United States
Environmental Protection
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-87/015  Sept. 1987
Project  Summary
Criteria  Pollutant  Emission
Factors  for the  1985  NAPAP
Emissions  Inventory

Margie B. Stockton and John H. E. Stalling
  As part of the National Acid Precip-
itation Assessment Program (NAPAP),
the U.S. Environmental  Protection
Agency (EPA) identified the need to
generate emission factors  for volatile
organic compound (VOC) emissions for
about 1,800 source  classification
categories (SCCs). Additionally, emis-
sion  factor development was needed
for nitrogen oxides (NOJ, sulfur oxides
(SO,), and VOCs for SCCs that states
have used  to report emissions. Each
SCC represents a specific process or
function that  is logically  associated
with a point source of air pollution. The
objective of this effort was  to estimate
VOC emission  factors  for all SCCs
where VOC factors were previously
absent, and to develop  NO, and SO,
emission factors for SCCs that states
had reported as emission sources. This
report includes emission factor esti-
mates for VOCs, NOX, and SO, which
were developed from  a  variety  of
readily available information. Emission
factors for particulate matter (PM) and
carbon monoxide  (CO) from AP-42
Fourth Edition and  Supplement A are
also  presented. Data gathered during
numerous standards-setting activities
as well as data provided  from state
emissions inventory data bases were
used to  calculate the  new emission
factor estimates. Technology transfer
of emission factors for similar pro-
cesses in different industries provided
emission factor estimates  for source
categories where no data  were avail-
able. A list of all valid SCCs used in
the 1985 NAPAP Emissions Inventory,
as well as about 90 SCCs which have
been added  to the inventory since
October 1985, is included along with
all emission factor estimates developed
through April 1987.
  This Project Summary was devel-
oped by EPA's Air and Energy Engi-
neering Research L aboratory, Research
Triangle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).

  As part of the National Acid Precipi-
tation Assessment Program (NAPAP), the
Air  and Energy  Engineering Research
Laboratory (AEERL) of the U.S. Environ-
mental Protection Agency (EPA) updated
the  October 1985 NEDS Source Classi-
fication Codes and Emission Factor
Listinglhat was prepared by EPA's Office
of Air Quality Planning and Standards
(OAQPS).  In  Phase  I of the update,
volatile organic compounds (VOC) emis-
sion factor estimates were generated for
source classification categories (SCCs)
where  substantial  amounts of  VOC
emissions were expected.  The  major
emphasis of that effort was on organic
chemical manufacturing processes and
storage  of petroleum products  and
organic  chemicals. This report describes
Phase II of the update which consisted
of developing VOC emission factor
estimates for all remaining SCCs. Addi-
tionally, state air offices have reported
to the National Emissions Data System
(NEDS) on emissions from point sources
within their states. The SCCs appearing
in these reports which previously lacked
emission factors  were targeted as high
priority  SCCs for the development of

VOC,  nitrogen oxide (NOX), and sulfur
oxide (S0) emission factors.
  The SCCs and emission factors that are
reported in OAQPS' 1985 NEDS report
resulted  from updating  all emission
factor changes through AP-42,  Fourth
Edition. During this effort, the SCC listing
was revised  to incorporate all changes
through Appendix Ato A P-42 (December
1986). This report also contains a
number of new SCCs and  changes to
existing SCCs that have been previously
listed. A  list of all SCCs and emission
factors published in the  1985 NEDS
document, as well as the emission factor
estimates developed during Phases I and
II of the update,  are  included  in this
  In the  current  work  by AEERL,  the
primary objective  was to provide VOC
emission factor estimates for all SCCs
that had  no current  listing of VOC
emission factors  Also included  in this
work was the development of NOx and
SOX emission factor estimates for SCCs
which were  included in reports submit-
ted by states that previously lacked these
factors. The new emission factor esti-
mates resulting from this current work
are not of the same.known quality as
emission factors  tabulated  in  AP-42.
They  represent best estimates which
have  not been subjected  to rigorous
quality assurance. These factors were
generated from estimates taken from the
literature, from averaging  of data sub-
mitted by 13 state air quality offices, and
through the  transfer of emission factors
for SCCs from similar industries. Exten-
sive notes and references are supplied
in an appendix explaining how the new
emission factor estimates were gener-
ated. In some cases, these notes indicate
data quality  by reporting the number of
emission tests used to develop a factor.

State Contacts
  Thirteen  states were  contacted to
obtain emission  data  from emission
inventories, test reports, and permit files.
States  which  have large  industrial
sectors and potentially large emission
sources were specifically targeted during
this effort. Emissions data were supplied
by  12 of the states, 7 through compu-
terized  emissions  inventories  and 5
through review of permit files. Emission
factors were estimated by averaging the
emissions data submitted for each SCC.
In some cases, states or industries were
recontacted  to provide more complete
process  descriptions  and production
rates. States provided a  substantial
amount  of  emissions data on  metal
operations (both primary and secondary)
and on mineral products operations.

Literature Review
  A  number  of source  specific docu-
ments, including Background  Informa-
tion  Documents (BIDs),  Industrial  Pro-
cess Profiles,  Source Assessments, and
chemical specific emission source survey
documents were  reviewed to  gather
information on emissions and processes.
These documents provided  useful infor-
mation on process descriptions, operat-
ing parameters, raw materials, and end
products for  many  source categories.
This information was used to compare
similar processes in different industries
in order to transfer emission  factors
across industries where appropriate. The
Industrial Process Profiles, although
somewhat outdated (published in 1977
and  1980), proved especially useful for
this exercise.

