2008 National Emissions Inventory:
Review, Analysis and Highlights
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EPA-454/R-13-005
May 2013
2008 National Emissions Inventory:
Review, Analysis and Highlights
Venkatesh Rao, Lee Tooly and Josh Drukenbrod
Emission Inventory and Analysis Group
Air Quality Assessment Division
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Emissions Inventory and Analysis Group
Research Triangle Park, North Carolina
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National Emissions Inventory
Review, Analysis and Highlights
m
United States
Environ mental Protection
Agency
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TABLE OF CONTENTS
1. Highlights 1
2. Introduction 3
2.1 Purpose and Contents of this Report 3
2.2 Background 5
3. National Emissions Information 14
3.1 Total National Emissions and Emission Density Maps 14
3.2 Current Year Emissions and National Emission Trends by Sector 16
3.3 Emissions by Sector Comparisons for 2005 and 2008 26
3.4 Biogenic Emissions and Wild Land Fire Emissions 31
3.5 Focus on the 2008 NEI: Summary of CAPs and Select HAPs 34
3.6 Mercury Emissions in the 2008 NEI 41
4. Regional Emissions Information 48
4.1 National Climatic Data Center (NCDC) Regions 48
4.2 Regional CAP and HAP Emissions Characterization 49
4.3 Regional Intensity for Ozone and PM Formation, HAPs and CAPs 50
4.4 Regional CAP/HAP Emissions, Top Sector Contributions 51
5. Local Emissions Information 59
5.1 Nexus of Air Quality Issues for Local Areas 59
5.2 Local Profiles for Two Nexus Areas 60
5.3 Examples and Recommendations for Developing Local Scale Inventories 63
6. Improvements for 2008 and Future NEIs 65
7. Concluding Remarks 67
References 68
Acronym List 70
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LIST OF FIGURES
Figure 1: Role of Emissions in the Air Quality to Health Effects Paradigm 5
Figure 2: Pollutant Percent Contribution to Total National Cancer Risk 7
Figure 3: Pollutant Percent Contribution to Total National Neurological Risk 7
Figure 4: Pollutant Percent Contribution to Total National Respiratory Risk 8
Figure 5: Simplified Diagram of Major Emissions Data Categories 11
Figure 6: SO2 Emissions Density, Entire U.S 16
Figure 7: SO2 Emissions Density, Eastern U.S 16
Figure 8: Lead Emissions Density 16
Figure 9: CO Emissions Density 17
Figure 10: NH3 Emissions Density 17
Figure 11: NOx Emissions Density 18
Figure 12: SO2 Emissions Density 18
Figure 13: VOC Emissions Density 19
Figure 14: PM25 Emissions Density 19
Figure 15: PM10 Emissions Density 20
Figure 16: Pb Emissions Density 20
Figure 17: National Air Emissions, 2002-2012 21
Figure 18: National Air Emissions, Fuel Combustion Sector, 2002-2012 23
Figure 19: National Air Emissions, Industrial Processes Sector, 2002-2012 23
Figure 20: National Air Emissions, On-road Mobile Highway Vehicles Sector, 2002-2012 24
Figure 21: National Air Emissions, On-road Mobile Highway Vehicles Sector,
2002-2008, Using Consistent MOVES 2010b 24
Figure 22: National Air Emissions, Nonroad Mobile Sector, 2002-2012 25
Figure 23: National Air Emissions, Miscellaneous/Other Sector, 2002-2012 25
Figure 24: Comparison of CAP Emissions from 2005 to 2008, Excluding Wildfires and Biogenics 26
Figure 25: Comparison of CAP Emissions from 2005 to 2008, Wildfires 27
Figure 26: Comparison of HAP Emissions from 2005 to 2008, Excluding Wildfires and Biogenics 29
Figure 27: Total VOC Biogenic Emissions Density, 2008 NEI 32
Figure 28: Spatial Distribution of Acres Burned by "Fire Type" in the 2008 NEI 34
Figure 29: Spatial Distribution of PM25 Emissions by "Fire Type" in the 2008 NEI 34
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LIST OF FIGURES
Figure 30: PM25 Emission Trends in Wild Land Fires, 2003-2009 35
Figure 31: National CAP Emissions for Stationary Sources, 2008 NEI 36
Figure 32: National CAP Emissions for Mobile Sources, 2008 NEI 36
Figure 33: National HAP Emissions for Stationary Sources, 2008 NEI 37
Figure 34: National HAP Emissions for Mobile Sources, 2008 NEI 38
Figure 35: National Lead Emissions From All Sources, 2008 NEI 38
Figure 36: Percent Emission Contribution by Source for CAPs and Select HAPs in 2008 NEI 42
Figure 37: High Emitting Hg Sectors 46
Figure 38: Medium-High Emitting Hg Sectors 46
Figure 39: Low Emitting Hg Sectors 46
Figure 40: NCDC Regions in the US 48
Figure 41: NCDC Regions and Their Relationship to EPA Regions 49
Figure 42: CAP Emissions by NCDC Regions, 2008 NEI 50
Figure 43: HAP Emissions by NCDC Regions, 2008 NEI 50
Figure 44: HAP Emissions by NCDC Regions, 2008 NEI 51
Figure 45: HAP Emissions by NCDC Regions, 2008 NEI 51
Figure 46: Regional CAP/HAP Intensities to Form Ozone and PM 52
Figure 47: Number of NCDC Regions With Sectors that Rank in Top 25 Percent of Emissions 54
Figure 48: NEXUS Areas Denned by 2008 Air Quality Data and NATA 2005 Cancer Risk Values 59
Figure 49: Areas that Experienced Multiple Air Quality Problems in 2008 Based on Figure 48 59
Figure 50: Total CAPs in Fresno, CA by Sector, 2008 NEI 60
F igure 51: Total HAPs in Fresno, CA by Sector, 2008 NEI 60
Figure 52: Key Point Sources in the Fresno, CA Area, 2008 NEI 62
Figure 53: Total CAPs in Pittsburgh, PA by Sector, 2008 NEI 63
Figure 54: Total HAPs in Pittsburgh, PA by Sector, 2008 NEI 63
Figure 55: Key Point Sources in the Pittsburgh, PA Area, 2008 NEI 64
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LIST OF TABLES
Table 1: Complete List of CAPs and HAPs Evaluated in this Report 4
Table 2: Pollutants Included in this Report at National and Regional Scales 9
Table 3: Listing of the 60 EIS Sectors and Crosswalks to Other Sector Groupings Used in this Report 12
Table 4: National Totals of CAPs and HAPs in the 2008 NEI (includes wild and prescribed fires, and biogenics) .. 15
Table 5: Percent Differences for Data Shown in Figure 17 21
Table 6: Emission Sum Differences for CAP Emissions Shown in Figures 24 and 25 27
Table 7: Explanations of the Differences Seen in CAP Emissions Between 2005 and 2008 28
Table 8: Emission Sum Differences for HAP Emissions Shown in Figure 26 30
Table 9: Explanations of the Differences Seen in HAP Emissions Between 2005 and 2008 30
Table 10: Biogenic VOCs in the 2008 NEI 31
Table 11: CAP Emissions from Wild Land Fires in the 2008 NEI 33
Table 12: HAP/CAP Emission Totals (in Tons) for Stationary and Mobile Sources 39
Table 12: HAP/CAP Emission Totals (in Tons) for Stationary and Mobile Sources (continued) 40
Table 13: A Detailed Look at the Industrial Processes Source Category: CAPs and HAPs 43
Table 14: A Detailed Look at the Fuel Combustion-Biomass Source Category: CAPs and HAPs 44
Table 15: A Detailed Look at the Fuel Combustion-Coal Source Category: CAPs and HAPs 45
Table 16: A Detailed Look at the Agriculture Source Category: CAPs and HAPs 46
Table 17: Summary of 2005 and 2008 Hg Emissions in the NEI 47
Table 18: Percent Region Contribution to National Pollutant Total for Stationary Sources 55
Table 19: Percent Region Contribution to National Pollutant Total for Mobile Sources 56
Table 20: Percent Region Contribution to National Pollutant Total for All Sources 57
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1. HIGHLIGHTS
Within the last 5 years, 2008-2012, emissions of
nitrogen oxides (NOx) and sulfur dioxide (SO2) have
decreased the most, while particulate matter (PM)
and ammonia (NH3) show the least change.
The large criteria air pollutant (CAP) emissions
decreases between the 2005 and 2008 inventories
occurred in: fuel combustion sources [NOx, SO2 and
PM]; nonroad mobile commercial marine vessels,
railroad and nonroad diesel equipment [NOx, SO2,
carbon monoxide (CO)]; and highway vehicle
emissions [volatile organic compounds (VOC),
CO]. Changes in emissions are based on both real
reductions and changes to methods for estimating
emissions from commercial marine vessels, nonroad
diesel equipment, and highway vehicles.
The largest hazardous air pollutant (HAP) emissions
decreases between the 2005 and 2008 inventories
are seen in: industrial processes (ethylbenzene,
tetrachloroethylene, 1,4-dichlorobenzene,
chromium); and highway vehicles (formaldehyde,
1,3-butadiene). Some of these changes are
attributable to methods changes in estimating
emissions.
The Eastern U.S. has the highest CAP emissions
density (tons/square mile). Some parts of California
and some Western mountain states also show
high emissions density for many CAPs. Ammonia
emission densities are highest in the Central U.S.
(Iowa, Minnesota and Kansas areas).
National trends by major sectors show that much
of the VOC and nearly all of the CO emission
reductions are coming from mobile sources. Many of
the SO2 reductions are coming from fuel combustion
sources, particularly from EGUs. NOx reductions are
evenly distributed between the fuel combustion and
mobile source categories. For PM, there are increases
in the highway vehicle category associated with data
improvements included in the emissions estimation
model.
There is a downward trend in HAP emissions
between 2005 and 2008, with the noted exceptions
being acetaldehyde and acrolein. The increase
in acetaldehyde and acrolein emissions can
be attributed to emissions from stationary fuel
combustion processes, highway vehicles and
prescribed fires. Increased use of ethanol in fuels
in 2008 likely contributed to the noted increases
in acetaldehyde, an ethanol combustion product.
National emissions of mercury in 2008 are 42
percent less than in 2005. Electricity generating
units (EGUs-coal boilers) comprise the majority of
mercury emissions in 2005 and 2008 and also the
majority of mercury reductions seen between 2005
and 2008.
In 2008, the largest portions of multiple CAPs and
HAPs are emitted by coal and biomass combustion,
residential wood combustion, light duty gasoline
vehicles, and industrial processes such as chemical
manufacturing, metal products, mineral products,
pulp and paper production, petroleum refineries,
and solvent use.
Regionally in 2008, the highest amounts of ozone
and PM-forming emissions occur in the Central,
South and Southeast regions, with key contributing
sectors of multiple CAPs and HAPs similar to
the national patterns noted in the report. The
West region has relatively low amounts of ozone
and PM-forming emissions, which can be partly
attributed to much of the West regions emissions
coming from a handful of high population centers.
These emissions are no less significant for addressing
air quality management in some areas of the West.
As part of this report, EPA used 2008 ozone and
PM air quality data along with the 2005 National
Air Toxics Assessment (NATA) modeled HAP risks
to illustrate which areas of the U.S. face multiple air
quality/risk issues. Emissions from two local areas
that show a "nexus" of air quality issues are further
examined for how they compare to the regional
emissions profiles.
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HIGHLIGHTS
Improvements sought in future NEI development
cycles include: more reliable control information;
more complete emissions from oil and gas
operations; more complete HAP emissions, especially
from some nonpoint sectors; and reviewing and
prioritizing reporting of emissions from previously
identified high-emitting facilities.
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2. INTRODUCTION
The United States Environmental Protection Agency
(EPA) has completed the National Emissions
Inventory (NEI) for 2008. EPA compiles the NEI
every three years and the 2008 NEI is the most recent
in that series. Unless otherwise noted, most of the
summaries and discussion in this report focus on the
2008 NEI version 2 General Public Release inventory
(2008v2GPR, released on February 16, 2012). This
version, referred to in this report as the "2008 NEI," is
a national compilation of emissions sources collected
from state, local and tribal air agencies (SLTs) and
uses data from EPA emissions programs including
the Toxics Release Inventory (TRI), emissions trading
programs such as the Acid Rain Program, and
data gathered for EPA regulatory development for
reducing air toxic emissions. Using quality assurance
procedures, the data from multiple sources are blended
together to complete the NEI.
The Clean Air Act requires EPA to set air quality
standards to protect public health and the
environment. EPA established National Ambient
Air Quality Standards (NAAQS) for six common air
pollutants: ground-level ozone, particulate matter,
carbon monoxide, sulfur dioxide, nitrogen dioxide and
lead. Because human health and environmental criteria
(science-based guidelines) are used to set standards
for these pollutants, they are called the "criteria"
pollutants. Some of the criteria pollutants are emitted
directly from sources, while others are secondarily
formed when their precursors react in the atmosphere.
For example, ozone is formed when its precursors
- volatile organic compounds (VOCs) and nitrogen
oxides (NOx) - react in the presence of sunlight. In this
report, emission profiles are presented for the criteria
air pollutants and precursors (CAPs), and for specific
hazardous air pollutants (HAPs) contained in the
NEI. This includes: carbon monoxide (CO), lead (Pb),
nitrogen oxides (NOx), volatile organic compounds
(VOCs), sulfur dioxide (SO2), ammonia (NH3) and
particulate matter (PM10 and PM25) and specific
HAPs from the list of 187 HAPs established by the
Clean Air Act.
The NEI is a readily-available U.S. inventory with
extensive spatial, pollutant and sector coverage -
representing detailed processes within industrial
facilities, county totals for non-industrial stationary
sources, on-road vehicles and nonroad mobile
sources, and emissions from large fires based
on day-specific events. One of the primary goals of
the NEI is to provide the best assessment of current
emission levels using the data, tools and methods
available. Uses of the NEI include regulatory analyses;
large-scale air quality, emissions and climate change
assessments; emissions trends; and international
reporting. The NEI undergoes continuous
improvement by EPA and SLT partners.
2.1 Purpose and Contents of this Report
The overarching purpose of this report is to present
analysis of the 2008 NEI and comparison to previous
years of inventory data, with a primary focus on
the last full NEI - the 2005 NEI. We describe the
national and regional patterns of CAP/HAP emission
distributions in the 2008 NEI and which sources
contribute to these releases. We do not assess nor
predict the absolute risks to human health and
ecosystems that may be associated with the presence
of any of these specific air pollutants, but rather focus
on the intensity of emission releases that may pose
elevated risks.
Pollutants of greatest interest include not only those
that contribute to ozone and particle pollution, but
also HAPs that are predicted by the 2005 NATA to be
the most harmful to human health. To facilitate a more
concise document, we have included just 27 pollutants
in the report, which are listed in Table 1. Eight of these
27 pollutants are either CAPs or precursors to CAPs,
and the remaining 19 are HAPs that were selected
based on criteria that will be discussed later in this
report.
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INTRODUCTION
About this Report:
All of the analyses presented here are based on the
publically released version 2 of the NEI (denoted
as "2008 NEI" throughout) from February, 2012, ex-
cept where otherwise noted. Subsequent versions
of the NEI may be released at later dates, and that
the data in those releases may differ from what is
shown in this report.
In those graphics and analyses that show emis-
sion changes over time, some of the changes
are caused by changes to the way emissions are
estimated for a given pollutant/sector, also called
"methods changes." In this report, we attempt to
identify where these methods changes contribute
to the changes seen in emissions over time. In
addition, we hold constant emissions between NEI
years in some cases, and this could lead to some
uncertainty in the time series shown for the pol-
lutant/sector in question. We also note this uncer-
tainty in relevant sections of the report.
We report particulate matter (PM) as PM25 (2.5
microns or smaller) or PM10(10 microns or smaller).
In both cases, the estimates of PM include both
condensable and filterable emissions.
Throughout the report, some charts have 2 verti-
cal axes. Care should be taken to ensure that the
appropriate axis is considered when viewing these
graphics. These types of charts occur most often in
the "regional" section.
Table 1: Complete List of CAPs
this Report
Pollutant
NOX
VOC
CO
so2
NH3
PM,,
2.5
PIVL
10
1 «J
Lead
1,3-Butadiene
1,4-Dichlorobenzene
Acetaldehyde
Acrolein
Arsenic
Benzene
Chlorine
Chromium compounds
Cyanide compounds
Ethylbenzene
Formaldehyde
Hydrochloric Acid
Manganese
Mercury
Methyl Chloride
Naphthalene
Polycyclic Organic Matter
Tetrachloroethylene
Xylenes
and HAPs Evaluated in
CAP or HAP?
CAP
CAP
CAP
CAP
CAP
CAP
CAP
r A n i\ i A n
CAP/HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
HAP
background on the NEI. We then provide summaries
to characterize the spatial patterns (national and
regional) of the emissions contained in the 2008 NEI
and show how CAP emissions have changed since
2002. We follow that with a CAP/HAP comparison to
the last full NEI developed for 2005. The latter part of
this report addresses multi-pollutant air quality issues
in two local areas and their emission profiles. Lastly,
we discuss improvements necessary to the NEI as EPA
looks ahead to the 2011 inventory cycle and beyond.
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INTRODUCTION
Regulatory or
Other Action
IMPROVED ACTION
IMPROVED ACTION
Compliance,
effectiveness
Emissions
IMPROVED ACTION
Atmospheric transport,
chemical transformation,
and deposition
Ambient Air
Quality
Human time-activity
patterns in relation to indoor
and outdoor air quality
Uptake, deposition
clearance, retention in body
Exposure/
Dose
Susceptibility
factors; physiologic
mechanisms of damage
and repair
Human Health
Response
Figure 1: Role of Emissions in the Air Quality to Health Effects Paradigm
2.2 Background
2.2.1 Role ofNEI in Air Quality Management
Emissions are not the only factor in determining
air quality status and potential health risks from air
pollution, but they can have a significant influence
on exposure factors that are harmful to humans and
ecosystems. Various policy and technical elements,
which include emission releases, account for air quality
status as illustrated in Figure 1 [ref 1].
For many purposes, the NEI is the main source
of information for the box labeled "Emissions" in
Figure 1. While emission information is only one
component of the information required to assess
health outcomes, it plays an important role in that
process as it feeds air quality and exposure models.
The NEI is created by EPA to provide federal and
state decision makers, the public and other countries,
the best and most complete estimates of CAP and
HAP emissions in the U.S. While EPA is not directly
obligated to create the NEI under the Clean Air
Act, the Act authorizes the EPA Administrator to
implement data collection efforts needed to properly
administer the NAAQS program. Therefore, EPA's
Office of Air Quality Planning and Standards (OAQPS)
maintains the NEI program in support of the NAAQS.
Because the NAAQS are the basis on which EPA
collects CAP emissions from state, local and tribal
air agencies, EPA does not require collection of
HAP emissions. The HAP reporting requirements
are voluntary; nevertheless, HAP emissions are an
essential part of the NEI program. These emissions
estimates allow EPA to assess progress in meeting
HAP reduction goals described in the Clean Air Act
Amendments of 1990. These goals include reducing the
negative impacts of HAP emissions on people and the
environment and assessing emission reductions since
1990. The 2008v2GPR Technical Support Document
[ref 2] shows that 44 states volutarily reported point
source HAPs and 41 states reported nonpoint source
HAPs to the 2008 NEI.
In addition to point, mobile and nonpoint source
emissions, the NEI also contains detailed CAP and
HAP emissions estimates from large fires (prescribed
and wild) as well as CAPs from smaller agricultural
fires. Emissions from natural sources are also included
in the NEI but are limited to the biogenic land-based
plant and soil emissions and not ocean, geogenic or
lightning emissions.
For many readers, the 2008 NEI webpage (http://www.
epa.gov/ttn/chief/net/2008inventory.html) provides a
convenient way to access NEI data summaries. Data for
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INTRODUCTION
both CAP and HAP emissions are provided in various
levels of aggregation. The 2008 NEI webpage gives
users the option of creating custom summaries for any
county, state or national total. This approach makes
the data more accessible to a large variety of data users,
from the general public to researchers.
2.2.2 Choice of Pollutants for this Report
As described above, while all CAPs and their
precursors (hereafter, "CAPs" means both directly
emitted pollutants and their precursors) will be
covered in this report, we chose a limited number of
the 187 HAPs for analysis and presentation. We gave
the highest priority to CAPs and HAPs that:
Contribute directly to, or are involved in, the
formation of air pollution for which there are
national ambient air quality standards, and
Are toxic pollutants identified by the national air
toxics assessment (NATA 2005) [ref 3] as potential
high inhalation risk for cancer and/or non-cancer
hazard. NATA 2005 identifies both "national" risk
drivers and "regional" risk drivers; both of these
classifications schemes were used here.
Further details on the 2005 NATA are provided below
but, in general, the purpose of NATA is to provide
answers to questions about emissions, ambient air
concentrations, exposures and risks across broad
geographic areas (such as counties, states and the
nation) at a moment in time. These assessments are
based on assumptions and methods that limit the
range of questions that can be answered reliably. The
results cannot be used to identify exposures and risks
for specific individuals, or even to identify exposures
and risks in small geographic regions such as a specific
census block, i.e., hotspots. These estimates reflect
chronic exposures resulting from the inhalation of
the air toxics emitted and do not consider exposures
which may occur indoors or as a result of exposures
other than inhalation (i.e., dermal or ingestion). These
limitations, or caveats, must always be kept in mind
when interpreting NATA results. For a complete
listing of NATA limitations, the reader is referred to
the NATA website at www.epa.gov/nata. Specifically,
for the 2005 emissions year, the assessment includes
four steps:
Compiling a national emissions inventory of air
toxics emissions from outdoor sources
Estimating ambient and exposure concentrations of
air toxics across the U. S.
Estimating population exposures across the U.S.
