects of ratios on aldehyde concentrations (Table 11, Fig-
ures 10 and 11) are reasonable in terms of general photochemical
knowledge. At very high HC/NOX ratios, insufficient NOX is available
for complete reaction to end products; hence, the slight decrease in
yield. The decrease in yield at ratios below 6 probably results from
the inhibition of the HC reaction by excess NOX.
The variations of aldehydes "with NOX concentration contrast
with the eye-irritation data (Table 12), -which show a maximum at
1 ppm nitric oxide. No such maximum occurs in the aldehyde yields.
These results substantiate the previous suggestions that while for-
maldehyde and acrolein (along with PAN) are known eye irritants,
they do not play an exclusive role in causing eye irritation. '
Other species probably depend strongly upon the NOX concentrations,
and these species determine the specific shape of the eye irritation
response curves (Figure 15).
The relative concentrations of individual hydrocarbons are
independent of auto exhaust concentration before irradiation in dyna-
mic irradiation experiments. The absolute concentrations of the in-
dividual hydrocarbons are linearly related to total HC concentration.
In general, increasing average irradiation time showed no effect
except on the NC>2 formation rate, -which appeared somewhat lower for
the exploratory 180-minute average irradiation time.
The effects of changes in initial HC concentration, initial NOX
concentration and HC/NOX ratio are summarized in terms of the
individual response variables.
1. Variation both in the initial concentrations of HC and NOX
and in the HC/NOX ratio produced distict differences in
the over-all NO-NO2 reaction system. Over-all reaction
rates were slower and less complete with decrease in the
HC/NOX ratio. At ratios of 3 and less, equilibrium was
reached with free NO existing and zero reduction of the total
NOX in the system.
Summary of Results 35
-------
2. The greatest single effect on NO2 formation rate resulted
from variation in initial HC concentrations. Increase in
initial HC concentrations produced a consistent increase
in NC>2 formation rate, greatest at 1 ppm NOX- The effects
of initial HC concentration on NO2 formation rate differed
from those produced by initial NOX concentration in that
the increase in initial NOX concentration from the 1/2-ppm
level resulted in an increase in NO2 formation rate, peaking
at 1 ppm NOX and decreasing as the concentration approached
2 ppm. Peaking effect was greatest at 12 ppmC hydrocarbon,
decreasing with decrease in HC concentration. Longer
average irradiation time caused a somewhat lower NO2 for-
mation rate.
3. A fourfold reduction in initial HC concentration at constant
HC/NOX ratio caused a slight increase in the relative
amounts (percent) of HC consumed during irradiation.
The same fourfold reduction in initial HC concentration
at constant NOX level resulted in a. decrease in the percent
of olefins reacted, but did not affect the percent of aro-
matics reacted. When the HC level was kept constant,
an increase in NO level caused a marked reduction in
the percent of olefinic and aromatic hydrocarbons reacted
during irradiation.
4. The aldehyde yields are linearly related to the total HC
level. No significant effect on aldehyde yields was found
when the average irradiation time was varied from 120
to 180 minutes. The aldehyde yields decreased both at
very high and very low HC/NOX ratios.
5. Oxidant formation was strongly influenced by the HC/NOX
ratio, consistently decreasing with decreasing ratio. At
ratios below 3 no free oxidant formed in the system. The
effect of HC/NOX ratio on oxidant formation was reflected
in the effects of individual HC and NOX concentrations;
oxidant concentration increased with increasing HC and
x
NOX ratio, decreasing consistently -with decreasing ratio.
No reduction in NOX was indicated at ratios of 3 or below.
Variations in initial HC and NOX concentrations, as reflected
by HC/NOX ratio, indicated an increase in percent NOX re-
acted with increasing initial HC concentration and decreasing
NOX concentration.
7. Average NO2 concentration increased and passed through a
maximum as the initial HC level was decreased from 12 ppm
to 3 ppm at NOX concentrations in the region of 1 ppm and
below. With further reduction in HC level below 3 ppm, a
decrease in average NO2 concentration may be expected at
all NO levels studied.
x
8. Variations in initial HC concentration produced the greatest
single effect on eye irritation, i. e. , increase in HC level
produced a consistent increase in eye irritation response.
36 EFFECTS OF HC/NOX RATIOS
-------
Increase in NOX concentration from the 1/2-ppm level re-
sulted in eye irritation response initially increasing to a
maximum at 1 ppm and decreasing as the NOX concentra-
tion reached Z ppm. Although the aldehydes may be respon-
sible in part for the eye irritation, the presence of other
eye-irritating species must be postulated to explain the
shape of the eye-irritation response curves when plotted
against NOX concentration, since aldehyde yields are linearly
related to the total HC level.
9. Three distinct types of plant injuries were produced by the
irradiated exhaust gases: (1) glazing and silvering of the
lower surface of the young primary leaves of the pinto bean;
(Z) dehydrated bleached sunken spots on the upper surface
of middle-aged leaves of the tobacco wrapper C; and (3) tan
or bronze discolorations of the upper surface of the petunia
plant. Each of the first two types of plant injury is attributed
to a different single phytotoxicant, •whereas the third type
appears to reflect the total phytotoxic development. The
undersurface glazing and the total phytotoxic injury were
related to HC/NOX ratio, decreasing with decrease in ratio.
No injury of these types was observed at ratios of 3 or lower.
The second type of injury is related to toal oxidant in the
system. No plant damage was observed at total oxidant
concentrations below 30 pphm.
10. As average irradiation time was reduced from static to 85
minutes, the NC>2 formation rate reached a maximum in
the region of 1ZO minutes. The decrease in the concentra-
tion of reactive hydrocarbons during irradiation was inde-
pendent of whether a 120- or a 180-minute average irradia-
tion time was used.
Summary of Results 37
-------
ACKNOWLEDGMENTS
The following organizations and people assisted in
the work reported in this publication:
LABORATORY OF ENGINEERING AND PHYSICAL SCIENCES BRANCH
CHEMICAL RESEARCH AND DEVELOPMENT SECTION
Dr. A. P. Altshuller, I.E. Sigsby, Jr.
P.W. Leach, L. J. Leng, T.A. Bellar
PHYSICAL RESEARCH AND DEVELOPMENT SECTION
Dr. H. J. R. Stevenson
ENGINEERING RESEARCH AND DEVELOPMENT SECTION
A.H. Rose, Jr.
R. C. Stahman
R. P. Lauch
LABORATORY OF MEDICAL AND BIOLOGICAL SCIENCES BRANCH
AGRICULTURAL SECTION
Dr. C.S. Brandt
Dr. I. J. Hindawi
CLINICAL RESEARCH SECTION
Dr. D. W. Lockwood
38 EFFECTS OF HC/NO RATIOS
x
-------
REFERENCES
1. M. W. Korth, "Dynamic Irratiation Chamber Tests of Automo-
tive Exhaust, " U.S. Public Health Service Publication No. 999-
AP-5, Robert A. Taft Sanitary Engineering Center, Cincinnati,
Ohio, 1963.
2. A.H. Rose, Jr., R. C. Stahman, M. W. Korth, "Dynamic Ir-
radiation Chamber Tests of Automotive Exhaust, Part I, "
J. Air Pollution Control Association, 1Z:468 (1962).
3. M.W. Korth, A.H. Rose, Jr., R. C. Stahman, "Effects of Hy-
drocarbon to Oxides of Nitrogen Ratios on Irradiated Auto Ex-
haust, Part I, " J. Air Pollution Control Association, 14:168,
(1964).
4. General Motors Research Laboratories, "Search, " September,
1962.
5. M. Luckiesh, "Applications of Germicidal, Erythemal and
Infrared Energy, " D. Van Nostrand Company, Inc. , 1946.
6. T. Bellar, J. E. Sigsby, Jr., C.A. demons, and A. P. Alt-
shuller, "Direct Application of Gas Chromatography to At-
mospheric Pollutants, " Anal. Chem. 34:763 (1962).
7. C.A. demons, P. W. Leach, and A. P. Altshuller, "1,2,3-
Tris (2-cyano-ethoxy) Propane as a Stationary Phase in the Gas
Chromatographic Analysis of Aromatic Hydrocarbons, " Anal.
Chem., 35:1546 (1963).
8. A. P. Altshuller and P. W. Leach, "Reactivity of Aromatic Hy-
drocarbons in Irradiated Automobile Exhaust, " Intern. J. Air
and Water Pollution, 8:37 (1964).
9. T. Bellar and J. E. Sigsby, Jr., "Application of the Electron
Capture Detector to Gas Chromatography in Air Pollution, "
presented at 144th Annual Meeting American Chemical Society,
March 31-April 5, 1963, Los Angeles, California.
10. A. P. Altshuller, D. L. Miller, andS.F. Sleva, "Determina-
tion of Formaldehyde in Gas Mixtures by the Chromotropic
Acid Method, " Anal. Chem. 33:621 (1961).
39
-------
11. A. P. Altshuller, L.J. Leng, and A. F. Wartburg, "Source and
Atmospheric Analysis for Formaldehyde by Chromotropic Acid
Procedures," Intern. J. Air and Water Pollution 6:381 (1962).
