United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 2771
Research and Development
EPA/600/S7-89/008 Dec. 1989
v>EPA Project Summary
Reranking of Area Sources in
Light of Seasonal/Regional
Emission Factors and
State/Local Needs
Sharon L. Kersteter
The Clean Air Act deadline for
attaining the national ambient air
quality standard (NAAQS) for ozone
was the end of 1987. The failure of 68
U.S. metropolitan areas to attain the
ozone standard by December 31,1987
was one of the major environmental
issues of 1988. Ozone is photo-
chemically produced in the atmos-
phere when volatile organic com-
pounds (VOCs) are mixed with
nitrogen oxides (NOX) and carbon
monoxide (CO) in the presence of
sunlight To develop and implement
an effective ozone control strategy,
information must be compiled and
reviewed on the sources of these
precursor pollutants.
Although substantial emission con-
trols have been placed on many
stationary point and mobile sources
and significant improvements have
been made, the ozone standard has
not been attained in many metro-
politan areas. Many area sources
have not yet had any controls applied
even though they are known to be a
substantial source of VOC emissions.
To determine the area source cate-
gories on which to place emission
controls, area sources must be evalu-
ated to identify those categories
where controls can be both effective
and feasible. Regional and seasonal
patterns of emissions should also be
investigated, as these characteristics
can influence the effectiveness of the
emission controls.
This project has been designed to
provide a better understanding of
area sources and their emissions, to
prioritize their importance as VOC
emitters, and to identify sources for
which better emission estimation
methodologies are needed. The
specific goals of this task are as
follows:
1. prioritize area sources, identifying
both seasonal and regional emis-
sion dependencies;
2. prioritize solvent categories for
future work, seasonally and
regionally, using tonnages;
3. identify factors affecting the vari-
ability of each area source cate-
gory; and
4. document inventory assumptions
and seasonal/regional factors and
discuss reliability, pointing out
the weakest and most important
assumptions.
This Project Summary was devel-
oped by EPA's Air and Energy Engi-
neering Research Laboratory, Re-
search 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).
Introduction
The goals listed above are designed to
build upon one another so that an
improved procedure and/or test case for
estimating emissions from a given area
source category can be developed. The
work outlined below (and discussed in
greater detail in the full report) leads up
to that point.
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Area Source Prioritization
Area sources are ranked from highest
emissions contributors to lowest for EPA
Regions 1, 2, 6, and 9 on both an annual
and seasonal basis (summer, or ozone
season, emissions). Two sets of seasonal
factors, one from the National Acid
Precipitation Assessment Program
(NAPAP) methodology and one from the
Regional Oxidant Modeling for Northeast
Transport (ROMNET) process, are used.
Rankings are compared within states and
between states and regions. Annual and
summer emissions for Region 9 are
shown in Figures 1 and 2, respectively.
The National Emissions Data System
(NEDS) Evaporative Loss—Solvents Pur-
chased category (SCC 053) is disaggre-
gated into the NAPAP solvent categories
078 through 101 and reported by State
and Regional totals for EPA Regions 1, 2,
6, and 9. The solvent categories are
identified in Table 1. These categories are
ranked from high to low with respect to
annual emissions and are reranked in light
of seasonal variations using ROMNET and
NAPAP seasonal adjustment factors. Data
for Region 9 are shown in Table 2 and in
Figures 3 and 4.
Table 1. NAPAP Area Source Solvent
Categories
SCC Category Description
078 Degreasing
079 Dry Cleaning
080 Graphic Arts/Printing
081 Rubber and Plastics
Manufacturing
082 Architectural Coatings
083 Auto Body Repair
084 Motor Vehicle Manufacture
085 Paper Coating
086 Fabricated Metals
087 Machinery Manufacturing
088 Furniture Manufacturing
089 Flat Wood Products
090 Other Transportation
Equipment Manufacturing
091 Electrical Equipment
Manufacturing
092 Shipbuilding and Repair
093 Miscellaneous Surface Coating
095 Miscellaneous Solvent Use
Validity of Results
NEDS/NAPAP-generated emission esti-
mates for four counties in Texas are
compared to estimates generated in an
Fuel Combustion-
Pesidential-Wood (8.3%)
Evaporative Loss-
Solvents Purchased (49.7%)
Figure 1. Percent of nonmobile area source categories —Region 9.
emissions trends analysis for the same
four counties using EPA ozone precursor
methodologies. The "top-down" proced-
ures used by NEDS/NAPAP are com-
pared with the "bottom-up" EPA ozone
precursor procedures for the categories
where the emissions estimates differed
significantly.
