EPA/600/i-92/006'
Residential Wood Combustion; Issues and
Emission Estimation Techniques
Robert C. McCrillis
Air and Energy Engineering Research Laboratory
and
Christopher S. Stoneman
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
and
Mark Saeger
Alliance Technologies Corporation
100 Europa Drive, Suite 150
Chapel Hill, NC 27514
ABSTRACT
Nonattainment areas for PM-10 (particulate matter nominally 10
micrometers or less in size) are required to submit State
Implementation Plans (SIP's) to the U.S. Environmental Protection
Agency (EPA) that include emission inventories for residential wood
combustion (RWC). The EPA also provides estimates of PM-10 emissions
on a county-by-county basis for a national database.
To improve RWC emission estimates, EPA will oversee three areas of
development: (1) EPA will issue emission factors (for inclusion in
Supplement D of AP-421) for wood stoves and fireplaces in fall 1991
that will reflect new test data and thus provide more accurate
estimates of RWC emissions—the emission factors will also be provided
for stoves certified to EPA's Phase I emission limits, and emission
factors for EPA-certified, Phase II stoves will be based on stove data
from actual Phase II stoves; (2) the Joint Emission Inventory
Oversight Group (JEIOG) at EPA will improve guidance for inventories
since existing guidance for the inventories is not adequate to meet
the demands of the amended Clean Air Act; and (3) the JEIOG will
develop a model for estimating RWC emissions for every U.S. county for
entry into EPA's national Area and Mobile Source Subsystem (AMS)
database.
INTRODUCTION
Wood smoke from residential wood burning is recognized as a serious
air quality problem. Approximately half of the 70 areas designated
nonattainment for PM-10 (particulate matter nominally 10 micrometers
or less size) by operation of law as of enactment of the 1990
amendments2 to the Clean Air Act (CAA) violated the PM-10 national
ambient air quality standards (NAAQS) due at least in part to wood
smoke. These and any additional areas redesignated to nonattainment
subsequent to enactment are required to submit State Implementation
Plans (SIP's) to EPA that demonstrate how the area will attain the PM-
10 NAAQS by the statutory deadline or that such attainment is
1
-------
impracticable. The SIP's will include emission inventories for all
sources that are causing the PM-10 violations.
The two most important factors affecting an accurate inventory of
the emissions impact of woodburning on an air shed are emission and
activity factors. This paper discusses the two main efforts underway
to address both of these areas: (1) it presents the revised
particulate and carbon'monoxide emission factor data base for wood
stoves and fireplaces to be published in Supplement D to AP-421 in
fall 1991, which are significant for several reasons and will provide
more accurate estimates of wood smoke emissions; and (2) it reviews
the current status of the two principal activities being performed
under the auspices of the Joint Emission Inventory Oversight Group
(JEIOG) to improve estimates of activity factors relating to
residential wood combustion (RWC): (a) guidance on the survey-based
approach to estimating wood burning activity in PM-10 nonattainment
areas will be improved for the PM-10 SIP emission inventories; and (b)
a model will be developed to enable EPA to estimate RWC activities
(and, thus, RWC PM-10 emissions) for any county in the U.S. to be
entered into EPA's national Area and Mobile Source Subsystem (AMS)
database, a subsystem of EPA's Aerometric Information Retrieval System
(AIRS), along with emissions estimates from the PM-10 nonattainment
areas.
BACKGROUND
The 70 areas in the U.S. designated nonattainment for PM-10 by
operation of law at enactment of the amendements to the CAA2 were also
classified as moderate (initial moderate areas). After enactment, EPA
was authorized to redesignate new areas as nonattainment for PM-10 on
the basis of air quality monitoring data showing a violation of the
PM-10 NAAQS. These new areas will also be classified initially as
moderate (additional moderate areas).
SIP's for the initial moderate areas are due by November 15, 1991,
and must demonstrate either attainment by the statutory deadline of
December 31, 1994, or that such attainment is impracticable. If in
its SIP an area cannot demonstrate attainment by the applicable date
or if it fails to actually attain, EPA must reclassify the area as
serious.
Attainment dates for serious areas are extended and in their SIP's
they must adopt best available control measures (BACM). The amended
CAA requires EPA to issue technical guidance for BACM by May 15, 1992.
