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KWJ
*1 PRO^^
Profile of the 2011 National Air Emissions
Inventory
-------
-------
EPA-454/R-19-007
April 2014
Profile of the 2011 National Air Emissions Inventory
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, NC
-------
Profile of the 2011 National Air Emissions Inventory
U.S. EPA 2011 NEI Version 1.0
Office of Air Quality Planning & Standards
Emissions Inventory & Analysis Group
April 2014
Acknowledgements
EIAG Data Analysis Team and NEI Team
-------
This report is an overview of the air pollutant emissions
in the 2011 National Emissions Inventory (NEI) Version
1.01 (vl) (2011 NEI vl) published by the U.S.
Environmental Protection Agency (EPA) in July 2013. The
pollutants included in the NEI are the pollutants related
to implementation of the National Ambient Air Quality
Standards (NAAQS), known as criteria air pollutants
(CAPs), as well as hazardous air pollutants (HAPs)
associated with EPA's Air Toxics Program. The CAPs have
ambient concentration limits from the NAAQS program.
These pollutants include lead (Pb), carbon monoxide
(CO), nitrogen oxide (NOx), sulfur dioxide (SO2),
particulate matter 10 microns in diameter or less (PM10)
and particulate matter 2.5 microns in diameter or less
(PM2.5). Precursors to CAPs include volatile organic
compounds (VOCs), SO2, ammonia (NH3), and nitrogen
oxide (NOx) emissions. The HAP pollutants include the
187 remaining HAP pollutants from the original 189 listed
in Section 112(b) of the 1990 Clean Air Act Amendments2.
In this report, we will be presenting information on CAPs,
HAPs, and precursors.
The NEI is developed every three years, i.e., 2005, 2008,
2011, etc. This overview of the 2011 NEI applies the
concepts developed in the 2008 NEI Report3 as well as
many of the graphics and tables contained in that report.
In some cases, 2011 data are compared to figures in the
2008 Report. A process is underway to update the 2011
NEI vl to version 2.0 (v2), with v2 expected to be
released in the fall of 2014. In this overview, emission
profiles are presented for most of the CAPs and
precursors, black carbon (which is a component of
particulate matter), and for some specific HAPs that
2
account for a large portion of the nationwide cancer or
non-cancer risks4 as well as contribute to the formation
of ozone or fine particulate matter.
The information presented here about the 2011 NEI vl
includes the following:
• Key emissions source contributions
• National and state emissions trends
• National emissions density maps
• Emission differences between 2008 and 2011 ("2011"
will pertain to the 2011 NEI vl throughout report)—it
should be noted that methods changes contribute to
some of the noted emission changes from 2008 to
2011. These will be appropriately noted in this report
for affected sectors.
• Distribution of emissions by climate region
To keep the amount of materials associated with this
report at the level of an overview, graphical summaries
are provided for some, but not all, pollutants. Some
detailed tabular emissions summaries associated with a
graphic are not included in this overview document.
Such additional materials are available by request, and
readers who would like additional information
associated with a given graphic or analysis are
encouraged to contact the Emissions Inventory and
Analysis Group, Data Analysis Team at
info.chief(S)epa.gov.
-------
1. 2011 NEI Version 1 (vl): Emissions data and documentation
2. 1990 Clean Air Act Amendments (CAA)
3. 2008 National Emissions Inventory: Review. Analysis and Highlights
4. U.S. EPA National Air Toxics Assessment 2005
(Remainder of page left intentionally blank)
3
-------
4
Table 1: Total Emissions all Sectors 2008 NEI v35 vs 2011 NEI vl
Pollutant
Anthropogenic, xlOOO Tons
(Man-made)
Biogenic, xlOOO Tons
(Natural)
Total, xlOOO Tons6
% Reduction in 2011 Total
compared to 2008 Total
2008
2011
2008
2011
2008
2011
CO
79,655
75,760
6,474
6,528
86,129
82,288
4
nh3
4,359
4,316
NA
NA
4,359
4,316
1
NOx
16,909
14,574
1,078
1,018
17,987
15,592
13
PMio
21,580
20,907
NA
NA
21,580
20,907
3
PM2.5
6,014
6,306
NA
NA
6,014
6,306
-5
S02
10,324
6,557
NA
NA
10,324
6,557
42
VOCs
17,759
18,169
38,909
39,653
56,668
57,822
-2
Pb
0.95
0.80
NA
NA
0.95
0.80
16
Total HAPs
2,749
3,643
5,000
5,101
7,749
8,744
-13
• Table 1 summarizes total emissions (all source sectors included) in the 2011 NEI vl as compared with 2008 NEI v3.