12. I. R. Cohen and A. P. Altshuller, "A New Spectrophotometric
Method for the Determination of Acrolein in Combustion Gases
and in the Atmosphere," Anal. Chem. 33:726(1961).
13. E. Sawicki, T.R. Hauser, T. W. Stanley, and W. C. Elbert,
"The 3-Methyl-2-Benzothiazolone Hydrazone Test," Anal. Chem.
33:93 (1961).
14. A. P. Altshuller and L.J. Leng, "Application of the 3-Methyl -
2-Benzothiazolone Hydrazone Method to Analysis of Aliphatic
Aldehydes in the Vapor State," Anal. Chem., 35 (1963).
15. I.E. Sigsby, Jr., T.A. Bellar, and L. J. Leng, "Dynamic Ir-
radiation Chamber Tests of Automotive Exhaust, Part II, " J.
Air Pollution Control Assoc. , 12:522 (1962).
16. A. P. Altshuller, L.J. Leng, andS.F. Sleva, "Determination
of Olefins in Combustion Gases and in the Atmosphere, " Am.
Ind. Hyg. Assoc. J. 23:289 (1962).
17. B.E. Saltzman, "Colorimetric Microdetermination of Nitrogen
Dioxide in the Atmosphere," Anal. Chem. 26:1949 (1954).
18. D.H. Byers and B.E. Saltzman, "Determination of Ozone in
Air by Neutral and Alkaline Iodide Procedures, " Advances in
Chemistry Series No. 21:93-101, (1959).
19. R.W. Hum, C.L. Dozois, J. O. Chase, C. F. Ellis, andP.E.
Ferrin, "The Potpourri that is Exhaust Gas, " 27th Midyear
Meeting, American Petroleum Institute's Division of Refining,
San Francisco, Calif. , May 17, 1962.
20. E. R. Stephans, "The Reactions of Auto Exhaust in Sunlight,"
presented at the Air Pollution Research Conferences on "At-
mospheric Reactions of Constituents of Motor Vehicle Exhaust, "
Los Angeles, California, December, 1961.
21. W. J. Hamming, P.P. Mader, S. W. Nicksic, J. C. Romanovsky,
and L. G. Wayne, "Gasoline Composition and the Control of
Smog, " Western Oil and Gas Association and Los Angeles
County Air Pollution Control District, Los Angeles, California,
1961.
22. C. S. Tuesday, "The Atmospheric Photooxidation of trans-Butene-
2 and Nitric Oxide" from "Chemical Reactions in the Lower and
Upper Atmosphere, " J. Wiley and Sons, New York, 1961.
40 EFFECTS OF HC/NO RATIOS
x
-------
23. W.L. Faith, N.A. Renzetti, L.H. Rogers, "Fourth Technical
Progress Report, No. 22," Air Pollution Foundation, San
Marino, California, 1958.
24. I. J. Hindawi, J.A. Dunning, andC.S. Brandt, "Morphological
and Anatomical Response of Tobacco Wrapper C. , Pinto Bean,
and Petunia Plants Exposed to Irradiated Auto Exhaust" (Ab-
stract), Submitted to Ohio Academy of Science, 1963.
25. I. J. Hindawi, J.A. Dunning, and C.S. Brandt, "Microscopical
Changes of Pinto Bean Leaf Exposed to Irradiated Auto Exhaust"
(Abstract), American Journal of Botany 49 (part 2):660, (1962).
26. R.A. Bobrov, " Tha Anatomical Effects of Air Pollution on
Plants, " Proc. Second National Air Pollution Symposium,
Stanford Research Institute, 129-134, (1952)
27. E.R. Stephens, E. F. Darley, O. C. Tayler, andW.E. Scott,
"Photochemical Reaction Products in Air Pollution, " Proc.
Am. Petroleum Institute 40, III, (I960).
28. A. C. Hill, M. R. Pack, M. Treshow, R.J. Downs, and L. G.
Transtrum, "Plant Injury Induced by Ozone, " Phytopathology
51:356-363, (1961).
29. A. P. Altshuller and I. R. Cohen, "Atmospheric Photooxidation
of the Ethylene-Nitric Oxide System, " Int. J. Air and Water
Poll. , 8:611-632 (1964).
30. W.A. Glasson and C.S. Tuesday, "Inhibition of the Atmospheric
Photooxidation of Hydrocarbon by Nitric Oxide, " presented at
148th National Meeting, American Chemical Society, Chicago,
111. , Aug. 30 Sept. 4, 1964.
31. E.A. Schuck, J.N. Pitts, Jr., J.K.S. Wan, "Atmospheric
Analytical Data and Photooxidation of Nitrogen Oxides, " pre-
sented at 148th National Meeting, American Chemical Society,
Chicago, 111, Aug. 30 - Sept. 4, 1964.
32. R.E. Neligan, "Hydrocarbons in the Los Angeles Atmosphere,"
Arch. Environ. Health 5:581 (1962).
33. A. P. Altshuller and T.A. Bellar, "Gas Chromatographic
Analyses in the Los Angeles Atmosphere," J. Air Pollution
Control Assoc. 13:81 (1963).
34. N.A. Renzetti and R.J. Bryan, "Atmospheric Sampling for
Aldehydes and Eye Irritation in Los Angeles Smog 1960, "
J. Air Pollution Control Assoc. 11:421 (1961).
References
41
-------
35. A. P. Altshuller and S. P. McPherson, "Spectrophotometric
Analysis of Aldehydes in the Los Angeles Atmosphere, " J.
Air Pollution Control Assoc. 13:109 (1963).
36. P.W. Leach, L.J. Leng, T.A. Bellar, J.E. Sigsby, Jr. and
A. P. Altshuller, "Effects of Hydrocarbon to Oxides of Nitrogen
Ratios on Irradiated Auto on Exhaust, Part II, " J. Air Pollution
Control Assoc. 14:168(1964).
42 EFFECTS OF HC/NO RATIOS
x
-------
APPENDIX
DETAILED TEST DATA
-------
Table Al. SUMMARY OF TEST CONDITIONS
AND RUN NUMBERS
Hydrocarbon
Hydrocarbon
(HC),
ppmC
1Z
12
12
12
12
6
6
6
6
6
6
6
3
3
3
3
3
3
3
3
12
12
6
6
6
3
3
6
Oxides
of
nitrogen
(NOX),
ppm
1/2
1
1
2
2
1/2
1/2
1/2
1
1
2
2
1/4
1/4
1/2
1/2
1
1
1
2
1
1
2
1/2
1
2
1/2
1
2
HC/NOX
ratio
24
12
12
6
6
12
12
12
6
6
3
3
12
12
6
6
3
3
3
1-1/2
12
6
12
6
3
6
3
3
Average
irradiation
time
(AIT),
minutes
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
180
180
180
180
180
180
180
0
Run
number
132
142
143
136
138
125
128
167
140
141
137
139
146
147
148
150
149
151
161
159
I60a
156
154
158
155
157
153
152
165b
Background air (no auto exhaust).
"Static run (no plant data).
44
EFFECTS OF HC/NO RATIOS
x
-------
Table A2. BIOLOGICAL. DATA
Plant damage index°
Eye irritation response
Run
number
125
128
132
136
137
138
139
140
141
142
143
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
165
167
Clean
air
8. 0
5. 0
7.0
3. 0
6. 0
7. 0
8. 0
2. 0
5.0
8.6
10. 0
4. 3
3. 6
7. 0
5.6
5. 6
8. 6
6.7
5. 0
4.4
7. 0
6.0
6. 0
4. 4
5. 0
Irradiated
exhaust
11.
13.
14.
9.
9.
12.
9.
11.
11.
15.
23.
7.
7.
"10.
10.
8.
15.
11.
21.
8.
12.
7.
12.
7.
11.
0
0
0
0
0
0
0
0
0
7
3
1
5
0
0
9
0
6
4
9
0
0
0
7
0
Index*
3.
8.
7.
6.
3.
5.
1.
9.
6.
7.
13.
2.
3.
3.
4.
3.
6.
4.
16.
4.
5.
1.
6.
3.
6.
0
0
0
0
0
0
0
0
0
1
3
8
9
0
4
3
4
9
4
5
0
0
0
3
0
6
o :
If
!
4
4
0
0
0
0
0
0
c
2
c
2
0
0
0
0
0
0
0
0
2
0
3
0
0
0
1
o ^
u £
rt i?
II
1
4
3
0
0
0
0
0
0
c
2
0
c
0
0
0
0
0
0
0
0
1
0
3
0
0
0
2
C —
Pinto " >.
bean J3 rt
trifoliate 2 &
5 'S
T P 0, A
0
3
0
0
0
0
1
1
3
3
0
1
0
0
0
0
0
0
0
0
2
0
2
0
0
0
3
0 0
0 0
0
0
0
0
0 0
0 0
0 1
0 0
0
0 0
0
0
0
0
0
0
0
0
0 0
0
0 0
0
0
0
1 0
o
"c
?«
5-°
o
SM
1
4
3
0
0
0
0
2
2
3
3
c
1
c
0
0
0
0
c
0
0
3
0
3
0
0
0
4
a
V
0,
1
2
0
0
0
0
2
2
3
3
c
2
c
0
1
0
0
1
0
0
3
0.
