GCA-TR-75-32-G(14)
ASSESSMENT OF PHTHALIC ANHYDRIDE
AS A POTENTIAL AIR POLLUTION PROBLEM
VOLUME XIV
FINAL REPORT
Contract No. 68-02-1337
Task Order No. 8
Prepared For
U.S. ENVIRONMENTAL PROTECTION AGENCY
Research Triangle Park
North Carolina 27711
January 1976
GCA/TECHNOLOGY DIVISION
BEDFORD, MASSACHUSETTS 01730
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GCA-TR-75-32-G(14)
ASSESSMENT OF PHTHALIC ANHYDRIDE
AS A POTENTIAL AIR POLLUTION PROBLEM:
Volume XIV
by
Robert M. Patterson
Mark I. Bornstein
• Eric Garshick
GCA CORPORATION.
GCA/TECHNOLOGY.DIVISION
Bedford,. 'Massachusetts
January 1976
Contract No. 68-02-1337
. Task Order No. 8
EPA Project Officer
Michael Jones
EPA Task Officer
Justice Manning
U.S. ENVIRONMENTAL PROTECTION AGENCY
Research Triangle Park
North Carolina 27711 :
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This report wns furnished to the U.S. Environmental Protection Agency by the
GCA Corporation, GCA/Tcchnology Division, Bedford, Massachusetts 01730, in
fulfillment of Contract No. 68-02-1337, Task Order No. 8. The opinions,
findings, and conclusions expressed are those of the authors and not neces-
sarily those of the U.S. Environmental Protection Agency or of the cooperating
agencies. Mention of company or product names is not to be considered as an
endorsement by the U.S. Environmental Protection Agency.
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ABSTRACT
This report is one of a series which assesses the potential air pollution
impacts of 14 industrial chemicals outside the work environment. Topics
covered in each assessment include physical and chemical properties,
health and welfare effects, ambient concentrations and measurement meth-
ods, emission sources, and emission controls. The chemicals investigated
in this report series are:
Acetylene
Methyl Alcohol
Ethylene Dichloride
Benzene
Acetone
Acrylonitrile
Cyclohexanone
Formaldehyde
Methyl Methacrylat**
Ortho-Xylene
Maleic Anhydride
Dimethyl Terephthalate
Adipic Acid
Phthalic Anhydride.
Volume I
Volume II
Volume III
Volume IV
Volume V
Volume VI
Volume VII
Volume VIII
Volume IX
Volume X
Volume XI
Volume XII
Volume XIII
Volume XIV
iii
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CONTENTS
Page
Abstract ill
List of Tables v
Sections
I Summary and Conclusions 1
II Air Pollution Assessment Report 3
Physical and Chemical Properties 3
Health and Welfare Effects 3
Ambient Concentrations and Measurements 6
Sources of Phthalic Anhydride Emissions 9
Phthalic Anhydride Emission Control Methods 12
III References 15
Appendix
A Phthalic Anhydride Manufacturers 17
iv
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TABLES
No. Page
1 Significant Properties of Phthalic Anhydride 4
2 Phthalic Anhydride Consumption - 1974 10
3 Sources and Emission Estimates of Phthalic
Anhydride - 1974 10
4 Water Scrubber and Incinerator 12
5 Direct Incineration 13
6 Incineration and Waste Heat Boiler 13
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SECTION I
SUMMARY AND CONCLUSIONS
Phthalic anhydride is a white, crystalline solid with a characteristic
choking odor. It is produced by the oxidation of either naphthalene
or ortho-xylene, and it is a key industrial intermediate in the manu-
facture of resins, polyesters, dyes, and plasticizers.
The major acute toxic effect of exposure to phthalic anhydride dust or
vapor is its irritating action on the skin, eyes, and mucous membranes.
3
A concentration of 25 mg/m (4.2, ppm) will cause mucous membrane irri-
tation. There is no record of serious injury due to acute exposure.
Phthalic anhydride dust or vapor in contact with moist skin will form
free phthalic acid. The U.S. occupational standard for exposure is
3
12 mg/m (2 ppm) for an 8-hour time weighted average.
Simple diffusion modeling estimates place the likely maximum 1-hour
3
average ambient concentration at about 0.7 mg/m , with a 24-hour aver-
age of about 0.3 mg/m .