• CO, NOx and VOC are emitted in the greatest amounts in 2008 and 2011.
• The greatest percent reductions from 2008 to 2011 have occurred in SO2, NOx, and Pb emissions. The increases in PM2.5,
VOCs, and HAPs are covered later in Figures 3 and 4.
• Only CO, VOC, NOx and total HAPs have a biogenic emissions component. Most of the biogenic HAP emissions consist of
formaldehyde, methanol, and acetaldehyde. The 13% increase in total HAPs from 2008 to 2011 reflects all HAPs,
including biogenic HAP and non-VOC, non-PM HAPs, and is caused mainly by an increase in fire activity.
• Pb, total HAPs and NOx emissions occur more commonly (greater than 65%) in urban than rural areas7. VOCs, SO2, and CO
emissions are also more prevalent in urban than rural areas (greater than 55%). All of the other pollutants, including PM
and NH3 occur more commonly in rural areas, though the PM urban/rural percentages are closer to 50:50.
5. 2008 NEI v3 represents EPA's final inventory for the year 2008
6. Total Emissions sum includes continental U.S., Alaska, Hawaii, all territories, tribal lands, and excludes off-shore areas of federal waters.
7. As defined in the CAA. urban and rural definitions based on population density in a given county
-------
Figure 1: National CAP Emission Trends, 2002-2013 (no Wildfires)
100,000
30,000
to
c
o
1-
~o
25,000
c
(T5
tO
3
o
-C
1-
20,000
to
c
o
'to
to
E
15,000
LU
o
u
bfl 10,000
c
73
3
i_>
X
5,000
Q_
<
u
0
More information on Trends can be found at:
http/www.epa.gov/ttn/chief/trends/idex.html
SO-
PM
2.5
NH,
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
90,000
80,000
70,000
60,000
50/100
40,000
30,000
20,000
10,000
0
W
e
.©
CD
u
in
£
O
w
lA
8
Percent Reduction from
Percent Reduction from
Percent Reduction from
Pollutant
2008-2011
2009-2013
2002-2013
CO
9
4
33
nh3
2
2
-8
NOx
14
18
46
PMio
4
3
4
PM2.5
-0.5
0.5
-7
S02
37
44
66
Anthropogenic VOCs
0.4
3
15
-------
6
• Figure 1 shows national CAP emission trends8 from 2002 to 2013. Note that these emission totals differ slightly from the
emission totals in Table 1 because wildfire emissions are included in Table 1 but not in Figure 1.
• The shaded area after 2011 indicates that specific NEI data are not available for 2012-2013 except for power plant data
and mobile sources. 2011 emissions values for all other sectors are used for 2012 and 2013 in the figure.
• From 2002 to 2013, all pollutants other than NH3 and PM show decreases greater than 10%. The slight increase in NH3 is
partly due to a methods change between the years 2005 and 2008 for prescribed fires and the addition of waste disposal
emissions in the 2008 NEI for municipal and commercial composting. The small increase noted in PM2.5 is mostly due to
methods change for fires and increased dust emissions.
• SO2 and NOx show the largest decreases from 2002 to 2013: 66% and 46%, respectively.
• The table shows that decreases in PM2.5, VOC, CO, and NH3 are lower from 2008-2011 and 2009-2013 than for the entire
12 years.
8. U.S. National CAP Emission Trends include explanation of the data sources, method for developing trends, and description of the 'Tier' emissions categories.