Characterizing potential public health risk due to
inhalation of air toxics including both cancer and
non-cancer effects
There are six national ambient air quality standards
(NAAQS) for carbon monoxide, lead, nitrogen
dioxide, ozone, particulate matter (PM10 and PM25),
and sulfur dioxide [ref 4]. Ozone is generally not
emitted directly into the air, but is created by chemical
reactions between oxides of nitrogen (NOx) and
volatile organic compounds (VOCs) in the presence of
sunlight. Particulate matter may be primary particles
that are emitted directly from a source, or secondary
particles that are a result of chemical interactions in the
atmosphere. The majority of fine particle pollution in
the U.S. consists of secondary particles [ref 5].
Directly emitted pollutants related to the formation of
these 6 CAPs include:
Nitrogen oxides (NO )
Volatile organic compounds (VOCs)
Sulfur dioxide (SO2)
Particulate matter (PM25, PM10)
Ammonia (NH )
Carbon monoxide (CO)
Lead (Pb)
These CAPs are included in this review of the 2008
NEI.
Since it is not possible to cover all of the 187 HAPs
that are in the NEI, we let the NATA 2005 [ref 3] help
identify key HAP pollutants that contribute to cancer
and non-cancer riskat both the national and regional
levels. The non-cancer hazards include respiratory
and neurological effects. NATA considers the cancer
and non-cancer toxicity of a pollutant to estimate its
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INTRODUCTION
potential risk. Note that a higher toxicity can indicate
that a pollutant, even if emitted in a small amount, can
pose a potential high risk.
Figures 2 through 4 below show the pollutant percent
contribution, based on the 2005 NATA, to the total
predicted national risk for cancer, neurological and
respiratory risk, respectively. In each of these graphics
the incremental contribution to risk by pollutant is
greatest up through 95 percent. As shown in Figure 2,
benzene and formaldehyde contribute up to 60 percent
of the total national cancer risk; ten more HAPs
contribute approximately 35 percent to the cancer risk.
Beyond that, other pollutants do not contribute any
significant risk.
Figures 3 and 4 show similar results for non-cancer
(neurological) and respiratory risk from the 2005
NATA. Five pollutants capture 95 percent of the
non-cancer risk, and four pollutants capture 95 percent
of the respiratory risk.
In this report, the 17 HAPs that contribute up to 95
percent of total national cumulative risk are labeled
as "key contributors" and are further analyzed. In
addition, the HAPs chlorine and hydrochloric acid are
included as key contributors due to high potential for
99%
Figure 2: Pollutant Percent Contribution to Total National Cancer Risk
\
$? Cumulative Percent Contribution to Risk
on _
en _
en
AH -
Tn _
-in _
* 99%
^,X94%
yXSl'Xi
Jf
^r
J*
s
Figure 3: Pollutant Percent Contribution to Total National Neurological Risk
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INTRODUCTION
ibution to Risk
Cumulative Percent Contr
4
* « - -* » * 99%
^*|X**90% 95%
^^
S///S//S///
**/ '/Sty's
Figure 4: Pollutant Percent Contribution to Total National Respiratory Risk
respiratory risk, resulting in 19 HAPs analyzed in this
report. The HAPs included in this review, plus lead,
comprise 65 percent of the total HAP emissions (in
tons) in the 2008 NEI.
NATA may identify other HAPs of concern for specific
local areas and these results can be consulted to
understand, in more detail, potential exposure risks
for a specific local area, e.g., county or census tract. For
instance, coke oven pollutant emissions and nickel do
not fall into the pool of pollutants that contribute up
to 95 percent of total national cancer risk but would be
a potentially important source of risk to consider in a
local area where such emission releases occur.
In addition, the 2005 NATA results indicate the
following for specific pollutants considered here:
Carbon tetrachloride - While the risks are high, they
are mainly driven by background levels associated
with persistent transport of past emissions, and
therefore we do not include carbon tetrachloride in
this review.
PM from diesel engines - When inhaled, can
contribute to chronic respiratory risks and have been
linked to increased cancer risk in epidemiological
studies. PM from diesel engines is quantified as the
PM2 5 portion of the emissions. This review includes
PM2 5 diesel emissions from mobile sources.
Mercury - Other HAPs, such as mercury, pose
multi-pathway risks through exposure routes
such as ingestion. Mercury exhibits a non-cancer
neurological risk via the ingestion pathway and is
addressed in this review.
Lead - A key contributor to the total national
neurological risk and is also a CAP for purposes of
the NAAQS. While "lead and lead compounds" is the
HAP, the emission from only lead is included.
Table 2 summarizes the above discussion and lists the
CAPs and HAPs included in this report and some of
the associated air quality and risk attributes. Attributes
identified include: 1) ozone precursors that can
facilitate the formation of ozone in the atmosphere,
2) ozone forming potential relative to VOC reactivity,
3) PM precursors that are constituents of particulate
matter or which can facilitate the formation of PM25,
4) secondary organic aerosols (SOA) which
can facilitate the formation of PM2 5, and 5) key
contributors to total national cancer/neurological/
respiratory risks. The mixture of CAP and HAP
emission releases and the local and regional climate
and weather patterns help determine how the
chemicals will interact to form ozone and fine particles
(PM25) and/or transform to other toxic species. The
footnotes for the table provide additional details on
these attributes as well as appropriate references. The
species noted as influential for secondary organic
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INTRODUCTION
Table 2: Pollutants Included in this Report at National and Regional Scales
NATA 2005 Estimate of
Inhalation Risk
Geo-level
profiles
Key contributor to the
Emissions included in 2008 NEI report national risk for category
Pollutant
NOX
voc
CO
»,
NH3
PM2.5
PM10
Lead5
1,3-
Butadiene
1,4-
Dichlorobenzene
Acetaldehyde
Acrolein6
Arsenic
Benzene
Chlorine
Chromium
compounds7
Cyanide
compounds8
Ethylbenzene
Formaldehyde
CAP Ozone
or Ozone PM forming SOA Cancer "Non-cancer "Non-cancer
HAP Precursor1 Precursor2 potential3 Potential4 risk respiratory" neurological"
CAP Y Y High
CAP Y Y Mfhm-
High
CAP Y
CAP Y
CAP Y
CAP Y
CAP Y
CAPS
HAP
HAP Y H Y
HAP Low Y
HAP Y H Y Y
HAP Y H Y
HAP Y Y
HAP Y Y L H Y
HAP Y H Y
HAP Y
HAP Y
HAP Y Y M H Y
HAP Y H Y Y
National
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
N
Y
N
Y
Y
Re-
gional
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
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INTRODUCTION
Table 2: Pollutants Included in this Report at National and Regional Scales (continued)
Emissions included in 2008 NEI report
CAP Ozone
or Ozone PM forming
Pollutant HAP Precursor1 Precursor2 potential3
NATA 2005 Estimate of
Inhalation Risk
Key contributor to the
national risk for category
SOA Cancer "Non-cancer "Non-cancer
Potential4 risk respiratory" neurological"
Geo-level
profiles
Re-
National gional
Hydrochloric Acid HAP
Manganese
Mercury9
HAP
HAP
Methyl Chloride HAP
Naphthalene
HAP
M
Polycyclic
Organic Matter10
HAP
Tetrachloroethylene HAP
Xylenes11 HAP Y
L Y
Y H H
Y
Y N
Y
Y
aerosol are only those specifically indicated in the
reference consulted (see footnote 4 of Table 2).
1. Ozone precursors can facilitate the formation of ozone in the
atmosphere.
2. PM precursors are constituents of particulate matter or can
facilitate the formation of PM2 5.
3. Ozone forming potential refers specifically to VOC reactivity:
High, Medium, Low. Incremental reactivity for VOC (ozone
formation) maximum incremental reactivity (MIR), larger
number higher reactivity [ref 6].
4. Secondary organic aerosol (SOA) can facilitate the formation of
PM2 5. SOA potential (SOAP) is expressed as High or Medium.
SOAP index is expressed relative to toluene = 100 [ref 7]
5. Lead is a criteria pollutant for purposes of NAAQS and is also
included in NATA due to toxic attributes.
6.
The respiratory hazard indicated by NATA for acrolein is based
on emission sources other than wildfires. Over seventy percent
of national acrolein emissions are from wildfires. As wildfires
are an uncontrollable intermittent source, NATA 2005 did not
include risks associated with wildfire emissions.
Chromium compounds include chromium (Cr) III and VI and
small amounts of reported chromium trioxide and chromic
acid. NATA cancer risk is based on Cr VI.
Cyanide compounds include cyanide and hydrogen cyanide.
Mercury has a potentially high non-cancer neurological risk
based on multi-pathway exposure including ingestion.
10. POM includes many reported species. See [ref 8] for
detailed list.
11. Xylenes include -m, -o, -p, and mixed isomers.
7.
9.
-------
INTRODUCTION
There is also the question of scale (regional versus
national) of the pollutants chosen for study in this
report, since we present some pollutants as national
summaries and some as regional summaries. CAPs are
generally considered to be important at both national
and regional scales. Of the key contributor HAPs
selected and included in this report, the 2005 NATA
designates some as national drivers (contributors) to
risk, and others as regional drivers of risk according
to the populations exposed. The national emission
summaries in this report include only the HAPs with
a national scope of influence and the regional/local
emission summaries include all the HAPs listed (both
a regional and national scope). In the context of NATA,
the national versus regional pollutant drivers of risk
are simply classified as follows:
National Drivers: More people exposed to elevated
risks
n For example, formaldehyde is a national driver
for cancer risk, emissions are from various point
and nonpoint sources, and formaldehyde is also
secondarily formed in the atmosphere making
exposure more likely in more areas.
Regional Drivers: Fewer people exposed to elevated
risks
n The 2005 NATA example is benzene as a driver for
cancer risk, emissions are mostly from on-road
vehicles, and exposures are highest in local areas of
high vehicular traffic.
2.2.3 Summary of Emission Sectors used in this Report
In addition to the choice of pollutants, an equally
important consideration is how we summarize
emissions by sectors (or sources). Emissions from
different source types maybe aggregated in numerous
ways to derive sector summaries. Figure 5 illustrates
the major emissions data categories and depicts
numerous sources within each category. In building an
emissions inventory, each of these "sub-sectors" needs
to be characterized properly to arrive at the correct
aggregated total.
In Figure 5, "nonpoint" refers to stationary sources
such as field burning and residential wood combustion
and emissions that are estimated across a county
area. "Mobile" category emissions are also typically
estimated across county areas - "on-road" refers to cars
and trucks, while "nonroad" refers to sources such as
aircraft and agricultural field equipment. "Point" refers
to large stationary sources like electric utilities, heavy
industry and emissions that are estimated for a distinct
location. These major emission data categories contain
numerous source types. The NEI Technical Support
Document provides additional details about the source
types within these major data categories, [ref 2].
For the purposes of this report, the most detailed
sector characterization we review are the 60
sectors from EPA's Emissions Inventory System (EIS),
which is used to build the NEI. These sectors are
listed in the left-most column of Table 3. The other
Nonpoint sources
Mobile nonroad sources
Point sources
Mobile on-road sources
* s^ f ri
, ^
Figure 5: Simplified Diagram of Major Emissions Data Categories
-------
INTRODUCTION
three columns in Table 3 show the related sector
aggregations that are used for different analyses
shown in this report. In practice, these different sector
aggregations are often requested by NEI data users as
ways to summarize and display emissions information.
Table 3 shows the "mapping" that is used in this report
to aggregate the 60 EIS sectors all the way up to just
seven sectors. In this report, summaries use different
levels of aggregation (as shown in the individual
columns in Table 3) depending on the national,
regional or local profile being depicted. Local patterns
are generally shown with more detailed sectors.
One exception to our use of the sectors in Table 3 is
that prescribed fires and wildfires (in sum, known
as "wild land" fires) are not included in most of the
analyses presented in this report. Emissions from these
Table 3: Listing of the 60 EIS Sectors and Crosswalks to Other Sector Groupings Used in this Report
SECTORS 60 EMISSION SECTORS 29
INVENTORY SYSTEM (EIS)
Agriculture-Crops & Livestock Dust Agriculture
Agriculture-Fertilizer Application Agriculture
Agriculture-Livestock Waste Agriculture
Bulk Gasoline Terminals MiscBulkGas
Commercial Cooking MiscCommCook
Gas Stations MiscGasStations
type of fires are dealt with separately in this report.
This approach is partly due to the fact that fires are so
variable from year to year (especially wildfires), that
including them in the 2008 summaries may cause the
other sectors' contributions to be minimized as a result
of a "high fire year" in 2008. In addition to the 2008
summaries, wild fires have also been removed from
the trends analysis (section 3.2) to allow for a more
accurate curve of anthropogenic sources. Agricultural
burning (also referred to as crop residue burning),
which is also a sector listed in the left-most column
of Table 3, has much smaller emissions and has more
consistent emissions from year to year; accordingly this
sector is included in all of the analyses in this report.
SECTORS 17
SECTORS 10
SECTORS 7
Miscellaneous Non-Industrial NEC
Waste Disposal
Dust-Construction Dust
Dust-Paved Road Dust
Dust-Unpaved Road Dust
Fires-Agricultural Field Burning
Fires-Prescribed Fires
Fires-Wildfires
FuelComb-Comm/lnstitutional-Biomass
FuelComb-Comm/lnstitutional-Coal
Fuel Comb-Comm/lnstitutional-Natural Gas
Fuel Comb-Comm/lnstitutional-Oil
FuelComb-Comm/lnstitutional-Other
Fuel Comb-Electric Generation-Biomass
Fuel Comb-Electric Generation-Coal
Fuel Comb-Electric Generation-Natural Gas
Fuel Comb-Electric Generation-Oil
MiscNon-lndustNEC
MiscWasteDisp
DustConstrc
DustPavedUnPaved
DustPavedUnPaved
Fires-Agricultural Field
Burning
Fires-Prescribed Fires
Fires-Wildfires
FuelComb-Biomass
FuelComb-Coal
FuelComb-Ngas
FuelComb-Oil
FuelComb-Other
FuelComb-Biomass
FuelComb-Coal
FuelComb-Ngas
FuelComb-Oil
Agriculture
Agriculture
Agriculture
Misc
Misc
Misc
Misc
Misc
Dust-RoadsConstrc
Dust-RoadsConstrc
Dust-RoadsConstrc
Fires-Agricultural Field
Burning
Fires-Prescribed Fires
Fires-Wildfires
FuelComb-Comm/lnstit
FuelComb-Comm/lnstit
FuelComb-Comm/lnstit
FuelComb-Comm/lnstit
FuelComb-Comm/lnstit
FuelComb-ElecGen
FuelComb-ElecGen
FuelComb-ElecGen
FuelComb-ElecGen
Agriculture
Agriculture
Agriculture
Misc
Misc
Misc
Misc
Misc
Dust-RoadsConstrc
Dust-RoadsConstrc
Dust-RoadsConstrc
Fires-Agricultural Field
Burning
Fires-Prescribed Fires
Fires-Wildfires
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Misc
Fires-Wildfires
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
-------
INTRODUCTION
Table 3: Listing of the 60 EIS Sectors and Crosswalks to Other Sector Groupings Used in this Report (continued)
SECTORS 60 EMISSION
INVENTORY SYSTEM (EIS)
Fuel Comb-Electric Generation-Other
Fuel Comb-Industrial Boilers, ICEs-Biomass
Fuel Comb-Industrial Boilers, ICEs-Coal
Fuel Comb-Industrial Boilers, ICEs-Natural
Gas
Fuel Comb-Industrial Boilers, ICEs-Oil
Fuel Comb-Industrial Boilers, ICEs-Other
Fuel Comb-Residential-Natural Gas
Fuel Comb-Residential-Oil
Fuel Comb-Residential-Other
Fuel Comb-Residential-Wood
Industrial Processes-Cement Manuf
Industrial Processes-Chemical Manuf
Industrial Processes-Ferrous Metals
Industrial Processes-Mining
Industrial Processes-NEC
Industrial Processes-Non-ferrous Metals
Industrial Processes-Oil & Gas Production
Industrial Processes-Petroleum Refineries
Industrial Processes-Pulp & Paper
Industrial Processes-Storage and Transfer
Solvent-Consumer & Commercial Solvent Use
Solvent-Degreasing
Solvent-Dry Cleaning
Solvent-Graphic Arts
Solvent-lndust Surface Coating & Solvent Use
Solvent-Non-lndustrial Surface Coating
Mobile-Aircraft
Mobile-Commercial Marine Vessels
Mobile-Locomotives
Mobile-Non-Road Equipment- Diesel
Mobile-Non-Road Equipment - Gasoline
Mobile-Non-Road Equipment - Other
Mobile-On-Road Diesel Heavy Duty Vehicles
Mobile-On-Road Diesel Light Duty Vehicles
Mobile-On-Road Gasoline Heavy Duty
Vehicles
Mobile-On-Road Gasoline Light Duty Vehicles
Biogenics-Vegetation & Soil
SECTORS 29
FuelComb-Other
FuelComb-Biomass
FuelComb-Coal
FuelComb-Ngas
FuelComb-Oil
FuelComb-Other
FuelComb-Ngas
FuelComb-Oil
FuelComb-Other
FuelComb-Biomass
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
SolvConsumerComm
SolvCommlndust
SolvCommlndust
SolvCommlndust
SolvCommlndust
SolvCommlndust
Aircraft
CMV
Railroad
MobNR-Diesel
MobNR-Gas
MobNR-Other
MobOR-DieselHD
MobOR-DieseILD
MobOR-GasHD
MobOR-GasLD
Biogenics
SECTORS 17
FuelComb-ElecGen
FuelComb-lndusBoilers
FuelComb-lndusBoilers
FuelComb-lndusBoilers
FuelComb-lndusBoilers
FuelComb-lndusBoilers
FuelComb-Residential
FuelComb-Residential
FuelComb-Residential
FuelComb-Residential
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Solvent
Solvent
Solvent
Solvent
Solvent
Solvent
Aircraft
CMV
Railroad
NonroadEquip
NonroadEquip
NonroadEquip
OnroadVehicles
OnroadVehicles
OnroadVehicles
OnroadVehicles
Biogenics
SECTORS 10
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Fuel Comb
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Industrial Proc
Solvent
Solvent
Solvent
Solvent
Solvent
Solvent
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Biogenics
SECTORS 7
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Fuel Combustion
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Industrial Processes
Mobile Nonroad
Mobile Nonroad
Mobile Nonroad
Mobile Nonroad
Mobile Nonroad
Mobile Nonroad
Mobile Onroad
Mobile Onroad
Mobile Onroad
Mobile Onroad
Biogenics
-------
3. NATIONAL EMISSIONS INFORMATION
In this section we present national CAP/HAP
emissions in a number of ways to show their spatial
distribution and their changes over time. We also
separately characterize the fire and biogenic sectors.
3.1 Total National Emissions and Emission
Density Maps
Table 4 shows the total national CAP and HAP
emissions in the 2008 NEI (including fire and biogenic
emissions). The total sum for all HAPs is shown. Later
in the report, results for specific HAPs and grouping
of HAPs are also available. The following general
comments apply to the data shown in Table 4:
For convenience of display, the units are shown as
"xlOOO" short tons. This means, for example, that the
first entry is 82,696,000 short tons of CO, and so on.
Among CAPs, CO is the largest emissions in total.
Lead is the smallest.
CO, VOCs, HAPs and NO emissions all have
x
anthropogenic (man-made) and biogenic (natural
source) contributions, VOC is the only CAP that has
more emissions from biogenic sources than from
anthropogenic sources.
Only three HAPs contribute to the biogenic
emissions listed in Table 4: formaldehyde,
acetaldehyde and methanol. Formaldehyde and
acetaldehyde have the dominant amounts of biogenic
emissions in the NEI.
In general, more CAP emissions are found in urban
areas than rural ones, with the notable exception
being NH3 emissions, which are mostly emitted
from fertilizer and livestock sources. The urban/
rural assignment for counties in the U.S. used in this
report is the same as the assignment used for the
2005NATA[ref3].
Figures 6 through 16 show the national emission
totals from Table 4 using the NEI s county emission
totals divided by the county area. This new
variable is referred to as "emissions density" and is
expressed as tons/square mile. Because county sizes
vary considerably, the emissions density is more
comparable from one county to the next than total
emissions. One important difference in the maps
from the emissions in Table 4 is that all of the maps
(Figures 6 through 16) exclude emissions from
wildfires, prescribed fires and biogenic sources.
Numerous observations about the spatial distribution
of pollutants are made from the information in
Table 4 and the maps in Figures 6 through 16:
CO emission densities (Figure 9) are generally higher
in the Eastern U.S. than the West. Three-fourths of
total CO emissions occur in urban counties. This
is an expected result since the vast majority of CO
comes from mobile sources.
NH3 emission densities (Figure 10) are high in
several areas of the country but highest in the North-
Midwest part of the U.S., and in parts of North
Carolina, California and Pennsylvania. Unlike most
other pollutants, the emissions density is highest
in more rural areas: 57 percent of total emissions
are estimated to occur in rural areas. This is an
expected result since most NH3 emissions come from
agricultural sources, including fertilizer application
and livestock.
While total NOx emissions are significantly lower
than CO, they follow a similar spatial pattern.
NOx emission densities (Figure 11) are higher in
the Eastern U.S. and some parts of California. The
urban/rural split for NOx is tilted towards urbanized
counties (69 percent), but is lower than the estimated
urban percentage for CO. This may be due to NOx
emissions coming from both mobile sources and
power plants, since many power plants are situated in
rural areas [ref 9].
