Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 i
Redesignation Demonstration and Maintenance Plan December 18, 2009
This document contains the technical support for North Carolina’s Division of Air
Quality to request the Hickory and Greensboro/Winston-Salem/High Point fine particulate
matter nonattainment areas be redesignated as attainment for the annual fine particulate matter
national ambient air quality standard pursuant to §§107(d)(3)(D) and (E) of the Clean Air Act, as
amended.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 ii
Redesignation Demonstration and Maintenance Plan December 18, 2009
Fine particulate matter, also known as fine particles and PM2.5, refers to airborne particles less
than or equal to 2.5 micrometers in diameter. Fine particles are treated as though they are a
single pollutant, but they come from many different sources and are composed of many different
compounds. PM2.5 exposure adversely affects human health, especially respiratory and
cardiovascular systems. Individuals particularly sensitive to PM2.5 exposure include children,
people with heart and lung disease, and older adults.
A variety of meteorological and geographic factors influence the concentration levels of fine
particles, including both the regional and local distribution of urbanized areas, primary and
precursor emissions sources, and natural features such as oceans and forests. PM2.5
concentrations can also be high and exceed the national ambient air quality standards (NAAQSs)
for fine particulate matter at any time of the year. Therefore, the United States Environmental
Protection Agency (USEPA) mandates the year round monitoring of PM2.5 concentrations
throughout the country.
The nonattainment designation was an action taken by the USEPA under Section 107(d) of the
Clean Air Act (CAA). The CAA requires that some areas be designated as nonattainment if a
monitor is found to be in violation of a NAAQS. The USEPA took designation action in 2005
based on the ambient data from 2001-2003. At that time, the design value for Hickory area
(Catawba County) was 15.6 micrograms per cubic meter (μg/m3) and the design value for the
Greensboro/Winston-Salem/High Point area (Davidson and Guilford Counties, referred to as the
Triad area) was 15.9 μg/m3.
The most recent three years of fine particulate monitoring data (2006-2008) for both the Hickory
and Triad PM2.5 nonattainment areas demonstrate compliance with the annual fine particulate
matter NAAQS. The three year design value at the Hickory monitor is 14.2 μg/m3. In the Triad
nonattainment area, the three year design value at the Lexington monitor is 14.5 μg/m3 and the
three year design value at the Mendenhall monitor is 12.9 μg/m3. Additionally, the annual
design values at all three sites are trending downward.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 iii
Redesignation Demonstration and Maintenance Plan December 18, 2009
The State of North Carolina has implemented permanent and enforceable reductions in sulfur
dioxide (SO2) and nitrogen oxide (NOx) emissions, which are precursors to fine particulates.
These actions include implementing the on-board diagnostic vehicle inspection and maintenance
program that began on July 1, 2002, and an open burning ban during air quality action days. In
addition, there have been several State rules that have resulted in reductions in emissions within
and surrounding the nonattainment area. These State actions include the NOx State
Implementation Plan (SIP) Call, the Clean Smokestacks Act legislation, and heavy-duty engine
stop-gap rule for model years 2005 and 2006. Finally, several actions at the Federal level by the
USEPA have resulted in lower emissions throughout the eastern portion of the country. These
Federal actions include the Tier 2 engine standards for light and medium duty vehicles, heavy-duty
engine standards, the low sulfur gasoline and diesel requirements, and off-road engine
standards.
This combination of State and Federal actions has resulted in cleaner air in the PM2.5
nonattainment areas, and the anticipated future benefits from these programs are expected to
result in continued maintenance of the 1997 annual PM2.5 NAAQS in this region. A baseline
year emissions inventory for NOx, SO2, and direct PM2.5 was developed for 2008, since the
design value for the 2006-2008 period showed attainment of the 1997 annual PM2.5 NAAQS.
Future year emissions inventories were also developed for the interim years 2011, 2014, 2017,
and a final year emission inventory was developed for 2021. The future year emissions were
lower than the 2008 emissions in all cases. This demonstrates that the PM2.5 nonattainment areas
are expected to maintain the 1997 annual PM2.5 NAAQS through 2021, since in no future year
are the emissions expected to be greater than they were in the baseline year. The areas are also
in compliance with Section 110 and Part D requirements of the CAA.