-------
Figure 2: Sector-based National CAP Trends 2002-2013
Stationary Fuel Combustion
2002
2003 2004 9nn=
2005 2006 onn7 —
2007 2008 9nnq
2009 2010 9ni1
2011 2012 2013
Industrial Processes
Highway Vehicles
£ 60000
§ 50000
1 40000
30000
.2 20000
CO
10000
'£
LU
Q_
<
O
20032004 2oo5
2007 2008 2009
20092010 2011 «ni7
2012 2013
Miscellaneous excluding WildFires
2002 2003onn4 ^
2004 2005 2006 2007 onno —^5*
2008 2009 2010 2Q11
2011 2012 2013
Nonroad Mobile
'2007200820092oio
2011
2012
2013
S02
NOx
1PM2.5
VOCs
NH3
CO
|PM10
See footnote 10 (next page) for a detailed listing of sectors included in "Miscellaneous" Category
-------
8
• Figure 2 shows the national emissions data from Figure 1 by five major source Tier9 categories.
• CO emissions are largest for the mobile sources, which drive the overall CO reductions.
• There are large amounts of NOx emissions for stationary fuel combustion and mobile source sectors, and the overall reductions
are driven by both these sectors.
• SO2 emissions are largest for the fuel combustion sector and for electric generating utilities in particular.
• Miscellaneous sectors10 show uneven changes, in part due to changes in estimation methods for some of the sources included,
e.g., prescribed fires. Prescribed fires contribute to the increase in CO emissions in 2007 and then decrease in 2008.
• Mobile sources highway vehicles and nonroad mobile emissions are based on use of a consistent version of the EPA's emissions
estimation model "MOVES" (2010b) for on-road emissions and "NONROAD" (2008) for nonroad emissions11. The 2011 NEI v2
is expected to switch to the MOVES2014 model.
• After 2011, the Electric-Utility Generation sector (EGUs) emissions (within the stationary fuel combustion sector) and mobile
source emissions show a decrease based on available year-specific data for 2012 and 2013. Other Tiers show no changes after
2011 (beyond 2011, these Tiers use constant emissions due to lack of year-specific emissions).
9. The five "Tier" categories shown in Figure 2 are aggregated from the 13 Tier categories described in the national air emissions trends page
10. A detailed listing of sectors included in "Miscellaneous" are outlined in the 2008 NEI Report (Page 12, Table 3—last column)
11. More information on mobile source emissions models
-------
Figure 3: State Trends of CAP Emissions
Mote: Percent change shown on maps does not equal magnitude of emissions (see Table 2}
NOx Emissions Percent Change by State
For Recent NEI Years - 2008, 2011 and 10 Year Period
Source: U.S. EPA National / State Air Emission Trends
CO Emissions Percent Change by State
For Recent NEI Years - 2008, 2011 and 10 Year Period
Emissions exclude forest wildfires and biogenics
Arrows
-Left- - Right -
2008 to 2011 2002 to 2013
Percent Change
(+) c-)
^^^>250
^^100-250
4—f
i 0-25 *
9
S02 Emissions Percent Change by State
For Recent NEI Years - 2008, 2011 and 10 Year Period
Emissions exclude forest wildfires and biogenics
Source: U.S. EPA National / State Air Emission Trends
Source: U.S. EPA National / State Air Emission Trends
VOC Emissions Percent Change by State
For Recent NEI Years - 2008, 2011 and 10 Year Period
Emissions exclude forest wildfires and biogenics
-------
10
Arrows
- L eft - - Right -
2008 to 2011 2002 to 2013
Percent Change
(+) (-)
>250
^^100-250
4 f
25-50 -f
~ 0-25 *
-------
11
• Building on Table 1 and Figure 2, the maps in Figure 3 describe the difference in state CAP emissions as the percent change between the two recent NEIs - the
2008 v3 and the 2011 vl; and the percent change over the last 10 years, during the period 2002-2013. The brown (up) arrows are emissions increases and the
blue (down) arrows are emission decreases. The size of the arrow describes the amount of the percent change in emissions that occurred, a larger arrow
means a larger percent change in emissions during the noted time period; a smaller arrow indicates a smaller percent change. The percent change does not
describe the magnitude of the emissions. For instance, there are some cases where a large percent change refers to a relatively small emissions magnitude.