The SO2 emissions density map (Figure 12) shows
high densities in the East, where most power plants
are located. Emissions occur more in urbanized
counties (58 percent), but there are significant
emissions in rural areas as well, since many power
plants are situated away from urban centers. Because
SO2 is mostly emitted by stationary sources (for
example, power plants), it is also interesting to
-------
NATIONAL EMISSIONS INFORMATION
Table 4: National Totals of CAPs and HAPs in the 2008 NEI (includes wild and prescribed fires, and biogenics)
Pollutant
CO
VOC
N0x
S02
PM25
PM10
NH3
Pb
Total HAPs
Anthropogenic
Contribution
(xl 000 Short
Tons)
82,696
17,871
18,168
10,827
6,123
21,693
4,367
1
3,649
Biogenic
Contribution
(x 1000 Short
Tons)
6,474
31,744
1,078
-
-
-
-
-
4,332
Total
(xl 000 Short
Tons)
89,170
49,615
19,246
10,827
6,123
21,693
4,367
1
7,981
Percentage of
Total occurring
in urban coun-
ties
74
70
69
58
58
55
43
80
53
Percentage of Total
occurring in rural
counties
26
30
31
42
42
45
57
20
47
review the emissions using an alternate "bubble
map," depicted in Figures 6 and 7. Each circle (or
"bubble") represents emissions density centered on
the county centroid. Larger circles indicate more
and/or larger emissions that emit SO2 in that county.
Figure 6 shows a high prevalence of larger emissions
in the East. Figure 7 shows the Eastern U.S. in more
detail and further illustrates that emissions density
is highest in and around the Tennessee Valley, due
primarily to large power plants in this region.
VOC emission densities (Figure 13) are higher in the
Eastern U.S., with some pockets of high emissions
in the Western mountain states and California. The
main source of anthropogenic VOCs in the U.S. are
mobile sources and solvent operations, both of which
tend to occur more in urbanized areas. Table 4 shows
that more than two-thirds of VOC emissions occur
in urban counties.
The emission density map for PM25 (Figure 14)
shows a larger fingerprint in the Eastern U.S. Direct
PM2 5 emissions occur more in urban counties
(58 percent), but there are sources of pollutants in
rural areas that play a role as well. It should be noted
that PM2 5 measured at ambient monitors captures
both primary and secondary contributions (see
"choice of pollutants" section above for more details),
with secondary contributions being very significant
for PM25. Emission inventories only deal with the
primary portion of the pollutants contribution to the
total. While this is true for all pollutants, it is most
important for PM25 where secondary contributions
are significant across the U.S. [ref 10].
The PM1Q emissions density map (Figure 15) shows
a pattern that is very similar to PM25 in the Eastern
U.S., as similar sources emit both these pollutants
in the Eastern U.S. In the West, there is a different
spatial pattern for PM10 compared to PM25, with
more emissions from sources like dust from
agricultural activities and unpaved roads. There are
also more PM10 emissions estimated to occur in rural
areas (45 percent) than PM25 due to the differences in
source types that contribute to these pollutants.
The last map (Figure 16) in this series depicts lead
emission densities. Lead, which is both a CAP as well
as a HAP, is primarily a local pollutant and is emitted
from point sources and aircraft. The states in and
adjacent to the Upper Midwest have the highest lead
emission densities from these sources. Most lead
emissions are found in urban counties (80 percent).
-------
NATIONAL EMISSIONS INFORMATION
Figure 6: SO2 Emissions Density, Entire U.S.
Figure 7: SO2 Emissions Density, Eastern U.S.
Legend
Pb Emissions Density
Ton/SqMi
o.ooo-o.om
0.002-0005
Figure 8: Lead Emissions Density
3.2 Current Year Emissions and National Emission
Trends by Sector
While most of this report focuses on the 2008 NEI,
this section deals with the common question of current
year emissions (2012 and recent historical trends).
EPA uses the triennial inventories, such as the 2008
NEI, to understand emissions changes over time. The
resultant inventory years, e.g., 2002, 2005, 2008, etc.,
establish the basis of the emission trends time series.
EPA also estimates the interim year emissions, such as
for 2003-2004, 2006-2007, 2009-2010, etc. using:
Available year-specific emissions data, e.g.,
continuous emissions monitoring (CEM) data
reported to the EPA by large electric generating
utilities, and mobile source modeled emissions for a
specific year;
Projected future-year emissions for mobile sources to
use as an end point for interpolating from the latest
past year of data available;
Constant emissions from previous year(s) for sectors
where year-specific or future-year emissions are not
available and emissions are highly uncertain or do
not vary much with time. In other words, emissions
from an interim year are assumed to be equal to
emissions from a collected year.
The EPA updates the national emission trends for
CAPs as new data become available. The most recent
information is posted on EPA's Emissions Trends
webpage [ref 11] and is summarized here to describe
the national trend during the last ten years, including
2002 to 2012. The trend in the national total CAP
emissions and emissions for each major sector group is
shown in Figures 17 through 23. The trend series does
not include HAP emissions due to the voluntary nature
of reporting.
Figure 17 summarizes the change in total CAP
emissions over this 11-year time frame. Most of the
pollutant levels have decreased over this decade. Some
of the national CAP totals are decreasing faster than
others, while pollutants like PM25, PM10 and NH3 show
little change. Within the last five years, 2008-2012,
the rate of decrease is highest for NOx and SO2. In
-------
NATIONAL EMISSIONS INFORMATION
Legend
CO Emissions Density
Tons/SqMi
I 16-10
I I 11-18
I \ 19-41
42-7570
Figure 9: CO Emissions Density
Legend
NH3 Emissions Density
Tons/SqMi
^B 00-03
| | 0.4-o.e
| 0.9- 1.5
Q~| 1.6-2.6
2.9-96.1
Figure 10: NH Emissions Density
-------
NATIONAL EMISSIONS INFORMATION
Legend
NOx Emissions Density
Tons/SqMi
ii i
I2-12G1
Figure 11: NOx Emissions Density
Legend
SO2 Emissions Density
Tons/SqMi
HM 000-0.03
Bl 004 -009
| | 0,10-0.31
H 0,32-2.28
^H 2.29-980.30
Figure 12: SO2 Emissions Density
-------
NATIONAL EMISSIONS INFORMATION
Legend
VOC Emissions Density
Tons/SqMI
j^H -in. i 1
^H 1.2-2.3
I I 24-4.1
Figure 13: VOC Emissions Density
Figure 14: PM2 Emissions Density
-------
NATIONAL EMISSIONS INFORMATION
Legend
PM1D Emissions Density
Tons/SqMI
D6-3
^j 14-514
Figure 15: PM Emissions Density
Legend
PB Emissions Density
Tons/SqMi
^B o.ooooo - 0.00001
| | 0.00002 - 0.00004
Q^ 0.00005-0.00010
000011 -0.00034
0.00035 - 0.04901
Figure 16: Pb Emissions Density
-------
NATIONAL EMISSIONS INFORMATION
U.S. National Air Emissions
25,000
20,000
15,000
10,000
5,000
Tons
xlO*
CO scale:
120,000
100,000
B0,000
60,000
40,000
- 20,DOO
2002 2003 2004 2005 2006 2007
Year
20DB 2009 2010 2011 2012
-NOX
-VOC
502
PM10
PM2.5 NH3
^CO 1
Exdudei wildfires
Source :UStPA Air Emission Tren* data
http://www.cpa.gov/rtn/
Figure 17: National Air Emissions, 2002-2012
addition, SO2 experienced the sharpest decline between
the years 2005-2009. Table 5 summarizes the overall
trends seen in Figure 17 for different time periods.
From Table 5 and Figure 17, it is evident that EPA's
inventories indicate that emissions of CO, NOx
SO2 and VOC decreased by significant amounts
from 2002 to 2012, with at least half of these reductions
occurring within the last five years. EPA emission
control programs that are helping areas meet national
ambient air quality standards (NAAQS) and that
influence such pollutant reductions include the:
NOx Budget Program and the Clean Air Interstate
Rule (CAIR);
New Source Performance Standards (NSPS);
Maximum Achievable Control Technology standards
(MACT), which though intended to reduce HAP
emissions, have co-benefits for VOC and PM
emission reductions;
Table 5: Percent Differences for Data Shown in Figure 17
Motor vehicle programs for cleaner fuels and
engines;
Nonroad engine control and clean fuels program
for small engines, commercial marine vessels, and
locomotives.
The current understanding of national trends is based
on the triennial NEI for 2002, 2005 and 2008, projected
2012 inventory data for the mobile source sectors
and reported available data through 2012 for power
plants. Otherwise, these data use 2008 emissions in
subsequent years. In Figure 17, the data points from
the 2002, 2005 and 2008 NEI are indicated with circles.
The shaded area after 2008 indicates that specific NEI
data are not available for 2009-2012, though power
plant data are included on data available through
the third quarter of 2012 and adjusted for the entire
year of 2012 based on available data. PM25 and PM10
emissions have decreased by a lesser amount, and
Time Period
2002-2012
2002-2008
2008-2012
NOX
-46
-19
-34
VOC
-29
-17
-14
S02
-63
-30
-47
PM,
-4
-4
-1
PM2
-11
-4
NH3
5
7
-1
CO
-49
-32
-25
-------
NATIONAL EMISSIONS INFORMATION
NH3 emissions are fairly constant. A sectors emissions
that are held constant between 2008 and 2012 create
uncertainties for both higher and lower emissions.
These uncertanties affect NH3 and PM emissions more
than other pollutants, because the trends for NOx,
VOC, SO2 and CO are based on more year-specific data
or available projected data. National trends updates
over time using new data can cause the 2008-2012
percent differences to change.
While Figure 17 shows the total national emission
trends, Figures 18 to 23 show these trends stratified
by five broad sectors over the same time period. The
five sectors are similar to the "Tier" aggregations
commonly used to summarize national trends and
follow the "Sectors 7" column Table 3, excluding
wildfires and biogenic emissions. Some observations
based on the sector-segregated trends include:
Sector-based trends correspond to the overall trends
shown in Figure 17. Much of the VOC reductions
and nearly all of the CO reductions are coming from
mobile sources. Much of the SO2 reductions are
coming from fuel combustion sources, primarily
from power plants. NOx reductions are evenly
distributed between the fuel combustion and mobile
source categories. The NOx and SO2 reductions in
fuel combustion include the power plant reductions
reported to EPA through the third quarter of 2012.
For highway vehicles, the emissions model used
to estimate on-road mobile source emissions was
different for the NEI 2002, 2005 and 2008. A version
of the MOVES model [ref 12] was used during
the development of 2008 NEI, and the previously
available MOBILE6 model [ref 13] was used to
develop NEI 2005 and 2002. The effect of this
method change and use of the different models is
shown in Figure 20 for NOx emissions, which appear
to increase between 2005 and 2008 and then decrease
after 2008. Figure 21 is provided to indicate the effect
on emissions for this sector when applying the same
model; in this case, the EPA's most recent available
MOVES2010b model. NOx emissions, which are
sensitive to the temperature impacts applied in
the MOVES2010b, are higher in 2002, with steady
reductions through 2008. CO and VOC emissions
are generally lower overall using the MOVES2010b.
PM emissions are somewhat higher with MOVES,
which includes temperature impacts on PM25 and
NOx emissions based on new emissions testing, with
higher emissions at colder temperatures. For more
discussions of the reasons for the differences between
the two models, see http://moves.supportportal.com/
lrnk/portal/23002/23024/ArticleFolder/1466/Mobile-
6-2-Transition.
Trends seen in nonroad mobile emissions between
2005 and 2008 are influenced by methods changes in
the emissions models ("NONROAD2005" model vs.
"NONROAD2008" model) between 2005 and 2008.
The increase in NH3 emissions for the miscellaneous
category comes from prescribed fires and waste
disposal sources. The former is due to methods
changes and the latter is due to the addition of
municipal/commercial composting emissions in
more recent NEIs.
The increases in the miscellaneous category
(Figure 23) emissions are related to increases in dust
from agricultural tilling and livestock, especially
for PM1Q. The apparent increase in PM25 from 2005
to 2008 is also related to a change in methods for
computing PM25 emissions from paved roads.
Specifically, a new method for 2008 paved road
emissions was based on truck vehicle miles tracking
and road particulate testing in collaboration with
industry groups, resulting in new emission factors
that give higher PM25 and lower PM10 emissions.
The PM25 increases offset PM25 decreases from other
sectors.
Some sectors (as shown in the totals in Figure 17 and
Table 5) show emissions decreases or little change
after 2008. This maybe due to our approach to hold
emissions contant from several categories in absence of
a projection year emissions inventory. For instance, the
NH3 trend for agriculture has been upward. The flat-
line of the agriculture emissions in the miscellaneous
category from 2008, along with increases in the other
sectors, allows for an apparent increase of 5 percent
from 2002 to 2012.
-------
NATIONAL EMISSIONS INFORMATION
Fuel Combustion
Includes electrical utilities, industrial/commercial boilers, residential
Tons 4<°°°
X103
2008
Year
2009
2010
2012
Figure 18: National Air Emissions, Fuel Combustion Sector, 2002-2012
Industrial Processes
Includes chemical manufacturing; metals processing, petroleum processing, storage & transport;
agriculture, solvents, waste disposal
Tons
X10s
2002
2003
2004
2005
2006
2007
2008
Year
2009
2010
2011
2012
NH3
VOC
PM2.5
«PM10
CO
NOX
SO,
Figure 19: National Air Emissions, Industrial Processes Sector, 2002-2012
-------
NATIONAL EMISSIONS INFORMATION
CO[=/10]
Tons
X103
Highway Vehicles
Includes gasoline and diesel cars, trucks, and buses
see Figure 21
2002
2003
2004
2005
2006
2007
2008
Year
2009
2010
2011
2012
Figure 20: National Air Emissions, On-road Mobile Highway Vehicles Sector, 2002-2012
Highway Vehicles
CO[=/10] with consistent emissions model, MOVES2012b
10,000
8,000
Tons
xlO3
2008
-IMOX
CO i
> voc
NH3
--PM10
-»-PM2.5
S02
Source: USEPA Model MOVES2010b
Figure 21: National Air Emissions, On-road Mobile Highway Vehicles Sector,
2002-2008, Using Consistent MOVES 2010b
-------
NATIONAL EMISSIONS INFORMATION
C0[=/10]
Nonroad Mobile
Includes aircraft, marine, railroad,
equipment-recreation, construction &farm
5,000
4,000
3,000
2,000
Tons
X10s 1,000
20022003
ZUUi 2004
2007
2008
2009
Year
2010
2011
2012
NH3
PM25
PM10
S02
CO
voc
NOX
Figure 22: National Air Emissions, Nonroad Mobile Sector, 2002-2012
Miscellaneous Other
Includes agricultural livestock waste, fertilizer application, dust,
fires agicultural burning & prescribed, excludes wildfires
Tons
X103
2002
2003
2004
2005
2006
S02
NOX
VOC
PM2.5
NH3
CO
PMln
2007
2008
2009
Year
2010
2011
2012
Figure 23: National Air Emissions, Miscellaneous/Other Sector, 2002-2012
-------
NATIONAL EMISSIONS INFORMATION
NH3 NOX PM10 PM25 SO2 VOC Lead
1,000
Tons x103
2008-2005
-1,000
-2,000
-3,000
-4,000
-5,000
IMisc Fuel Comb IndustProc DNonroad Mobile D Highway Vehicle
Emissions Difference from 2005 to 2008
Source: USEPA NEI2005 V2,2008 V2; excludes Tribal, PR, VI, federal waters.
Figure 24: Comparison of CAP Emissions from 2005 to 2008, Excluding Wildfires and Biogenics
3.3 Emissions by Sector Comparisons for 2005
and 2008
3.3.1 CAP Comparisons
In the previous section we discussed the general CAP
emission trends over time at a national level, both
in total sum and by broad sector aggregation. In this
section we review and compare, in more detail, the
most recent comprehensive inventories completed
by the EPA - the NEI for years 2005 and 2008 - to
see where emission reductions have occurred and to
explain how much of the differences result from real
changes rather than methods differences. Figures 24
and 25 compare the latest CAP inventories for 2005
and 2008. The y-axis shows the emissions difference as
estimated by subtracting the 2005 emissions from the
2008 emissions. Values greater than zero indicate that
2008 emissions are larger than 2005 values. Figure 24
compares CAP emissions for five of the seven broad
sectors as described in Table 3 (excluding wildfires
and biogenic emissions), while Figure 25 compares
the wildfire emissions. Table 6 describes the emission
changes for each pollutant/sector combination and
Table 7 identifies the source within the sector that
drives the decrease or increase observed by pollutant /
sector combination and notes where some differences
are also due to method changes.
Explanations for these differences are shown by
pollutant/sector in Table 7. Figure 24-25, together with
Table 6, illustrate that:
For most sectors and most of the CAPs, emissions
are lower in 2008 than in 2005; the exceptions are
some small increases in NOx, PM25 and PM10 for the
highway vehicle sector, PM10 from fuel combustion
and NH3 from the miscellaneous sector, nonroad
mobile and fuel combustion. Table 7 identifies the
source within the sector that drives the observed
increase. Wildfire CAP emissions are significantly
higher in 2008 than in 2005.
For highway vehicles, the emissions model available
and used to estimate source emissions was different
for the NEI 2005 (MOBILE6) and 2008 (MOVES).
The effect of this method change and use of the
different models is an apparent increase for NOx
and PM emissions between 2005 and 2008. As
-------
NATIONAL EMISSIONS INFORMATION
Tons x103
2008-2005
2,500
2,000
1,500
1,000
500
I Fires-Wildfires
PM,
SO,
voc
Emissions difference from 2005 to 2008
10,000
8,000
6,000
4,000
2,000
Figure 25: Comparison of CAP Emissions from 2005 to 2008, Wildfires
Table 6: Emission Sum Differences for CAP Emissions Shown in Figures 24 and 25
EMISSIONS SUM DIFFERENCE
TOTAL SUM
DIFFERENCE
EXCLUDES
WILDFIRE
Sector
Miscellaneous
Fuel Combustion
Industrial Processes
Nonroad Mobile
Highway Vehicle
116,791
NH3
351,833
40,065
-117,038
970
-159,039
-20,500,373
CO
-4,466,303
-758,726
-324,165
-2,610,750
-12,340,429
-1,914,466
NOX
-124,828
-1,280,291
-31,943
-1,110,248
632,843
-515,461
PM,o
-183,959
-469,882
37,250
-79,987
181,117
-221,214
PM2,
68,657
-311,270
-57,140
-79,609
158,146
-4,527,812
S°2
-45,950
-3,581,292
-247,786
-624,566
-28,218
-2,996,339
VOC
-1,387,799
-223,469
-71,762
-273,620
-1,039,690
-227
Pb
-54
0
-255
81
0
Fires-Wildfires
Total percent Dif-
ference excludes
wildfire
164,606 10,161,767
65,901
968,203 820,866
53,863
2,364,983
POLLUTANT PERCENT DIFFERENCE 2005 TO 2008
-23 -10 -2 -4 -31
-17
-19
-------
NATIONAL EMISSIONS INFORMATION
Table 7: Explanations of the Differences Seen in CAP Emissions Between 2005
Miscellaneous
NH3 Increases: Prescribed fires;
Waste disposal -addition
of municipal/ commercial
composting results in increase
for NH3. This sector drives the
overall small increase in NFL.
3
CO Increases: Prescribed fires;
Agricultural field burning.
Decreases: Misc Non-Industrial
NEC processes which includes
other combustion structure
fires. Magnitude drives overall
decrease for sector.
N0x Decreases:
Waste Disposal, which
includes open burning; Misc
Non-Industrial NEC, includes
nonpoint processes for petro-
leum product storage, other
combustion structure fires,
and cremation.
PM25 Increases:
Prescribed fire 76 percent;
Agricultural crop tilling &
livestock dust 67 percent; Dust
from paved road 128 percent -
due to method change.
S02 Increase: Prescribed fires
Decreases: Misc Non-industrial
NEC, which includes nonpoint
processes for petroleum prod-
uct storage, other combustion
structure fires, and cremation.
Magnitude drives overall
decrease for sector.
VOC Decreases:
Bulk gas terminals;
Fires -agriculture field
burning; Misc Non-industrial
NEC, which includes nonpoint
petroleum product storage.
Lead Large decrease in waste
disposal.
Fuel
Combustion
Slight increase is in
residential wood
combustion.
Slight decrease,
most of which is in
industrial boilers.
General decreases
in commercial/
institutional boil-
ers and heating,
electric utilities, and
industrial boilers.
General decrease
in all combustion
processes.
Magnitude drives
overall decrease for
PM25.
Large decreases in
commercial/institu-
tion, electric utili-
ties, and industrial
boilers.
General decreases
in all combustion
processes.
Industrial Processes
Decreases:lndustrial Processes
Not Elsewhere Classified,
which includes mostly point
processes - food & agriculture
and food & kindred products.
Slight decrease, mostly in
petroleum refineries, pulp
& paper, and storage and
transfer.
General decreases in all
processes, somewhat larger
decrease in mineral products
and storages transfer.
General decrease in all
processes.
General decreases in most
processes, somewhat larger
decrease in petroleum refin-
eries and pulp & paper.
General increase for some
processes, most notably for
oil and gas.
General decreases across
many other processes with
substantial decrease in sol-
vent surface coating - both
industrial and non-industrial.
Decreases most notably in
industrial processes-NEC and
storages transfer.
and 2008
Nonroad Mobile
Decrease for com-
mercial marine and
largest decrease in gas
equipment.
Decreases:
railroad 24 percent;
commercial marine 70
percent; gas equip-
ment 45 percent; non-
road diesel equipment
7 percent
Decrease:
aircraft 56 percent;
commercial marine 79
percent
Decreases:
railroad 86 percent;
commercial marine 88
percent; nonroad die-
sel equip 84 percent;
gas equipment 33
percent.
General decreases
across all processes.
Small increase, mostly
aircraft.
Highway Vehicle
Decreases:
gasoline vehicles.
Increases:
diesel vehicles 17 percent
Decreases:
gasoline vehicles 56
percent. Drives overall
decrease.
Increases: diesel vehicles
47 percent
Decreases:
gasoline vehicles 21
percent
Overall increase due to
change in mobile model.
Increases:
gasoline vehicles 43
percent; diesel vehicles 155
percent. Due to change
in mobile model. Not a
nationally significant
source of PM.