About 1 billion pounds of phthalic anhydride were produced at 16 loca-
tions in 1974, and production is expected to increase 6 percent per
year through 1978. The primary end use is the manufacture of plasti-
cizers, with polyester resin production second. The major emission
sources in descending order are product storage, manufacturing, end
product manufacturing, and product handling. Total emissions are
estimated to have been about 5 million pounds in 1974.
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Scrubbers and incinerators are currently being used by industry to con-
trol phthalic anhydride emissions wit:h efficiencies of 86 and 99 percent,
respectively. The product is stored in the molten state and blanketed
with dry nitrogen to prevent fire and hydrolysis to phthalic acid. Cur-
rently used practices to control the continuous gaseous effluent are the
use of knock-out pots for removal of solid phthalic anhydride and the
venting of storage tanks to the main process vent gas incinerator.
Based on the results of the health effects research presented in this
report, and the ambient concentration estimates, phthalic anhydride as
an air pollutant apparently does not pose a threat to the health of the
general population. In addition, phthalic anhydride does not appear to
pose other environmental insults which would warrant further investiga-
tion or restriction of its use at the present time.
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SECTION II
AIR POLLUTION ASSESSMENT REPORT
PHYSICAL AND CHEMICAL PROPERTIES
Phthalic anhydride is a white, crystalline solid with a characteristic
choking odor. It is manufactured by the oxidation of either naphtha-
lene or ortho-xylene. Phthalic anhydride is a key industrial interme-
diate in the manufacture of resins, polyesters, dyes, and plasticizers.
Significant properties are given in Table 1.
HEALTH AND WELFARE EFFECTS
Effects on Man
Acute Poisoning - The major acute toxic effect of exposure to phthalic
anhydride dust or vapor results from its marked irritating properties
on the skin, eyes, and mucous membranes of the nose and respiratory
tract. A concentration of 25 mg/m (4.2 ppm) causes some mucous mem-
brane irritation. A concentration of 30 mg/m (5.0 ppm) causes defi-
nite conjunctival irritation as well as increased mucous membrane
irritation. Symptoms of exposure to such concentrations include
coughing, sneezing, a burning sensation in the throat and increased
2 3
mucous secretion. ' Continued exposure or exppsure to higher levels
may result in general respiratory tract irritation, nasal ulceration
and bleeding, loss of smell, and hoarseness. Pulmonary sensitization
2
and allergic reaction is possible. However, there is no record of
4
serious injury due to short exposures to high concentrations.
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Table 1. SIGNIFICANT PROPERTIES OF PHTHALIC ANHYDRIDE
Synonyms
phthalic acid anhydride, phthalandione,
1, 2-benzcnc dicarboxylic acid anhydride
Chemical formula
Molecular weight
Boiling point
Melting point
Specific gravity
Vapor pressure
Solubility
Minimum explosive
concentration
Explosive limits
Ignition temperature
Flash point
At 25°C and 760 mm Hg
148.11
284.5°C (sublimes)
130.8°C
1.527 (4°C)
1.4 mm Hg at 110°C
42 mm Hg at 180°C
Soluble in ethanol, benzene
Slightly soluble in water, ethyl ethers,
carbon disulfide
16.5 g/m3
1.77. at 140°C
10.5% at 193°C
584°C
151°C
2
1 ppm vapor = 6.0 mg/m
1 mg/r'3 =0.17 ppm
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Phthalic anhydride dust and vapor ;irc particularly irritating to moist
skin as a result of the formation of free phthalic acid. Contact pro-
duces redness and chapping, with urtjcaria possible. It is a skin sen-
sitizing agent." The worst symptom of eye irritation is a persistent
conjunctivitis, with no permanent injury resulting.
Chronic Poisoning - Workers chronically exposed to phthalic anhydride
vapors or dust suffered from aggravated, acute exposure symptoms.