The BACM guidance will provide information on what EPA regards as the
best measures available for the control of wood smoke from RWC and-a
methodology for implementing agencies to use to analyze the cost
effectiveness of the RWC measures described in the document.
Moderate and serious areas are required to submit emission
inventories with their SIP's for all PM-10 sources causing the
violations of the PM-10 NAAQS, including RWC activity. In 1989, EPA
2
-------
published guidance on how to prepare an emission inventory for RWC in
Appendix A of the Guidance Document for Residential Wood Combustion
Emission Control Measures .In the RWC guidance document/EPA
recognizes that measuring emissions directly from each RWC device is
impractical and, therefore, has recommended that household surveys be
used as the basis for estimating household wood consumption.
Emission inventories for the 70 initial moderate areas whose SIP's
are due November 15, 1991, were prepared using this and other more
general emission inventory guidance. However, the emissions
preparation guidance in Appendix A and the general guidance are not
adequate to meet the increased emission inventory needs of the PM-10
SIP program as required by the amended CAA as discussed below.
Improved and consolidated PM-10 emission inventory requirements and
preparation guidance are needed for additional moderate areas, as well
as for serious areas. Serious areas will be required to submit
revised emission inventories and meet reasonable further progress
requirements toward attainment that will necessitate emission
inventory revisions. For instance, the areas EPA must reclassify to
serious by December 31, 1991, will have draft revised emission
inventories^ due as early as December 1992 and be required to attain
the PM-10 air quality standards as expeditiously as practicable but no
later than December 31, 2001.
In addition, EPA also intends to develop national emission
estimates of PM-10 sources, including RWC. In addition to the need
for improving SIP emission inventory guidance, a methodology is needed
to estimate RWC emissions county-by-county across the U.S. to be
included in AMS of AIRS, which is expected to be fully operational by
late 1992.
DISCUSSION
Emission Factors
Revised AP-42 Emission Factors
To improve estimates of PM-10 emissions in nonattainment areas and
nationally, EPA is preparing a Supplement D update to AP-42, which
will be issued in fall 1991 and reflect additional data gathered on
wood stoves and fireplaces. The new wood stove particulate and carbon
monoxide (CO) emission factors will be based solely on the results of
field studies completed since 19854'5'6'7'8'9'10'11,12The
new fireplace particulate emission factors will be based on recent
field and laboratory studies. Neither polycyclic organic matter (POM)
and volatile organic compound (VOC) emission factors for woodstoves
and fireplaces nor CO emission factors for fireplaces only will be
changed since no new data have been generated. For the woodstove
subcategory a recent paper14 summarizes the field studies and the
correlations between the field and laboratory emissions sampling
equipment. Emission factors presented in the reference are superceded
3
-------
by those presented here. The final values for the woodstove and
fireplace particulate emission factors (PM-10) are presented in Table
I. Wood stove and fireplace CO emission factors are summarized in
Table II.
TABLE I. Woodstove and fireplace particulate emission factor (PM-10)
summary data in grams per kilogram dry wood burned Method
5H equivalent values.
Wood Burning Technology
Study Name Conventional Catalytic Noncatalytic Pellet
Av of all stoves 14.9
Av pre-Phase I stoves 14.9
Av Phase I stoves a
Av Phase II stoves
Av fireplace 10.8
a A blank space means no stoves i
9.7 9.3 1.9
11.6 12.3 1.9
9.4 9.5
7.7 7.0 1.9
that technology included in study.
TABLE II. Woodstove and fireplace CO emission factor summary data in
grams per dry kilogram wood burned.
Wood Burning Technology
Study Name Conventional Catalytic Noncatalytic Pellet
Av of all stoves 115.4
Av Phase I stoves a
Av Phase II stoves
Av fireplace 61.1
a A blank space means no stoves
52.4 70.4 19.7
52.2
53.5 70.4 19.7
that technology included in study.
The stoves included in each category depend on their certification
status. In Tables I and II, the stoves included in the "Phase I" and
"Phase II" categories are certified to EPA's Phase I and II
particulate emission limits, respectively. EPA established the Phase
I and II emission limits when it promulgated a new source performance
standard for residential wood heaters in early 198815. The
regulation requires new wood heaters manufactured after July lr 1988,
or sold after July 1, 1990, to meet the Phase I emission limits. New
wood heaters manufactured after July 1, 1990, or sold after July 1,
1992, are required to meet the more stringent Phase II emission
limits.