3
0
0
0
3
aPanelists reported irritation response on scale of 0 (none) to 3 (heavy); index determined
for each run by adding highest response numbers reported twice by each of ten panelists.
"On a scale of 0 to 4; 4 maximum damage.
cTrace.
Appendix
-------
Table A3. RESULTS OF CHEMICAL ANALYSES
H
a
H
w
o
4
ffi
n
—
O
Actual
concentrations
before
irradiation
Hydrocarbon
Run
numbe r
125
128
132
136
137
138
139
140
141
142
143
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
165
167
(FIA),
ppmC
5.7
5.8
11.7
10.7
6.6
11. 6
5.8
5.9
5.7
11. 1
11. 1
2.8
2.7
3.6
2.7
3. 0
3.0
3.0
3.2
11.3
6.3
12.0
6. 6
6. 1
2.8
2.7
5.0
6.5
NOX,
ppm
0. 53
0.38
0. 65
1. 90
2.20
2. 10
2.00
1.02
1.02
0.74
0.72
0. 33
0.34
0. 53
1. 05
0.48
1. 05
1.20
0.47
1.86
0.92
1.05
1.96
0.47
2. 14
0.97
0. 99
2. 15
0. 41
NO 2
formation
rate,
pphm/min
1.30
1. 36
1.97
1. 75
0. 84
1. 94
1.05
1.38
1. 55
2.50
2.50
0.86
0.72
0.78
0.52
0.79
0.60
0.61
0.70
1.40
1.00
1.56
0. 69
1.31
0.56
0. 15
0. 67
0. 95
1.23
Oxidant
(corrected
for NO2),
NOX
reacted,
%
41
71
65
42
8
27
0
40
43
51
60
47
44
26
0
20
0
0
36
8
0
68
0
61
0
0
7
13
63
pphm
Wet
42
47
52
7
3
3
19
19
39
47
49
50
27
0
8
0
25
0
3
67
0
53
0
0
0
0
42
Mast
28
44
10
0
4
0
40
46
32
30
22
0
23
0
0
25
4
10
53
0
41
0
0
0
0
35
Olefin,
g/1
Before
irrad
0. 56
0.78
1.20
0.46
1.45
0.43
1. 10
0.51
1. 17
1. 12
0. 63
0. 34
0. 54
0. 50
0.43
0.53
0. 63
1.20
0.76
0.72
0.82
0. 32
0.63
0.42
1.00
After
irrad
0. 09
0. 13
0. 15
0.23
0. 05
0.24
0.09
0. 12
0.03
0.01
0. 22
0. 08
0. 05
0. 07
0. 09
0. 12
0. 08
0. 11
0.29
0. 11
0. 14
0. 16
0.32
0.03
0. 03
0. 08
0. 00
0.27
Formaldehyde, Acolein,
ppm ppm
Before
irrad
0.02
0. 04
0.06
0. 02
0.07
0. 01
0. 04
0. 04
0. 05
0. 04
0. 02
0. 02
0. 04
0. 02
0. 01
0..01
0. 01
0. 07
0.05
0. 05
0. 02
0. 02
0.02
0.00
0.00
0.07
After Before
irrad irrad
0.21
0. 17
0. 37
0.28
0.20
0.40
0. 18
0.22
0.26
0. 35
0.38
0. 12
0. 12
0. 13
0. 08
0. 13
0.09
0. 10
0. 11
0.47
0.22
0.40
0. 18
0.23
0. 07
0. 01
0. 13
0.25
After
irrad
0. 017
0. 027
0. 025
0. 027
0. 032
0.025
0. 018
0.018
0. 016
0. 017
0.035
0. 028
0. 017
0. 024
0. 012
0. 017
Total
aldehydes
(as formaldehyde),
ppm
Before
irrad
0. 10
0. 12
0.09
0. 03
0. 04
0.03
0.03
0. 03
0. 05
0.05
0.01
0. 06
0. 03
0. 00
0.03
0. 00
0. 06
0. 03
0. 10
0. 12
0. 02
0. 00
0. 02
0. 02
0. 02
0. 09
After
irrad
0. 37
0.35
0. 52
0. 55
0.21
0. 64
0.28
0. 37
0. 34
0.48
0.53
0. 18
0. 19
0.25
0. 17
0.20
0. 19
0. 17
0.65
0.27
0. 58
0.40
0.36
0. 12
0. 03
0.14
0. 27
0. 34
-------
Table A4. CHROMATOGRAPHIC DATA: Run 132, Light Hydrocarbons
Time
10:00
10:30
11:05
11:30
12:15
1:00
1:30
2:00
2:30
3:00
3:30
Ethane
0.039
0. 041
0. 042
0.042
0.043
0. 043
0.044
0. 044
0.044
0.043
0. 044
Ethylene
0. 328
0. 362
0. 369
0. 353
0. 310
0. 036
0. 276
0.271
0.263
0.259
0.250
Propane
0.004
0.007
0. 006
0.006
0.006
0. 007
0. 005
0. 005
0.006
0. 006
0. 006
Acetylene
0.360
0.407
0.405
0.405
0.435
0.431
0.434
0.442
0.448
0.441
0.429
Isobutane
0. 016
0.010
0. 010
0. 012
0.014
0. 012
0.012
0. 014
0.007
0.011
0.010
n- Butane
0.068
0.068
0.069
0.070
0.069
0.072
0.074
0.071
0.064
0. 068
0.062
Propylene
0.092
0.088
0.091
0. 088
0.039
0. 027
0. 025
0.041
0.020
0.023
0.025
Table A5. CHROMATOGRAPHIC DATA: Run 137, Light Hydrocarbons
Time
9:25
9:50
10:30
11:00
1 1:30
12-30
1:00
2:00
2:40
3:20
3:45
Ethane
0. 024
0.024
0.024
0.025
0.025
0.024
0.024
0.025
0.023
0. 023
0. 022
Ethylene
0. 164
0. 177
0. 189
0. 192
0. 187
0. 177
0. 155
0. 158
0. 152
0. 147
0. 138
Propane
0.004
0.003
0. 003
0.004
0.004
0.003
0. 003
0.003
0.002
0.002
0.002
Acetylene
0. 177
0. 199
0.221
0.223
0.212
0.208
0. 195
0. 196
0. 185
0. 187
0. 178
Isobutane
0. 005
0.010
0. 007
0. 007
0. 008
0. 004
0. 005
0. 003
0. 005
0. 005
0. 005
n- Butane
0. 033
0.034
0. 040
0.039
0.038
0. 040
0.037
0.038
0.035
0.038
0. 041
Propylene
0.037
0.038
0. 049
0. 051
0. 044
0. 036
0. 026
0. 030
0. 023
0. 024
Table A6. CHROMATOGRAPHIC DATA: Run 138
Time
10:15
10:45
11:20
12:15
1:45
2:30
2:45
3:40
Ethane
0. 040
0. 040
0. 043
0. 042
0. 039
0.039
0.039
0.039
Ethylene
0.315
0. 318
0. 322
0.285
0. 243
0. 245
0.250
0.242
Propane
0. 004
0. 004
0.004
0.004
0. 004
0. 004
0. 003
0.003
Acetylene
0. 337
0. 336
0. 349
0. 343
0. 322
0. 325
0. 337
0. 338
Isobutane
0. Oil
0. 012
0. 013
0. 009
0. 009
0. 006
0. 009
0. 008
n -Butane
0. 070
0. 071
0. 071
0. 068
0. 075
0. 069
0. 066
0. 063
Propylene
0.082
0.092
0. 087
0.053
0.046
0.046
0.038
0. 043
Aromatic Hydrocarbons3
Time
9:45
10:15
10:50
11:20
12:15
1:45
2:30
3:00
3:40
Benzene
0.029
0.066
0. 067
0. 069
0.070
0. 065
0. 061
0. 065
0.062
Toluene
0.061
0. 128
0. 126
0. 123
0. 119
0. 106
0. 102
0. 109
0. 103
Ethyl-
benzene
0.010
0.038
0.039
0.034
0.037
0.030
0. 030
0. 030
0.031
^ -and p-
xylene
0. 032
0. 114
0. 116
0.098
0. 094
0.067
0.067
0. 073
0. 067
Comp'd
X
0. 016
0.031
0.033
0. 027
0.033
0.028
0.031
0.035
0.030
o-Xylene
0. 016
0.042
0. 042
0. 037
0. 038
0. 030
0. 031
0. 033
0. 032
n -Propyl-
benzene
0.011
0. 015
0.010
0.008
0.007
0. 007
0.011
0.010
Isopentane
0. 095
0. 101
0. 089
0.076
0. 077
0.088
0.083
0.077
3 and 4
Ethyl-
toluene
0.014
0.049
0.045
0.033
0.045
0.033
0.032
0.030
0.031
alsopropylbenzene not detected.