Clinical findings included atrophy of the nasal mucous membrane
(reversible), sometimes with blood-stained discharge, irritation of
the larynx, and hoarseness and cough, and sometimes with blood-stained
sputum. Bronchitis, irritation of the gastric mucous membrane with
loss of appetite and weight, and asthma and allergic rhinitis (inflam-
mation of the nose lining) due to sensitization have been seen. The
allergy can develop such that lower doses of phthalic anhydride can no
longer be tolerated. Direct dose-response data for chronic exposure
are lacking in the literature. The U.S. occupational standard for ex-
>- I
o
posure is a 12 mg/m (2 ppm) 8-hour time weighted average, based on
human sensory response.
Effects on Animals
Acute Poisoning - Animal response to acute exposure has not been well
documented in the literature. On the basis of available data, mucous
membrane irritation, eye irritation and related symptoms would occur
in animals at concentrations above 30 mg/m (5.0 ppm). Sensory re-
sponse and exposure symptoms would be the same as those seen in humans.
Values for the acute oral DD,n in the rat have been reported as high as
' 12
2,500 to 5,000 mg/kg, and as low as 800 to 1,600 mg/kg body weight. '
Death after ingcstion was due to tubular necrosis (cell death) of the
kidney. In cats the LD_0 is 800 me/kg, and for guinea pigs it is 100
mg/kg.
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Chronic Poisoning - Cats exposed to 3,700 nig/m (617 ppm) for 6 hours
a day for 7 days became drowsy, showed a loss of appetite, and vomited,
Liver and kidney damage was seen. Rats and rabbits exposed to 10,000
4
3
mg/m (1,667 ppm) for 4 hours per day for several days experienced
25 percent fatalities.'
Skin scnsitization in guinea pigs has been illustrated by the intracu-
taneous injection of 20 mg-of phthalic anhydride dissolved in dioxane
and olive oil twice a week for 2 weeks. Animals tested 2 weeks after
0
the last injection were markedly sensitized.
Effects on Vegetation
The effects of phthalic anhydride on plants have not been documented
in the literature.
Other Effects
The dust and vapors form explosive mixtures with air. The lower explo-
sive limit is 1.7 percent and the upper explosive limit is 10.A percent,
The flash point by closed cup method is 151 C.
AMBIENT CONCENTRATIONS AND MEASUREMENTS
Ambient Concentration Estimates
The largest emission source of phthalic anhydride is a production
facility with a capacity of 130 million pounds per year. This facil-
ity is located near Chicago, which IMS a population of over 3 million.
The emission factor for phthalic anhydride is 0.0017 pound per pound
produced.
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Hence, the emission rate is
(0.0017 emission factor) (130 x 1Q6 Ib/yr) (453.6 g/lb)
3.1536 x 107 sec/yr
= 3.2 g/sec of phchalic anhydride.
Some assumptions must be made regarding this chemical release to the
atmosphere. First of all, the emissions do not all come from one source
location, but rather from a number of locations within the plant where
phthalic anhydride leaks to the atmosphere. Thus, the emissions can be
characterized as coming from an area source which will be taken to be
100 meters on a side. Secondly, the emissions occur at different heights,
and an average emission height of 10 meters is assumed.
Ground level concentrations can then be estimated at locations downwind
of the facility. To do this, a virtual point source of emission is
assumed upwind of the facility at a distance where the initial horizontal
dispersion coefficient equals the length of a side of the area divided
by A.3. In this case:
o = 100m/A.3 = 23.3m.
yo
Assuming neutral stability conditions (Pasquill-Gifford Stability Class D)
with overcast skies and light winds, the upwind distance of the virtual
point source is approximately 310 meters. With consideration of the plant
boundary, it is reasonable to assume that the nearest receptor location
is thus 500 meters from the virtual point source. Finally, taking 2 m/sec
as an average wind speed, the ground level concentration may be calculated
from:
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-ft)1
3 2 -1/2
or X = (2) ir (36) (18.5) e U8'5
!'0.66 mg/m
for a 10-minute average concentration. Over a period of an hour this
3
becomes 0.66 (0.72) = 0.48 mg/m (or 0.08 ppm vapor) 1-hour average
concentration. Over a 24-hour period, the average concentration might
3
roughly be expected to be about 0.26 mg/m (0.04 ppm vapor).
Phthalic Anhydride Measurement Techniques
Phthalic anhydride present as an airborne particulate should be collected
on Whatman No. 1 filter paper or on a glass filter. For the collection
of vapor or fumes, two gas washing bottles or bubblers in series contain-
3
ing appropriate absorbing solutions such as ethanol or 0.1 N HC1 are used.