Decreases: gasoline
vehicles.
Drives the overall small
decrease for sector.
Decreases: gasoline
vehicles 96 percent.
Drives overall decrease for
sector.
-------
NATIONAL EMISSIONS INFORMATION
/ /
Misc FuelComb IndustProc HNonroad Mobile Highway Vehicle
Comparisonof 2008 NEI V2 and 2005 NEIv2
Excludes: Tribal, PR, vi;and wildfires Emissions Difference from 2005 to 2008
Misc includes prescribed fires.
Chromium
Compounds Arsenic
Figure 26: Comparison of HAP Emissions from 2005 to 2008, Excluding Wildfires and Biogenics
indicated in Figure 21, when applying the same and
most recent available EPA model to both 2005 and
2008 - all CAP emissions decline through 2008.
3.3.2 HAP Comparisons
For the national HAPs of relevance shown in Table 2,
Figure 26 compares 2005 to 2008 emissions for the
same sectors depicted in Figure 24 (fires are not
shown for HAPs), using the NATA 2005 inventory for
the 2005 emission values. Some observations from
this figure and from the associated emission totals in
Table 8 include:
There are greater than 5,000 tons of emission
reductions of ethylbenzene, tetracholoroethylene,
and 1,4-dichlorobenzene from industrial processes.
Highway vehicle emissions decreased in 2008 for
1,3-butadiene and formaldehyde compared to 2005
levels.
In combination with the emissions changes shown
in Table 8, most of the HAPs show reductions from
2005 to 2008, with the reductions ranging from
84 percent for dicholorobenzene to 2 percent for
chromium compounds. Note that percent differences
can be high even when corresponding amounts
of emissions are low. The reader should use both
Figure 26 and Table 8 as a guide for which pollutants
have decreased by the most significant amounts, both
on a percentage basis and on a mass basis.
Acetaldehyde and acrolein both show increases in
total emissions from 2005 to 2008. Acetaldehyde
increases are from increased industrial natural
gas combustion and increases in on-road mobile
estimates that have occurred by changing to
the MOVES model. In addition, ethanol in the
fuel supply increased between 2005 and 2008,
contributing to increased acetaldehyde. Increases
in acrolein are from higher prescribed burning
emissions (because of new estimation methods)
and higher industrial combustion of fossil fuels and
biomass. Table 9 provides further descriptions for
each HAP/sector s change from 2005 to 2008.
The emissions changes for specific sources described
in Table 9 are caused by a combination of actual
emission changes and method changes. For example,
emission estimation models for on-road mobile
sources and fire emissions changed and cause some
of the emission differences noted in this section.
Table 9 also shows that much of the change for the
industrial process sector is caused by solvent use
emissions changes. This resulted from procedural
changes in the portion of specific solvent emissions
estimated by the EPA and the portion estimated by
the states/ local agencies. Many of the changes to
methods are described more fully in the 2008 NEI
Technical Support Document [ref 2].
-------
NATIONAL EMISSIONS INFORMATION
Table 8: Emission Sum Differences for HAP Emissions Shown in Figure 26
EMISSION SUM DIFFERENCES
TOTAL SUM
-15,468 2,987 3,739 -24,188 -27,911 -6,041 -11,094
hXCLUUhb
WILDFIRE
3
a
un
Miscellaneous
Fuel
Combustion
Industrial
Processes
Nonroad Mobile
Highway Vehicle
QJ QJ
(~ QJ
QJ -O
LLJ <
-1,187 137
-117 1,729
-5,753 -128
-9,530 -1,338
1,120 2,588
QJ
QJ
= "O
"QJ PO
o E
< £
1,572 -13,026
1,467 4,665
50 -2,097
299 -3,660
352 -10,070
QJ
QJ
H
B|
1 W
-912
17
-27,015
0
0
POLLUTANT PERCENT DIFFERENCE 2005 TO
Total percent
Difference
excludes
wildfires
-14 3
Table 9: Explanations of the Differences
Sector
Ethylbenzene
Acetaldehyde
Acrolein
Formaldehyde
Miscellaneous
Decreases:
waste disposal;
gas stations
Large increase -
Prescribed fires
Decreases:
Misc Non-Industrial
NEC; Waste Disposal
13 -9
-83
QJ
|
QJ QJ
"i S
O T3
I ~ S . ^ CO
-45 -4,521
0 -805
-5,997 -524
0 -381
0 -4,863
2008
-84 -22
-13 -184
E H
1 1 E
£ E v
36 -4
58 -184
-100 3
2 1
-8 0
^^H
-2 -57
Seen in HAP Emissions Between 2005 and 2008
Fuel Combustion
Increases:
Industrial boilers
natural gas
Increases:
Mostly in Industrial
boilers natural gas,
and some biomass;
smaller increases in
electric utility biomass
and coal
Industrial
Processes
Decreases:
Industrial processes-
NEC; Solvents-
consumers commercial,
and industrial surface
coating
Decreases:
Industrial processes-
NEC;
Oil & Gas Production
Nonroad Mobile
Large decrease in
nonroad gasoline
equipment
Decreases:
commercial marine
vessels and nonroad
diesel equipment
Highway
Vehicle
Slight increase, both
onroad gasoline and
diesel vehicles
General increases in
on-road gasoline and
diesel vehicles
-------
NATIONAL EMISSIONS INFORMATION
Table 9: Explanations of the Differences seen in HAP Emissions Between 2005 and 2008 in Table 8 (continued)
Sector Miscellaneous
Tetrachloroethylene
1,4-Dichlorobenzene
1,3-Butadiene Decreases:
Misc Non-Industrial
NEC
Chromium Compounds Small increase, in
agriculture crops
and livestock dust;
construction dust
Arsenic Compounds
Fuel Combustion
Industrial
Processes
Decreases:
Solvents - consumer &
commercial, degreasing,
and dry cleaning
Large decrease in
Solvents -
consumers
commercial
Nonroad Mobile
Highway
Vehicle
Small increase in
electric utility coal
Decreases:
electric utility coal;
industrial boilers coal
Small decrease is
mostly due to Industrial
Processes-NEC and Sol-
vent Industrial Surface
Coating
Slight increase,
commercial marine
and nonroad gasoline
equipment
Large decrease in
onroad gasoline
vehicles
Slight increase in
heavy duty diesel
and heavy duty
gasoline vehicles
3.4 Biogenic Emissions and Wild Land
Fire Emissions
3.4.1 Biogenic Emissions in the 2008 NEI
Table 4 shows that several pollutants in the NEI
have a biogenic contribution: the most notable of
these are the VOCs, of which there are about twice
as much biogenic VOC emissions as anthropogenic
emissions. For the spatial distribution of non-biogenic
sources illustrated by the VOC emission density
map (Figure 13), we pointed out that most of the
anthropogenic VOC emissions come from mobile
sources and solvent operations. On the other hand,
biogenic VOC emissions come mostly from vegetation.
This section reviews the spatial and chemical nature of
biogenic emissions in the 2008 NEI. It should be noted
that biogenic emissions are the largest source of HAP
emissions for the sectors analyzed in this report.
Table 10: Biogenic VOCs in the 2008 NEI
Total Emissions 2008 (Tons)
Total Biogenic 39,755,361
VOC 38,909,251
Sesquiterpenes 846,110
Figure 27 shows total VOC biogenic emissions
(including terpenes) [ref 14] using emissions density.
As stated previously, emissions in a county are divided
by area to arrive at the density values shown on the
map. Sesquiterpene emissions are shown in total
in Table 10 but omitted from Figure 27. Figure 27
shows that the greatest density of total VOC biogenic
emissions is in the Southeast and the West Coast, areas
where vegetation is abundant and average ambient
temperatures are high. Table 10 shows that biogenic
VOCs contribute, on average, 97 percent of the total
mass of biogenic organics. The key pollutants include
isoprene, formaldehyde, methanol, acetaldehyde
and terpenes. Sesquiterpene emissions constitute the
remaining 3 percent.
Average Fraction of Total Biogenic Emissions 2008
0.974
0.026
-------
NATIONAL EMISSIONS INFORMATION
Legend
VOC Biogenic Emissions Density
Tons/Sq/Mi
| 10-14
15-23
24 - 438
Figure 27: Total VOC Biogenic Emissions Density, 2008 NEI
3.4.2 Wild Land Fires in the 2008 NEI
In most of the emission summaries shown in this
report, we have excluded wild land fires (large wildfires
and prescribed fires) because the emissions are highly
variable from year to year, so changes can skew the
conclusions of relative importance of emissions from
other sectors. Also wildfires occur naturally and are
not an anthropogenic source of emissions that can be
readily controlled.
In contast, agricultural fires (also a sector in Table
3) are included in all of the analyses and graphics
presented in this report. These fires are generally
much smaller (and emit much less) than wildfires or
prescribed fires, do not vary as much year to year and
their occurrences and timing can be planned.
As described previously, the emission estimates in
the 2008 NEI are a combination of SLT-submitted
and EPA-generated estimates. In the case of these
large fires, very few states submitted emission
estimates and, as such, EPA estimates were used in
most cases. EPA estimates are based on a modeling
framework that combines results from BlueSky and
SMARTFIRE2 (SF2) modules [ref 15]. The BlueSky
framework was developed to compute smoke
emissions (and impacts) given known fire information.
The SF2 system was later developed to help reconcile
disparate sources of fire information for use in
BlueSky. Additional information and references on
these methods are included in the 2008 NEI Technical
Support Document [ref 2]. Together these modules
estimate daily, location-specific fire emissions. The
improved algorithms in SF2 allow for every fire to be
assigned to a fire type (either prescribed or wildfire).
Table 11 shows annual CAP emission totals from these
types of fires with the following highlights:
Wild land fires are a major contributor to national
PM2 5 emissions in 2008 (they contribute 28 percent
of the total emissions). They produced an estimated
total of nearly 1.8 million tons of PM25 in 2008.
-------
NATIONAL EMISSIONS INFORMATION
Table 11: CAP Emissions from Wild Land Fires in the 2008 NEI
Pollutant
CO
NH3
NO
X
PM10
so2
voc
Prescribed
Fires,
Emissions
in Tons
815,760
118,766
138,584
699,907
824,000
65,327
1,696,194
Wildfires,
Emissions
in Tons
12,200,112
198,112
96,370
998,605
1,178,000
69,993
2,846,633
Total 2008
NEI Emissions,
Tons
89,170,000
4,367,000
19,246,000
6,123,000
21,693,000
10,287,000
49,615,000
Percent
Contribution
from
Prescribed
Fires
1
3
1
11
4
1
3
Percent
Contribution
from
Wildfires
14
5
1
16
5
1
6
Total
Contribution
from Wild Land
Fires, percent
15
7
1
28
9
1
9
Wild land fires also contribute over 9 percent to total
CO, PM1Q and VOC emissions in the 2008 NEI.
Wild land fires are a very minor contributor to NOx
and SO2 emissions.
Due to the nature of the burns, wildfires contribute
more to emissions for all CAPs except NO than do
prescribed burns. This is despite there being about
an equal amount of acres burned nationally with
prescribed burns in 2008.
Wild land fires are also a dominant contributor to
acrolein emissions and a significant contributor
to 1,3-butadiene, acetaldehyde, formaldehyde and
benzene emissions.
The 2008 NEI data on fires allow us to look at
wildfires and prescribed fires in more detail. Figure
28 shows the spatial distribution of acres burned, and
Figure 29 shows PM25 emissions by the fire type (either
prescribed or wild fires). These maps also identify a
third fire type: wild land fire use. These fires are started
as wildfires but then brought under control and used
as a prescribed burn. These types of fires make up a
very small part of the total fires (usually in the Western
U.S.) and are part of the wildfire emission estimates
shown in Table 11.
Some interesting highlights from Figures 29 and 30
include:
States that have larger amounts of area burned
associated with prescribed fires (GA, KS and most
Eastern states) tend to have lower PM, emissions
than states with higher amounts of activity associated
with wildfires (CA, TX), which have higher PM25
emissions. This is due to the fact that wildfires emit
more pollutants than prescribed fires due to nature
and conditions of burning, which is captured by the
models used to estimate the emissions.
Both acres burned and PM2 5 emissions are low in
the Northeastern and Midwestern states, with the
exception of Minnesota, where deep organic fires in
2008 caused higher activity and emissions from fires
[ref!6]
The Eastern U.S. is dominated by prescribed fires,
with Southeastern states showing much higher
activity (acres burned) associated with prescribed
burns than elsewhere in the country.
North Carolina has a low amount of acres burned
by wildfires, yet the corresponding PM2 5 emissions
are very high. This was primarily caused by the
Evans Road fire [ref 17], which burned in Eastern
NC for over a month in summer 2008, resulting in
significant amounts of smoldering emissions.
As discussed earlier, in the 2008 NEI EPA used SF2
to estimate wild land fire emissions. Most of these
emissions are shown in Figures 28 to 29. To examine
how these emissions have changed over the past
few NEI cycles, EPA has relied on older versions
of SMARTFIRE to develop these wild land fire
emission estimates, and while the methods within
SMARTFIRE (SF) have changed over time, the
overall approach used in the NEI is the same since
-------
NATIONAL EMISSIONS INFORMATION
Legend
Acres Burned by Fire Type
Sum of Fields
t' 870,000
J Prescribed
IWildlandFireUse
Figure 28: Spatial Distribution of Acres Burned by "Fire
Type" in the 2008 NEI
Legend
PM25 Emissions by Fire Type
Sum of Fields
^147,000
^Wild Fires
I I Prescribed
Wildland Fire Use
Figure 29: Spatial Distribution of PM2 5 Emissions by
"Fire Type" in the 2008 NEI
about 2003. Figure 30 provides the trends in U.S.
PM25 emissions from wild land fires from 2003 to
2009 for the lower 48 states. The bar graph shows
trends in PM2 5 emissions for prescribed and wildfires
separately. In sum, no consistent trend is seen in
PM25 emissions from 2003 to 2011, though 2006,
2007 and draft 2011 are seen to be "high fire" years,
and have been identified as such by other sources
[ref 18]. Total emissions not having a consistent
pattern is due to the year-to-year variation seen in
wildfires (green). Prescribed fires (red) are seen to
be very similar in emission levels from 2003-2011.
Figure 30 also reveals that in total (for the lower 48
states) PM25 emissions vary from an estimated low
of about 900,000 tons in 2004 to about 2.3 million
tons in 2007. Regardless of the year in question, the
contribution of PM2 5 emissions from these fires
to the overall total PM25 emissions in the NEI is
significant.
3.5 Focus on the 2008 NEI: Summary of CAPs and
Select HAPs
3.5.1 Emissions Percent Distributions and Emissions
from Stationary and Mobile Sources
In this section we take a more detailed look at the
2008 NEI and the national profile of CAPs and
the select HAPs to better understand the multiple
pollutant nature of emissions from different sectors.
Figures 31 and 32 depict national-level CAP emissions
for the stationary and mobile emissions categories,
respectively. Along the x-axes of both these figures
are the 15 sectors that make up the total for each of
these two broad categoriesthese are the sectors from
the "sector 17" column in Table 3 without wild and
prescribed fires. The y-axes in these figures show the
percent contribution by pollutant in each of the sectors
displayed on the x-axes. These figures only describe the
relative proportion of pollutant emissions within each
sector and do not confirm the amount of emissions
contributed by each sector. The emission magnitudes
are provided in subsequent tables. For example, the
first bar in Figure 31 shows that within the agriculture
sector, about 40 percent of the total CAP emissions
are from NH3; about 50 percent from PM10; and the
remaining 10 percent comes from PM25 and VOCs.
Figures 31 and 32 together show that at the national
level for CAPs:
The solvent sector emits exclusively VOC emissions.
SO2 is the primary pollutant emitted from fuel
combustion for electricity generation, and emit
twice as much SO, as NOV. In contrast, industrial,
2. A
commercial and institutional fuel combustion emit
multiple pollutants (NOx, CO and SO2) in near-
similar proportions.
The dust sector emits mostly PM, while agricultural
burning emits mostly CO emissions. The dust sector
includes road and construction dust.
The industrial processes and miscellaneous categories
emit multiple CAPs in significant proportions.
-------
NATIONAL EMISSIONS INFORMATION
2,500,000
en 2,000,000
I
1,500,000
'en
.en
1,000,000 -
500,000 -
X"
D Wildfires Pi esciibed Fires
Figure 30: PM2 5 Emission Trends in Wild Land Fires, 2003-2009
Further details on some of these emission sources are
provided in the following sections.
CO emissions represent a significant proportion of
total mass of CAPs emitted by on-road, nonroad
equipment and aircraft.
Commercial Marine Vessels (CMV) and rail contain
high proportions of NOx emissions and CMV also
has a high proportion of SO2 emissions, due to high
sulfur fuel being used in the larger CMV engines.
The proportions of CO emissions from several
mobile source categories tend to mask the
contribution by other CAPs to these categories
(PM25, VOC and NOx). In the sections to follow we
will address these multi-pollutant releases in more
detail.
Next, Figures 33 and 34 show the same details as
Figure 31 and 32, except that select HAPs are shown
in these graphics. Only the HAPs of relevance at the
national level (as discussed earlier) are displayed in
Figures 33 and 34 below. Lead emissions are shown
separately in Figure 35.
Figures 33 to 35 show that at the national level, for
these select HAPs:
The agriculture and dust sectors are comprised
mainly of chromium emissions. While the
percent contribution is high for these sectors,
Table 12 indicates that the amount of chromium
compound emissions is 15 and 35 tons respectively.
For the agriculture sector, chromium emissions
were reported by California for crops and livestock
dust. For dust, California data also account for
the majority of chromium emissions reported for
construction dust. California is currently looking
further into the accuracy of these estimates.
Acrolein accounts for a high proportion of HAP
emissions from agricultural burning.
The fuel combustion categories have high
proportions of total HAP emissions from
formaldehyde and acetaldehyde.
The miscellaneous and solvent categories have
equal proportions of multiple HAP emissions.
The predominate portions of the solvent category
are VOC HAPs such as ethylbenzene and
tetrachloroethylene.
Industrial processes have numerous HAPs emitted in
significant proportions, including chromium (about
5-6 percent of total).
-------
NATIONAL EMISSIONS INFORMATION
National 2008 CAP Emissions
Stationary Sources
percent CAP contribution - for total source sector
IVOC
S02
INOX
IPM2.5
IPM10
NH3
l CO
///////*" * ^
/°* _/ -f if & -^
^ .^e- FC=fuel combustion
Source: USEPA NEI 2008 v2, includes fed waters (DM), PR, VI; excludes
Figure 31: National CAP Emissions for Stationary Sources, 2008 NEI
National 2008 CAP Emissions
Mobile Source Sectors
percent CAP contribution - for total source sector
voc
SO 2
NOX
PM2.5
-PM10
NH3
CO
Source: USEPA NEI 2008 v2, includes fed waters (DM), PR, VI; excludes Tribal
Figure 32: National CAP Emissions for Mobile Sources, 2008 NEI
-------
NATIONAL EMISSIONS INFORMATION
National 2008 Select HAP Emissions
Stationary Sources
percent HAP contribution - for total source sector
Agriculture
Dust-RoadsConstrc
Fire-Ag Field Burning
FC-Comm/lnstit
FC-ElecGen
FC-lndusBoilers
FC-Residential
Industrial Proc
Misc
Solvent
FC=fuel combustion
0%
10% 20% 30% 40%
Ethylbenzene
Acetaldehyde
Acrolein
Formaldehyde
Tetrachloroethylene
1,4-Dichlorobenzene
1,3-Butadiene
Chromium
Compounds
Arsenic
50% 60% 70% 80% 90% 100%
Source: USEPA NEI 2008 v2, includes fed waters (DM), PR, VI; excludes Tribal
Figure 33: National HAP Emissions for Stationary Sources, 2008 NEI
On-road vehicles and nonroad equipment have near
equal proportions of ethylbenzene and formaldehyde
emissions. Acetaldehyde is also emitted in significant
proportions.
Aircraft, CMV and rail categories all have a high
proportion of formaldehyde emissions and a
significant proportion of acetaldehyde emissions.
In the Table 12 summary of CAP and HAP emission
totals, lead is indicated as a relatively small amount
nationally, with most of the contributions coming
from aircraft (piston engines). Figure 35 shows that
the largest portion of the national lead contribution
is from aircraft, industrial processes and fuel
combustion from ECU and industrial boilers. All of
the aircraft-based lead emissions occur from piston
engine aircraft.
Figures 31 to 34 show the fraction of the multiple
pollutant emission contributions within a given
sector but does not describe the amount of emissions
contributed by each sector. To better understand
the magnitude of emissions at the national level for
these sectors, Table 12 summarizes the actual tons
of emissions for these pollutant/sector groupings
for stationary and mobile sources. Some interesting
observations for these national-level emissions include:
About 90 percent of CO emissions come from mobile
sources.
Both mobile sources and stationary sources are
important contributors to NOx and VOC emissions.
A majority of PM emissions come from stationary
sources.
Among the HAPs, formaldehyde is emitted in the
highest quantity with a majority of the emissions
coming from mobile sources. Ethylbenzene and
acetaldehyde emissions are also emitted at significant
levels nationally. As indicated in Section 3.4,
biogenic sources are the largest source of these HAP
emissions.
-------
NATIONAL EMISSIONS INFORMATION
National 2008 Select HAP Emissions
Mobile Sources
percent HAP contribution - for total source sector
OnroadVehicles
NonroadEquip
Aircraft
CMV
Railroad
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Source: USEPANEI 2008 v2, includes fed waters (DM), PR, VI; excludesTribal
Ethylbenzene
Acetaldehyde
Acrolein
Formaldehyde
11,3-Butadiene
i Chromium
Compounds
I Arsenic
Figure 34: National HAP Emissions for Mobile Sources, 2008 NEI
National 2008 Lead
Percent Contribution in All Sources
Fire - Ag Field Burning
Railroad
CMV
D FC-Residential
Solvent
D FC-Comm/lnstit
HMisc
DFC-lndusBoilers
FC-ElecGen
D Industrial Proc
Aircraft
Figure 35: National Lead Emissions From All Sources,
2008 NEI
Nearly all 1,3-butadiene emissions come from
mobile sources. For the aldehydes and metal HAPs
(chromium, lead, arsenic), there are contributions
from both mobile and stationary sources.