Appendix
-------
Table A7. CHROMATOGRAPHIC DATA: Ru
Li
ght Hydrocarbons
Ethyl-
Time
9
10
11
11
12
1
i
i
3
Ar
:30
:00
-00
-30
:30
:30
•00
-45
•30
Ethane
0
. 030 0.
0.035 0.
0
0
0
0
.024 0.
.023 0.
.026 0.
. 027 0.
0.029 0.
0
0
.027 0.
. OZB 0.
ornatic Hydroca
ene
057
034
171
1 67
144
130
130
121
115
rbor
Acetyl
Propane ene
0.
0.
0.
0.
0.
0.
0.
0.
0.
>sa
004
017
003
003
004
004
004
004
005
0. 064
0. 038
0. 21 1
0. 21 1
0.203
0. 200
0.201
0. 200
0. 196
Ethyl-
Ti
9
me
-30
Benzene
10:00
10
1 1
1 1
12
1
1
2
i
3
:30
00
:30
•30
:00
:30
:00
:45
•30
0. 043
0.03K
0.047
0. 054
0.054
0. 052
0.050
0. 049
0. 050
0. 049
0. 04K
Toluene
0
0
0
0
0.
0
0
0
0
0
0
.072
. 057
. 093
. 094
.092
. OK4
. 089
. OK3
. OHO
. 079
. 075
be
0.
0.
0.
0.
0.
n/.ene
018
015
022
025
025
0. 023
0.
0.
0.
0.
0.
020
017
020
017
023
Iso-
butane
0. 018
0. 071
0.012
0. 013
0. 015
0. 016
0. 007
0.010
0. 006
and : -
Xylene
0. 043
0. 042
0. 067
0. 06«
0. 04h
0. 045
-. 044
0. 042
-. 03b
0. 042
n-Butane
0. 042
0. 1KO
0. 039
0. 040
0. 044
0. 044
0. 041
0. 03K
0. 03S
Comp'H
X
0.042
o. 029
0. 037
0. 03b
0. 046
0. 039
0. 040
0. 03=.
0.035
0. 041
Propyl -
Iso-
ene pentane n-pentane
0. 017
0.017
0. 047
0 . 0 3 M
0. 026
0. 021
0. 020
0. 014
0. 017
-, -Xylenc
0. 020
0.014
0. 021
0. 025
0. 026
0. 024
0. 024
0. 022
0. 02 1
0. 02 1
il. 024
0. 041
0. 123 0. 072
0. 57
0. 061
0. 053
0. 050
0. 054
No peak
0. 042
Flhvl-
• -Propyl- i and 4
b.-n^riu lulurm-
0. 0 12
0. OO'I
tr.ico 0.0)1
trace 0. 027
trace 0.05*
trace 0.022
l race' 0. 022
trace 0.0 In
I race 0. i)2n
lra< e
l race 0. II 1 1
alsopropylbenz
Table A8. CHROMATOGRAPHIC DATA: Run 141
Light Hydrocarbor
Time
10:15
10:45
11:15
12:15
12:45
1:30
2.00
2:30
3.00
3:30
Ethane
0. 026
0. 026
0. 026
0. 026
0.025
0.025
0. 026
0. 025
0. 025
0.026
Aromatic Hvdroca
Time
10-15
10:45
11:15
12:15
12:45
1:30
2;00
2:30
3:00
3:30
Benzene
0. 040
0. 040
0.040
0. 040
0. 040
0.037
0. 038
0. 039
0.038
0.039
is
Ethylene
0. 162
0. 169
0. 164
0. 141
0. 137
' 0. 125
0. 115
0. 113
0. 1 17
0. 1 13
rbonsa
Toluene
O.D71
0.070
0.075
0. 069
0.071
0.061
0.062
0.062
0. 062
0.061
Propane
0. 004
0. 004
0. 004
0. 004
0. 004
0. 004
0. 004
0. 004
0. 004
0. 005
Ethyl-
benzene
0. 024
0. 020
0.024
0. 019
0. 020
0. 018
0. 017
0. 014
0. 020
0.016
Acetylene
0. 185
0. 196
0. 192
0. 189
0. 181
0. 185
0. 183
0. 183
0. 190
0. 191
m - and p-
Xylene
0. 064
0. 055
0. 066
0. 048
0. 047
0. 039
0.038
0. 034
0. 036
0. 035
Isobutane
0.008
0. 007
0. 006
0. 008
0. 006
0. 007
0. 006
0. 007
0. 008
0. 007
Comp'd
X
0. 033
0. 034
0. 031
0. 036
0. 034
0. 034
0. 032
0. 035
0. 037
0. 038
"-Butane
0. 038
0. 038
0. 039
0. 037
0. 036
0.039
0. 037
0. 037
0. 036
0. 038
o -Xylene
0. 023
0. 021
0. 026
0. 028
0. 028
0.022
0. 020
0. 020
0. 020
0. 019
Propylene Isopentane
0.027
0.044
0.042
0.022
0.022
0. 018
0. 017
0. 018
0.014
0. 019
n'-Propyl-
benzene
trace
trace
0. 029
trace
trace
trace
trace
trace
trace
trace
0. 054
0.048
0.052
0. 047
0.044
0.047
0. 040
0. 041
0. 041
0. 044
3 and 4
Ethyl-
toluene
0.046
0.024
0.039
0.024
0.03)
0.015
0.020
0.021
0.015
0. 021
alsopropylbenzene not detected.
48 EFFECTS OF HC/NO RATIOS
x
-------
Table A9. CHROMATOGRAPHIC DATA: Run 142
Light Hydrocarbons
Time
10:30
11:00
11:30
1:00
1-35
2:15
2:45
3:30
Ethane
0. 033
0. 033
0. 034
0. 034
0. 038
0. 035
0.036
0.036
Ethylene
0.289
0. £95
0. 301
0.236
0.212
0. 197
0. 187
0. 181
Propane
0. 004
0. 003
0. 004
0. 003
0. 004
0. 003
0. 004
0. 003
Acetylene
0. 349
0. 363
0. 367
0. 360
0. 362
0. 356
0. 353
0. 357
Isobutane
0. 007
0. 007
0. 007
0. 006
0. 007
0. 007
0. 007
0. 007
-Butane
0. 058
0. 060
0. 063
0. 060
0. 060
0. 054
0. 055
0. 057
Proylene
0. 072
0.071
0. 072
0. 036
0. 023
0.020
0.020
0. 021
Isopentane
0.081
0. 083
0.079
0.083
0. 075
0. 067
0. 070
0. 061
Aromatic Hydrocarbonsa
Time
10:30
11:00
11:30
1:00
1:35
2:15
2:45
Benzene
0.978
0.081
0. 080
0.074
0.079
0.073
0.078
Toluene
0. 154
0. 168
0. 164
0. 137
0. 141
0. 124
0. 135
Ethyl-
benzene
0. 045
0. 048
0. 043
0. 039
0. 050
0. 031
0. 036
--and Cj-
Xylene
0. 121
0. Ml
0. 131
0. 091
0.095
0. 067
0. 077
Comp'd
X
0. 031
0. 037
0. 041
0.036
0. 043
0.031
0. 031
o-Xylene
0. 042
0. 059
0. 086
0. 043
0. 046
0. 046
0. 038
r< -Propyl-
benzene
0. 012
0. 028
0.029
0.011
0.010
0.013
3 and 4
Ethyl-
toluene
0. 066
0.052
0.056
0.034
0.039
0. 035
0.038
alsopropylbenzene not detected.
Table A10. CHROMATOGRAPHIC DATA: Run 143
Light
Time
9:50
10:20
10:55
1 1 :25
12.30
1:00
2:10
2-35
3:00
3:30
Hydrocar
Ethane
0.035
0. 035
0. 035
0. 036
0.037
0.03H
0. 038
0.03H
0. 037
0. 038
bons
Ethylene Propane Acetylene
0.248
0.284
0.298
0.293
0. 234
0.215
0. 197
0. 194
0. 191
0. 189
0.
0.
0.
0.
0.
0.
0.
0.
0.
004
004
003
003
004
004
004
003
004
0. 004
0
0.
