United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S2-84-194 Jan. 1985
Project Summary
Hazardous/Toxic Air  Pollutant
Control  Technology:
A  Literature  Review

Gunseli Sagun S ha reef, Andrew J. Miles, and Barbara K. Post
  This report summarizes literature on
 hazardous/toxic air pollutant (HAP)
 sources and control techniques em-
 ployed in their reduction and/or de-
 struction.  The information was ab-
 stracted from an extensive computerized
 and manual literature search and data
 base development study. The primary
 emphasis of the report is on HAP con-
 trol technology. However, a brief sum-
 mary  of major source categories that
 emit HAPs is also included.
  About 70 hazardous/toxic com-
 pounds or groups of compounds are
 covered in this study; most are volatile
 organic compounds.
  In the HAP  control technology data
 base,  most of the information is for the
 Synthetic  Organic Chemical Manu-
 facturing Industry (SOCMI) source
 category. However, data also are avail-
 able for the combustion, solvent use,
 and metal processing industries.
  The major add-on control techniques
 for volatile organic HAPs discussed in
 this report are combustion, absorption,
 adsorption, and condensation. Com-
 bustion techniques include thermal and
 catalytic incineration, flaring, and
 disposal of waste streams in boilers and
 process  heaters.  The  add-on control
 devices identified in the literature for
 control of particulate  HAP emissions
 are electrostatic precipitators,  bag-
 houses, wet scrubbers, and cyclones.
  A list of references identified during
 this study, along with abstracts of those
 references, is included in the Bibli-
 ography section of the full report.

  This Project Summary was developed
 by EPA's Air  and Energy Engineering
 Research Laboratory,  Research  Tri-
angle Park, NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).

Introduction
  The initial objective of this study was to
compile,  organize,  and review scientific
literature and Government publications
relating  to: (a) hazardous air pollutant
(HAP) sources and (b) control techniques
used in reducing and  destroying  HAPs.
This objective was later narrowed: the
study focused on HAP control technology.
Table 1 lists the HAPs for which controls
were identified in the literature search.
  In this  study, the term HAPs is used to
designate noncriteria air pollutants that
are, or have the potential to be, hazardous
or toxic to humans. Since this definition is
very broad and can encompass hundreds
of specific compounds, a preliminary
screening of the literature resulted in a
very large number of references. Therefore,
EPA's list of 37 potentially toxic substances
was chosen as the basis for a compound-
specific literature search. From this list
(Table 2), 14 compounds/groups that are
not well  characterized in the literature
were selected  for further  study. A
preliminary evaluation of the references
in the data base indicated that much of
the data  and literature applies to control
technology, covering several pollutants in
addition  to the 14  indicated in Table 2.
Following a review of the classification of
references by the Project Officer,  the
decision was made to focus on evaluation
of control technology literature.
  This project was not a definitive study
of HAP emissions or control techniques,
but rather an  attempt  to summarize the

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Table 1.   HAPS Included in this Study
Compound
Acetaldehyde
Acetic acid
Acetic anhydride
Acetone
Acrolein
Acrylic acid
Acrylonitrile
Adipic acid
Ally/ alcohol
Ally/ chloride
Aniline
Benzene
Benzyl chloride11
1,3 Butadiene
Cadmium
Caprolactam
Carbon tetrachloride
Chlorobenzene
Chloroform
Chloroprene
Chromium
Coke oven emissions
Copper
m-Cresol
o-Cresol
p-Cresol
Cumene
Cyclohexane
Cyclohexanol
Cyclohexanone
Diethanolamine
Dimethyl nitrosamine"
Dimethyl terephthalate
Epichlorohydrin
Ethylbenzene
Ethylene
Ethyl ene di chloride
Ethylene glycol
Ethylene oxide
Fluorocarbons
Formaldehyde
CAS No*
75-07-0
64-19-7
108-24-7
67-64-1
107-02-8
79-10-7
107-13-1
124-04-9
107-18-6
107-05-1
62-53-3
71-43-2
100-44-7
106-99-0
7440-43-9
105-60-2
56-23-5
108-90-7
67-66-3
126-99-8
7440-47-3
—
7440-50-8
108-39-4
95-48-7
106-44-5
98-82-8
110-82-7
108-93-0
108-94-1
111-42-2
62-75-9
62-75-9
106-89-8
100-41-4
74-85-1
107-06-2
107-21-1
75-21-8
—
50-00-0
Compound
Hexachlorocyclopentadiene
Ma/eic anhydride
Methanol
Methyl chloride
Methyl chloroform
Methyl ethyl ketone
Methyl methacrylate
Methylene chloride
Nitrobenzene
Nitrosomorpholine
Perchloroethylene
Penol
Phosgene
Phthalic anhydride
Polychlorinated biphenyls
Propylene oxide
Styrene
Terephthalic acid
Toluene
Toluene disocyanate
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
Vinyl acetate
Vinyl chloride
Vinylidene chloride
m-Xylene
o-Xylene
p-Xylene
Zinc