Rankings using NAPAP seasonal
(summer) adjustment factors are com-
pared to rankings using ROMNET sea-
sonal adjustment factors. ROMNET sea-
sonal adjustment factors have been
developed for the following categories:
pleasure boating/ gasoline vessels (SCC
052); gasoline service stations (SCC
054); trade paints/ architectural surface
coatings (SCC 082); pesticides (SCC
094); bulk gas terminals (SCC 103); and
hazardous waste treatment, storage, and
disposal facilities (SCC 109). These
factors are substituted for NAPAP sea-
sonal adjustment factors (where
appropriate) and emissions are recal-
culated for the area source categories
affected. The solvent categories are
reranked using the ROMNET factors to
identify their effects.
The bases for the development of the
NAPAP and ROMNET seasonal adjust-
ment factors are reviewed and com-
pared. Several "bottom-up" methodolo-
gies, are discussed.
Evaluation of Three Area
Source Solvent Categories
The identification and discussion of the
basis for the NAPAP solvent allocation
methodology and emission estimates for
three NAPAP solvent categories, (SCC
082-Architectural Coatings, SCC 093-
Miscellaneous Surface Coatings, and
SCC 095—Miscellaneous Solvent Use)
are outlined. The original algorithm used
in the NAPAP methodology and recent
updates to the methodology are dis-
cussed.
Conclusions and
Recommendations
• Among States and Regions, the
ranking of area source categories
based on annual emissions consis-(
tently shows the evaporative loss
categories (Solvents Purchased and
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.—^Fuel Combustion-Residential-Wood (1.2%)
Evaporative Loss-
Gasoline Marketed (12 8%)
Evaporative Loss-
Solvents Purchased (60.4%)
Figure 2. Percent of summer emissions for top nonmobile area source categories—Region 9.
Gasoline Marketed) and Residential
Wood Combustion to be the top three
categories. Adjustment for the ozone
season results in a drop in the ranking
of Residential Wood Combustion,
however, the evaporative loss cate-
gories still show the highest rankings
overall.
Further breakdown of the Solvents
Purchased category shows that Misc-
ellaneous Solvent Use and Miscellan-
eous Surface Coatings rank first and
second, respectively, for most states
and regions covered in this study.
These rankings remain the same for
both annual and ozone season emis-
sions. In fact, seasonal adjustments to
the annual emissions result in almost
no change in the rankings of solvent
categories for all states and regions.
Comparisons of different methodol-
ogies used to estimate emissions
from certain area sources show that
results of the different methodologies
can vary drastically. In general, the
use of local data to estimate
emissions through "bottom-up" meth-
odologies provides more accurate and
reliable data than the use of State or
national data allocated to the county
or local area ("top-down" methodol-
ogies). "Bottom-up" methodologies,
however, often require greater re-
sources, both in terms of time and
money, than "top-down" method-
ologies.
Use of seasonal adjustment factors
shows changes in ranking from the
annual rankings of some categories.
While actual tonnages may differ, use
of two different groups of seasonal
adjustment factors, NAPAP and
ROMNET, result in the same seasonal
rankings in almost all cases. The
availability of additional ROMNET
seasonal adjustment factors may
cause minor differences in seasonal
rankings, compared to the NAPAP
rankings.
A review ol NEDS/NAPAP source
methodologies and comparison with
bottom-up methodologies could be
used by state and local inventorying
agencies. These would include identi-
fication and resolution of variations in
the emission estimates between these
two inventory sources. Feasible and
effective control measures to reduce
emissions can not be applied effec-
tively to the area source categories if
the estimated emissions from the
categories are misrepresented by
either overestimation or underesti-
mation.
The Miscellaneous Solvent Use cate-
gory (SCC 095), especially the
Commercial/Consumer Solvent Use
portion of this category, requires fur-
ther disaggregation, with emphasis on
how the solvents are apportioned to
the various subcategories and on what
can be done to improve this process.