Stoves included in the "Pre-Phase I" category include units that
are certified to Oregon.Department of Environmental Quality's 1986 or
1988 particulate emission limits but not to EPA's Phase I or II
4
-------
limits. Lastly, stoves not certified to either EPA's or Oregon's
certification emission limits are included in the "Average of all
stoves" category under conventional wood burning technology.
The Phase I and II emission factors are significant because, for
the first time, EPA will be providing emission factors for Phase I
stoves, and the Phase II emission factors {the latest generation of
clean-burning stoves) are based on stove data from stoves that were
actually certified to Phase II emission limits before they were
tested.
Mood Stove Degradation
While the wood stove database has been substantially improved, the
issue of degradation has not been adequately addressed. The field
studies to date have attempted to identify degradation in emissions
performance over time. In most cases, however, the studies have
collected particulate emission samples for only a few months of stove
operation starting with a nearly new stove. In some cases7'16
substantial degradation has been measured indicating that applying the
same emission factor to any year of a stove's life may not produce an
accurate estimate of its PM-10 emissions. But the data on degradation
gathered to date constitute a relatively small subset of the total
database and are not available for current technology Phase II stoves.
Because degradation may be a substantial problem, EPA is initiating
a field study beginning this winter with other interested regulatory
and industry parties. The tentative plan is to retest to Phase II
stoves previously tested and measure their performance periodically.
Depending on the availability of funds, additional Phase II stoves
could be installed and monitored to further enlarge the database.
Additional Pellet Stove Data
In addition to the new emission factor data presented here, EPA. is
reviewing additional emissions test data on "exempt" pellet stoves
from a study sponsored by the Department of Energy performed last
winter17. An exempt wood heating device not subject to the
certification requirements of the wood heater new source performance
standard (NSPS) is any heater that does not meet all of the following
criteria: (1) air-to-fuel ratio averaging less than 35 to 1; (2)
firebox volume less than 20 cubic feet; (3) minimum burn rate less
than 5 kilograms per hour; and (4) maximum weight of less than
800 kilograms.
Many stoves that burn biomass pellets are not subject to the wood
heater NSPS because their air-to-fuel ratio exceeds 35 to 1. Since
pellet stoves seem to be inherently cleaner burning compared to
cordwood stoves, the field study last winter measured the in-house
performance of several exempt pellet stoves. These data will also be
included in the AP-42 update.
C,
-------
JEIOG RWC Activities
Under the auspices of JEIOG, EPA has initiated a study whose
purpose is to improve the quality of RWC emission estimates in both
SIP emission inventories and AMS. The study tasks, therefore,
include: (1) improvement of the existing RWOspecific emissions
inventory preparation guidance in Appendix A of the RWC guidance
document cited in Reference 4; and (2) development of a model to
estimate RWC wood consumption in any county in the U.S.
RWC SIP Emission Inventory Guidance
The enhanced Appendix A from the RWC guidance document will be used
by states producing SIP emission inventories for additional moderate
and serious PM-10 nonattainment areas. Its improvement is part of a
larger effort currently underway at EPA's Office of Air Quality
Planning and Standards to improve PM-10 emission inventory guidance
for all PM-10 source categories. The guidance produced under this
JEIOG task, therefore, will be integrated into overall PM-10 emission
inventory guidance due to be available in December 1991 to provide the
states with the information they need for planning, preparing, and
producing PM-10 emission inventories in their PM-10 SIP's. Emissions
estimates from PM-10 nonattainment areas will also be entered into AMS
Of AIRS.
Six areas of the existing guidance in Appendix A on preparing an
RWC SIP emission inventory are planned for improvement. Task 1 will
develop a model survey for use by agencies preparing emission
inventories to accurately ascertain the wood burning patterns of the
community. In PM-10 SIP's, such surveys have formed the basis of RWC
emission inventories, and under this task many have been gathered that
provide examples of the types of questions being asked and how the
surveys are being conducted. The information obtained from the
surveys gathered (described below under the "model" discussion) will
provide the basis for the model survey. Among other questions, the
model survey will contain questions enabling the emission inventory •
preparer to: (1) properly match wood stove and fireplace types to
emission factors, (2) determine the age of the stove population, and
(3) address serious area BACM guidance requirements, including cost
effectiveness analysis needs.