0
. 299
.340
.362
0. 365
0
0
0
0
0
0
. 373
. 372
. 370
. 374
. 379
. 377
Isobutane
0. 009
0. 007
0. 009
0. 009
0. 008
0. 007
0.008
0. 009
0. 008
0. 008
n -Butane Propylene Isopentane
0. 053
0. 058
0. 064
0. 065
0. 062
0. 057
0. 058
0. 061
0. 056
0. 056
0. 062
0.074
0.074
0. 064
0. 030
0. 025
0. 019
0.019
0. 016
0.021
0.075
0. 078
0.071
0.077
0. 080
0.073
0. 075
0.073
0.076
0.069
Aromatic Hydrocarbons
Time
9:50
10:20
10-53
1 1:25
12:30
1:00
2:10
2:35
3:00
3:30
Benzene
0. 068
0.075
0. 077
0. 078
0. 079
0.078
0. OHO
0. 080
0. 080
0. 080
Ethyl-
m-ar.d p-
Comp'd
Toluene benzene Xylene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
138
156
164
164
153
150
145
145
147
145
0.036
0. 043
0.045
0.043
0. 048
0.037
0. 047
0. 038
0. 042
0. 044
0. 101
0. 128
0. 143
0. 120
0. 105
0.089
0.092
0. 084
0. 084
0. 087
X
0. 031
0. 034
0.037
0.035
0.033
0.031
0. 047
0.039
0.036
0.043
Isopropyl-
benzene
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
c-Xylene
0.039
0.046
0. 046
0. 056
0. 053
0. 051
0. 042
0. 042
0. 044
0. 049
" -Propyl-
benzene
0. 007
0. 012
0. 010
0. 012
0. 022
0. 025
0. 015
0. 022
0. 009
0. 014
3 and 4
Ethyl-
toluene
0. 043
0.051
0.053
0.054
0. 040
0. 044
0.041
0.033
0.038
0. 027
Appendix '
-------
Table AD. CHROMATOGRAPHIC DATA- Run 146
Light
Time
9:20
10:20
10-52
1 1:25
1 1:55
12:3K
1:10
Z-30
3-00
9:20
10 tO
10:52
1 1:25
1 1 -55
12. 3H
] 10
2 30
3-00
Hydrocarbons
Ethane
0. 025
0. 016
0. 020
0. 014
0.01 3
0. 012
0. 013
0. 013
0.015
atic Hydruc;
0.019
0. 022
0. 022
0. 022
0. 021
0. 018
0. 020
O.OIH
0.020
Fthy lene
0. 063
0. 076
0.056
0. 075
0.071
0. 058
0. 056
0. 051
0. 049
0. 042
0. 044
0.042
0. 041
0. 042
0. 037
0. 034
0. 033
0. 032
Propane
0. 005
0.003
0. 004
0.002
0. 002
0.002
0. 002
0.002
0. 003
Ethyl-
0. 010
0. OIK
0. 013
0.012
0. 014
0. 018
0. 020
0. 012
0. 009
Acetylene
0. 074
0. 095
0. 066
0. 092
0. 090
0. 083
0. 086
0. 090
0. 08H
-• -and !--
0. 028
0. 043
0. 035
0. 051
0. 041
0. 042
0. 029
0. 024
0. 021
Isobutane
0. 010
0. 006
0. 005
0. 005
0. 005
0. 003
0. 004
0. 005
0. 003
Comp'd
x
0. 034
0. 029
0. 035
0. 036
0. 037
0. 034
0. 032
0. 027
0. 031
n -Butane
0. 020
0. 019
0. 042
0. 022
0. 022
0. 018
0. 017
0. 021
0. 019
0. 014
0. Old
0. 01 1
0. 012
0. 01 1
0. 012
0. 009
trace
Propylene
0. 021
0. 017
0. 019
0. 018
0. 022
0. 013
0.009
trace
none
n - Propyl-
trace
0.015
trace
trace
trace
trace
trace
trace
trace
Isopentane
0. 024
.0.024
''0.034
trace
0.018
trace
trace
trace
trace
3 and 4
Ethyl-
0. 023
0. 016
0. 017
0.026
0. 008
trace
trace
trace
alsopropylben7,ene not detected.
Table A1Z. CHROMATOGRAPHIC DATA' Run 147
Light Hydrocarbons3
Time
10:00
10:30
11:00
1 1:30
12:30
1:00
2:00
2-30
3:00
3:30
Ethane
0.011
0. 012
0.011
0.011
0.011
0. 013
0.012
0.012
0. Oil
0.011
Ethylene
0.066
0.071
0. 074
0. 071
0. 058
0.045
0.049
0. 048
0. 045
0.045
Acetylene
0. 075
0. 087
0. 085
0. 079
0. 079
0. 067
0. 077
0. 079
0.077
0.079
aNo measurements of propane, isobutane
baseline fluctuation caused by temperati
Aromatic Hydrocarbonsa
Ethyl-
Time
10:30
11:00
1 1 :30
12:30
1:00
2:00
2:30
3:00
Be:
0.
0.
0.
0.
0.
nzene
019
020
020
019
022
0. 018
0.
0.
016
019
Toluene
0. 038
0. 039
0.036
0.032
0.030
0.028
0.027
0.028
benzene
0.
0.
0.
0.
0.
0.
0.
0.
017
014
014
009
017
008
Oil
014
, n- butane,
ire change
m-and p-
Xylene
0. 053
0. 036
0.037
0.024
0.029
0. 016
0. 018
0. 022
propylene, or isopent;
in room.
Comp'd
0.
0.
0.
0.
0.
0.
0.
0.
X
037
033
025
036
025
024
027
031
o -Xylene
0. 028
0. 019
0. 009
0. 019
0. 007
me because of
n -Propyl-
benzene
trace
trace
trace
trace
trace
trace
trace
trace
3 and 4
Ethyl-
toluene
0. 018
0.007
0. 024
0. 017
alsopropylbenzene not detected.
50 EFFECTS OF HC/NO RATIOS
x
-------
Table A13, CHROMATOGRAPHIC DATA: Run 149
Light Hydrocarbons
Time Ethane Ethylene Propane Acetylene Isobutane 1 - Butane Propylene
9:30
10:30
11:10
12:40
1:10
1:40
2:10
3:00
3:30
0.015
0.013
0.013
0.013
0.013
0. 013
0.01Z
0. 013
0. 012
0.
0.
0.
0.
0.
0.
0.
0.
0.
.057
072
075
071
067
066
063
062
060
0.
0.
0.
0.
0.
0.
0.
0.
0.
.006
004
004
003
003
002
002
003
003
0.
0,
0.
0.
0.
0.
0.
0.
0.
. 065
. 087
. 088
,088
086
087
087
087
081
0. 012
0. 010
0. 005
0. 005
0. 006
0. 007
0. 004
0. 004
trace
0
0.
. 022
.024
0. 025
0.
0.
0.
0.
0.
0.
025
020
022
022
018
021
0. 018
0. 024
0. 027
0. 019
0. 010
0.012
0. 012
0. 010
0. 009
^Aromatic Hydrocarbcms
3 and 4
Ethyl- m -and p - Comp'd Isopropyl- r,-Propyl- Ethyl-
Time Benzene Toluene benzene Xylene X benzene o-Xylene benzene toluene
10
11
11
12
1
1
2
3
3
:30
:10
:40
:40
:10
:40
:10
:00
:30
0.018
0.018
0.018
0.019
0.018
0.017
0.017
0.017
0.017
0.034
0. 039
0. 042
0. 038
0. 038
0. 034
0. 034
0. 034
0.034
0.
0.
008
008
0.012
0.
0.
0.
0.
0.
0.
012
012
008
OOH
007
009
0.032
0.028
0.032
0.029
0.026
0.020
0.027
0.022
0.021
0. 026
0.025
O.OZ1
0.024
0. 027
0. 022
0. 027
0. 026
0.024
trace
trace
trace
trace
trace
trace
trace
0.018
0. 020
0.013
0. 015
0. 016
0.019
0.016
0.01 1
0.015
0. 031
0. 016
0. 019
0. 019
0. 013
0. 015
0. 012
0. 01 1
0. 013
trace
trace
trace
trace
trace
trace
trace
trace
trace
Appendix ^
-------
Table A14. CHROMATOGRAPHIC DATA: Run 1=10
Light Hydrocarbons
Time Ethane Ethylene Propane Acetylene Iso butane -Butane Propvlc
10:10
10:40
11:10
12:10
12:50
1:20
1 50
2:20
3.00
3:40
o.ote
0. 020
0. 019
0.018
0.017
0. 015
0.015
0. 015
0. 016
0. 015
0.
0.
0.
0.
0.
0.
0.
0.
0.
083
088
087
080
072
063
065
065
065
0. 062
0. 004
0.004
0. 004
0.005
0. 003
0.004
0. 003
0. 004
0.003
0.002
0. 098
0. 104
0. 102
0. 101
0. 102
0. 103
0. 102
0. 104
0 . 108
0. 102
trace
0. 005
0. 006
0. 005
0. 004
0. 005
0. 008
0. 004
0. 005
0. 005
0. 023
0. 024
0. 023
0. 020
0. 021
0.020
a
0. 022
0.022
0. 020
0. 024
0. Oil
0. 025
0. OIK
0.012
0. 012
,1
a
0. 012
0. 00'"
aNot measurable.
Aromatic
ime
10:40
11:10
11:40
12:50
1:20
1:50
2:20
3:00
3:4JD
Hydrocarbons
enzene
0.
0.
0.
0.
022
022
023
022
0. 022
0.
0.
0.
0.
021
022
022
020
Toluene
0.
0.
0.
0.
0.
0.
0.
0.
.045
046
046
039
039
039
037
036
0. 035
Ethyl- m-and p -
Comp'H
V
beniene Xy ene
0
. 013
0. 012
0.