Based on the information above and criteria established in Section 107(d)(3)(E) of the CAA,
North Carolina is requesting that the USEPA redesignate the Hickory and Greensboro/Winston-
Salem/High Point fine particulate matter nonattainment areas to attainment. The monitoring data
clearly shows that the region has attained the annual fine particulate matter standard, and the
maintenance demonstration shows that the future emission inventories are expected to be lower
than the attainment year inventory through the implementation of the various control measures
listed above.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 iv
Redesignation Demonstration and Maintenance Plan December 18, 2009
EXECUTIVE SUMMARY ............................................................................................................ ii
1.0 INTRODUCTION ................................................................................................................. 1-1
1.1 WHAT IS FINE PARTICULATE MATTER? ................................................................. 1-1
1.2 CLEAN AIR ACT OF 1990 .............................................................................................. 1-2
1.3 AIR QUALITY HISTORY ............................................................................................... 1-2
1.4 CLEAN AIR ACT REDESIGNATION CRITERIA ........................................................ 1-3
2.0 AIR QUALITY ...................................................................................................................... 2-1
2.1 HISTORIC AIR QUALITY (1999 – 2007) ...................................................................... 2-1
2.2 RECENT AIR QUALITY VALUES (2006 –2008) ......................................................... 2-3
2.3 PERMANENT AND ENFORCEABLE EMISSIONS REDUCTIONS ........................... 2-4
3.0 MAINTENANCE PLAN ....................................................................................................... 3-1
3.1 CONCEPT OF NORTH CAROLINA'S MAINTENANCE PLAN ................................. 3-1
3.2 FOUNDATION CONTROL PROGRAM ........................................................................ 3-2
3.2.1 Federal Control Measures .......................................................................................... 3-2
3.2.2 State Control Measures .............................................................................................. 3-5
3.2.3 Additional Programs Supporting Maintenance .......................................................... 3-9
3.3 EMISSIONS INVENTORIES AND MAINTENANCE DEMONSTRATION ............. 3-10
3.3.1 Theory of Approach ................................................................................................. 3-10
3.3.2 Emission Inventories ................................................................................................ 3-11
3.3.3 Summary of Emissions ............................................................................................ 3-15
3.3.4 Maintenance Demonstration .................................................................................... 3-16
3.4 CONTINGENCY PLAN ................................................................................................. 3-17
3.4.1 Overview .................................................................................................................. 3-17
3.4.2 Primary and Secondary Triggers ............................................................................. 3-18
3.4.3 Action Resulting From Trigger Activation .............................................................. 3-19
3.4.4 Tracking Program for Ongoing Maintenance .......................................................... 3-20
4.0 MOTOR VEHICLE EMISSIONS BUDGET FOR CONFORMITY ................................... 4-1
4.1 TRANSPORTATION CONFORMITY ............................................................................ 4-1
4.2 POLLUTANTS TO BE CONSIDERED ........................................................................... 4-1
4.2.1 Precursor Pollutants NOx, VOC, and Ammonia ........................................................ 4-2
4.2.2 Reentrained Road Dust .............................................................................................. 4-2
4.2.3 Precursor Pollutant SO2 ............................................................................................. 4-3
4.2.4 Direct PM2.5 Emissions .............................................................................................. 4-5
4.3 SAFETY MARGIN ........................................................................................................... 4-7
4.4 MOTOR VEHICLE EMISSION BUDGETS ................................................................... 4-7
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 v
Redesignation Demonstration and Maintenance Plan December 18, 2009
4.5 NEW SAFETY MARGINS ............................................................................................ 4-10
5.0 STATE IMPLEMENTATION PLAN APPROVAL ............................................................. 5-1