State Reports Requiring Emis-
sion Factor Calculations
  In 1985, EPA asked states to  submit
emissions  data  for  large  sources  of
criteria pollutants,  emphasizing SO,,
NOx, and VOC emissions from sources
emitting over  100 tons/year. Source test
emissions data have been submitted, as
well as emission estimates based on AP-
42 emission factors or  engineering
judgment. Where no emission  factors
were available, states  have requested
that emissions be calculated for them by
the NEDS, using emission factors  already
in the system for  an SCC. Where  no
emission  factors  have  ever been
reported,  the SCCs  were  flagged for
emission factor development as a high
priority for this work assignment.
  At the completion of the Phase II effort,
99%  (2725)  of  the SCCs have VOC
emission factors or  emission factor
estimates associated with them or do not
need emission  factors due to their
general  description.  Of  these, 37%
(1006) were developed during this effort.
Emission factors for NOx  and S0 are
included for 75% of the SCCs in the list.
Table 1 summarizes the emission factor
development  for the SCCs currently in
NEDS and breaks  down  progress  by
major source category. During this effort,
over  100 VOC emission  factors were
developed in the following  major source
categories:  chemical  manufacturing.
primary metals operations,  and secon- I
dary metals operations.
  Forty-six states reported on emissions
for SCCs in  which  emission factor
development  was  necessary for  NO,,
SOX, and VOC. Emission factors for 293
SCCs were included in these reports. Of
the 293  SCCs for which factors  were
needed, 130 NO, emission factors  (98%
of the NOX requests) were developed, 128
SO, emission  factors  (99% of the SO,
requests) were developed, and 1 69 VOC
emission  factors (100% of  the  VOC
requests) were developed. These emis-
sion factors are based on data supplied
in published literature and the transfer
of existing factors from similar  pro-
cesses. Many of  the state  submittals
were received late  in the project, and
emission factor development is on-going.
Two states had not yet submitted emis-
sions data to NEDS as of April 30, 1987.
In its  final  form,  this  document will
address all SCCs for which state reports
on  emissions  require  emission  factor
  Recommended  activities for future
study include the  development of addi-
tional  NOx and SO,  emission factor
estimates. The approach would be sim-
ilar to that used for VOCs. Further review
of data which have been collected from
states and  the literature may  help
estimate additional NOX and SO, emis-
sion  factors. Source categories targeted
are chemical manufacturing  industries
and  primary and secondary metals
  The emission factors developed during
this effort are considered of "E" quality
by AP-42 standards primarily because
they are of unknown or uncertain quality.
In some cases, the factors may be of
much higher quality; however, the data
should be reviewed and verified before
higher ratings  are  applied.  Emissions
testing  is recommended for  improving
some of these  "E" rated factors, with
emphasis on testing of sources with large
VOC emission factors. Identification of
the SCCs for which testing is desirable
should be included in future work.
   Emission factor development needs for
particulate  matter (PM)  and carbon
monoxide (CO)  should be identified to
determine the amount  of additional work
necessary if  filling  of emission  factor
gaps for SCCs for these two  pollutants
is desired.

Table 1.
Summary of Emission Factor Development
Major Source Category
Combustion Sources
Chemical Manufacturing
Inorganic Chemical Storage
Food and Agricultural
Primary Metals
Secondary Metals
Mineral Products
Petroleum Operations
Pulp and Paper
Rubber and Plastics
Fabricated Metals
Oil and Gas Production
Organic Solvent Evaporation
Petroleum Storage
Chemical Storage
Solid Waste Disposal
Total SCCs
in Category
SCCs for Which
Emission Factors
are Inappropriate"
SO, Emission
(% Completed)"
1 79 (98%)
1 79 (34%)
15 (75%)
142 (70%)
126 (68%)
321 (91%)
39 (84%)
51 (89%)
6 (34%)
24 (83%)
12 (69%)
45 (79%)
/VOX Emission
(% Completed)"
192 (36%)
131 (70%)
328 (93%)
39 (84%)
52 (90%)
6 (34%)
26 (86%)
1 1 (66%)
44 (77%)
142 (90%)
VOC Emission
(% Completed)"
31 (100%)
21 (100%)
9(1 OO%)
58 (100%)
2725 199%)
"These include the "General Processes" (-01) codes, the "Other/Not Classified" (-98. -99) codes, and "Specify in Comments" (-888) codes.
 These percentages include SCCs for which emission factors have been developed and SCCs for which emission factor development is not
 required (see note a).
"Emission factors for fugitives cannot be developed until nationwide equipment counts become available for each chemical manufacturing industry
""Other" category includes numerous small categories  such as building construction,  electrical equipment, printing  and publishing,  and
 photographic equipment.

     M. B.  Stockton and J. H. E.  Stelling are with Radian Corporation, Research
     Triangle Park, CA 27709.
     J. David Mobley is the EPA Project Officer (see below).
     The complete report entitled "Criteria Pollutant Emission Factors for the 1985
     NAPAP Emissions Inventory," (Order No. PB 87-198 735/AS; Cost:  $24.95,
     subject to change)
     will be available only from:
             National Technical Information Service
             5285 Port Royal Road
             Springfield, VA22161
             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, NC 27711
United States
Environmental Protection
Center for Environmental Research
Cincinnati OH 45268
Official Business
Penalty for Private Use $300

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