By looking at the individual columns in Table
12, sectors that have significant multi-pollutant
emissions include on-road vehicles, fuel combustion
sources and industrial processes.
In the next section multiple pollutant emission
contributions by sector will be reviewed in more detail.
3.5.2 Top Pollutant/Sector Emission Contributions in the
2008 NEI
In this section we review the national profile of
multiple emissions contributions at a more detailed
sector level to show which pollutant/sectors stand out
-------
NATIONAL EMISSIONS INFORMATION
Table 12: HAP/CAP Emission Totals (in Tons) for Stationary and Mobile Sources
2008 CAP and Select HAP Emissions (tons) for Stationary Sources, excluding wildfire and prescribed fires
C71
Pollutant
NFL,
CO
NOX
PM10
PM2.5
S02
voc
Ethylbenzene
Acetaldehyde
Acrolein
Formaldehyde
Tetrachloroethylene
1,4-Dichlorobenzene
1,3-Butadiene
Chromium Compounds
Lead
Arsenic
Footnote:
o
1 1
= to
3,636,596 1
168
73
4,671,081 11,745,767
930,446 1,311,903
1
91,888 17
0
0
0
15 35
0
0 0
£:
rv^ '-^
^^ IS)
£= 'E
^71
3,882 2,263
569,531 160,940
24,743 239,972
67,814 19,302
66,219 15,063
3,416 157,937
52,584 13,452
10 9
612 46
3,957 47
414 600
2
0
170 2
0 4
1 7
0 2
JD
= o
S 1
QJ "O
LLJ =
I^_J I^_J
26,835 10,356
721,973 841,517
3,030,541 1,294,501
398,239 168,377
303,080 125,630
7,761,470 928,850
42,642 81,598
112 81
412 2,472
308 2,114
1,565 12,471
24 18
1 1
4 198
209 39
59 48
65 18
PO
"i >
c
-------
NATIONAL EMISSIONS INFORMATION
Table 12: HAP/CAP Emission Totals (in Tons) for Stationary and Mobile Sources (continued)
2008 CAP and HAP Emissions (tons) for Mobile Sources
Pollutant
Chromium Compounds
Lead
Arsenic
Onroad Vehicles
15
7
Nonroad Equip
i
0
7
Aircraft
0
571
0
CMV
17
5
15
Railroad
0
2
0
Total Mobile
33
578
28
Footnote:
Selected HAPs are those indicated by NATA 2005 as nationally significant risk drivers
Zero values = values that round to zero
Data source = NEI 2008 v2, includes federal waters, PR, and VI; excludes Tribal
from an emissions perspective. This is done using the
tile chart in Figure 36 in which the rows list the sectors
and the columns list the CAPs and select HAPs from
the previous charts and tables. The top pollutant/sector
combinations are indicated using emission thresholds
as a color benchmark. Figure 36 presents a convenient
way to quickly gauge the multi-pollutant significance
of a given sector, with additional information to
indicate the importance of a pollutant/sector to the
national emissions total for a given pollutant.
There are two distinct pieces of information in
Figure 36. First, the colors of the cells represent the
percent contribution (based on emissions) within each
of the stationary and mobile source groups, with red
cells representing contributions greater than or equal
to 70 percent; and second, the numbers shown in some
of the cells indicate the pollutant/sector contribution
that is also greater than or equal to 15 percent of the
total 2008 NEI emissions for that pollutant. As an
example, the first cell in Figure 36 for agriculture/NH3
emissions: the red color indicates the contribution
to total stationary source ammonia emissions is
70 percent or greater; in addition, the number "90
percent" in the cell indicates that agricultural NH3
emissions constitute greater than 15 percent (in this
case, 90 percent) of the total NH3 emissions in the
2008 NEI. Grey cells indicate pollutants which are
not emitted for the noted sector. For example, lead
emissions are not present in any of the on-road mobile
source categories.
Noteworthy observations from Figure 36 include the
fact that:
The dust sectors (from paved and upaved roads
and construction) have only PM emissions and the
amount of the total PM emissions contributed from
this source type is significant.
Agriculture is important for NH3 and PM emissions.
The fuel combustion categories generally contribute
large amounts of HAPs and CAPs, with biomass and
coal combustion standing out for 1,3-butadiene and
SO2 emissions, respectively, within the stationary
source categories.
Industrial processes also emit large amounts of many
of the HAPs and CAPs listed; they also make major
contributions to the national total for some of the
metal HAPs and for VOC.
The solvent sector has major emissions for
several HAPs, including tetrachloroethylene and
1,4-dichlorobenzene, as well as for total VOCs.
On-road gasoline vehicles are major emitters of
several CAPs and HAPs. NH, emissions from
5
on-road gasoline sources are significant within the
mobile source sector.
Piston-engine aircraft is the only significant source of
lead among all mobile sources. CMV has a significant
amount of SO2 emissions.
3.5.3 Example Sectors that emit multiple HAPs/CAPs:
Industrial Processes and Fuel CombustionBiomass
Figure 36 provides a convenient way to understand the
multi-pollutant significance of a given sector, and what
pollutants/sectorsare significant relative to the national
emissions total for all sources.
Four sectors are chosen from Figure 36 to illustrate
how "digging deeper" into the sector and source
classifications can lead to more information about
-------
NATIONAL EMISSIONS INFORMATION
which individual sources cause a sector to stand out in
terms of its multipollutant characteristics.
The industrial processes sector under stationary
sources shows all pollutants listed in Figure 36 with
emission contributions and also indicates that some
of the metal HAP emissions are important at a
national level. For this reason, we took a closer look
at the contributing sources to this sector. The results
are shown in Table 13. In this table the industrial
processes sector is further revealed by its more detailed
sectors (the columns in Table 13) and the emission
contributions from each to the sector total. Pollutant
emissions for the individual source types are reported
as a percentage of the total emissions for the industrial
processes sector as a whole.
Six sectors stand out for contributing more than 25
percent of the total industrial processes emissions
(highlighted in gold in Table 13) for four or
more pollutants: storage and transfer; pulp and
paper; non-ferrous metals; industrial NEC (not
elsewhere classified); ferrous metals; and chemical
manufacturing. Pulp and paper (top 25 percent for five
HAPs) and industrial NEC (top 25 percent for several
HAPs and PM2 5 and NH3) have greater than 25 percent
contribution for five or more pollutants. The industrial
NEC is an important source type within industrial
processes at the national level for multiple pollutant
emission releases and includes various manufacturing
processes related to food and agriculture, food and
kindred products and mineral products.
Fuel combustion-biomass is the next aggregated
sector reviewed in more detail from Figure 36.
Figure 36 indicates emission contributions for all
criteria pollutants and national risk-driver HAPs, and
many with large contributions to the stationary source
national pollutant totals. For example, 1,3-butadiene,
has greater than a 70 percent contribution to that
pollutant total for all stationary sources. Table 14
expands the list of the related sources for this biomass
sector that lead to the overall characterization shown
in Figure 36. Table 14 indicates that within this sector,
at the national level, residential wood combustion is
the dominant contributor of CAP and HAP emissions.
Industrial boilers that combust biomass as fuel are also
important contributors nationally, especially for many
of the metal HAPs as well as for hydrochloric acid, NO
and SO2.
Fuel combustion-coal is also seen to be an important
sector nationally (Figure 36). Table 15 further breaks
out coal-based fuel combustion by the sub-categories
that make up the sector. Electric generation is the
dominant contributor to this sector for nearly all CAPs
and HAPs examined.
In Figure 36, the agriculture sector stands out for
PM and NH3 emissions. In looking further at the
contributions to the agriculture sector in Table 16,
crop and livestock dust stand out for PM10 and PM25
emissions, while fertilizer application and livestock
waste contribute significantly to NH3 emissions.
Livestock waste also contributes all of the VOC
emissions in the agriculture sector. The chromium
emissions were reported by California for crops and
livestock dust.
3.6 Mercury Emissions in the 2008 NEI
Mercury (Hg) has not been included in any of the
previous review and analysis. The primary reason
is that the sectors used to categorize mercury are
different than the sectors presented for the other
pollutants. Primary focus for the mercury sectors is
on regulatory categories and categories of interest to
the international community. The following charts
summarize the Hg emissions using these sectors
which keeps the traditional categorization used in past
mercury summaries. Emission differences between
2005 and 2008 are shown by sector and grouped by
degree of emission magnitude: high (red Figure 37);
medium (blue Figure 38); and low (green Figure 39).
Note the difference in scales in each of the charts
presented. Table 17 summarizes all of the emission
amounts from the charts and leaves the color coding
to emphasize the high, medium and low emission
magnitudes. Some of the highlights from this
information include:
National emissions for 2008 are 42 percent less than
in 2005.
For 2008, the sum total of 61 tons is comprised of
59 tons from stationary sources and 2 tons from
-------
NATIONAL EMISSIONS INFORMATION
2008 CAP and Select HAP Emission Tons Distribution Within Stationary and Mobile Sources
Percent Contributions > to 15% of the National Pollutant SumJotal (stationary + mobile) Are Also Indicated
Stationary Sources
Agriculture
DustConstrc
DustPavedUnPaved
Fire-Ag Field Burning
FC-Biomass
FC-Coal
FC-Ngas
FC-Oil
FC-Other
Industrial Proc
MiscBulkGas
MiscCommCook
MiscGasStations
MiscNon-lndustNEC
MiscWasteDisp
SolvCommlndust
SolvConsumerComm
Mobile Sources
Aircraft
CMV
Railroad
MobNR-Diesel
MobNR-Gas
MobNR-Other
MobOR-DieselHD
MobOR-DieseILD
MobOR-GasHD
MobOR-GasLD
25%
52%
Sta
19%
19%
24%
49%
Eion
21%
25%
arv
/
^^5
1
19%
17%
20%
31%
53%
28%
29%
16%
17%
20%
:
17%
29%
46%
42%
36%
26%
^M
52%
22%
Footnote:
Selected HAPs are those indicated by NATA2005 as nationally significant risk drivers.
Sector percent emission contribution is calculated as portion of the pollutant tola I for each sector group - Stationary and Mobile.
Emission thresholds = | (>70% 50%-69% | (21-49% 0-20% noemiss
Percent contribution greater than or equal > 15% the national pollutant sum is based on the sum of stationary and mobile.
FC = fuel combustion; CMV = commerical marine vessel
Data source = NEI 2008 v2, includes federal waters, PR, and VI; excludes Tribal; excludes sectors - wilfires and biogenics.
Figure 36: Percent Emission Contribution by Source for CAPs and Select HAPs in 2008 NEI
-------
NATIONAL EMISSIONS INFORMATION
mobile sources. In 2005 the sum total of 105 tons is
comprised of 1.2 tons from mobile sources and the
remaining 103.8 tons from stationary sources.
Stationary source emissions for 2008 consist of
29.5 tons from coal-fired EGUs with units larger than
25 megawatts (MW).
Table 13: A Detailed Look at the Industrial Processes Source Category: CAPs and HAPs
Industrial Processes - Distribution of Source Type Emissions
Emissions Contributions > to 25 percent of Industrial Processes Total are Highlighted
Industrial Process Sources
Pollutant
NH3
CO
NOX
PM10
PM25
S02
voc
Hydrochloric Acid
Chlorine
Benzene
Ethylbenzene
Naphthalene
Xylenes
Acetaldehyde
Acrolein
Formaldehyde
Cyanide
Compounds
Tetrachloroethylene
Methyl Chloride
1 ,4-Dichlorobenzene
1 ,3-Butadiene
Poly cyclic
Organic Matter
Manganese
Chromium
Compounds
Lead
Arsenic
Cement
Manuf
1.0%
5.5 %
16.6%
2.0 %
3.2 %
12.1 %
0.4%
18.7%
2.1 %
7.4%
0.9 %
9.2 %
0.9 %
0.3 %
0.1 %
2.5 %
0.3 %
0.0 %
0.4%
1.1%
4.6 %
0.8 %
1.9%
1.6%
3.3 %
2.0 %
Chemical
Manuf
22.2 %
11.1%
6.8 %
2.5 %
5.6 %
22.3 %
4.0 %
5.7 %
47.1 %
10.0%
16.2%
6.1 %
16.1 %
12.6%
3.8 %
4.5 %
47.2 %
13.8%
55.1 %
20.7 %
73.8 %
2.5 %
1.2%
2.7 %
4.8 %
1.6%
Ferrous
Metals
0.7 %
25.4%
5.6 %
3.7 %
8.6 %
3.7 %
0.8 %
4.4 %
7.3 %
5.3 %
0.4 %
10.5%
0.7 %
0.1 %
0.7 %
0.8 %
1.1 %
0.0 %
0.0 %
0.0 %
0.0 %
1.5%
51.0%
44.2 %
31.8%
19.2%
Mining
0.0 %
1.6%
0.5 %
62.5 %
25.7 %
0.4 %
0.1 %
4.5 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
2.2 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
2.1 %
0.2 %
1.0%
1.7%
Industrial
NEC
58.8 %
14.1%
17.6%
15.6%
29.1 %
18.0%
8.7 %
18.3%
13.2%
11.1%
22.8 %
18.6%
26.4%
24.2 %
15.7%
25.9 %
28.3 %
29.8 %
8.4 %
4.1 %
6.2 %
43.7 %
30.2 %
39.9 %
16.3%
37.7 %
Non-ferrous
Metals
1.1%
17.9%
1.5%
2.1 %
4.9 %
15.0%
0.7 %
30.2 %
11.7%
0.7 %
1.0%
1.2%
0.6 %
0.1 %
0.3 %
0.3 %
9.2 %
17.1 %
0.8 %
0.0 %
1.8%
36.4%
6.2 %
7.7 %
34.7 %
29.2 %
Oil & Gas
Production
0.0 %
11.8%
35.9 %
0.9 %
1.7%
7.0 %
67.9 %
0.0 %
0.0 %
22.9 %
8.1 %
0.3 %
11.3%
0.2 %
1.3%
12.2%
0.0 %
0.2 %
0.0 %
9.4%
1.0%
0.0 %
0.0 %
0.0 %
0.0 %
0.1 %
Petroleum
Refineries
3.5 %
4.6 %
8.2 %
2.2 %
5.7 %
16.3%
2.7 %
3.1 %
7.1 %
12.1 %
15.7%
26.0 %
13.0%
0.2 %
0.6 %
6.0 %
8.7 %
4.9 %
0.3 %
0.2 %
4.4%
4.5 %
0.4%
1.0%
2.1 %
1.9%
Pulp&
Paper
6.9 %
7.2 %
6.6 %
4.1 %
9.8 %
4.5 %
5.2 %
14.0%
4.3 %
2.0 %
2.3 %
13.2%
3.8 %
60.8 %
76.7 %
45.6 %
0.1 %
25.2 %
34.6 %
0.2 %
0.0 %
6.4%
2.9 %
1.1%
2.1 %
1.9%
Storage &
Transfer
5.7 %
0.9 %
0.6 %
4.4%
5.6 %
0.6 %
9.6 %
1.0%
7.2 %
28.4%
32.5 %
14.9%
27.3 %
1.5%
0.9 %
2.2 %
2.9 %
9.0 %
0.3 %
64.3 %
8.2 %
4.3 %
4.2 %
1.5%
3.8 %
4.5 %
% Total
Sum
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
"ootnote:
Select HAPs of both national and regional scope are shown.
4EC source category = Not Elsewhere Classified
4EC is attributed to Food & Agriculture, Kindred Products; Mineral Products, i.e., glass, lime; clay asphalt; and Industrial Products NEC.
-------
NATIONAL EMISSIONS INFORMATION
Table 14: A Detailed Look at the Fuel CombustionBiomass Source Category: CAPs and HAPs
Fuel Combustion Biomass - Distribution of Sector Emissions
Emissions Contributions > to 25% of FC Biomass Total are Highlighted
Pollutant
NH,
CO
NOX
PM1n
PM,=
50,
\/OC
Hydrochloric Acid
Chlorine
Benzene
:thylbenzene
Maphthalene
Xylenes
^cetaldehyde
^crolein
:ormaldehyde
Cyanide Compounds
fetrachloroethylene
Methyl Chloride
L,4-Dichlorobenzene
L,3-Butadiene
'olycyclic Organic Matter
Manganese
Chromium Compounds
.ead
Arsenic
Fuel Combustion Biomass Sources
Commercial /
Institutional
0.9%
0.7%
4.2%
0.8%
0.7%
4.3%
0.2%
3.6%
1.1%
1.4%
30.1%
1.1%
3.0%
0.1%
1.8%
0.2%
2.4%
6.1%
4.1%
0.0%
0.0%
1.6%
7.2%
3.3%
3.3%
6.7%
Electric
Generation
6.3%
0.8%
8.0%
0.5%
0.4%
7.0%
0.3%
19.6%
7.3%
0.9%
14.8%
0.3%
0.1%
0.4%
8.2%
0.8%
2.2%
14.5%
12.0%
22.9%
0.0%
0.5%
17.8%
8.6%
10.7%
21.9%
Industrial
Boilers, ICEs *
7.2%
7.4%
60.9%
9.9%
8.4%
63.2%
2.3%
76.8%
20.9%
6.3%
55.1%
5.0%
9.4%
2.1%
24.3%
3.2%
95.3%
79.4%
83.8%
77.1%
0.0%
7.9%
74.1%
88.1%
83.4%
66.6%
Residential
Wood
85.5%
91.2%
26.9%
88.8%
90.5%
25.6%
97.2%
0.0%
70.7%
91.5%
0.0%
93.5%
87.5%
97.5%
65.7%
95.8%
0.0%
0.0%
0.0%
0.0%
100.0%
90.0%
0.9%
0.0%
2.6%
4.8%
% Total
Sum
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
:ootnote:
Select HAPs of both national and regional scope are shown.
" ICEs = internal and external combustion
-------
NATIONAL EMISSIONS INFORMATION
Table 15: A Detailed Look at the Fuel CombustionCoal Source Category: CAPs and HAPs
Fuel Combustion Biomass - Distribution of Sector Emissions
Emissions Contributions > to 25% of FC Biomass Total are Highlighted
Pollutant
NH,
CO
NOX
PMln
PM, =
50,
\/OC
Hydrochloric Acid
Chlorine
Benzene
:thylbenzene
Maphthalene
Xylenes
^cetaldehyde
^crolein
:ormaldehyde
Cyanide Compounds
fetrachloroethylene
Methyl Chloride
L,4-Dichlorobenzene
L,3-Butadiene
'olycyclic Organic Matter
Manganese
Chromium Compounds
.ead
Arsenic
Fuel Combustion Biomass Sources
Commercial /
Institutional
0.9%
0.7%
4.2%
0.8%
0.7%
4.3%
0.2%
3.6%
1.1%
1.4%
30.1%
1.1%
3.0%
0.1%
1.8%
0.2%
2.4%
6.1%
4.1%
0.0%
0.0%
1.6%
7.2%
3.3%
3.3%
6.7%
Electric
Generation
6.3%
0.8%
8.0%
0.5%
0.4%
7.0%
0.3%
19.6%
7.3%
0.9%
14.8%
0.3%
0.1%
0.4%
8.2%
0.8%
2.2%
14.5%
12.0%
22.9%
0.0%
0.5%
17.8%
8.6%
10.7%
21.9%
Industrial
Boilers, ICEs *
7.2%
7.4%
60.9%
9.9%
8.4%
63.2%
2.3%
76.8%
20.9%
6.3%
55.1%
5.0%
9.4%
2.1%
24.3%
3.2%
95.3%
79.4%
83.8%
77.1%
0.0%
7.9%
74.1%
88.1%
83.4%
66.6%
Residential
Wood
85.5%
91.2%
26.9%
88.8%
90.5%
25.6%
97.2%
0.0%
70.7%
91.5%
0.0%
93.5%
87.5%
97.5%
65.7%
95.8%
0.0%
0.0%
0.0%
0.0%
100.0%
90.0%
0.9%
0.0%
2.6%
4.8%
% Total
Sum
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
:ootnote:
select HAPs of both national and regional scope are shown.
* ICEs = internal and external combustion
-------
NATIONAL EMISSIONS INFORMATION
Table 16: A Detailed Look at the Agriculture Source
Category: CAPs and HAPs
Agriculture- Distribution of Source Type Emissions
Emissions Contributions > to 25% of Agriculture Total are Highlighted
Militant
NH3
PM10
PM2.5
WDC
Chromium Compounds
Agriculture Sources
Crops & Livestock
Dust
0.0%
99.5%
99.2%
0.0%
100%
Fertilizer
Application
32.7%
0.0%
0.0%
0.0%
0.0%
Livestock
Waste
67.3%
0.5%
0.8%
100%
0.0%
% Total
Sum
100%
100%
100%
100%
100%
Footnote
Select HAPs of both national and regional scope are shown.
Chromium emissions for Crops & Livestock Dust is approx 15 tons.