• While there may be an overall decrease in pollutant emissions at the national level, some states experience emission increases over time. The states listed in
the Table 2 below have some of the larger percent emission increases for specific pollutants, mostly over the 10-year time period, and also several increases
over the time period for the recent NEIs 2008 and 2011, particularly for VOC and CO. The table corresponds to the pollutant maps and details the predominant
sector(s) that drive the emissions increase in the states with the larger percent increases in emissions. The reasons for these increases can include not only
actual increases, but also methods changes. Such issues may be considered when assessing the potential impacts on air quality.
Table 2: Sectors with Emission Increases
Sector
Pollutant
States with increases
NOx
VOC
so2
CO
NHs
PM2.5
PMio
agriculture livestock operations
s
CA, HI (very small emissions), LA, MT, ND, SD, WY
chemical manufacturing
s
LA
commercial marine vessels
s
AK
consumer commercial solvent use
s
KS
dust - agriculture operations
s
s
PM2.5: AR, MS, SD; PM10: AR, LA, MS
dust - roads
s
s
PM2.5: AR, MS, SD; PM10: AR, LA, MS, UT
fertilizer application
s
CA, HI (very small emissions), LA, MT, ND, SD, WY
fires - agricultural burning
s
s
VOC, SO2, PM2.5, CO: SD; CO: AK, ND
fires - prescribed
s
s
s
s
s
s
s
NOx: KS
(Note: method changes in
VOC: AK, AR, CO, KS, LA, MT, ND, NM, SD, UT, WY
estimating agricultural fire and
SO2: SD, OR
prescribed fire emissions occurred
CO: AK, ND, SD, WY
in going from 2008 to 2011)
NHs: AK, LA
PM2.5: AR, LA, MS, SD; PM10: AR, LA
fuel combustion EGU oil
s
s
NOx: HI; S02: OR
fuel comb industrial boilers oil
s
s
NOx: LA; S02: OR
fuel comb indust boilers natural gas
s
OK
fuel comb indust boilers biomass
s
s
S02: OR; PM2.5, PM10: LA
fuel comb residential other nat gas
s
AK (very small emissions)
highway vehicles heavy duty diesel
s
ID
oil & gas production*
s
s
s
NOx: CO, KS, LA, NM, OK
(Note: improved reporting in 2011)
VOC: AK, AR, CO, KS, LA, MT, ND, NM, UT
CO: MT, ND
stone quarrying/ mining
s
LA
waste disposal & recycling compost
s
CA
Oil and gas emissions are based on state-submitted point and nonpoint data as well as data from an EPA oil and gas emissions estimation tool.
More information on the data and tool is available in the 2011 NEI documentation
-------
12
Figure 4: National Select HAP Trends, 2005-2011
National Emissions - Select HAPs
Changes in Sector Emissions Between 2005, 2008, and 2011
National areas excluded are PR, VI, Tribal lands, federal waters; Sectors exclude Biogenics; Wildfires and Prescribed Burning are included
EPA Data Sources: NATA 2005, NEI 2008 v3, NEI 2011vl/2
300
250
200
150
100
Tons xlO3
50
2005 - first bar
2008 - middle bar
2011 - last bar
2005
2011
2008
2005-
J
i Tetrachloroethylene
i Formaldehyde
Ethyl Benzene
i Coke Oven
I Chromium (VI)
Benzene
I Arsenic
i Acrolein
Acetaldehyde
1,4-Dichlorobenzene
1,3-Butadiene
ll
Vt®3
,
ir
<.c
O*
?se
S°
¥
• For the select HAPs shown, many of the
largest emission increases going from
2005 to 2011 are driven by fires. In the
case of prescribed and wildfires, 2008 and
2011 were more active seasons than 2005.
The 2011 emissions for agriculture burning
are from the draft 2011 NEI v2 which
corrects overestimated emissions for
many Midwestern states in vl of the 2011
NEI.