For maximum value, NAPAP meth-
odology for the 1990 NAPAP inven-
tory should be updated periodically.
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Table 2. Top Area Source Categories-Region 9
Arizona
California
oiaie > -
Ranking
1
2
3
4
5
6
7
Total Area Source VOC
(Excluding Hwy. Mobile
Hwy. Mobile Sources
Total State Area Source
Ranking
1
2
3
4
5
6
7
Total Area Source VOC
(Excluding Hwy. Mobile
Hwy. Mobile Sources
Source Category %
(Tons')
Evap. Loss Solv. Purch.
50,901
Evap. Loss Gas Mkted
14,618
Fuel Comb. Res. Wood
14,486
Managed Burning
8,645
Gas Off Hwy. Veh.
6,058
Res. On-Site Incn.
5,329
Cutback Asphalt
5,280
123,934
Sources)
88,700
VOC 212,634
Nevada
Source Category %
(Tons')
Evap. Loss Solv. Purch.
13,741
Fuel Comb. Res. Wood
6,652
Evap Loss Gas Mkted
4,682
Railroad Locomotives
1,815
Gas Off Hwy. Veh.
1,748
Cutback Asphalt
1,606
Vessels — Gasoline
1,481
37,932
Sources)
32,808
Nonhwy
VOC
41.1
11.8
11.7
7.0
4.9
4.3
4.3
(85.0)
100.0
-
-
Nonhwy
VOC
36.2
17.5
12.3
4.8
4.6
4.2
3.9
(83.6)
100.0
-
Total State Area Source VOC 70,740 -
% Total Area
Source VOC
23.9
6.9
6.8
4.1
2.8
2.5
2.5
(49.5)
58.3
41.7
100.0
% Total Area
Source VOC
19.4
9.4
6.6
2.6
2.5
2.3
2.1
(44.8)
53.6
46.4
100.0
Source Category %
(Tons)
Evap. Loss Solv. Purch.
526,525
Evap. Loss Gas Mkted
107,951
Fuel Comb. Res. Wood
77,013
Res. On-Site Incn.
59,899
Gas Off Hwy. Veh.
54,905
Forest Wildfires
42,541
Vessels-Gasoline
26,934
1,026,855
666,314
1,693,169
Region
Source Category %
(Tons)
Evap. Loss Solv. Purch.
591,167
Evap. Loss Gas Mkted
127,251
Fuel Comb. Res. Wood
98,151
Res. On-Site Incn.
66,694
Gas Off Hwy. Veh.
62,710
Forest Wildfires
44,014
Vessels — Gasoline
32,750
1.188,722
787,823
1,976,545
Nonhwy
VOC
51.3
10.5
7.5
5.8
5.3
4.1
2.6
(87.2)
100.0
-
-
IX
Nonhwy
VOC
49.7
10.7
8.3
5.6
5.3
3.7
2.8
(86.0)
100.0
-
—
% Total Area
Source VOC
31.1
6.4
4.5
3.5
3.2
2.5
1.6
(52.9)
60.6
39.4
100.0
% Total Area
Source VOC
29.9
6.4
50
3.4
3.2
2.2
1.7
(51.7)
60.1
39.9
100.0
"1 ton = 0.907 tonne
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Miscellaneous Solvent
Use (36.2%)
Degreasing (8 4%)
Auto Body (9.5%)
Miscellaneous Surface
Coating (11.6%)
Architectural
Coatings (10.0%)
Figure 3. Solvent category emissions—Region 9.
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Flat Wood Products (0.3%)
Motor Vehicle Manufacturing (0.3%)
Electrical Equipment Mfg. (0.4%) •
Other Transportation Equipment (0.2%)
Shipbuilding and Repair (0.1%)
Figure 4. Solvent "others" category emissions—Region 9.
U.S. GOVERNMENT PRINTING OFFICE: 1989/748-012/
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Sharon L Kersteter is with Alliance Technologies Corp., Chapel Hill, NC 27514.
Michael Kosusko is the EPA Project Officer (see below).
The complete report, entitled "Reranking of Area Sources in Light of
Seasonal/Regional Emission Factors and State/Local Needs," (Order No. PB 90-
110 115/AS; Cost: $23.00, 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, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S7-89/008
pSSfBCTIOi
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