Task 2 will provide guidance on a statistical method for conducting
surveys and on the type of survey to conduct (e.g., telephone, mail,
door-to-door). Task 3 will provide a methodology for projecting RWC
emissions. Task 4 will identify factors specific to areas in the U.S.
that may influence wood smoke emissions. Task 5 will provide guidance
on how to calculate emission reduction credits. Task 6 will develop a
process for use of a screening model in nonattainment areas to
determine whether a more thorough, survey-based emission inventory is
necessary. The model (discussed in greater detail below) will be
developed using the survey data gathered, as well as any demographic
or other data obtainable from other sources.
6
-------
Model For Estimating County PM-10 Emissions
In addition to the need for improving SIP emission inventory
guidance, a methodology is needed to estimate RWC emissions county by
county across the U.S. for inclusion in AMS of AIRS. The second
purpose of this effort under JEIOG is, therefore, to create a model
for EPA to estimate RWC emission for every county in the U.S. for
which a SIP emission inventory is not available.
An analysis of existing residential wood use surveys has already
been conducted under this task to determine if the information
available from these surveys can be used to develop a model of
residential wood use. The surveys reviewed were obtained from many
states and are listed in Table III along with the survey types and
availability of results. In many cases, more than one survey was
obtained for the same locality. The additional surveys may have been
conducted in earlier years or by different agencies for the same area.
Some survey reports included results of wood combustion surveys
performed in other areas for comparison purposes. Table III also
lists a national survey conducted by the U.S. Consumer Product Safety
Commission (CPSC).
While most of the surveys reviewed were conducted to determine the
wood burning activity in a specific area,- some of the surveys were
conducted for other purposes but still included questions pertaining
to residential wood burning. The Fircrest/Edmonds survey assessed the
impact of an RWC public awareness campaign, while the Silver Valley,
Puget Power, Seattle City Light, Snohomish, Washington Water Power,
Pacific Power, and Tacoma City Light surveys generally targeted
residential energy use. The CPSC survey addressed consumer exposure
to the hazards of room heating equipment which included solid fuel
room heaters. In all, 45 surveys and results of earlier or
comparative surveys were reviewed in this study. The CPSC survey
results were not included in the initial study, but will be
incorporated in the development of the model.
Surveys are conducted by mail, telephone, or door-to-door.
Although all three methods are universally accepted as reliable, mail
surveys can be more extensive, provide higher respondent anonymity,
and cover more cases than either of the other two survey types.
Generally, household surveys include information on patterns of
combustion for residential heat, the types and quantities of wood
burned, and the types and numbers of residential wood burning devices
in use. The survey data were divided into five categories:
demographics," dwelling unit, wood burning device, and wood fuel
characteristics; and wood burning practices. While several data items
are routinely collected in most of the surveys, other information is
specific for only one or a few of the surveys. The CPSC survey
results are summarized by average annual usage by region and heating
device. Regional comparisons are based on census divisions and,
therefore, show national, rather than local or state, heater use
patterns.
7
-------
TABLE III. Residential wood burning surveys.
Survey area, State
Heating
season
Survey
type
Results
available ?
State of CA
1987
-------
The surveys reviewed generally asked questions predictive of
residential wood combustion activity, although at least three
important limitations were apparent: (1) individuals surveyed often
have different conceptions of what constitutes a cord of wood (the
dependence of the surveys on respondents' conceptions of cords burned
may be the weakest element of these surveys); (2), the vast majority
of the surveys do not specify the length or severity of a particular
heating season or when the heating season starts, making it difficult
to compare localities or activity estimates between winters for the
same survey area; and (3) although fuel loads and firebox sizes are
important parameters in estimating wood use (and consequently
emissions), very few surveys include questions on them.
A preliminary list of all of the data elements obtained from the
surveys that could be useful in the development of a model is shown in
Table IV. The data from each of the local area surveys were subjected
to a statistical test to determine which data elements were
representative of the sample of surveys. An indicator of the
statistical significance of each data element is also provided in
Table IV. Data elements from the CPSC survey were not included in the
statistical significance test, but will be used in developing the
final model.
As the model is developed, data parameters (e.g., percent of
surrounding land that is forested, heating degree days, typical size
of house heated) most predictive of household wood burning habits will
be selected as input. As candidate parameters, the model will include
any relevant parameters from the survey data gathered that are
statistically significant, as well as data from any other sources such
as the National Weather Service or U.S. Bureau of the Census.