D2005
12008
ICI Boilers and
Process Heaters
Portland Cement
Non-Hazardous Waste
Electric Arc Furnaces
Utility Coal Boilers
10 20 30 40 50 60
Figure 37: High Emitting Hg Sectors
D2005
2008
Mercury Cell
Chlor-Alkali Plants
Municipal Waste
Combustors
Gold Mining
Mobile Sources
Other Categories
10
15 20
Incineration
Hospital/Med/lnfectious
Waste
Sewage Sludge
Commercial/Industrial
Solid Waste
Hazardous Waste
12005
12008
0 0.5
1.5
2.5
3.5
Figure 39: Low Emitting Hg Sectors
Figure 38: Medium-High Emitting Hg Sectors
-------
NATIONAL EMISSIONS INFORMATION
Table 17: Summary of 2005 and 2008 Hg Emissions in the NEI
Sector
Utility Coal Boilers
Electric Arc Furnaces
"Portland Cement Non-Hazardous Waste"
Industrial Commercial Insitutional Boilers and Process Heaters
Chlor-Alkali Plants
Municipal Waste Combustors
Gold Mining
Mobile Sources
Other Categories
Hazardous Waste
Commercial/Industrial Solid Waste
Sewage Sludge
Hospital/Med/lnfectious Waste
2005
52.2
7
7.5
6.4
Year
2008
29.5
4.7
4.2
4.5
Total (all categories)
61
Source: 2008 NEI v2 Technical Support Document [ref 2]
-------
4. Regional Emissions Information
All of the previous review and analyses have
characterized emissions at the national level. In this
section, we provide a regional emissions profile of
NEI CAPs and select HAPs. The HAPs included here
are those important at both the national and regional
level as indicated in Table 2. We start by providing
an overview of the choice of regions, and then
analyze emissions based on these regions and present
summary results. As before, all these analyses do not
contain emissions from wildland fires and biogenic
sources.
4.1 National Climatic Data Center (NCDC) Regions
The regions used for this review are shown in
Figure 40 below and are based on the climatological
map developed and maintained by NOAA (National
Oceanic and Atmospheric Administration). This map
splits the U.S. into 9 regions based on homogeneity
in meteorological conditions as determined by data
analysis conducted by NOAA [ref 19]. These are the
national climatic data center regions and are regularly
used in climate-based analyses and summaries. These
NCDC regions will be used in this report to aggregate
and display regional emission patterns.
Readers may also be interested in how these NCDC
regions relate to the more traditional EPA regions that
are often used. Figure 41 shows this relationship by
including a white border to identify these EPA regions.
Since there are nine NCDC regions and ten EPA
regions, some of the NCDC regions overlap multiple
EPA regions.
NCDC_Region
I Central
I Southeast
EastNorthCentral
Southwest
I Northest
I West
I Northwest I I South
WestNorthCentral
Figure 40: NCDC Regions in the U.S.
-------
REGIONAL EMISSIONS INFORMATION
4.2 Regional CAP and HAP Emissions
Characterization
Figure 42 shows total CAP emissions as a stacked bar
for each NCDC region. The select HAPs are grouped,
and group totals are shown in Figure 43 for each
NCDC region. The HAPs are grouped based on the
attributes noted in Table 2 for ozone and PM-forming
potential, as well as chemical similarities (metals,
aromatics, carbonyls, etc.) The following observations
are based on the regional patterns of CAP emissions
shown in Figure 42:
The Central, South and Southeast regions have the
highest total CAP emissions. These regions also
contain some of the most populated areas in the
U.S. In the Central region, SO2 emissions are the
second highest contributor (after CO) to total CAP
emissions; in the South region, PM10 is the second
highest contributor; while in the Southeast region,
NOx, VOC, SO2 and PM10 are emitted in about equal
amounts after CO.
The Northwest, West North Central, West and
Southwest regions have the smallest amounts of
total CAP emissions. While the West has a smaller
amount of total CAP emissions, there are areas of
high emissions within the region (such as the large
cities in California).
Except in the West North Central region, where PM10
(from paved/unpaved roads and construction dust)
is the major contributor to total CAP emissions, CO
emissions are the dominant contributor to total CAP
emissions.
Proportionally, the South region has more PM10 than
all the other regions. Most of the PM10 comes from
dust sources.
For the HAPs, Figures 43 to 45 present emission
summaries by NCDC region for various HAP groups.
The horizontal axis identifies each region similar to
Figure 42 above. Each of the Figures 43 to 45 has two
different vertical axes that reflect different scales for
emission strength that correspond to the two different
pollutant groups. Figure 43 shows emission sums for
two groups of HAPs: Group 1 contains the pollutants
xylenes, napthalenes, ethylbenzene and benzene;
NCDC_Region
Figure 41: NCDC Regions and Their Relationship to EPA Regions
South
-------
REGIONAL EMISSIONS INFORMATION
Figure 42: CAP Emissions by NCDC Regions, 2008 NEI
1,3-Butadiene
Formaldehyde
Acrolein
Acetaldehyde
Group 2
Figure 43: HAP Emissions by NCDC Regions, 2008 NEI
Group 2 is displayed on the right vertical axis and
contains 1,3-butadiene, formaldehyde, acrolein and
acetaldehyde. These HAPs are grouped due to their
similar ozone and PM forming potential as well as a
similarity in the chemical class they represent. Some
interesting observations from Figure 43 include:
Group 1 HAP emissions are highest in the Southeast
region and lowest in the West North Central region.
Several regions have high emissions of group 1 HAPs
(South, Central, East North Central) and xylenes are
emitted in the highest proportion.
The Group 2 HAPs are highest in the Southeast and
lowest in the West North Central region. Several
regions (East North Central, Northeast, and South)
are high emitters of group 2 HAPs. Formaldehyde
and acetaldehyde are emitted in the highest
proportion in all regions.
The relative proportions of HAPs within Group 1
and Group 2 are relatively consistent amongst all
regions.
Figure 44 also contains two HAP groups summed by
NCDC region. Group 1 is chlorine and hydrochloric
acid (HC1), and Group 2 consists of POM (polycyclic
organic matter) compounds, methyl chloride,
tetrachloroethylene, and 1,4-dichlorobenzene. Group 2
emission sums are indicated on the right vertical
axis and by a different scale. Some highlights from
Figure 44 include:
Emissions from Group 1 compounds are highest
in the Central and Southeast regions. In all regions
except the West, the majority of emissions are from
HC1. In the West region, there are about equal
amounts of HC1 and chlorine.
Emissions of the Group 2 HAPs vary widely amongst
the regions, both in sum and relative proportions for
individual HAPs. The highest emissions are in the
West, and the least emissions are in the West North
Central region. Tetrachloroethylene and POM are
significant Group 2 HAPs emitted in nearly all regions.
The amount of methyl chloride is also significant in the
South.
Finally, Figure 45 shows regional emissions of HAP
metals and cyanide compounds. Group 1 contains
lead, arsenic, chromium and manganese compounds,
while Group 2 contains cyanide compounds. Items
worth noting from Figure 45 include:
The splits among the Group 1 metals are fairly
consistent region to region. The Group 1 metals sum
is highest in the Central region. Six of nine regions
show manganese to be the predominant HAP in
Group 1.
Cyanide is emitted in much higher amounts than
any single Group 1 metal HAP and is highest in the
Central, South and Southeast regions.
The Northwest region has very low levels of both
Group 1 HAPs and cyanide compounds.
4.3 Regional Intensity for Ozone and PM
Formation, HAPs and CAPs
In the previous section, the relative distribution of
-------
REGIONAL EMISSIONS INFORMATION
Group 1
Chlorine
Hydrochloric Acid
POM
Methyl Chloride
Tetrachloroethylene
1,4-Dichlorobenzene
Group 2
Figure 44: HAP Emissions by NCDC Regions, 2008 NEI
Scale:Group2
3000
Group 2
Figure 45: HAP Emissions by NCDC Regions, 2008 NEI
CAPs and HAPs are shown by NCDC region. Another
way to view emissions by NCDC region is based on
the intensity of the multiple pollutants that form both
ozone and PM. This is done in Figure 46. Each climate
region has similar meteorological patterns that help
determine how the chemicals will interact to form
ozone and fine particles (PM25) and/or transform to
other toxic species. For each region, there are two
bars, or "spare" lines: the top one shows the sum total
of CAP emissions (excluding CO and PM10) and the
lower one shows the sum of the select HAP emissions.
The HAPs selected are those in Table 2 indicated to
have a high potential to end up as secondarily formed
aerosol (SOA) which can facilitate formation of PM2 5,
and those also with limited or high ozone forming
potential based on high VOC reactivity.
The scales are the same for CAPs and HAPs across the
regions: 10 million tons for CAPs and 200,000 tons
for HAPs. The legend describes the specific CAPs and
HAPs that are summed in the color bars. For the top
CAP bar, the two different colors separate those CAPs
that contribute to ozone and PM formation versus
just PM formation. Similarly, for the bottom HAP bar,
the two colors describe the sum of the select HAPs by
their propensity to form either ozone and PM or just
ozone. Figure 46, therefore, presents a convenient way
to compare region-by-region emissions loading that
influences ozone and PM formation. Some interesting
highlights from Figure 46 include:
CAP emissions that form ozone and PM are highest
in the Central, South and Southeast parts of the
country. CAP emissions that contribute solely to PM
are most prevalent in the Central region.
HAP emissions that contribute to PM and ozone are
high in many Eastern regions, and HAP emissions
that contribute solely to ozone formation are highest
in the Central and Southeast regions.
Most of the Western regions have comparatively
lower amounts of emissions (HAP and CAP) that
participate in ozone and PM formation. The number
of populated centers in the West are fewer than in the
East and emissions densities are accordingly lower
there for most pollutants (see Figure 9-16). This does
not mean, however, that specific local areas do not
experience ozone or PM problems in the West. This is
discussed further in the "local profiles" section.
The regional patterns shown in Figure 46 correspond
directly to some of the patterns of regional emissions
shown in the previous section. In translating from
areas of high emissions to air quality, other factors
such as those reviewed in the earlier background
discussion (climate, topography, etc.) also play a role
in determining air quality and need to be considered
along with emissions when describing the entire air
quality picture for a region/locale.
4.4 Regional CAP/HAP Emissions, Top Sector
Contributions
This section reviews the top sector contributions of
HAP/CAP emissions, region by region. The regional
tile chart in Figure 47 has a similar format as the
-------
REGIONAL EMISSIONS INFORMATION
CAPS in million Lons
HAPsin thousand tons
CAPS HAPS
0.1 & PM
NOX Benzene
VOC | | Ethylbenzene
Naplhdenc
Xylencs
PM
S02
NH3
03
Acetaldehyde
Acrolcin
Formaldehyde
1,3-Butadiene
Chlorine
Hydrochloric Acid
NCDC_Region
I EaslNorthCentrai
I WestNorthCenlral
Figure 46: Regional CAP/HAP Intensities to Form Ozone and PM
national tile chart shown in Figure 36, with one key
difference. Here, the investigation of emissions by
region is based on the sectors that rank in the top
25 percent of pollutant emissions (rather than based
on specific emission thresholds). This reveals the
top emitters for individual pollutants and multiple
pollutants even if the emissions contribution for
a pollutant varies widely among the top emitters.
Figure 47 shows the higher emitting sectors that the
majority of regions have in common, identified by
the red color. For instance, for stationary source NH3,
the agriculture sector ranks in the top 25 percent of
NH3 emissions for all nine regions - and is therefore
identified in red. While agriculture contributes
most of the NH3 emissions for all regions, NH3 from
industrial processes is also in the top ranked 25
percent of stationary source NH3 emissions for many
regions. Sources of NH3 within industrial processes
include manufacturing of food, agriculture and
kindred products, and mineral products such as glass,
lime, clay and asphalt. Looking at the top ranked
emitting sectors reveals the top emitters for individual
pollutants even if the emissions contribution for a
pollutant varies widely among the top emitters. The
range of emissions among the top emitters may be
small for some pollutants and sectors. For example,
mobile on-road light duty gas vehicles highlight
manganese, chromium and arsenic - for which the
ranges of emissions for an individual region are
between 3 and less than 0.5 tons. So even though
these pollutant emissions are low in magnitude
relative to stationary sources, they are a significant
contribution when considered among only the mobile
source sectors. The mobile source inventory for these
metals is also based on very limited data and is highly
uncertain. Some other interesting observations based
on Figure 47 include:
The majority of regions, i.e., equal to or greater than
six, as shown by dark and light red colors, have the
same pollutants that rank in the top 25 percent for
stationary sources and for mobile sources as follows:
Stationary sources -
NH3 - agricultural; industrial processes
CO - fuel combustion biomass; industrial processes;
waste disposal
NOx - fuel combustion coal and natural gas
PM1Q, PM25 - agriculture; road and construction dust
-------
REGIONAL EMISSIONS INFORMATION
SO2 - fuel combustion coal; industrial processes
VOC - solvent uses
Lead - fuel combustion coal; industrial processes
HAPs - fuel combustion biomass, coal, and natural
gas; industrial processes; gas stations; waste disposal;
solvent uses
Mobile sources -
NH3 - on-road light duty gasoline vehicles
CO and VOC - nonroad gasoline equipment;
on-road vehicle light duty gas
NOx - on-road heavy duty diesel and light duty
gasoline vehicles
PM10, PM25 - on-road heavy duty diesel and light
duty gasoline vehicles; nonroad diesel equipment
SO2 - commercial marine vessels; on-road heavy duty
diesel vehicles
Lead - piston-engine aircraft
HAPs - nonroad gasoline equipment; on-road heavy
duty diesel and light duty gasoline vehicles
In general, the sectors that show low contributions
across all regions (bulk gas, commercial cooking, etc.)
maybe important for some pollutants at a local level.
Tables 18 and 19 describe the proportion of pollutant
emissions contributed by each region to the national
pollutant total for all stationary sources and for all
mobile sources. The higher percent (10 percent or
more) contributions for each pollutant and sector are
highlighted within the stationary and mobile source
tables. The regional observations from the data shown
in Tables 18 and 19 include:
For stationary sources, Table 18 indicates that:
The Central region has large percent contributions
for the most pollutants-sector combinations.
The larger portions of NH3 are in the South, East
North Central, and Central regions and come from
the agriculture sectors.
Road dust PM is predominant in the South.
The Central, East North Central, and Northeast
regions have large contributions from fuel
combustion biomass for several HAPs, and the West
has a large proportion of 1,3-butadiene, and POM.
This is attributed to more residential wood burning
in those areas.
The Central, Northeast and Southeast regions
contribute large portions of NOx, SO2 and several
HAPs coming from stationary coal combustion; the
South has a large portion of cyanide, also from coal
combustion.
In the South, a large proportion of several HAPs
comes from natural gas fuel combustion and
industrial processes. VOC from industrial processes
in the South is also a predominant contributor (24
percent), though this sector is not a large emitter in
other regions.
The Central, East North Central, Northeast and
West regions have large portions of several HAPs
emitted from solvent use. 1,4-dichlorobenzene
from commercial/industrial solvent uses is also
predominant (17 percent) in the West, though not a
high emitter shared by a majority of the regions.
For Mobile Sources, Table 19 indicates that:
The largest contributions of lead are in the South and
Southeast regions from piston-engine aircraft.
The Southeast has a large portion of xylenes from
nonroad gasoline equipment and of POM from
on-road heavy duty diesel vehicles.
The Central and Southeast regions have some of the
largest portions of NH3, CO, VOC and HAPs, all
from on-road light duty gasoline vehicles; and the
West also has large portions of NH3 and manganese
from this sector.
Tables 18 and 19 show for each region the relative
percent emission contribution to national pollutant
totals by sector within stationary sources and mobile
sources. Table 20 shows the regional contribution
of the noted pollutant and sector to the national
total emissions, i.e., stationary plus mobile, for that
pollutant.
-------
REGIONAL EMISSIONS INFORMATION
2008 CAP and Select HAP Emissions
Number of NCDC Regions with Sectors that Rank in Top 25% for Pollutant Emissions
1=9
Stationary Sources
Agriculture
DustConstrc
DustPavedUnPaved
Fire-Ag Field Burning
FuelComb-Biomass
FuelComb-Coal
FuelComb-Ngas
FuelComb-Oil
FuelComb-Other
Industrial Proc
MiscBulkGas
MiscCommCook
MiscGasStations
MisclMon-lndustNEC
MiscWasteDisp
SolvCommlndust
SolvConsumerComm
Mobile Sources
Aircraft
CMV
Railroad
MobNR-Diesel
MobNR-Gas
MobNR-Other
MobOR-DieselHD
MobOR-DieseILD
MobOR-GasHD
MobOR-GasLD
Footnotes
NCDC is National Climate Data Center Regions (NOAA) - http://www.ncdc.noaa.gov/temp-and-precip/us-climate-regions.php
Selected HAPs are those indicated by NATA2U05 as nationally and regionally significant risk drivers
FC = Fuel combustion
Top ranked 25 percent values a re calculated separately by pollutant and Stationary and Mobile sectors groups.
Data source = NEI 2008 v2, includes federal waters, PR, and VI; excludes Tribal - excludes wildfires and prescribed fires
Figure 47: Number of NCDC Regions With Sectors that Rank in Top 25 Percent of Emissions
The observations from comparing the regional
contributions within source categories (Tables 18
and 19) to Table 20, which shows the relative regional
contributions for all sources (stationary + mobile), are
noted:
Some of the same regions that contributed large
portions of pollutant emissions within the stationary
sources or within the mobile sources also contribute
the largest percentage of the pollutant total for all
sources. Examples include fuel combustion - coal
has the highest SO2 in the Central region for both
stationary and all sources. Commercial/industrial
solvent sources has the highest contribution in the
Western region both in stationary and all sources.
For piston-engine aircraft, lead is highest within
mobile sources and all sources in the Southern
region. Ethylbenzene is highest in the Southeastern
region for both mobile and all sources. While the
Central region has large percent contributions for
the most pollutants/sector combinations within
stationary sources, it also contributes the largest
percentages to the national pollutant totals, and
these come from the same stationary sectors, as were
shown in Table 18.
Many of the large regional contributions
within stationary sources are also predominant
contributions to national emissions totals for all
-------
REGIONAL EMISSIONS INFORMATION
Table 18: Percent Region Contribution to National Pollutant Total for Stationary Sources
Stationary Sources
Agriculture
Pollutant
NH3
PMIO
PM2.5
DustConstrc PMIO
DustPavedUnPaved PMIO
FuelComb-Biomass
PM2.5
CO
Benzene
Naphthalene
Acetaldehyde
FuelComb-Coal
FuelComb-Ngas
Industrial Proc
Acrolein
Formaldehyde
1,3-Butadiene
POM
Manganese
NOX
SO 2
Hydrochloric Acid
Methyl Chloride
Cyanide Compounds
Cr Compounds
Arsenic
Lead
NOX
Acrolein
Formaldehyde
NH3
CO
SO 2
Naphthalene
Chlorine
Methyl Chloride
Manganese
Cr Compounds
Arsenic
Lead
MiscWasteDisp CO
Benzene
SolvCommlndust
VOC
Ethyl benzene
Xylenes
Tetrachloroethylene
SolvConsumerComm voc
Ethyl benzene
Xylenes
1,4-Dichlorobenzene
Tetra ch 1 oroethyl ene
Central
5.5%
5.5%
2.1%
7.0%
3.8%
5.8%
13.6%
10.6%
7.6%
2.1%
7.3%
9.8%
10.6%
0.0%
19.8%
32.5%
29.0%
6.8%
17.1%
13.4%
22.1%
9.1%
4.0%
1.4%
3.1%
0.1%
9.3%
2.6%
5.0%
7.9%
14.1%
34.8%
13.8%
3.0%
29.4%
3.0%
7.7%
4.9%
5.2%
12.9%
22.3%
3.8%
1.7%
2.1%
4.8%
0.8%
ENC
16.8%
4.4%
4.4%
0.7%
3.9%
2.3%
6.5%
12.7%
10.3%
9.3%
3.6%
9.3%
12.3%
9.6%
3.7%
5.7%
8.3%
6.3%
0.0%
9.3%
7.0%
14.2%
3.3%
2.0%
1.0%
2.0%
0.0%
0.0%
0.6%
0.9%
0.0%
2.7%
6.6%
5.2%
6.0%
5.1%
1.2%
2.1%
2.3%
3.0%
7.2%
11.6%
2.4%
1.3%
2.5%
18.8%
1.2%
NE
4.7%
0.6%
0.0%
1.0%
2.7%
1.7%
6.8%
10.2%
10.6%
7.9%
2.5%
9.4%
15.5%
11.1%
2.3%
5.4%
14.6%
11.1%
2.0%
5.0%
3.6%
10.4%
1.7%
2.9%
0.0%
2.0%
0.0%
2.2%
0.5%
1.7%
2.2%
5.6%
6.6%
10.4%
0.0%
8.6%
2.7%
2.5%
4.2%
0.0%
5.0%
2.0%
3.3%
23.5%
2.0%
9.5%
2.2%
NCDC Regions
NW S SE
4.8% 19.3% 10.8%
0.8%
0.7%
0.5%
3.4%
2.2%
2.8%
4.0%
4.8%
3.9%
1.6%
5.0%
7.9%
5.7%
0.7%
0.5%
0.2%
0.0%
0.2%
0.0%
0.1%
0.4%
0.0%
1.3%
0.1%
0.6%
0.1%
1.0%
0.2%
0.0%
1.9%
0.0%
0.4%
0.1%
0.4%
0.3%
0.0%
1.0%
0.5%
0.6%
1.9%
0.2%
1.3%
0.5%
0.9%
5.3%
0.4%
6.8%
6.8%
2.2%
8.1%
0.0%
0.0%
2.6%
0.0%
0.0%
2.5%
0.0%
0.0%
4.2%
6.2%
9.7%
6.6%
0.0%
13.0%
5.7%
8.0%
1.5%
8.5%
1.0%
4.8%
3.0%
4.7%
8.3%
33.3%
6.0%
3.9%
3.2%
7.1%
0.0%
2.5%
3.7%
3.9%
6.4%
5.0%
0.0%
0.0%
0.0%
0.0%
0.0%
1.2%
0.0%
1.1%
6.2%
3.7%
2.7%
3.1%
3.2%
3.0%
3.4%
3.7%
5.0%
5.0%
6.1%
9.7%
18.0%
23.1%
3.1%
10.7%
10.6%
10.5%
2.0%
1.9%
1.7%
3.4%
sw
4.7%
0.8%
0.8%
0.9%
5.9%
3.3%
1.7%
2.5%
3.0%
2.4%
0.7%
3.1%
5.0%
3.5%
0.0%
3.6%
1.5%
1.3%
1.3%
2.8%
2.6%
0.0%
0.5%
1.7%
3.4%
4.7%
0.3% 0.1%
3.4% 1 0.0%
1.4% 1 0.5%
1.9% 1 0.0%
5.1% 0.0%
9.7% 0.0%
3.4% 0.0%
2.6%
1.6%
5.9%
5.3%
3.2%
3.9%
4.0%
7.8%
1.0%
4.5%
0.0%
0.0%
0.0%
0.0%
0.3%
4.5%
5.0%
0.7%
0.0%
0.9%
1.4%
1.8%
4.2%
1.3%
0.0%
0.7%
6.9%
0.5%
w
6.9%
0.2%
0.0%
2.4%
2.0%
1.2%
3.8%
0.0%
0.0%
7.5%
2.7%
4.8%
11.2%
15.8%
0.6%
0.0%
0.1%
0.5%
0.0%
0.6%
0.0%
0.0%
0.0%
1.2%
0.0%
2.2%
0.0%
0.0%
0.3%
3.6%
0.0%
0.0%
1.5%
2.9%
8.0%
2.1%
0.6%
0.5%
1.6%
2.4%
5.7%
0.8%
2.2%
2.7%
2.8%
WNC
11.8%
4.3%
4.4%
0.0%
4.9%
2.6%
0.5%
0.8%
0.9%
0.7%
0.4%
0.0%
1.4%
1.0%
0.0%
4.0%
3.4%
1.7%
1.7%
3.6%
2.0%
2.6%
0.6%
1.1%
1.8%
2.2%
0.2%
0.7%
0.3%
0.1%
1.4%
0.0%
0.6%
0.1%
1.3%
1.0%
0.0%
0.4%
0.0%
0.3%
0.6%
0.0%
0.9%
1.7%
1.9%
0.0%
0.0%
Footnote:
Pollutant/ sector selections are based on Figure 47 - the h gher emitting sectors that the majority of regions have in common.