0.
0.
012
Oil
017
0. 012
0.
0.
0.
008
012
009
0.042
0. 039
0. 033
0. 032
0. 029
0. 027
0. 024
0. 028
0. 017
0. 03K
0.037
0. 044
0. 048
0. 043
0. 040
0. 041
0. 047
0. 037
Isopropyl-
e e e
trace
trace
- Prupvl-
0. 016 0. 03"
0. 012 0. Oil
0. 024 0. 027
0. 01 1 0.011
0. 010 0.017
0. 012
0.010 0. 009
0. 01 1 0. 010
3 and 4
Fthvl-
n. 020
o. on
0. 021
1 rare
trace
trace
trace
trace
Mid-range Hydrocarbons
Time 1 1:00 - 11 :30
COMPOUND
acetylene
ethylene
ethane
methyl acetylene
propadiene
propylene
propane
butadiene
but ene - 1 , Isobutylene
cis -butene -2
trans- butene- 2
pentene- 1
cis -pentene-Z
trans-pentene-2
2. -methyl but ene -2
2-methylbutene - 1
iso-pentane
"-pentane
2-methylpentane
2. 5
0. 8
1. 95
5. 3
trace
trace
1. 3
t race
trace
4. 4
1. 7
18.4
6. 8
10. 1
52 EFFECTS OF HC/NO RATIOS
x
-------
Table A15. CHROMATOGRAPHIC DATA: Run 151
Light
Time
9:02
9:33
10:05
10:35
11:04
12:35
2:37
3:10
3:50
Hydrocarbons
Ethane
0.013
0.014
0. 015
0.013
0.013
0. 013
0.012
0.012
0.013
aNot measured
Arom;
Time
9:02
9:33
10:05
10:35
11:04
11:35
12:35
2:10
2:37
3:10
3:50
Ethylene Propane
0.053 0.002
0.078 0.002
0. 086 0. 002
0.089 0.003
0.092 0.002
0. 080 0. 002
0.073 0.002
0.075 0.002
0.074 0.002
Acetylene
0. 060
0. 093
0. 102
0. 109
0. 106
0. 103
0. 103
0. 106
0. 107
Isobutane ' -Butane P
a 0.016
0.005 0.021
0.003 0.020
0.007 0.022
0.008 0.021
a 0.022
trace 0.018
trace a
trace 0.019
ropylene
0. 018
0. 024
a
0. 027
0. 024
0. 030
a
a
0. 012
because of temperature fluctuations.
itic Hydrocarbons
Benzene
0. 017
0. 022
0. 023
0.025
0. 025
0. 024
0. 023
0. 023
0.022
0. 022
0. 022
Ethyl- <"-and P-
Toluene benzene Xylene
0.028 0.012 0.028
0.043 0.015 0,034
0.044 0.0)2 0,030
0.047 0.021 0.048
0.050 0.018 0.041
0.044 0.014 0.040
0.045 0.013 0.031
0. 041
0.045 0.019 0.051
0.042 0.018 0.032
0.041 0.015 0.031
Comp'rl
X
0. 028
0. 033
0.028
0. 033
0.032
0. 030
0. 032
0. 033
0.033
0. 028
Isopropyl- ''-Propyl-
benzene 0-Xylene benzene
0.005 0.014 trace
trace 0.015 0.016
trace 0.020 0.018
trace 0.026 0.017
trace 0.021 0.021
trace 0.017 0.017
0.016 0.016
0.013
0.018 trace
0.011 trace
0.015
3 and -i
Ethyl-
toluene
trace
trace
0.016
0.023
trace
trace
trace
trace
trace
trace
Mid-range Hydrocarbons
Time 11:00 -
COMPOUND
acetylene
ethylene
ethane
methyl acetylene
propadiene
propylene
propane
butadiene
butadiene
butene-1, Isobutylene
cis -butene-2
trans-butene-2
trans-butene-2
iso-butane
''-butane
pentene- 1
cis -pentene-2
trans -pentene -2
2-methylbutene-2
2-methylbutene- 1
iso-pentane
"-pentane
2-methylpentane
11:30
PPB
doublet
2.9
Bad peak
9. 1
trace
trace
trace
2. 7
16.7
trace
trace
trace
6. 8
trace *'
22. 0
7. 1
11.5
Appendix
-------
Table Alb. CHROMATOGRAPHIC DATA: Run 152
Light Hydrocarbons
Time Ethane Ethylene Propane Acetylene Isobutane ' -Butane Propylene
9:00
9:30
10:00
10:30
11:05
11:30
12:10
12:40
1:15
1:45
2:25
3:00
3:30
0.017
0.017
0. 016
0.017
0.016
0. 016
0.016
0.016
0. 016
0.017
0.016
0. 015
0.016
0.
0.
0.
0.
0.
0.
0.
057
076
086
090
092
091
084
0. 080
0.
0.
077
077
0. 077
0.
0.
077
075
0.002
0. 002
0.002
0.002
0.002
0.003
0.002
0.002
0.002
0. 002
0.002
0. 002
0. 002
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
069
094
101
106
111
113
115
114
1 14
113
1 1 1
118
112
0. 005
0. 008
0. 010
trace
trace
trace
trace
0. 005
trace
trace
trace
trace
trace
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
.014
019
016
018
018
023
018
022
020
023
019
0. 020
0.
021
0. 040
0. 016
0. 023
0. 028
0. 022
0. 028
0. 014
0. 016
0. 016
0. 016
0. 015
0. 016
0. 014
Aromatic Hydrocarbons
Time
10:30
1 1:05
1 1:30
12:10-
12:40
1:15
1:45
2:25
3:00
3:30
Benzene
0. 020
0. 021
0. 021
0.020
0. 020
0. 021
0. 021
0. 020
0. 020
0. 021
Toluene
0.
0.
0.
0.
0.
0.
0.
0.
0.
040
041
039
038
037
036
039
037
037
0. 038
Ethyl-
benzene
0.018
0.014
0. 017
0.017
0.013
0. 013
0.011
0.015
0. 014
0.013
m -and p -
Xylene
0. 041
0.040
0.038
0. 036
0.029
0.030
0. 029
0. 032
0. 023
0. 025
•Comp'd Isopropyl-
X benzene
0.
031 trace
0. 028 trace
0.
0.
0.
0.
0.
0.
0.
0.
031
034 trace
028 trace
029
033
029
023 trace
026
o -Xylene
0.015
0.017
0.017
0.012
0.015
0. 010
0.011
0.016
0. 009
ii - Propy 1-
benzene
0.
0.
0.
0.
0.
0.
013
022
020
010
01 1
013
0. 016
0.
0.
009
013
3 and -1
Ethyl-
toluene
0.028
trace
trace
trace
trace
trace
trace
trace
0. 014
Table A17. CHROMATOGRAPHIC DATA: Run 153
Light Hydrocarbons
Time Ethane Ethylene Propane Acetylene Isobutane < -Butane Propylene
10:00
10:30
11:00
11:30
12:30
1:00
1:30
2:00
2:30
3:00
0. 034
0.025
0.023
0.022
0.020
0.020
0.019
0. 019
0.019
0. 019
0.092
0.093
0.094
0.091
0. 075
0.070
0.067
0. 064
0. 065
0.061
0. 010
0.007
0. 005
0.005
0. 004
0. 004
0.004
0.004
0. 004
0. 004
0. 120
0. 119
0. 125
0. 122
0. 115
0. 113
0. 1 10
0. 114
0. 113
0. 112
0.
0.
0.
0.
0.
0.
0.
0.
0.
006
005
007
005
010
006
006
004
005
trace
0. 030
0. 033
0.026
0. 024
0.023
0. 021
0. 023
0.020
0.021
0.020
0.
0.
0.
0.
0.
0.
0.
0.
021
024
025
019
013
020
016
008
0. 01 1
0.