CONCLUSIONS
This paper discusses the three efforts underway at EPA to improve
both components of a sound RWC emission inventory, the emission and
activity factors: (1) revised emission factors will be available this
fall that represent a significant improvement (especially for wood
stoves) over the current emission factors (although degradation has
not been adequately addressed, additional testing for this winter and
maybe beyond is slated to be performed to try and quantify emissions
degradation in EPA-certified stoves); (2) under JEIOG, a plan has been
developed for improving the existing RWC SIP emission inventory
guidance found principally in Appendix A of the RWC guidance cited in
Reference 4 (EPA intends to provide states with the guidance necessary
to meet the emission inventory challenges of the amended CAA); and (3)
the JEIOG is overseeing work to develop a model to enable EPA to
estimate RWC activity in counties other than those required to
complete an emission inventory to meet its SIP requirements under the
CAA (i.e., PM-10 nonattainment areas). Such activity estimates, along
with other data, will form the basis of RWC emissions estimates to be
entered into EPA's national AMS database, a subsystem of EPA's AIRS.
9
-------
TABLE IV. Important parameters in estimating wood use.
Parameter
Number of
observations
(a)
Statistical
significance
-------
REFERENCES
1. Compilation of Air Pollution Emission Factors Volume I:
Stationary Point and Area Sources, AP-42, Supplement C
(GPO 055-000-00369-6), September 1990.
2. 56 Federal Register 11101-11105, March 15, 1991 and 5 6
Federal Register 37654 - 37665, August 8, 1991.
3. Guidance Document for Residential Wood Combustion Emission
Control Measures, EPA-450/2-89-015, U.S. Environmental
Protection Agency, Research Triangle Park, 1989.
4. Burnet, P.G., The Northeast Cooperative Woodstove Study,
Volume I, EPA-600/7-87-026a, and Volume II - Technical
Appendix. EPA-600/7-87-026b (NTIS PB88-140769 and -140777,
respectively), U.S. Environmental Protection Agency,
November 1987.
5. Houck, J.E., C.A. Simons, P.G. Burnet, and R.G. Merrill, "A
System to Obtain Time Integrated Woodstove Emission
Samples," In Proceedings: 1986 EPA/APCA Symposium on
Measurement of Toxic Air Pollutants, Raleigh, NC, April
1986, EPA-600/9-86-013 (NTIS PB87-182713).
6. Simons, C.A.r P.D. Christiansen, L.C. Pritchett, and G.A.
Beyerman, Whitehorse Efficient Woodheat Demonstration,
Prepared for the City of Whitehorse, 2121 Second Ave,,
Whitehorse, Yukon, Canada, Y1A 1C2, September 1987.
7. Simons, C.A., P.D. Christiansen, J.E. Houck, and L.C.
Pritchett, Woodstove Emission Sampling Methods
Comparability Analysis and In-situ Evaluation of New
Technology Woodstoves, EPA-600/7-89-002 (NTIS DE89-
001551), U.S. Environmental Protection Agency, January
1989.
8. Barnett, S.G., Field Performance of Advanced Technology
Woodstoves in Glens Falls, NY, 1988-89, Volume I, EPA-
600/7-90-0l9a, and Volume II. Technical Appendices, EPA-
600/7-90-019b (NTIS PB91-125641 and -125658, respectively),
U.S. Environmental Protection Agency, October 1990.
9. Jaasma, D.R. and M.R. Champion, Field Performance of
Woodburning Stoves in Crested Butte During the 1988-8 9
Heating Season, Prepared for the Town of Crested Butte,
Crested Butte, CO, June 1989.
10. Jaasma, D.R., M. Gundappa, M.R. Champion, and R.C.
McCrillis, "Field Performance of Woodburning Stoves in
Crested Butte, Colorado," in Proceedings: 84th Annual
11
-------
Meeting, AWMA, Paper No. 91-130.1, Vancouver, B.C., June
1991.
11. Barnett, S. G., In-Home Evaluation of Emission
Characteristics of EPA-Certified High Technology Non-
Catalvtic Woodstoves in Klamath Falls, Oregon, 1990,
Prepared for the Canada Centre for Mineral and Energy
Technology, Energy Mines and Resources Canada, DSS File No.