Emissions > 10% of pollutant total in all stationary sources are h gh lighted.
Emissions in federal waters are excluded.
-------
REGIONAL EMISSIONS INFORMATION
Table 19: Percent Region Contribution to National Pollutant Total for Mobile Sources
Mobile Sources Pollutant
Aircraft Lead
CMV S02
MobNR-Diesel
PM2.5
MobNR-Gas CO
voc
Benzene
Ethyl benzene
Xylenes
1,3-Butadiene
MobOR-DieselHD NH3
INOX
PM10
PM2.5
SO2
Naphthalene
Acetaldehyde
Acrolein
Formaldehyde
POM
Manganese
MobOR-GasLD NH3
CO
NOX
PM10
Central
11.6%
1.0%
3.6%
4.5%
5.8%
5.1%
5.4%
6.9%
4.7%
0.8%
5.3%
6.1%
6.5%
2.2%
4.9%
3.3%
6.0%
4.1%
10.7%
1.6%
14.2%
11.6%
5.5%
3.6%
VOC 8.4%
Benzene
Ethyl benzene
Naphthalene
Xylenes
Acetaldehyde
Acrolein
Formaldehyde
1,3-Butadiene
POM
Manganese
Cr Compounds
Arsenic
110.6%
11.0%
10.3%
10.4%
8.3%
4.7%
5.1%
9.8%
5.6%
4.3%
7.1%
3.8%
ENC
7.4%
1.3%
2.4%
2.9%
5.9%
3.6%
3.3%
5.3%
6.0%
0.4%
2.5%
2.9%
3.1%
1.0%
2.3%
0.0%
2.8%
0.0%
5.1%
0.8%
6.9%
6.1%
2.8%
2.1%
4.6%
6.1%
6.0%
6.0%
5.7%
5.4%
2.8%
3.0%
5.5%
3.5%
2.2%
3.5%
1.9%
NE
12.7%
3.6%
2.4%
6.2%
8.2%
6.1%
5.9%
8.2%
6.1%
0.6%
3.4%
3.8%
4.1%
1.4%
3.1%
2.1%
3.8%
2.6%
6.8%
1.1%
14.2%
8.4%
4.2%
3.3%
6.5%
7.9%
8.3%
7.9%
7.9%
6.7%
3.7%
4.1%
8.1%
4.6%
4.7%
7.7%
4.2%
NCDC Regie
NW S
8.1% 18.5%
2.6%
0.8%
1.4%
2.1%
1.7%
1.9%
2.4%
1.6%
0.2%
1.1%
1.3%
1.4%
0.4%
1.0%
0.0%
1.2%
0.8%
2.2%
0.0%
3.3%
3.6%
1.5%
1.0%
2.4%
4.1%
3.2%
2.9%
3.0%
1.9%
1.3%
1.3%
2.7%
1.7%
1.0%
1.6%
0.9%
5.2%
3.6%
3.4%
5.1%
4.7%
5.2%
6.1%
3.2%
0.8%
4.9%
5.7%
6.1%
2.0%
4.3%
2.9%
5.3%
3.7%
0.0%
2.2%
12.4%
8.5%
4.4%
0.0%
6.7%
7.8%
8.7%
7.8%
8.3%
5.6%
0.0%
4.0%
8.0%
3.8%
4.0%
6.6%
3.6%
3ns
SE
17.3%
3.7%
3.2%
6.5%
8.0%
8.1%
8.9%
10.5%
6.2%
1.0%
5.8%
7.2%
7.7%
2.8%
5.7%
3.8%
7.0%
4.8%
1.9%
17.9%
13.1%
7.1%
3.7%
10.2%
12.6%
13.5%
11.9%
12.8%
7.9%
5.3%
5.9%
12.3%
5.8%
5.5%
9.1%
4.9%
SW
8.1%
0.0%
1.0%
1.3%
1.7%
1.7%
1.8%
2.1%
1.5%
0.3%
1.8%
2.0%
2.1%
0.7%
1.5%
1.0%
1.8%
1.3%
3.3%
0.0%
4.5%
3.3%
1.8%
1.0%
2.7%
3.6%
3.5%
3.0%
3.3%
2.2%
1.4%
1.5%
2.9%
1.6%
1.4%
2.4%
1.3%
W
12.1%
1.7%
1.9%
1.9%
2.6%
2.6%
2.0%
0.5%
3.7%
0.0%
3.3%
2.2%
2.3%
0.0%
2.4%
4.0%
0.0%
4.4%
0.3%
0.0%
14.6%
4.1%
1.9%
2.0%
4.1%
3.5%
4.0%
5.2%
0.7%
0.0%
3.6%
0.0%
4.4%
0.0%
17.5%
0.5%
0.0%
WNC
2.9%
0.0%
1.6%
0.5%
0.8%
0.6%
0.7%
0.9%
0.7%
0.1%
0.0%
0.8%
0.8%
0.3%
0.7%
0.0%
0.8%
0.0%
1.4%
0.2%
1.6%
1.3%
0.0%
0.0%
0.9%
1.3%
1.2%
1.2%
1.2%
1.1%
0.0%
0.6%
1.2%
0.7%
0.5%
0.8%
0.4%
Footnote
Pollutant/ sector selections are based on Figure 47 - the higher emitting sectors that the majority of regions have in common.
Emissions ^ 1 0% of pollutant total in all mobile sources are highlighted.
Emissions in federal waters are excluded.
-------
REGIONAL EMISSIONS INFORMATION
Table 20: Percent Region Contribution to National Pollutant Total for All Sources
Stationary Sources Pollutant
Agriculture
IMH3
PM10
PM2.5
DustConstrc PM10
DustPavedUnPaved PM10
PM2.5
FuelComb-Biomass
CO
Benzene
Naphthalene
Acetaldehyde
Acrolein
Formaldehyde
1,3-Butadiene
POM
Manganese
FuelComb-Coal NOX
SO 2
Hydrochloric Acid
Methyl Chloride
Cyanide Compounds
Cr Compounds
Arsenic
Lead
FuelComb-Ngas NOX
Acrolein
Formaldehyde
Industrial Proc
NH3
CO
SO 2
Naphthalene
Chlorine
Methyl Chloride
Manganese
Cr Compounds
Arsenic
Lead
MiscWasteDisp CO
Benzene
SolvCommlndust VOC
Ethyl benzene
Xylenes
SolvConsumerComm
Tetrachloroethylene
VOC
Ethyl benzene
Xylenes
1,4-Dichlorobenzene
Tetrachloroethylene
Central
12.9%
5.3%
4.8%
2.0%
6.7%
3.3%
0.7%
3.2%
3.9%
2.4%
1.3%
2.2%
1.5%
6.2%
0.0%
6.2%
29.0%
6.8%
17.1%
12.5%
17.6%
3.6%
1.2%
0.9%
1.0%
0.1%
1.2%
2.4%
1.9%
7.9%
14.1%
34.3%
13.0%
2.4%
11.8%
0.4%
1.8%
2.8%
0.6%
1.7%
22.3%
2.2%
0.2%
0.3%
4.8%
0.8%
ENC
16.2%
4.2%
3.8%
0.6%
3.8%
2.0%
0.8%
3.0%
3.8%
2.9%
2.3%
2.9%
1.9%
5.7%
3.6%
1.8%
7.6%
6.3%
0.0%
9.3%
6.5%
11.3%
1.3%
0.6%
0.6%
0.6%
0.0%
0.0%
0.6%
0.3%
0.0%
2.7%
6.5%
4.9%
4.8%
2.1%
0.2%
0.5%
1.3%
0.3%
1.0%
11.6%
1.4%
0.1%
0.3%
18.8%
1.2%
NE
4.5%
0.6%
0.0%
1.0%
2.6%
1.4%
0.9%
2.4%
3.9%
2.5%
1.6%
2.9%
2.4%
6.5%
2.3%
1.7%
13.4/1)
11.1%
2.0%
5.0%
3.4%
8.3%
0.7%
0.9%
0.0%
0.6%
0.0%
0.3%
0.5%
0.6%
2.2%
5.6%
6.5%
9.8%
0.0%
3.4%
0.4%
0.6%
2.4%
0.0%
0.7%
2.0%
1.9%
2.6%
0.3%
2.2%
NCDC Regions
NW S SE
4.6% 18.6% 10.4%
0.7% 1 6.6% 1.2%
0.6% 5.8% 1 0.0%~
0.4% | 2.2% | 1.1%
3.2% 14.5% 6.0%
1.9% 7.0% 3.2%
0.4% 0.0% 0.3%
1.0%
1.8%
1.2%
1.0%
1.5%
1.2%
3.3%
0.6%
0.2%
10.2%
0.0%
0.2%
0.0%
0.1%
0.3%
0.0%
0.4%
0.1%
0.2%
0.1%
0.1%
0.2%
0.0%
1.9%
0.0%
0.4%
0.1%
0.3%
0.1%
0.0%
0.2%
0.3%
0.1%
0.3%
0.2%
0.8%
0.1%
0.1%
5.3%
0.4%
0.0%
1.0%
0.0%
0.0%
0.8%
0.0%
0.0%
4.1%
2.0%
9.0%
6.6%
0.0%
13.0%
5.3%
6.4%
0.6%
2.7%
6.2%
4.3%
0.9%
0.6%
2.7%
1.7%
8.3%
33.3%
5.9%
3.7%
2.5%
2.8%
0.0%
0.6%
2.1%
0.4%
0.9%
5.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.7%
1.2%
0.9%
2.2%
1.1%
0.8%
3.0%
6.0%
3.1%
16.6%
23.1%
3.1%
10.7%
10.0%
8.4%
0.8%
0.6%
1.1%
1.0%
0.3%
0.4%
1.3%
0.7%
5.1%
9.7%
3.4%
2.4%
1.2%
2.3%
0.7%
0.8%
2.2%
0.4%
1.0%
1.0%
2.6%
0.0%
0.0%
0.0%
0.0%
sw
4.5%
0.8%
0.7%
0.9%
5.7%
2.8%
0.2%
0.6%
1.1%
0.8%
0.5%
1.0%
0.8%
2.0%
0.0%
1.1%
1.4%
1.3%
1.3%
2.8%
2.4%
0.0%
0.2%
0.5%
2.2%
1.5%
0.1%
0.0%
0.5%
0.0%
0.0%
0.0%
0.0%
0.3%
3.6%
2.0%
0.1%
0.0%
0.5%
0.2%
0.2%
4.2%
0.8%
0.0%
0.1%
6.9%
0.5%
Footnote
Pollutant/ sector selections are based on Figure 47 - the higher emitting sectors that the majority of regions
Emissions ^ 1 0% of pollutant total in all sources (stationary + mobile) are highlighted.
Emissions in federal waters are excluded.
W
6.7%
0.2%
0.0%
2.3%
1.9%
1.0%
0.5%
0.0%
0.0%
2.3%
1.8%
1.5%
1.7%
9.3%
0.6%
0.0%
0.1%
0.5%
0.0%
0.6%
0.0%
0.0%
0.0%
0.4%
0.0%
0.7%
0.0%
0.0%
0.3%
1.3%
0.0%
0.0%
1.5%
2.8%
6.3%
0.9%
0.1%
0.1%
0.9%
0.3%
0.8%
36.6%
0.5%
0.3%
0.4%
33.5%
2.8%
WNC
4.2% 1
3.8%
0.0%
4.7%
2.3%
0.1%
0.2%
0.3%
0.2%
0.3%
0.0%
0.2%
0.6%
0.0%
1.3%
3.1%
1.7%
1.7%
3.6%
1.9%
2.0%
0.3%
0.3%
1.1%
0.7%
0.2%
0.1%
0.2%
0.1%
1.4%
0.0%
0.6%
0.1%
1.0%
0.4%
0.0%
0.1%
0.0%
0.0%
0.1%
0.0%
0.5%
0.2%
0.3%
0.0%
0.0%
have in common.
-------
REGIONAL EMISSIONS INFORMATION
Table 20: Percent Region Contribution to National Pollutant Total for all Sources (continued)
Mobile Sources
Aircraft
CMV
Pollutant
Lead
SO2
MobNR-Diesel PM2.5
MobNR-Gas CO
MobOR-DieselHD
VOC
Benzene
Ethyl benzene
Xylenes
1,3-Butadiene
NH3
NOX
PM10
PM2.5
SO2
Naphthalene
Acetaldehyde
Acrolein
Formaldehyde
POM
Manganese
NCDC Regions
Central
6.9%
0.1%
0.5%
3.9%
2.5%
3.9%
4.8%
6.0%
4.0%
0.0%
3.5%
0.2%
0.9%
0.2%
3.1%
2.3%
2.1%
2.9%
4.4%
0.0%
0.6%
CO
NOX
PM10
VOC
Benzene
Ethyl benzene
Naphthalene
Xylenes
Acetaldehyde
Acrolein
Formaldehyde
1,3-Butadiene
POM
Manganese
Cr Compounds
Arsenic
10.1%
3.6%
0.1%
3.6%
8.1%
9.8%
6.5%
9.0%
5.7%
1.7%
3.5%
8.3%
2.3%
0.1%
0.4%
0.7%
ENC
4.5%
0.1%
0.3%
2.5%
2.5%
2.7%
2.9%
4.6%
5.0%
0.0%
1.7%
0.1%
0.4%
0.1%
1.5%
0.0%
1.0%
0.0%
2.1%
0.0%
0.3%
5.3%
1.8%
0.1%
2.0%
4.7%
5.3%
3.8%
4.9%
3.7%
1.0%
2.1%
4.7%
1.5%
0.0%
0.2%
0.4%
NE
7.6%
0.3%
0.3%
5.4%
3.5%
4.7%
5.3%
7.1%
5.2%
0.0%
2.2%
0.1%
0.6%
0.1%
1.9%
1.4%
1.4%
1.8%
2.8%
0.0%
0.6%
7.3%
2.7%
0.1%
2.8%
6.1%
7.4%
5.0%
6.9%
4.6%
1.3%
2.8%
6.8%
1.9%
0.1%
0.5%
0.8%
NW
4.9%
0.2%
0.1%
1.2%
0.9%
1.3%
1.7%
2.1%
1.4%
0.0%
0.7%
0.0%
0.2%
0.0%
0.6%
0.0%
0.4%
0.6%
0.9%
0.0%
0.1%
3.1%
1.0%
0.0%
1.0%
3.2%
2.9%
1.9%
2.6%
1.3%
0.5%
0.9%
2.3%
0.7%
0.0%
0.1%
0.2%
s
11.1%
0.4%
0.5%
3.0%
2.2%
3.6%
4.6%
5.3%
2.7%
0.0%
3.2%
0.2%
0.8%
0.1%
2.7%
2.0%
1.9%
2.6%
0.0%
0.0%
0.5%
7.4%
2.9%
0.0%
2.9%
6.0%
7.8%
4.9%
7.2%
3.9%
0.0%
2.7%
6.8%
1.6%
0.1%
0.4%
0.7%
Footnote
Pollutant/ sector selections are based on Rgure47 -the higher emitting sectors that the majority of regions have
Emissions > 1 0% of pollutant total in all sources (stationary + mobile) are highlighted.
Emissions in federal waters are excluded.
SE
10.4%
0.3%
0.4%
5.6%
3.4%
6.2%
7.9%
9.1%
5.2%
0.0%
3.8%
0.3%
1.0%
0.2%
3.6%
2.6%
2.5%
3.3%
5.2%
0.0%
0.8%
£
4.6%
0.1%
4.4%
9.6%
7.5%
5.5%
1.9%
4.1%
2.4%
0.1%
0.5%
0.9%
sw
4.9%
0.0%
0.1%
1.2%
0.7%
1.3%
1.6%
1.8%
1.3%
0.0%
1.2%
0.1%
0.3%
0.1%
1.0%
0.7%
0.7%
0.9%
1.3%
0.0%
0.2%
2.8%
1.2%
0.0%
1.1%
2.7%
3.1%
1.9%
2.8%
1.5%
0.5%
1.0%
2.4%
0.6%
0.0%
0.1%
0.2%
w
7.3%
0.1%
0.3%
1.6%
1.1%
2.0%
1.8%
0.4%
3.1%
0.0%
2.1%
0.1%
0.3%
0.0%
1.5%
2.7%
0.0%
3.1%
0.1%
0.0%
0.6%
3.6%
1.2%
0.1%
1.7%
2.7%
3.6%
3.3%
0.6%
0.0%
1.3%
0.0%
3.7%
0.0%
0.3%
0.0%
0.0%
WNC
1.8%
0.0%
0.2%
0.5%
0.4%
0.5%
0.6%
0.8%
0.6%
0.0%
0.0%
0.0%
0.1%
0.0%
0.4%
0.0%
0.3%
0.0%
0.6%
0.0%
0.1%
1.2%
0.0%
0.0%
0.4%
1.0%
1.1%
0.8%
1.0%
0.8%
0.0%
0.4%
1.0%
0.3%
0.0%
0.0%
0.1%
n common.
sources, i.e., stationary and mobile sources. These
regional contributions are seen in agriculture, road
dust, and fuel combustion coal for NH3, PM10, and
NOx /SO2 respectively. Similarly, large regional
contributions to national emissions totals are
indicated for numerous HAPs - in fuel combustion
coal, industrial processes and solvent uses. By
contrast, and within stationary sources, specific
regions make significant HAP contributions to fuel
combustion-biomass, but they are not predominant
contributions to those national HAP emissions totals
for all sources.
For mobile sources, the South and Southeast also
contribute the largest portions of lead to the national
total, from aircraft. The Southeast is also a major
contributor of the pollutants listed for on-road
vehicles light duty gas, based on those pollutant
totals for all sources. Emissions from these sectors
in these regions are the largest contributor to the
National Inventory across all sectors.
-------
5. Local Emissions Information
As discussed previously, the mixture of CAP and
HAP emission releases, and the local and regional
climate and weather patterns, help determine how the
chemicals will interact to form ozone and fine particles
(PM25) and transform to other toxic compounds.
Areas that are experiencing multiple air quality issues,
such as exceeding one or more NAAQS and having
elevated risks from HAP emissions, may benefit from
addressing such problems and possible solutions in
an integrated fashion. Such solutions may include
emission control programs that simultaneously
provide desired air quality improvements, reduced
overall costs and greater health benefits from targeting
multiple pollutants together. Local control strategies
are reliant on air quality modeling, which benefits
from more detailed and localized information on
emissions. Local emission inventories may also show
important sector-pollutant patterns that are different
from what the regional patterns for those areas show.
So far, we have discussed national and regional
emission patterns. This section investigates local
emission profiles for two areas that are experiencing
multiple air quality issues. While other factors such
as meteorology, topography, distance between source
and monitor and transport likely contribute to the
air quality problems, only the emissions part of that
contribution is considered here. In looking at the local
emissions profiles, patterns of sources will be identified
and contrasted with the regional patterns discussed
earlier.