Three methods are available for the determination of the concentration of
phthalic anhydride in air: colorimetric, ultraviolet absorption, and gas
chromatography. However, only gas chromatography is suitable for ambient
concentrations.
In the colorimetric method phthalic anhydride is extracted from the
filter paper using benzene. The sample is dried, treated with hydro-
quinone and sulfuric acid, left alone for 2 hours, and then diluted with
water and benzene. An aliquot of the water layer is treated with potas-
sium hydroxide and ascorbic acid. The absorbence of the aqueous layer
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is then measured on a spcctrophoLomeLer at 560 my and compared to a
standard curve. Concentrations in the range of 80 ppm have been de-
termined by this method.
The ultraviolet absorption method involves the extraction of phthalic
anhydride in 0.1 N HC1. The absorbency of the resulting solution is
measured at 275 my and compared to a standard calibration curve. Con-
centrations detected by this method are similar to those of the colori-
metric method.
The gas chromatograph method, which is used when small sample volumes
are available, is the most accurate of the three methods. Concentra-
tions as low as 1 ppb can be detected if used in conjunction with a
12
flame ionization detector.
SOURCES OF PHTHALIC ANHYDRIDE EMISSIONS
Phthalic Anhydride Production and Consumption
The production of phthalic anhydride in 1974 is estimated to have been
1,030 million pounds, and it is expected to increase at 6 percent per
year through 1978. Phthalic anhydride is primarily used in the pro-
duction of plasticizers, accounting for 50 percent of total production.
Alkyd resins and polyester resins account for a major portion of the
remaining production. Twelve companies at 16 locations are manufactur-
ing phthalic anhydride as listed in Appendix A. The consumption of
phthalic anhydride for final produces is shown in Table 2. This table
also presents the expected growth r.ites for each sector of the market.
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Table 2. PHTHALIC ANHYDRIDE CONSUMPTION - 1974
Flastlclzers
Alkyd resins
Polyester resins
Export and miscellaneous
Total
Million
pounds
515.0
195.7
247.2
72.1
1,030.0
% Annual
growth
6
0
15
Variable
6%
Phthalic Anhydride Sources and Emission Estimates
Primary sources of emissions of phthalic anhydride result from phthalic
anhydride production, bulk storage and handling, and end product manu-
facture. Total emissions from all categories are estimated to be
4.86 million pounds, representing 0.5 percent of total production.
See Table 3.
Table 3. SOURCES AND EMISSION ESTIMATES
OF PHTHALIC ANHYDRIDE - 1974
Source
Million
pounds
Phthalic anhydride manufacturing
Product handling
Product storage
End product manufacturing
Total
1.56
0.10
1.64
1.56
4.86
Phthalic anhydride is produced from two raw materials, naphthalene and
ortho-xylene. Ortho-xylene account:; for 54 percent of production and
14
naphthalene for the remaining 46 percent.
10
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Emissions from Che manufacturing of phthalic anhydride occur from process
reactors and vents, product handling, and product storage. A recent study
of phthalic anhydride production has estimated losses from reactors and
14
vents. An emission rate of 0.0017 ,md 0.0013 ton of phthalic anhydride
per ton of phthalic anhydride produced from the ortho-xylene and naphtha-
lene processes, respectively, have been reported. Using these factors,
and the corresponding production rate from each process, will result in
0.96 million and 0.60 million pounds, respectively, emitted from the
ortho-xylene and naphthalene processes. These emission rates are based
on extensive controls already in use by the industry.
Product handling losses, estimated from the same report, are based on
90 percent of the product sold in the molten state, and the remaining
10 percent sold as a solid flake. It is estimated that 0.0001 ton of
product is lost per ton of phthalic anhydride produced. This results
in 0.01 million pounds lost from the bagging operation and 0.09 million
pounds lost from truck loading of molten product.
Phthalic anhydride is stored in fixed roof storage tanks in the molten
state (149°C). The reported emission factor is 0.0016 ton emitted per
14
ton of product stored. There'f<
mated to be 1.64 million pounds.
ton of product stored. Therefore, losses from bulk storage are esti-
The last major source of phthalic anhydride emissions results from the
production of end products. The literature does not contain any data
on the emission rates from these processes. It is, therefore, estimated
that the emission rates are the same as the emission rates for the pro-
duction of phthalic anhydride. Emissions from end product manufacturing
are estimated to be 1.56 million pounds.