• The small emission increase in 2011 for
the fuel combustion sectors is mostly for
formaldehyde and acetaldehyde from
residential wood combustion.
• The 2011 emissions for the solvents sector
are from the draft 2011 NEI v2 to illustrate
some known HAP corrections, including
for tetrachloroethylene from drycleaning.
• All of these HAP emissions have decreased
over the time period for the mobile source
sectors.
• Solvent emissions are included in
"industrial" sector in Figure 2.
-------
Figure 5: National CAP Emission Differences between 2008 and 2011, a closer look
13
Sector Emissions CAPs
Amount of Difference Between Years 2008 and 2011
2011-2008
Data Source: US EPA NEI 2008v3, 2011vl/v2
NH3
NOX
PM2.5
S02
VOC
(4,500)
i Miscellaneous
-14%
-1%
-2%
-1%
-38%
¦
1
(10,000)
Nonroad Mobile
Fuel Combustion olndust Processes
Emissions sectors exclude Biogenics, Wildfires; Prescribed Fires are included in Miscellaneous.
Geographic coverage includes PR, VI, federal waters; excludes Tribal.
Highway Vehicle
Wildfire Emissions CAPs
Amount of Difference Between Years 2008 and 2011
2011 - 2008
NH3 NOX PM2.5 S02 VOC CO
Geographic coverage includes PR, VI; excludes Tribal.
The difference in CAP emissions between 2008 and 2011 are shown for five major source sectors12. The chart on the left shows all
sectors other than wildfires, while the chart on the right shows just wildfires. While emissions increased in 2011 from 2008 for
some sectors, overall emissions are still lower in 2011 than in 2008. Corrected values from the draft 2011 v2 are used for
agriculture field burning (in Miscellaneous) and for solvent sectors (in Industrial Processes).
• Nationally, emission increases in 2011 occur in the following sectors:
o Miscellaneous—Waste disposal (CO); prescribed fires (CO, VOC)
o Fuel Combustion—residential wood burning (CO, VOC)
o Industrial Processes—oil and gas production (CO, VOC, NOx)13
• In general, CAP decreases in 2011 are due to mobile sources and coal combustion, and emission increases are largely
attributable to fires and the oil and gas production sector.
• The chart on the right shows emissions from wildfires to be somewhat higher in 2011 compared to 2008, due to higher fire
activity in 2011. Note that the CO bar reflects CO emissions divided by 5.
12. A description of the type of sources included in these major sectors, i.e.,Sectors_7, is found in the 2008 NEI Report, page 12
-------
14
Figure 6: Closer Look at National NOx and S02 differences between 2008 and 2011
NOx: 18 to 15.6 million tons decrease
SO2: 10.3 to 6.6 million tons decrease
Oil & Gas
Fires
EGUs
Non-EGU Fuel
Other industrial
Nonroad
Onroad
Biogenic (Soil)
172 K ton increase
0 2 4 6
Million tons NOx/year
8
2008 2011
Fires
EGUs
Non-EGU Fuel
Industrial
Commercial
Marine
1
79
K ton
ncrea
se
¦
¦
0 2 4 6 8
Million tons S02/year
10
• NOx and SO2 have shown the most decrease from 2008 to 2011.
• Much of the SO2 emissions decreases are a result of emission reductions in the EGU sector, a very small increase is noted
for fires.
• Mobile sources and EGUs account for much of the NOx decreases from 2008 to 2011. The increase in NOx from 2008 to
2011 is from the Oil & Gas and Fires sectors13.
13. Oil and gas emissions are based on state-submitted point and nonpoint data as well as data from an EPA oil and gas emissions estimation tool. More information on the data
and tool is available in the 2011 NEI documentation
-------
Figure 7: 2011 NEI CAP Emissions
15
Density Maps (Tons/Sq. ML), no prescribed burning or wildfires
NHa
¦fkk *
hi p a
-------
16
• These maps show 2011 CAP emissions at a county level using an emissions density metric.
• County-specific emissions density is defined as: emissions in Tons/square-mile.