5.1 Nexus of Air Quality Issues for Local Areas
The term "nexus" is used here to describe the
confluence of ozone, PM and HAP air quality/risk
issues. These nexus areas are revealed by examining
2008 ambient monitoring data and cancer risk data
from the 2005 NATA (subject to caveats in the 2005
NATA as previously detailed in the report). Figure 48
shows the areas that exceed the level of the ambient
NAAQS for annual PM2 5 and ozone and which also
have potential cancer risks that are in the top 10
percent for the country. The ambient annual air quality
standard is 15 micrograms/cubic meter ((ig/m3) for
PM25 and 75 parts per billion (ppb) for ozone. The
top 10 percent of potential cancer risk areas are also
referred to as the 90th percentile. The nexus based on
Core Based Statistical Area (CBSA) that satisfy these
criteria are indicated in black color. A CBSA is a U.S.
geographic area defined by the Office of Management
and Budget (OMB) based around an urban center
Legend
NEXUS of PM-Oj-HAPs
All Colors
^Annual PM25 - Ozone - HAPs
I I Ozone Only
I I Ozone - HAPs
^| Annual PM25 Only
I HAPs Only
Legend
NEXUS of PM - 0, -HAPs
I I Annual PM2 s- Ozone - HAPs
Figure 48: NEXUS Areas Defined by 2008 Air Quality
Data and NATA 2005 Cancer Risk Values
Figure 49: Areas that Experienced Multiple Air Quality
Problems in 2008 Based on Figure 48
-------
LOCAL EMISSIONS INFORMATION
Fresno CAPs
I Pb D PM10 D NO* D VOC
I CO D PM2.5 S02 D NH3
Figure 50: Total CAPs in Fresno, CA by Sector, 2008 NEI
Fresno HAPs
2000
LO
d
1
i_n
S 1000
i_n
LO
Q
Stationary Sources
^ n ~
gf!sg = l.il8.gifEJSj
I I 1 I 1 1 1 i | I I j i
°*Q(S"-C £ u-
-------
LOCAL EMISSIONS INFORMATION
Using the "Sector29" emissions groups from Table 3,
Figures 50 to 51 and 53 to 54 summarize emissions in
each area and exclude emissions from wild land fires
and biogenic sources. Figures 50 and 51 show the CAP
and HAP sector emission totals for Fresno, CA. The
CAP bars in each figure represent the sum of CAPs
in the 2008 NEI: CO, NH3, VOC, SO2, NOx, PM25
and PM1Q. The HAP bars represent the sum of all the
HAPs in the 2008 NEI, not just the specific list of HAPs
analyzed in other parts of this report. A similar set of
charts is shown in Figures 53 and 54 for Pittsburgh, PA.
Based on Figures 50 and 51, Fresno shows the
following characteristics:
The ratio of total CAP to HAP is 35. The sum of
CAP emissions is 208,382 tons and the sum of HAP
emissions is 6,026 tons.
Mobile sources emit the highest amounts of both
HAP and CAP emissions.
CAP Highlights:
Largest CAP source - on-road mobile sources. Other
significant contributors include agriculture and dust.
Most of the emissions from agriculture are NH3 and
all of the emissions in the dust categories are PM.
Within on-road mobile sources, light duty gasoline
vehicles contribute a much higher fraction of
emissions than do the heavy duty diesel vehicles. All
of the CAPs except for SO2 are emitted in significant
amounts from mobile sources.
The stationary fuel combustion categories have only a
small portion of the total CAP emissions.
HAP Highlights:
Largest HAP sources - mobile sources, solvents,
and anthropogenic fires (agricultural/crop residue
burning).
Within the anthropogenic fires category, the HAP
acrolein is significant and accounts for over 90
percent of the HAP emissions; chlorine (4 percent)
and 1,3-butadiene (2 percent) make smaller
contributions from fires.
Within mobile sources, nonroad and on-road
sources contribute equal fractions of total HAPs.
A significant amount (>70 percent) of the HAP
emissions are from BTEX - benzene, toluene,
ethylbenzene and xylenes; and 1,3-butadiene.
For the solvent sectors, the HAPs emitted in
significant amounts include ethylene glycol, methyl
chloride, hexane and xylene.
The fact that fires and solvents are key sectors for
HAP emissions in Fresno is supported by the 2005
NATA results, which indicate that Fresno county
is among the highest 61 counties in terms of total
cancer risk, and that the biggest contributor to that
total risk comes from the nonpoint sector.
Priority Facilities:
As part of the 2011 NEI planning cycle, EPA has
developed a list of 2008 NEI point sources that
contribute to the top 80 percent of the national
point source total for any of the CAPs and key HAPs
[ref 21]. Of the 8,784 facilities identified on the list,
Fresno county has only 11 of those facilities (two
are airports and three are breweries/distilleries/
wineries), as shown in Figure 52, and most of them
are significant only for VOC emissions.
Based on Figures 53 and 54, the Pittsburgh, PA area
shows these characteristics:
The total CAP to HAP ratio is about 75. The
estimated amount of CAPs emitted is 1.1 million tons
while the total amount of HAPs emitted is 14,300
tons. The magnitude of CAP and HAP emissions is
much higher than in Fresno county, in part because
the metropolitan (and PM non-attainment) area here
is much larger and encompasses seven counties.
Emissions in the Pittsburgh area are dominated
by CAPs compared to the Fresno area. The total
emission mix in the Pittsburgh area is dominated
by large stationary sources and sources such as fuel
combustion and industrial processes.
CAP Highlights:
Nearly 40 percent of the CAP emissions in Pittsburgh
come from coal-based fuel combustion. Other
significant contributors to total CAPs in Pittsburgh
include nonroad gasoline equipment (11 percent)
and on-road gasoline vehicles (25 percent). Most of
-------
LOCAL EMISSIONS INFORMATION
Legend
Fresno Point Sources
Facility_Type
O Airport
Breweries/DistilleriesMflneries
Electricity Generation via Combustion
Oil or Gas Processing
Other
Figure 52: Key Point Sources in the Fresno, CA Area, 2008 NEI
the CAP emissions from coal-based fuel combustion
are SO2 and NOx. Nearly all CAPs are emitted
in significant amounts from the mobile source
categories with the exception of SO2 emissions.
Biomass-based fuel combustion and industrial
processes are also large contributors for CAP
emissions as well, but to a lesser extent than the
sources mentioned previously. CO, VOCs and PM
are emitted at high levels in the biomass-based
fuel combustion categories, while the industrial
sources are dominated by direct PM, NO and VOC
' ' X
emissions.
based fuel combustion, benzene, formaldehyde,
acetaldehyde, toluene and 1,3-butadiene are the
most-abundant HAPs emitted.
2005 NATA results support the fact that fuel
combustion and industrial sources are key sectors
for HAP emissions in the Pittsburgh vicinity, which
indicate that Allegheny county is among the highest
counties in terms of total cancer risk, and that the
biggest contributor to the total cancer risk comes
from the point sector. Point sources are also the most
important contributing sources for cancer risk in all
of the other counties.
HAP Highlights:
The HAPs are emitted mainly by mobile source
categories, fuel combustion categories and solvent
utilization. The specific HAPs for the mobile sources
and solvent categories are the same as noted for
the Fresno area. For coal-based fuel combustion,
the highest emitting HAPs are hydrochloric acid,
hydrogen sulfide and hydrogen cyanide. For biomass-
Priority Facilities
Of the 8,784 facilities identified on the list, the
counties that comprise the Pittsburgh metropolitan
area have 61 of those facilities (many ECUS, steel
mills, iron and steel foundries, smelters and airports)
and 11 of them are significant for more than six
pollutants. These sources are shown in the map in
Figure 55.
-------
LOCAL EMISSIONS INFORMATION
Pittsburgh CAPs
400000
CO
£ 300000
no
I 200000
nn
no
1 100000
LJJ
ill
I Pb D PM10 D NOx D VOC
I CO n PM2.5 S02 n NH3
Figure 53: Total CAPs in Pittsburgh, PA by Sector, 2008 NEI
6000
£ 5000
° 4000
in
o 3000
in
01 9finn
^ 1000
0
Stationary Sources
Pittsburgh HAPs
i j II I I
| | S o 1 |
ifl 33
Mobile Sources
_ :
1 f \ I { j | j 1 f 1 1 1 ! i j 1 1 1 l
Figure 54: Total HAPs in Pittsburgh, PA by Sector, 2008 NEI
5.3 Examples and Recommendations for
Developing Local Scale Inventories
To understand the source mix in a local area of
interest, this review suggests that a more detailed
analysis is warranted to support local-scale modeling
for multiple air quality issues. Many areas are engaged
in developing local-scale emissions inventories.
An EPA study provides examples for inventory
approaches that investigate possible contributions to
multiple air quality issues (http://www.epa.gov/ttn/
chief/local scale/sti epa local scale ei final report.
pdf). The study results [ref 22] provide details
on these approaches, and some of the high-level
recommendations include:
Start with what you knowbegin by identifying
emissions sources in your area of interest, using
existing inventories, permit data and other sources of
information.
Use simple approaches, such as emissions-to-distance
(Q/D) analysis, to prioritize sources in terms of
potential impact on monitoring sites. Emissions-to-
distance ratios provide a quick way of comparing
local sources.
-------
LOCAL EMISSIONS INFORMATION
Legend
Pittsburgh Point Sources
Facility Type
'.J Airport
Coke Battery
Compressor station
s_.-' Electiicity Generation via Combustion
. Foundries, Iron and Steel
Institutional - schools, hospitals, prisons
Portland Cement Manufacturing
Primary Metal Smelting Refining
O Rail Yard
G SteeJ Mill
Other
Westmoreland
rV3P
Figure 55: Key Point Sources in the Pittsburgh, PA Area, 2008 NEI
When conducting analyses on local source
contributions, use a weight-of-evidence approach,
combining the results of receptor modeling, wind
analyses and inter-monitor comparisons to identify
sources with significant impacts on monitored
concentrations.
Compare state and local agencies' local-scale
emissions data and the NEI to evaluate differences in
key elements such as control information.
-------
6. IMPROVEMENTS FOR 2008 AND FUTURE NEIs
The NEI represents a readily-available comprehensive
inventory in terms of spatial, pollutant and sector
coverage. It undergoes continuous improvement by
EPA and with the assistance of state, local and tribal
agencies by their reporting emissions information
for facilities, other stationary sources and mobile
sources. Each cycle of NEI development incorporates
improvements based on lessons learned from the
previous cycles. Estimation procedures for significant
emissions sectors of key pollutants (the available
data, tools and methods) typically evolve over time
in response to identified deficiencies as the data are
used. Some of the uses of the NEI include regulatory
analysis using air quality modeling, general emission
assessments, national and county-level trends and
international reporting. Although the accuracy of
individual emission estimates will vary from facility-
to-facility or county-to-county, the NEI largely meets
the needs of these uses.
The supporting documentation for the 2008 NEI
describes some of the improvements for this inventory
and data issues that are being resolved. Improvements
include:
More automated QA checks for reported data
More complete point source augmentation
procedures for HAP emissions expected but not
reported
Verification of location coordinates for priority
facilities with significant emissions and/or high risk
Collaboration with state, local and tribal agencies to
devise a more consistent method for estimating some
important stationary source emissions
Use of updated estimation models for mobile
sources - on-road and nonroad; and wild and
prescribed fires
The development cycle for the 2011 NEI is already
underway. Some specific improvements anticipated
for the 2011 NEI include:
a Additional and more stringent QC procedures for
reported data
a More consistent approaches to filling in expected
HAP nonpoint emissions that are not reported
a Ensure emissions information is reported for
priority facilities
There will always be aspects of the NEI that may
warrant a more thorough review of the data to ensure
its reliability. This typically results from questions or
new information about potentially significant sources
of emissions, or from a use that needs more complete
information. Examples of some desired improvements
for future NEIs include:
Control Information -
Processing emissions for air quality modeling and
pollution control and cost scenarios is one of the
significant uses of control information in the NEI.
Inaccurate control information can be an important
factor in over- or under-estimating the potential
emission reductions and associated costs of proposed
control programs. If controls are in place, but that
information is not part of the NEI, then the EPA may
assume that no controls exist and suggest adding
controls on processes that are already controlled. A
lack of information on existing controls also makes it
hard to determine the benefit of additional controls.
EPA is trying to better organize such information
in more efficient tools for application in regulatory
analysis. At this time the NEI is generally not a
reliable source of control information, despite existing
requirements for this information to be provided
by SLTs. State/local or regional air quality modeling
efforts typically seek control information outside of
the NEI. Possible state and local resources include
permits, compliance and emission inventory databases.
-------
IMPROVEMENTS FOR 2008 AND FUTURE NEIS
EPA also receives some control information as part
of the data gathering and analysis for developing
industry standards for specific sectors. It is expected
that reliable control information in the NEI will
benefit national, regional, and therefore local modeling
for attainment of the air quality standards. Having
more complete control information in the NEI in the
future relies on improvements in electronic reporting
between industry, states and the EPA.
Specific sector improvements, example: Oil and
Gas sector -
High levels of growth in the oil and natural gas
production sector, coupled with harmful pollutants
emitted during oil and gas production, underscore
the need for EPA to gain a better understanding of
emissions and potential risks from the production of
oil and gas. The 2008 NEI for oil and gas is incomplete.
Current and anticipated efforts for improvement
include: a focus on state/local/tribal involvement
to enable their development and reporting of more
complete information; the development of updated
emission rates applicable to the various production
processes of the oil and gas sector, and to leverage
resources and results from on-going studies and other
efforts that are addressing emissions from the oil
and gas sector. Using these information sources, EPA
is developing an oil and gas production estimation
tool that will allow for augmentation of oil and gas
emissions using nonpoint estimates. Much of this
information is outlined in the recently completed
Office of Inspector General (OIG) report on oil and
gas. This report can be found at: http://www.epa.gov/
oig/reports/2013/20130220-13-P-0161 .pdf
HAP inventory-
While many states voluntarily submit some HAPs
to the 2008 NEI, future improvements could center
on making the HAP data more complete in terms of
sector and pollutant coverage, as well as developing
EPA-based fallback methods for more sectors to fill
in data when states do not submit HAPs. Specifically,
HAPs from nonpoint stationary sources need
improvements for categories such as agricultural
burning which currently do not have estimates for
HAP emissions.
Improve reporting for key facilities identified in the 2008
NEI-
EPA identified facilities in the 2008 NEI with emissions
that put them in the top 80 percent of the national
point source category total for any of 18 key criteria
and key hazardous air pollutants, i.e., those CAPs and
HAPs reviewed in this report. The list is available at
http://www.epa.gov/ttn/chief/net/2011inventory.html.
With the help of state, local and tribal agencies, we will
conduct a focused review of these facilities to result in
more complete information for the 2011 NEI. EPA is
also working to better use facility emissions estimates
from its residual risk program.
-------
7. CONCLUDING REMARKS
We would like to thank everyone who helped us
complete this report, including all of the state, local
and tribal agencies that report data to the NEI.
Special thanks for the EPA Office of Research and
Developments assistance to format and publish the
report. All of the preceding analyses are based on
Version 2 of the 2008 NEI that was released to the
public in February 2012. Currently, version 3 of the
2008 NEI is available. While there are differences
between versions 2 and 3 of the 2008 NEI, many of the
major differences have been captured in this report.
The reader is directed to http://www.epa.gov/ttn/
chief/net/2008inventory.html for further details on
version 3. The next full inventory will be completed for
the year 2011 and is expected to be released in 2013.
-------
REFERENCES
1. HEI Communication 11: Assessing Health Im-
pact of Air Quality Regulations: Concepts and
Methods for Accountability Research. Account-
ability Working Group, Health Effects Institute.
September 2003.
2. 2008NEI Version 2 Technical Support Document.
http://www.epa.gov/ttn/chief/net/2008neiv2/2008
neiv2 tsd draftpdf
3. EPA's National Air Toxics Assessments, http://
www.epa.gov/ttn/atw/natamain
4. NAAQS webpage. http://www.epa.gov/air/criteria.
html
5. EPA's PM Report, http://www.epa.gov/airtrends/
aqtrnd04/pm.html
6. Carter, W.P.L. (1994). Development of ozone
reactivity scales for volatile organic compounds.
Journal of Air and Waste Management Association
44, 881-889. http://www.cert.ucr.edu/~carter/pubs/
7. Secondary Organic Aerosol Production ("SOAP")
Reference. Derwent, R. G., Jenkin, M. E., Utembe,
S. R., Shallcross, D. E., Murrells, T. P., and N. R.
Passant, Secondary organic aerosol formation
from a large number of reactive man-made com-
pounds," Science of the Total Environment, Vol-
ume 408, Issue 16, July 2010. http://www.science-
direct.com/science/article/pii/S0048969710003918
8. List of POM species included in Report summaries
- see list at end of this reference section.
9. Webb, S., Krannich, R., and F. Clemente, Power
Plants in rural area communities: Their size, type
and perceived impacts, Community Development
Society Journal, 11(2). http://www.tandfonline.
com/doi/abs/10.1080/15575330.1980.9987117#pre
view
10. B.J. Finlayson-Pitts & J.N. Pitts Jr. (1993): Atmo-
spheric Chemistry of Tropospheric Ozone Forma-
tion: Scientific and Regulatory Implications, Air &
Waste, 43:8, 1091-1100. http://dx.doi.Org/10.1080/l
073161X.1993.10467187
11. NEI Air Pollutants Trends Data, http://www.epa.
gov/ttn/chief/trends/index.html
12. MOVES (Motor Vehicle Emission Simulator),
http://www.epa.gov/otaq/models/moves/index.htm
13. MOBILE6 Vehicle Emission Modeling Software
and technical information, http://www.epa.gov/
oms/models/mobile6/m6tech.htm
14. CAMx Air Quality Model user Guide. http://www.
camx.com/files/camxusersguide v5-40.aspx
15. SMARTFIRE2 and Bluesky Presentation/Paper at
2012 Emissions Inventory Conference. http://www.
epa.gov/ttn/chief/conference/ei20/session2/sraf-
fuse.pdf
16. Personal communication with staff at Minnesota
DEQ, April 2012.
17. NC Evans Road Fire, 2008. http://www.coastalwild-
Iiferefuge.com/pr/pr011209.pdf
18. National Interagency Fire Center, http://www.nifc.
gov/firelnfo/firelnfo statistics.html
19. NOAA Climate Center. National Climatic Data
Centers, http://www.ncdc.noaa.gov/temp-and-
precip/U.S.-climate-regions.php
20. Core Based Statistical Area (CBSA). http://
en.wikipedia.org/wiki/CoreBasedStatisticalArea
21. Facilities that are top emitters for one or more pol-
lutants in the point source sector in the 2008 NEI.
http://www.epa.gov/ttn/chief/net/2011inventory.
html (third bullet under "References" sub-section)
22. Report on methods to use in developing local scale
inventories, http://www.epa.gov/ttn/chief/local
scale/sti epa local scale ei final report.pdf
-------
REFERENCES
Reference 8 - List of POM species
Polycyclic organic matter (POM)
12-Methylbenz(a)Anthracene
1-Methylnaphthalene
1-Methylphenanthrene
1-Nitropyrene
2-Chloronaphthalene
2-Methylnaphthalene
3-Methylcholanthrene
5-Methylchrysene
7,12-Dimethylbenz[a] Anthracene
7H-Dibenzo[c,g]carbazole
Acenaphthene
Acenaphthylene
Anthracene
Benz[a]Anthracene
summarized in this Report:
Species with emissions in 2008 V2 NEI
Benzo(a)Fluoranthene
Benzo(g,h,i)Fluoranthene
Benzo[a]Pyrene
Benzo[b]Fluoranthene
Benzole] Pyrene
Benzo[g,h,i,]Perylene
Benzo[j]fluoranthene
Benzo[k]Fluoranthene
Benzofluoranthenes
Carbazole
Chrysene
Dibenz[a,h]acridine
Dibenzo[a,e]Pyrene
Dibenzo[a,h]Anthracene
Dibenzo[a,h]Pyrene
Dibenzo[a,i]Pyrene
Dibenzo[a,j]Acridine
Dibenzo[a,l]Pyrene
Fluoranthene
Fluorene
lndeno[1,2,3-c,d]Pyrene
Methylanthracene
Methylchrysene
PAH, total
PAH/POM-Unspecified
Perylene
Phenanthrene
Pyrene
-------
ACRONYM LIST
NEI
EPA
AQAD
OAQPS
EIAG
CHIEF
CAP
HAP
CO
NH3
N0x
PM
PM,5
so2
voc
Pb
Hg
HCL
BTEX
POM
SESQ
TERP
TSD
NAAQS
NATA
ECU
MOVES
GPR
TRI
EIS
NCDC
NOAA
National Emissions Inventory
Environmental Protection Agency
Air Quality Analysis Division
Office of Air Quality Planning and
Standards
Emissions Inventory Analysis Group
Clearinghouse for Inventories &
Emissions Factors
Criteria Air Pollutant
Hazardous Air Pollutant
Carbon Monoxide
Ammonia
Nitrogen Oxides
Particulate Matter
Particulate Matter 10 Microns or less
Particulate Matter 2.5 Microns or less
Sulfur Dioxide
Volatile Organic Compounds
Lead
Mercury
Hydrochloric Acid
Benzene, Toluene, Ethylbenzene, and
Xylenes
Polycyclic Organic Matter
Sesquiterpenes
Terpenes
Technical Support Document
National Ambient Air Quality
Standard
National-Scale Air Toxics Assessment
("2005" refers to NATA conducted for
year 2005)
Electric Generating Unit
Motor Vehicle Emission Simulator
General Public Release
Toxic Release Inventory
Emissions Inventory System
National Climatic Data Center
National Oceanic and Atmospheric
Administration
SLT
SOAP
MIR
SOA
GEM
NEC
CMV
FC
MobNR
MobOR
MobOR
DieselHD
MobOR
DieselLD
MobOR
GasHD
MobOR
GasLD
Solv-
Commindust
Wild Land
Fires
ICI
Ngas
FC
SqMi
Ppm
MW
GTE
Mfg
Agric
PR
VI
DM
BS
SF2
OMB
CBSA
State/Local/Tribe
Secondary Organic Aerosol
Production
Maximum Incremental Reactivity
Secondary Organic Aerosol
Continuous Emissions Monitoring
Not Elsewhere Classified
Commercial Marine Vehicle
Fuel Combustion
Mobile Nonroad
Mobile Onroad
Mobile On-road Diesel Heavy Duty
Vehicles
Mobile On-road Diesel Light Duty
Vehicles
Mobile Gasoline Heavy Duty Vehicles
Mobile Gasoline Light Duty Vehicles
Solvent Commercial Industry
Includes both wildfires and
prescribed fires
Industrial, Commerical and
Institutional
Natural Gas
Fuel Combustion
Square Mile
Parts per million
Megawatts
Greater than or equal (>)
Manufacturing
Agriculture
Puerto Rico
Virgin Islands
Federal Waters (Domestic Waters)
BlueSky
SMARTFIRE2
Office of Management & Budget
Core Based Statistical Area
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