11
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PHTHALIC ANHYDRIDE EMISSION CONTROL METHODS
Two types of control devices — scrubbers and incinerators — are currently
14
being used by the industry. In a recent study it was reported that
these two control methods are used extensively in the manufacture of
phthalic anhydride. The main source of emissions from the ortho-xylene
process occurs from the main process vent gas stream. The main source
of emissions from the naphthalene process occurs from the switch-condenser
vent. Depending on the plant, one or two types of control devices may be
used: scrubbers and/or incinerators. The water scrubber is reported to
have an efficiency of 86 percent, and the incinerator has a reported
14
99 percent efficiency. Cost data for the various systems are presented
in Tables 4, 5, and 6.
Table 4. WATER SCRUBBER AND INCINERATOR
a, 14
Feed gas, Ib/hr
Gaseous effluent, Ib/hr
Gaseous effluent, SCFM
Total capital investment, $
Total operating cost, $
Net annual cost, $
Emission control efficiency
Water scrubber
536,962
544,005
122,100
1,398,000
335,000
86%
Incinerator
10,460
39,235
9,700
444,800.
198,900
533,900C
99%d
Costs updated to first quarter 1975.
Includes depreciation, interest charges, maintenance,
labor and utilities.
£
Combined annual cost: water scrubber with incinerator.
Combined efficiency: water scrubber with incinerator.
12
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Table 5. DIRECT INCINERATION'
,a,l4
Feed gas, Ib/hr
Gaseous effluent, Ib/hr
Gaseous effluent, SCFM
Total capital investment, $
Total operating cost, $
Net annual cost, $
Emission control efficiency
536,962
540,052
120,200
1,093,000
502,000
502,000
92%
Costs updated to first quarter 1975.
Includes depreciation, interest charges, mainte-
nance, labor and utilities.
Table 6. INCINERATION AND WASTE HEAT BOILER'
a,14
Feed gas, Ib/hr
Gaseous effluent, Ib/hr
Gaseous effluent, SCFM
Total capital investment, $
Total operating cost, $
f*
Steam production (credit), $
Net annual cost, $
Emission control efficiency
536,962
545,767
122,350
1,589,000
1,101,000
591,000
510,000
92%
Costs updated to first quarter 1975.
Includes depreciation, interest charges, mainte-
nance, labor and utilities.
C$0.59/thousand pounds (450 psig, 750°F).
13
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Most production plants store phthalic anhydride in the molten state
and maintain it at 149°C. In several cases, the tanks are blanketed
with dry nitrogen to prevent the entry of oxygen (fire) or water vapor
(hydrolysis to phthalic acid). Consequently, there is a continuous
gaseous effluent. Current control practices are the use of knock-out
pots (settling and/or impactor chambers) for removal of solid phthalic
anhydride and the venting of storage tanks to the main process vent
gas incinerator. No cost data are available for these processes, but
it is expected that capital and operating costs would be fairly low.
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SECTION III
REFERENCES
1. Baader, E. W. Illnesses Caused by Phthalic Acid and Its Compounds.
Arch f Gewerbepath u Gewerbehyg. 13:419-53, 1955. Summary in Bull
Hyg. 30:699-700, 1955; and Pub Health Eng Abstr. 35:9-10, 1955.
2. Fassett, D. W. Organic Acids and Related Compounds. In: Industrial
Hygiene and Toxicology, Patty, F. A. (ed.). Vol. 2. New York, Inter-
science Publishers, 1963. p. 1822-23.
3. American Industrial Hygiene Association. Hygienic Guide Series:
Phthalic Anhydride. Amer Ind Hyg Assoc J. 28:395-98, 1967.
4. Fairhall, L. T. Industrial Toxicology. 2nd Edition. New York,
Hafner Publishing Co., 1909. p. 322-23.
5. Kern, R. A. Asthma and Allergic Rhinitis Due to Sensitization to
Phthalic Anhydride. J Allergy. 10:164-65, 1939.