007
Aromatic Hydrocarbons
3 and 4
Ethyl- rr -and p- Comp'd Isopropyl- f -Propyl- Ethyl-
Time Benzene Toluene benzene Xylene X benzene o-Xylene benzene toluene
10:00
10:30
11:00
11:30
12:30
1:00
1:30
2:00
2:30
3:00
0. 023
0. 023
0.021
0. 021
0. 021
0. 019
0. 020
0. 020
0. 019
0. 019
0.042
0, 042
0. 044
0. 041
0. 037
0.034
0. 037
0. 035
0. 034
0. 032
0.011
0. 010
0. 010
0. 009
0. 009
o.'oio
0.011
0. Oil
0.010
0.012
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
037
034
035
035
027
020
024
021
018
024
0.027
0. 030
0. 027
0. 030
0. 026
0.030
0.029
0.030
O.OZ8
0.029
trace
trace
trace
trace
0.021
0. 007
trace
trace
trace
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
015
015
014
013
01 1
012
010
008
Oil
009
0. 028
0. 016
0. 023
0. 023
0. 014
0. 014
0. 014
0.022
0. 012
0. 018
trace
trace
trace
0.020
trace
trace
trace
trace
trace
trace
54 EFFECTS OF HC/NO RATIOS
x
-------
Table A18. CHROMATOGRAPHIC DATA: Run 154
Time
9:45
10:15
10:45
11:20
1Z:00
12:30
1:00
1:30
2:05
2:35
3:05
3:35
Arorrit
Time
9:45
10:15
10:45
11:20
12:00
12:30
1:00
1:30
2:05
2:35
3:05
3:35
Hydrocarbons
Ethane
0.039
0.041
0.045
0.043
0.044
0.046
0.044
0.045
0.046
0.048
0.046
0.048
itic Hydroce
Benzene
0.062
0.063
0. 068
0.070
0. 071
0.071
0. 072
0.073
0.072
0.072
0.072
0.072
Ethylene
0.267
0.288
0.307
0. 308
0.297
0. 287
0.278
0. 271
0.263
0.258
0.246
0.235
irbons
Toluene
0. 116
0. 116
0. 134
0. 138
0. 136
0. 135
0. 135
0. 131
0. 131
0. 130
0. 130
0. 127
Propane
0.005
0.006
0.005
0.005
0.005
0.005
0.005
0.005
0.006
0.006
0. 006
0.006
Ethyl-
benzene
0.035
0.036
0. 039
0. 037
0.040
0.040
0.043
0.036
0.037
0.037
0.037
0.035
Acetylene Isobutane
0. 314
0. 342.
0. 353
0.364
0. 371
0.374
0. 379
0.380
0. 384
0. 382
0.371
0. 371
''-and 0-
Xylene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0
0
0,
. 101
. 097
.111
, 114
109
. 105
. 101
.083
.088
. 086
.078
.081
0. 010
0. Oil
0.008
0.010
0.009
0. Oil
0.011
0.012
0. 012
0. Oil
0. 009
0. Oil
Isopropyl-
benzene
trace
trace
trace
trace
0. 004
0. 01 1
trace
trace
0.004
trace
trace
trace
- Butane
0.060
0.070
0.077
0.067
0.068
0. 069
0.071
0.074
0.070
0. 070
0.067
0.064
Propylene
0.074
0. 082
0.
0.
0.
0.
0.
0.
0.
0.
0.
088
079
067
055
055
048
043
037
038
0.039
r -Propyl-
rj -Xylene benzen
0.
044
0. 044
0.
0.
0.
0.
0.
0.
0.
053
052
045
055
042
046
037
0. 042
0.
039
0. 041
0. 009
0. 015
0. 014
0. 014
0.014
0. 010
0.013
0.015
0.014
0.013
0.014
0.017
le
3 and 4
Ethyl-
toluene
0.043
0.050
0.054
0. 064
0.053
0. 056
0.051
0. 059
0.051
0.045
0.046
0. 052
Table 19. CHROMATOGRAPHIC DATA: Run 155
Light Hydrocarbons
Time
10:00
10:30
11:00
11:30
12:15
1:15
1:55
2:25
3:00
3:30
Ethane
0.026
0. 026
0.025
0.025
0.025
0.026
0.024
0.026
0.026
0.026
Ethylene
0. 170
0. 170
0. 171
0. 166
0. 151
0. 142
0. 140
0. 138
0. 137
0. 137
Propane
0. 005
0. 005
0. 005
0.004
0.004
0.003
0.004
0. 003
0.004
0. 004
Acetylene Isobutane "-Butane
0. 196
0. 195
0. 191
0. 196
0. 190
0. 197
0. 195
0.203
0. 208
0.207
0. 007
0. 006
0. 008
0. 008
0.007
0. 006
0. 008
0. 006
0. 006
0. 004
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
037
043
045
039
039
037
041
036
036
038
Propylene
0.
0.
0.
048
041
051
0. 042
0.
0.
031
026
0. 023
0.
0.
0.
021
020
022
Aromatic Hydrocarbons
Time
10:00
10:30
11:00
11:30
12:15
1:15
1:55
2:25
3:00
3:30
Benzene
0.041
0.039
0.039
0.039
0.036
0.038
0.040
0.039
0. 039
0.039
Toluene
0.078
0.080
0.079
0.078
0.072
0.070
0.073
0. 072
0.071
0.070
Ethyl-
benzene
0.018
0.017
0.022
0.021
0. 018
0.029
0. 016
0.022
0.019
0.024
n -and p-
Xylene
0.063
0. 059
0. 065
0.061
0.050
0.060
0. 049
0. 041
0.041
0.045
Isopropyl-
benzene
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
n-Propyl-
o -Xylene benzene
0. 023
0. 029
0. 028
0. 028
0.024
0.026
0.021
0. 020
0. 020
0.025
0.006
0.
006
0.009
0.
0.
0.
0.
0.
0.
005
004
007
007
008
005
trace
3 and 1
Ethyl-
toluene
0.037
0.036
0.036
0.035
0.038
0.016
0.027
0. 019
0. 022
0.016
Appendix
-------
Table A20. CHROMATOGRAPHIC DATA: Run 156
Light Hydrocarbons
Time Ethane Ethylene
9:40 0. 046 0. 251
10:15 0.046 0.298
10:45 0.046 0.313
11:15 0.046 0.322
11:45 0.046 0.307
12:22 0.047 0.284
12:50 0.046 0.265
1:20 0.048 0.247
1:50 0.045 0.226
2:25 0.043 0.208
3:00 0. 044 0. 189
3:30 0.043 0. 177
Aromatic Hydrocarbons
Time Benzene Toluene
10:15 0.069 0.136
10:45 0. 071 0. 144
11:15 0.074 0.149
11:45 0. 072 0. 143
12:22 0. 075 0. 145
12:50 0.073 0.134
1:20 0. 074 0. 137
1:50 0.073 0. 133
2:25 0. 070 0. 125
3:00 0.068 0.121
3:30 0.065 0. Ill
Propane
0.008
0.006
0. 006
0.005
0. 004
0.005
0. 005
0.005
0. 004
0.004
0. 003
0.004
Ethyl-
benzene
0.036
0.035
0. 041
0. 042
0. 039
0.033
0. 039
0.035
0. 033
0. 032
0.030
Table A2 1 . CHROMATOGRAPHIC DATA:
Light Hydrocarbons
Time Ethane Ethylene
9:30 0.019 0.122
10:00 0.022 0.147
10:30 0.023 0.157
11:02 0.024 0.159
11:31 0. 024 0. 147
12:35 0.025 0. 119
1:00 0. 025 0. 112
1:30 0.025 0.106
2:00 0.025 0.096
2:30 0.024 0.089
3:00 0.024 0.086
3:35 0.024 0.085
Aromatic Hydrocarbons
Time Benzene Toluene
10:00 0.037 0.076
10:30 0.038 0.080
11:02 0.038 0.081
11:31 0.039 0.078
12:35 0.040 0.070
1:00 0.039 0.068
1:30 0.038 0.068
2:00 0.037 0.062
2:30 0.037 0.060
3:00 0.035 0.057
3:35 0.035 0.058
Propane
0.003
0.003
0. 004
0. 004
0.003
0.004
0. 004
0.004
0.003
0.004
0. 003
0.004
Ethyl-
benzene
0.018
0.022
0. 020
0.021
0.020
0. 018
0.017
0.019
0. 014
0.016
0.016
Acetylene
0. 286
0. 347
0. 367
0. 367
0. 375
0. 389
0. 388
0. 391
0. 384
0. 375
0. 357
0. 347
^ -and p -
Xylene
0. 102
0. 124
0. 121
0. 116
0. 096
0. 086
0. 084
0.075
0.064
0. 067
0. 067
Run 158
Acetylene
0. 143
0. 175
0. 190
0. 189
0. 196
0. 190
0. 194
0. 193
0. 186
0. 174
0. 177
0. 177
m-and 0-
Xylene
0.058
0. 064
0. 059
0.053
0. 044
0. 031
0. 038
0. 041
0. 033
0.032
0. 026
Isobutane
0. 010
0. 010
0.012
0.012
0.014
0. 014
0. 01 1
0. 013
0.011
0. 008
0. 010
0. 008
Isopropyl-
benzene o
0. 005
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
Isobutane
0. 004
0. 007
0.006
0. 008
0.008
0. 006
0. 008
0. 006
0. 006
0. 004
0. 006
0. 006
Isopropyl-
benzene o
none
none
trace
trace
trace
trace
trace
trace
trace
trace
trace
n - Butane Propylene
0.059 0.067
0.072 0.083
0.074 0.082
0.072 0.070
0.074 0.070
0.074 0.049
0.068 0.030
0.077 0.025
0.070 0.019
0. 067 0. 018
0.067 0.018
0.066 0.012
3 and 4
"-Propyl- Ethyl-
-Xylene benzene toluene
0.046 0.010 0.054
0.046 0.008 0.059
0.050 0.010 0.059
0.049 0.012 0.051
0. 050 0. 010 0. 048
0.037 0.011 0.037
0.038 0.017 0.046
0.042 0.020 0.043
0. 034 0. 010 0. 032
0.029 0.010 0.030
0. 026 0. 007 0. 026
"-Butane Propylene
0.031 0.034
0.036 0.034
0.040 0.042
0.041 0.042
0.039 0.029
0.038
0.040 0.012
0.036 0.012
0. 039 0. 009
0.038 0.010
0. 038 trace
0.033 trace
3 and 4
"-Propyl- Ethyl-
-Xylene benzene toluene
0.023 0.009 0.025
0.024 0.007 0.034
0. 025 0. 013 0. 021
0.026 0.007 0.032
0.020 0.008 0.020
0.019 0.009 0.019
0. 020 0. 005 0. 014
0.016 0.004 0.022
0.015 0.007 0.018
0.015 0.008 0.027
0.020 0.003 0.013
56 EFFECTS OF HC/NO RATIOS
x
-------
Table A2.;. CHROMATOGRAPHIC DATA: Run 160
Light Hydrocarbons
Time Ethane ELhylene Propane Acetylene Isobutane ' -Butane Propylene
9:30
10:00
10:30
11:03
11:35
12:13
12:43
1:13
1:43
2:13
2:43
3:15
3:30
0. Oil
0. 018
0.017
0.015
0.013
0.011
0.010
0.009
0.008
0.008
0.007
0.007
0.007
0. 014
0.011
0.010
0.00")
0.009
0. 006
0. 005
0. 004
0.004
0.004
0.003
0.004
0.003
0.005
0.005
0. 004
0.004
0.003
0. 003
0.003
0.003
0.003
0.002
trace
0.002
0.002
0. 018
0.015
0. 013
0.011
0.010
0.007
0.007
0.006
0. 004
0.005
0.005
0. 007
0. 004
none
0. 004
trace
trace
trace
trace
0. 004
trace
trace
trace
trace
trace
trace
0. 008
0. 008
0.011
0.014
0.010
0.008
0. 008
0.007
0.006
0.006
0.004
0. 006
0.005
none
none
none
none
none
none
none
none
none
none
none
none
none
^Aromatic Hydrocarbons
Small traces of benzene and toluene were present throughout the day (amounts less than
0.001 ppm). Ethylbenzene, m. and p-xylene, isopropylbenzene, o -xylene, r-propyl-
benzene, and 3- and 4-ethyltoluene were not detectable even in trace amounts.