• With fire emissions omitted from the analysis, most of the CAP emissions are concentrated on the East Coast
and in major urban areas. They compare well to similar maps generated using 2008 data14
• While some of these CAPs are more concentrated in urban areas (CO, NOx, VOCs), others are more
prominent in rural areas (NH3) and others are split evenly (PM2.5).
• PM10 is not shown, but its spatial pattern is very similar to the PM2.5 map.
14. 2008 NEI Report. Figures 13-14, page 19
-------
Figure 8: Acrolein Emission Density Maps, 2011 NEI vl
17
Acrolein Emissions (all sectors)
I
I
0.017
0.016
0.015
0.014
0.013
0.012
0.012
0.011 a.
9.80e-03 E
8.91G-03
8.02e-03 g
7.13e-03 S
6.24e-03
5.34e-03
4.45e-03
3.56e-03
2.67e-03
1.78e-03
8.91e-04
0.056
0.053
0.050
0.047
0.044
0.041
0.038
0.035 a,
0.032 E
cr
0.029 £
0.026 g
0.023 s
0.020
0.018
0.015
0.012
8.78e-03
5.85e-03
2.93e-03
• These maps provide examples of HAP emission
density (tons/year/sq mile) for acrolein (Figure 8)
and benzene (Figure 9).
• While these sample maps describe the national
and regional patterns of HAP emission
distributions in the 2011 NEI vl, they do not assess
or predict the absolute risks to human health and
ecosystems that may be associated with the
presence of any of these specific air pollutants.
Rather, they focus on the intensity of emission
releases.
• The top map excludes fires (wild, prescribed and
agricultural). The bottom map shows emissions
when these large fires are included.
• Fires are a significant contributor to acrolein
emissions. The bottom map indicates a higher
magnitude of emissions when fires are included.
Including fires also changes the spatial pattern -
highlighting the western U.S. where many large
wildfires occurred in 2011 and in the southeast as
well as for some of the middle states where many
prescribed fires occurred in 2011.
-------
Figure 9: Benzene Emission Density Maps, 2011 NEI vl
18
Benzene Emissions (no fires)
I
0.382
0.362
0.342
0.322
0.302
0.282
0.262
0.241
Si
0.221
I
0.201
I
x
0.181
H
£-
0.161
o
0.141
0.121
0.101
0.080
0.060
0.040
0.020
Fires are also a significant contributor to benzene
emissions. The bottom map in Figure 9 indicates a
higher magnitude of emissions when fires are
included. Including fires also changes the spatial
pattern - highlighting the western U.S. where
many large wildfires occurred in 2011 and in the
southeast as well as for some of the middle states
where many prescribed fires occurred in 2011.
Urban areas are seen to have higher emission
densities as mobile sources and some industrial
processes are also important contributors to
benzene emissions.
Other HAP density maps are available upon
request. See Page 2 of this report for contact
information.
Benzene Emissions (all sectors)
?Pi leg (NAtA.1 cou"tY total toy CQUT'SV *u VKtQry inc'yjinq Wh* PQOut-UnC Iw
-------
19
Figure 10: Wild, Prescribed and Agricultural Fires in the 2011 NEI
2500
£
° 2000
O
o
o
1500
c
o
1000
E
LU
LT)
-------
Figure 11: Sector Distribution of 2011 CAP and HAP Emissions
20
2011 CAP and Select HAP Emission Tons Distribution Within Stationary and Mobile Sources
Percent Contributions greater than or equal (GTE) to 15% of the National Pollutant Sum Total (stationary + mobile) Are Also Indicated
Footnote:
The pollutant emissions contribution in sector is calculated as the portion of the pollutant/sector emissions in each group sum - Stationary and Mobile.
Percent of pollutant/sector emissions in group: ^^MGTE70% 50%-69% 21-59% 0-20% no emission
A percent value in a cell indicates that the portion of the pollutant/sector emissions is greater than or equal to 15% of the national sum for that pollutant.
Selected HAPs are those indicated by NATA 2005 as nationally significant risk drivers.