CAS No."
77-47-4
108-31-6
67-56-1
74-87-3
71-55-6
78-93-3
80-62-6
75-09-2
98-95-3
110-91-8
127-18-4
108-95-2
75-44-5
85-44-9
1336-36-3
75-56-9
100-42-5
100-21-0
108-88-3
91-08-7
79-01-6
75-69-4
76-13-1
108-05-4
75-01-4
75-35-4
108-38-3
95-47-6
106-42-3
7440-66-6











 ^Chemical Abstracts Service number.
 b/Vo specific control information was identified for this compound.
readily available literature on HAP
emissions and controls for the compounds
studied.  The full report  should help
identify  primary references for HAP
studies. It can also be  used to indicate
significant gaps  in  the  existing HAP
literature.

Literature Search
  Initially, a general literature search for
HAPs was conducted. By definition, HAPs
can potentially encompass  hundreds of
specific compounds. For this reason, the
general HAP literature  search produced
very many references  relating to HAPs
and  control technology.  Therefore, 14
compounds from the EPA's list of 37
potentially  toxic  substances for  which
Radian did not have in-house information
were selected for a compound-specific
literature search. These compounds are
listed in Table 2.  EPA's list was chosen
because it is well-known,  containing
pollutants  that  are being  studied by
several organizations. Information on the
remaining 23 compounds was available
in in-house Radian project files from
earlier studies. The literature search was
later supplemented by in-house data and
on-going programs on the 23 compounds.
The  data  base  generated  from the
computerized and manual search contains
references  that cover several HAPs  in
addition to those in Table 2.
  For the computerized literature search.
Radian screened the Compendex, Chemi-
cal Abstracts, and NTIS (National Techni-
cal  Information Service) data bases.  A
description  of the search and the key
words used in each are summarized  in
Table 3.
  During the review process, the references
were organized  and classified into six
broad classifications: (1) references that
provide data on the physical and chemica
properties of HAPs; (2) references that
contain data on manufacturers, production
rate, and plant  locations; (3) reference
containing information on manufacturing
processes and/or reactions associated
with HAP emissions; (4) references that
contain HAP emission source information
and data on emission factors and emission
rates; (5) references containing information
on actual plant control practices and/or
applicable control techniques for several
HAPs (they contain  data  pertaining to
HAP controls  for organic compounds);
and (6) general references; e.g., published
literature searches.


HAP Sources
  Major source categories of HAP emis-
sions include  the  Synthetic Organic
Chemical Manufacturing Industry (SOCMI),
combustion, mobile sources,  metal
processing, and solvent use. Much of the
emission source  information reviewed
for this study lies in the SOCMI area; com-
bustion,  metal  processing, and  solvent
use source  categories are not covered as
extensively. For  the combustion and
metal processing categories, information
was extracted from in-house Radian data
bases.
  From the literature  review, it appears
that point sources such as reactor vents
and furnace stacks in  manufacturing
operations  are  well  characterized with
respect to emissions. But there are little
data on process fugitive sources except in
the coating and metal processing industries.
Similarly,  not  much information is
available on area sources, except for
storage tanks, pump seals, and valves.