Table A23. CHROMATOGRAPHIC DATA: Run 161
Light Hydrocarbons
Time Ethane Ethylene Propane Acetylene Isobutane n - Butane Propylene
10:30
11:08
11:37
12:16
1:55
2:28
3:28
0.016
0. 017
0.016
0.016
0.013
0.012
0.013
0.060
0.065
0.060
0.053
0.049
0.048
0.045
0.003
0.002
0.002
0.003
0. 002
0.002
0. 002
0.067
0. 077
0.075
0.074
0.073
0.071
0. 074
a
0. 003
0.003
a
trace
a
a
0.024
0.019
0.023
0.018
0. 023
0. 016
0.016
0. 015
0. 019
0. Oil
0. 010
0. 019
trace
0. 008
Impossible to measure because of irregular base.
Aromatic Hydrocarbons
3 and 4
Ethyl- m-and P- Isopropyl- r,-Propyl- Ethyl-
Time Benzene Toluene benzene Xylene benzene o-Xylene benzene toluene
10:30
11:08
12:16
1:55
2:28
3:30
0.018
0.017
0.017
0.016
0.017
0.017
0.035
0.037
0. 035
0.033
0.030
0.033
0. 007
0.011
0.012
0.013
0. 010
0.007
0. 025
0. 033
0. 024
0. 024
0. 020
0. 020
None
None
None
None
None
None
0. 009
0. 010
0. 018
0. 009
0. 009
0. 006
trace
trace
trace
trace
trace
trace
0.011
0.018
0.011
0. 009
trace
0.011
Appendix
-------
Table A24. CHROMATOGRAPHIC DATA: Run 165
Light Hydrocarbons
Time
9:30
10:00
11:00
1 1:30
12:36
1:07
1:48
2:06
2:40
3:05
3:33
4:06
Aromat
Ethane
0.014
0.015
0.014
0.015
0.015
0.014
0. 014
0. 014
0. 014
0.013
0.013
0.013
Ethylene
0
0
0
0
0
0
0.
0
0.
0.
0.
0.
. 071
. 082
.089
. 088
. 074
.066
. 063
.060
. 051
. 047
044
045
Propane
0
0
0
0
0
0
0
. 002
.003
. 002
.002
. 002
.002
.002
0.002
0.
0.
0.
0.
.002
.001
002
002
Acetylen
0.049
0.059
0. 060
0. 064
0.056
0. 056
0. 050
0.052
0. 048
0. 049
0. 048
0.044
e Isubutane -Butane Propylene
0. 004
0. 005
0. 003
0. 004
0. 004
0. 006
trace
0. 005
trace
trace
0. 004
not
recorded
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
032
032
033
032
030
029
026
029
024
023
024
0. 020
0. 030
0. 034
0. 029
0. 017
0. 021
0. 018
0. 016
trace
trace
0. 009
not recorded
ic Hydrocarbonsa
3 and 4
Ethyl-
Time
10.00
1 1:00
11:30
12:36
1:07
1:48
2:06
2:40
3:05
3:33
4:06
Benzene
0.022
0. 023
0.023
0. 020
0.021
0. 021
0.020
0.019
0.018
0.016
0. 016
Toluene
0.
0.
0.
058
061
059
0.054
0.
0.
0.
0.
0.
0.
0.
050
049
047
043
041
037
038
benzene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
b
022
019
021
023
016
008
014
014
014
014
^-and P-
Xylene
b
0. 054
0. 051
0.042
0. 041
0. 060 '
0. 025
0. 024
0. 017
0.013
0. 013
Isopropyl-
benzene
b
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
-Propyl
'-Xylene benzene
0. 022
0. 022
0. 020
0. 021
0. 019
0. 017
0. 018
0.012
0. 013
trace
trace
trace
0.008
0. 008
trace
trace
trace
trace
Ethyl-
toluene
0.
019
0.022
0.
0.
0.
0.
0.
0.
0.
024
020
018
023
01 1
Oil
013
al, 3, 5-trimethylbenzene and sec- and tert-butylbenzene were not recorded in the first and
last runs; irregular baseline contact occurred in all other runs.
bbad baseline.
Table AZ5. CHROMTOGRAPHIC DATA: Run 167
Light Hydrocarbons
1 ime
9:41
10:11
10:43
11:13
11:43
12:14
12:43
1:14
1:45
2:17
2:47
3:37
Ethane
0.030
0. 029
0.030
0.029
0. 028
0. 027
0.026
0.026
0. 024
0.024
0. 024
0.023
Ethylene
0. 123
0. 136
0. 142
0. 137
0. 123
0. 1 13
0. 104
0.099
0.096
0.091
0.090
0.086
Propane
0.
0.
0.
0.
0.
0.
0.
0.
0.
006
006
006
005
005
004
003
003
003
0.003
0.
0.
003
003
Acetylene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
153
176
176
178
175
174
171
172
172
166
166
165
Isobutane
trace
0.004
0. 005
0.006
0. 005
0.005
trace
0.006
trace
trace
0. 004
0. 004
n- Butane
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
040
044
047
039
040
034
038
034
036
032
030
032
Propylene
0.
0.
0.
0.
0.
0.
028
029
040
039
024
014
trace
0.
0.
013
017
trace
trace
trace
58 EFFECTS OF HC/NO RATIOS
x
-------
•d
V
a
Aromatic Hydrocarbons
Ethyl-
1 ime
9:41
11:11
10:43
11:13
11:43
12:14
12:43
1:14
1:45
2:17
2:47
3:37
Benzene
.0. 039
0. 041
0.044
0.041
0.040
0.040
0. 040
0. 039
0.037
0.039
0. 038
0. 039
To
0.
0.
0.
0.
0.
0.
0.
0.
0.
luene
102
109
106
104
094
091
087
081
076
0.075
0.
0.
073
066
benzene
0.
0.
0.
0.
0.
0.
022
026
026
021
023
020
0. 022
0.
0.
0.
0.
0.
019
019
023
021
019
"'-and p-
Xylene
0. 060
0. 069
0. 076
0. 069
0. 066
0. 050
0. 049
0. 046
0. 032
0. 039
0. 044
0. 034
Isopropyl-
benzene
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
trace
o -Xylene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
019
034
031
032
023
030
020
022
019
030
0. 022
0.
017
- Propyl-
benzene
0. 007
0. 008
0. 013
0.011
0. 012
0. 009
0. Oil
0.011
0. 020
0. 017
0. 010
0. 013
3 and 4
Ethyl-
toluene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
036
031
037
050
028
027
035
031
036
026
027
036
1, 3, 5-Tri- 1, 2,4-Tri-
methyl- methyl-
benzene
0. 024
0.023
0.029
trace
trace
trace
trace
trace
trace
trace
trace
trace
benzene
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
off
040
057
051
035
047
046
028
043
023
019
scale
------- |