FC = fuel combustion; CMV = commercial marine vessel
Data source = NEI 2011 vl/v2 draft, includes federal waters, PR, and VI; excludes Tribal; excludes sectors - prescribed fires, wildfires, and biogenics.
Stationary
Agriculture
DustConstrc
DustPavedUnPaved
Fire Ag Field Burning
FC-Biomass
FC-Coal
FC-Ngas
FC-Oil
FC-Other
Industrial Proc
MiscBulkGas
MiscCommCook
MiscGasStations
Misc Non-1 ndustN EC
MobNR-Other
MobOR-DieselLD
MobNR-Gas
MobOR-DieselHD
MiscWasteDisp
SolvCommlndust
SolvConsumerComm
Mobile
Aircraft
CMV
MobNR-Diesel
MobOR-GasHD
MobOR-GasLD
Railroad
• This chart shows the distribution of HAP and CAP
emissions within sector groups for stationary (top)
and mobile sources (bottom).
• The colors in the cell represent emission contributions
within either the stationary or mobile group, and the
dark blue color indicates sources that contribute
greater than or equal to 70% of the emissions to that
sector group.
• A percent value is shown in cells for pollutant/sector
combinations where the pollutant emissions
contribution to that sector is greater than 15% of the
national pollutant total.
• For example, the agriculture sector contributes
greater than 70% of NH3 emissions within stationary
sources (as indicated by the dark blue box) and also
contributes 90% of the total NH3 emissions across all
sectors (mobile + stationary) in the 2011 NEI vl.
• This distribution pattern for 2011 is very similar to the
pattern described for the 2008 NEI15 except that for
2011 several HAPs have a higher emissions
contribution from agricultural fires and solvent
operations. Corrected values from the draft 2011 v2
are used for agriculture field burning and for solvent
sectors.
15. 2008 National Emissions Inventory: Review. Analysis and Highlights. Figure
36, page 42
-------
21
Figure 12: Black Carbon Emissions in the 2011 NEI vl
U.S. 2011
Black Carbon Emissions
Industrial
Processes
MiscOther 2<>/0
4°/o
Source: U.S. EPA 2011 NEI VI; 2011v6 Emissions Modeling Platform
2011 National
Black Carbon Emissions
10
20
30
40
50
Tons
60 70
80
90
Thousands
100 110 120
Fires
Mobile
Nonroad
Mobile
Onroad
Fuel
Combustion
Wildfires
Prescribed Fires
Agricultural Field Burning
DieselEquipment
Railroad
CMV
Gas
Aircraft |
Other |
DieselHeavyDuty |
GasLightDuty |
DieselLightDuty |
GasHeavyDuty |
Residential
IndusBoilers
Comm/Instit
ElecGeneration
Misc Other
WasteDisposal
CommercialCooking I
DustPavedUnPavedRoads |
Agriculture |
Non-IndustrialNEC I
Industrial industrial Processes
Processes SolvCommerciallndustriaI
95% is from biomass burning
51% is from natural gas, 20% from biomass
51% is from natural gas, 37% from coal
95% is from open burning of residential waste a,
nd debris from land clearing
Black carbon (BC) is a component of PM2.5
emissions. For most sectors, BC is estimated
by applying speciation profiles to the PiVh.s
emissions.
BC is about 9% of total PM2.5 emissions in
the 2011 NEI vl.
The chart on the left shows that in 2011,
fires (wild, prescribed, and agricultural fires) account for 42% of BC emissions and mobile sources about 41%.
90% of the mobile source BC emissions come from diesel fuel combustion.
EPA previously reported BC for 200516. In that inventory, about 52% of total BC came from mobile sources and about 35%
from open burning.
The chart on the right shows that significant BC contributions for 2011 are from: mobile source diesel equipment and
engines; biomass burning from wild and prescribed fires; and fuel combustion - residential wood and EGUs.