HAP Control Technology
  In the HAP control technology data
base developed in this study, most of the
data are for  SOCMI. However, information
on combustion, solvent  use, and metal
processing  is also available. A large
proportion  of  the control technology
information pertains to  point sources
within the  source categories; therefore,
add-on control technique applications are
covered extensively.
  Volatile organic compound (VOC) add-
on  control  techniques identified in the
literature are absorption, adsorption,
combustion, and condensation. Combustion
techniques  include catalytic and thermal
incineration, flaring, and disposal of
waste  streams in boilers and process
heaters. Based  on the literature review,
thermal  incineration is  applicable to a
wide variety of compounds and is not very
sensitive to HAP characteristics or waste

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Table 2.    EPA's list of 37 Potentially Toxic
Substances
Acetaldehyde
Acrolein'
Acrylonitrile
Ally I Chloride
Benzyl Chloride*
Beryllium
Cadmium
Carbon Tetrachloride
Chlorobenzene'
Chloroform
Chloroprene"
Coke Oven Emissions'
o-, m-, p-Cresof*
p -Dichlorobenzene
Dimethyl Nitrosamine*
Dioxin
Epichlorohydrin
Ethylene Dichloride
Ethylene Oxide
Formaldehyde
Hexachlorocyclopentadiene'
Maleic Anhydride
Manganese
Methyl Chloroform (1,1,1, Trichloroethane)
Methylene Chloride
Nickel
Nitrobenzene
Nitrosomorpholine"
Perchloroethylene
Phenol
Phosgene"
Polychlorinated Bipheny/sa
Propylene Oxide
Toluene*
Trichloroethylene'
Vinyl/dene Chloride
o-, m-, p-Xylenea
"Included in compound-specific literature
 search.
                            stream  conditions.  The other control
                            techniques,  however, depend on HAP
                            characteristics and process parameters.
                              The add-on  control devices used  for
                            control of particulate  HAP emissions  are
                            electrostatic precipitators  (ESPs), bag-
                            houses,  cyclones, and  wet  scrubbers.
                            ESPs  and  baghouses have been widely
                            used  to  control metal  emissions; very
                            high removal  efficiencies  are obtained
                            with these devices. Wet scrubbers have
                            been used for controlling both metal and
                            organic particulate emissions.
                              Except for  the solvent  use source
                            category, little data are  available  in  the
                            references for  control of process fugitive
                            and area  sources. Except for  SOCMI,
                            work  practices, process modifications,
                            and material  substitutions  are not well
                            documented.
 Table 3.    Summary of Computerized Literature Search

                      Compendex                  CA (Chemical Abstracts)
                                                                 Compendex
                                                                                             NTIS
Description of the
 Search
General literature search for
HAPs
Compound-specific search
Compound-specific search
Compound-specific search
(Air Pollution and Control
and Pesticides Pollution and
Control Sections of the data
base were included. Biological
and medical sciences and Water
Pollution and Control Sections
were excluded The terms
monitor, measurement, analysis,
exposure, and occupational were
also excluded.)
Key Words Used
noncritena, toxic, hazard
chemical, gas, fume, emission
air pollution control,
effluent, manufacture,
source, plant, flare,
condensation, carbon
adsorption, thermal oxidation
incineration, hydrocarbon
(Several comb/nations were
used)
                                               acro/em, chlorobenzene. cresols,
                                               phosgene, coke oven emissions,
                                               PCB, benzyl chloride, chloroprene
                                acrolein, chlorobenzene,
                                cresols, phosgene, toluene.
                                coke oven emissions
                                manufacture, plant,
                                effluent
                          acrolein, benzyl chloride,
                          chlorobenzene, cresol,
                          dimethyl nitrosamme,
                          hexachlorocyclopentadiene,
                          toluene, xylene. PCB,
                          trichloroethylene, coke
                          oven emissions, phosgene
                          chlorof>rene, nitrosomorpholme

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    G. S. Shareef, A. J. Miles. andB. K. Post are with Radian Corporation, Research
      Triangle Park, NC 27709.
    Bruce A. Tichenor is the EPA Project Officer (see below).
    The complete report. entitled"Hazardous/Toxic Air Pollutant Control Technology:
      A Literature Review," (Order No. PB 85-137 107; Cost: $22.00,  subject to
      change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA 22161
            Telephone: 703-487-4650
    The EPA Project Officer can be contacted at:
            Air and Energy Engineering Research Laboratory
            U.S. Environmental Protection Agency
            Research Triangle Park, NC27711
                                     * U S. GOVERNMENT PRINTING OFFICE; 1985 — 559-016/7893
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