6. Gervais, P. Asthma in the Plastics Industry. Connais Plast.
7:20-22, 1966. Cited in: Chemical Abstracts 66:49043t, 1967.
7. The NIOSH Toxic Substances List - 1974 Edition. U.S. Department of
Health, Education and Welfare. Publication No. (NIOSH) 74-134. p. 621.
8. Jacobs, J. L., T. S. Golden, J. J. Kelley. Immediate Reactions to
Anhydrides, of Wheal and Erythema Type. Proc Exp Biol Med. 43:74-77,
1940.
9. Monsanto Material Data Sheet. Form No. OSHA-20. May 1971.
10. Turner, D. B. Workbook ,of Atmo&pheric Dispersion Estimates. U.S. En-
vironmental Protection Agency. Report No. AP-26. April 1973.
11. Kesy, I. The Determination of Phlhalic Anhydride in the Air. In:
Proceedings - Thirteenth International Congress on Occupational Health.
New York. 1960.
15
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12. Leithe, W. The Analysis of Air Pollution. Ann Arbor-Humphrey
Science Publishers, 1970.
13. Chemical Profiles. Schnell Publishing Co., July 1974.
14. Phthalic Anhydride Manufacture from Ortho-xylene. U.S. Environ-
mental Protection Agency. Publication No. EPA-450/3-73-006g. 1975.
16
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APPENDIX A
PHTHALIC ANHYDRIDE MANUFACTURERS
14
Allied Chemical
Allied Chemical
Allied Chemical
BASF Wyandotte
Exxon Chemical Co.
W. R. Grace
Koppers Co.
Koppers Co.
Monsanto Co.
Monsanto Co.
Reichhold Chemicals
Sherwin-Williams
Standard Oil of California
Stepan Chemical Co.
Union Carbide Corp.
United States Steel Corp.
Total
El Segundo, Calif.
Philadelphia, Pa.
Ironton, Ohio
Kearny, N. J.
Baton Rouge, La.
Fords, N. J.
Bridgeville, Pa.
Chicago, 111.
Bridgeport, N. J.
Texas City, Tex.
Morris, 111.
Chicago, 111.
Richmond, Calif.
Millsdale, 111.
Institute, W. Va.
Pittsburgh, Pa.
Capacity,
million pounds/year
40
100
33
130
90
75
95
130
80
130
100
20
50
50
75
125
1,323
17
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TECHNICAL REPORT DATA
(Please read Instructions on the re- crse before completing)
i. REPORT NO.
2.
3. RECIPIENT'S ACCESSIOftNO.
4. TITLE AND SUBTITLE
Assessment of Phthalic Anhydride as a Potential
Air Pollution Problem
5. REPORT DATE
January 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Robert M. Patterson
Mark I. Bornstein
Eric Garshick
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
GCA Corporation
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts
11. CONTRACT/GRANT NO.
68-02-1337
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
16. SUPPLEMENTARY NOTES
16. ABSTRACT
This report is one of a series which assesses the potential air pollution
impacts of 14 industrial chemicals outside the work environment. Topics covered
in each assessment include physical and chemical properties, health and welfare
effects, ambient concentrations and measurement methods, emission sources, and
emission controls. The chemicals investigated in this report series are:
Volume I
Volume II
Volume III
Volume IV
Volume V
Volume VI
Volume VII
Acetylene
Methyl Alcohol
Ethylene Dichloride
Benzene
Acetone
Acrylonitrile
Cyclohexanone
Volume VIII
Volume IX
Volume X
Volume XI
Volume XII
Volume XIII
Volume XIV
Formaldehyde
Methyl Methacrylate
Ortho-Xylene
Maleic Anhydride
Dimethyl Terephthalate
Adi pic Acid
Phthalic Anhydride
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Phthalic Anhydride
Ambient Concentrations Health Effects
Measurement Methods
Emission Sources
Emission Controls
Industrial Chemicals
Physical Properties
Chemical Properties
Welfare Effects
Phthalic Anhydride
Air Pollution Assessment
Air Pollution Control
Organic Chemicals
IB. DISTRIBUTION STATEMENT
19. SECURITY CLASS (Thu Report)
21. NO. OF PAGES
Unlimited
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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