Source: U.S. EPA 2011 NEI VI; 2011v6 Emissions Modeling Platform
16. EPA Report to Congress. Chapter 4
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Figure 13: 2011 Emissions by Climate Region
22
U. S. Climate Regions
Central
(Ohio Valley)
EastNorthCentral
(Upper Midwest)
Northeast
Southwest
West
WestNorthCentral
(Northern Rockies and Plains)
Source: NOAA National Climatic Data Center - U.S. Climate Regions
http://www.ncdc.noaa.gov/crn/usrcrn/regionmap. html
• This map describes the National Climatic Data Center (NCDC) Regions based on the climatological map developed
and maintained by NOAA (U.S. National Oceanic and Atmospheric Administration). The U.S. is split into 9 regions
based on homogeneity in meteorological conditions (meteorology, in turn, affects many emissions and emission
processes) as determined by data analysis conducted by NOAA. HI and AK are excluded from these maps and
related analyses.
• This map is basis of the regional analysis shown in Figure 14.
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23
Figure 14: Regional Ozone and PM2.5 Formation Potential Based on State CAP/ HAP Emission Intensity
2011 CAP/HAP Emissions Associated With Ozone Formation
State Contributions to Climate Region
Sources: U.S. Climate Regions NOAAA; USEPA 2011 NEI vl, 201 lv6 emissions modeling platform
+•
Amount of Emissions
in Climate Region
Million Tons
(15.1-18.0 Highest
] 12.1-15.0 Med - High
I 9.1 -12.0 Medium
| 6.1 - 9.0 Med - Low
¦ 4.0 - 6.0 Lowest
State Emissions Contribution
in Climate Region
© <10% s \
^ 30 - 50%
© 10-20%
Q 20 - 30% (*)
50 - 90%
Climate Regions
Sum of CAP & HAP
NOX, VOC, CO
1,3-Butadiene
Acetaldehyde
Acrolein
Chlorine
Ethylbenzene
Formaldehyde
Hydrochloric acid
Napthalene
Xylenes
2011 CAP/HAP Emissions Associated With PM2.5 Formation
State Contributions to Climate Region
Sources: U.S. Climate Regions NOAAA; USEPA 2011 NEI vl, 201 lv6 emissions modeling platform
Amount of Emissions
in Climate Region
Million Tons
| 8.6-10.0 Highest
~^\ 7.1 - 8.5 Med - High
| 5.1 -7.0 Medium
| 3.1 - 5.0 Med - Low
¦ 2.0 - 3.0 Lowest
State Emissions Contribution
in Climate Region
A < 10%
A 10-20%
20 - 30%
L.
A
30 - 50%
50 - 90%
Climate Regions
Sum of CAP & HAP
PM2.5
S02
NH3
NOX
VOC
Benzene
Ethylbenzene
Napthalene
Xylenes
• These maps use the 9 climate regions defined on the previous page
and show the state CAP and HAP emission contributions associated
with the formation of ozone (top) and PM2.5 (bottom map).
Emissions from biogenics and wildfires are excluded.
• The pollutants listed on each map are CAPs and HAPs known to be
ozone and PM2.5 precursors. The HAPs listed have been identified
for these maps due to their cancer and non-cancer risks1'.
• The intensity of color for each climate region indicates the amount
of emissions in a given region and how regions rank against each
other, with red and orange being high emission zones. For both
PM2.5 and ozone, the-higher emission areas are in the south,
southeast, and the industrial midwest regions.
• The symbols located on each state indicate the relative percent
contribution of the state emissions to the corresponding climate
region. Larger symbols indicate a larger contribution of emissions to
the region. For example, the south, southeast, and central regions
have relatively large amounts of both PM2.5 and ozone forming
emissions, and Texas, Florida, and Ohio contribute the most in each
region respectively.
• In regions with relatively low amounts of PIVh.sand ozone forming
emissions, states such as Michigan, Colorado, Wyoming, Nebraska,
and North Dakota contribute significant amounts of emissions to
their respective regions. In the western climate region, California is
the dominant contributor to both ozone and PM2.5.
17. U.S. EPA National Air Toxics Assessment 2005
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United States Office of Air Quality Planning and Standards Publication No. EPA-454/R-19-007
Environmental Protection Air Quality Assessment Division April 2014
Agency Research Triangle Park, NC
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