14SQ.23440—9—9230, June 1, 1990.
12. Dernbach, S., Woodstove Field Performance in Klamath Falls,
Oregon, Prepared for the Wood Heating Alliance, April 18,
1990.
13. Barnett, S.G. and R.B. Roholt, In-Home Performance of
Certified Pellet Stoves in Medford and Klamath Falls,
Oregon, Prepared for the Department of Energy and the
Oregon Department of Environmental Quality, DOE/BP-04143-1,
August 1990.
14. McCrillis, R.C. and D.R. Jaasma, "Comparability Between
Various Field and Laboratory Woodstove Emission Measurement
Methods," In Proceedings; 84th Annual Meeting, AWMA, Paper
No. 91-64.6, Vancouver, B.C., June 1991.
15. 53 Federal Register 5860 - 5926, February 26, 1988.
16. Barnett, S.G. and J. Fesperman, Field Performance of
Advanced Technology Woodstoves in their Second Season of
Use in Glens Falls, New York, 1990, Prepared for the Canada
Centre for Mineral and Energy Technology, Energy Mines and
Resources Canada, DSS File No. 14SQ.23440-9-9012, August
16, 1990.
17. Barnett, S.G. and P.G. Fields, In-Home Performance of
Exempt Pellet Stoves in Medford, Oregon, Prepared for the
U.S. Department of Energy, Oregon Department of Energy,
Tennessee Valley Authority, and the Oregon Department of
Environmental Quality, DOE/BP-04143-1, August 1990.
12
-------
„r_ TECHNICAL REPORT DATA
A Jtii lixx L - ir_ o u 0 (Please read Instructions an the reverse before cotnple,' ~\
1. REPORT NO, 2.
EPA/600/'a92/00#
3{ PB92-139^35 I
t, I
J
4. TITLE AND SUBTITLE
Residential Wood Combustion; Issues and Emission
Estimation Techniques
g REPORT date
q PERPORMING ORGANIZATION CODE
?.author(s) McCrillis (EPA/AEERL), C. S. Stone-
man (EPA/OAQPS), and M, Saeger (Alliance)
8. PERFORMING ORGANIZATION REPORT NO.
9, PERFORMING ORGANIZATION NAME AND ADDRESS
Alliance Technologies Corporation
100 Europa Drive, Suite 150
Chapel Hill, North Carolina 27514
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D9-0173, Task 1-111
12. SPONSORING AGENCY NAME AND AODRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
13, TYPE OF REPORT AND PERIOD COVERED
Published paper; 9/91
14. SPONSORING AGENCY CODE
EPA/ 600/13
15. supplementary notes ^EERL project officer is Robert C. McCrillis, Mail Drop 61, 919
541-2733. Presented at AWMA/EPA Specialty Conference, Emission Inventory
TssiiRsHmthe 1990s. 9/9-12/91. Durham. NC.
- The paper discusses issues and emission estimation techniques for residen-
tial wood combustion (RWC). Nonattainment ar-eas for PM-10 (particulate matter
nominally 10 micrometers or less in size) are required to submit State Implementa-
tion Plans (SIPs) to the U. S. EPA that include emission inventories for RWC. The
EPA also provides estimates of PM-10 emissions on a county-by-county basis for a
national database. To improve RWC emission estimates, EPA will oversee three
areas of development; (l) EPA will issue emission factors (for inclusion in Supple-
ment D of EPA report AP-42) for woodstoves and fireplaces that will reflect new
test data and thus provide more accurate estimates of RWC emissions--the emission
factors will also be provided for stoves certified to EPA's Phase I emission limits,
and emission factors for EPA-certified Phase II stoves will be based on stove data
from actual Phase II stoves; (2) the Joint Emission Inventory Oversight Group
(JEIOG) at EPA will improve guidance for inventories since existing guidance for
the inventories is not adequate to meet the demands of the amended Clean Air Act;
and (3) the JEIOG will develop a model for estimating RWC emissions for every U. S.
county for entry into EPA's national Area and Mobile Source Subsystem (AMS) data-
base.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution Stoves
Wood Fireplaces
Combustion
Emission
Estimating
Inventories
Pollution Control
Stationary Sources
Woodstoves
Emission Factors
•13B 13 A
11L
21B
14G
15E
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report/
Unclassified
21. NO. OF PAGES
13
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (3-73)
------- |