5.1 INTRODUCTION ............................................................................................................. 5-1
5.2 EVIDENCE OF COMPLIANCE ...................................................................................... 5-1
6.0 STATE COMPLIANCE WITH CLEAN AIR ACT REQUIREMENTS.............................. 6-1
7.0 CONCLUSION ...................................................................................................................... 7-1
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 vi
Redesignation Demonstration and Maintenance Plan December 18, 2009
APPENDIX A: CORRESPONDENCE AND GUIDANCE DOCUMENTS
APPENDIX B: STAKEHOLDER CORRESPONDENCE REGARDING MOTOR VEHICLE
EMISSION BUDGETS
APPENDIX C.1: POINT SOURCE EMISSION INVENTORY DOCUMENTATION
APPENDIX C.2: AREA SOURCE EMISSION INVENTORY DOCUMENTATION
APPENDIX C.3: ON-ROAD MOBILE SOURCE EMISSION INVENTORY
DOCUMENTATION
APPENDIX C.4: NONROAD MOBILE SOURCE EMISSION INVENTORY
DOCUMENTATION
APPENDIX D: MENDENHALL DATA REPLACEMENT DOCUMENTATION
APPENDIX E: PUBLIC NOTICE REPORT, COMMENTS RECEIVED AND RESPONSES
Table 2-1 Historic PM2.5 Annual Averages (1999-2007) ............................................................ 2-2
Table 2-2 Historic PM2.5 Design Values (2000 – 2007) .............................................................. 2-3
Table 2-3 Current PM2.5 Data (2006 -2008) ................................................................................ 2-4
Table 2-4. Annual Emissions from NC Sources in USEPA Acid Rain Database ....................... 2-7
Table 2-5. Annual SO2 Emissions for Utilities Near the PM2.5 Nonattainment areas (tons/year) 2-9
Table 3-1 OBDII Phase-in Effective Dates ................................................................................. 3-6
Table 3-2 I/M NOx Benefits by County ....................................................................................... 3-6
Table 3-3 Estimated Emission Reductions from Open Burning Regulation ............................... 3-8
Table 3-4. Point Source NOx Emissions (tons per year) ............................................................ 3-11
Table 3-5 Point Source SO2 Emissions (tons per year) ............................................................. 3-12
Table 3-6. Point Source PM2.5 Emissions (tons per year) .......................................................... 3-12
Table 3-7. Area Source NOx Emissions (tons per year) ............................................................ 3-12
Table 3-8. Area Source SO2 Emissions (tons per year) ............................................................. 3-13
Table 3-9. Area Source PM2.5 Emissions (tons per year) .......................................................... 3-13
Table 3-10. On-road Mobile Source NOx Emissions (tons per year) ........................................ 3-13
Table 3-11. On-road Mobile Source SO2 Emissions (tons per year) ......................................... 3-14
Table 3-12. On-road Mobile Source PM2.5 Emissions (tons per year) ...................................... 3-14
Table 3-13. Nonroad Mobile Source NOx Emissions (tons per year) ........................................ 3-14
Table 3-14. Nonroad Mobile Source SO2 Emissions (tons per year) ........................................ 3-15
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 vii
Redesignation Demonstration and Maintenance Plan December 18, 2009
Table 3-15. Nonroad Mobile Source PM2.5 Emissions (tons per year) ...................................... 3-15
Table 3-16. Total Man-Made NOx Emissions (tons per year) ................................................... 3-15
Table 3-17. Total Man-Made SO2 Emissions (tons per year) .................................................... 3-15
Table 3-18. Total Man-Made PM2.5 Emissions (tons per year) ................................................. 3-16
Table 3-19 Maintenance Demonstration for Hickory PM2.5 Nonattainment Area ................... 3-16
Table 3-20 Maintenance Demonstration for Triad PM2.5 Nonattainment Area ........................ 3-16
Table 3-21 Safety Margin for Hickory PM2.5 Nonattainment Area .......................................... 3-17
Table 3-22 Safety Margin for Triad PM2.5 Nonattainment Area ............................................... 3-17
Table 4-1. On-Road Mobile Source PM2.5 Emissions ................................................................ 4-8
Table 4-2. On-Road Mobile Source NOx Emissions .................................................................. 4-9
Table 4-3 Catawba County MVEB ............................................................................................. 4-9
Table 4-4 Davidson County MVEB ........................................................................................... 4-9
Table 4-5 Guilford County MVEB ........................................................................................... 4-10
Table 4-6 New Safety Margins for the Hickory PM2.5 nonattainment area .............................. 4-10
Table 4-7 New Safety Margins for the Triad PM2.5 nonattainment area .................................. 4-11
Figure 1-1. USEPA Designated Annual PM2.5 Nonattainment Areas in North Carolina ........... 1-3
Figure 2-1. PM2.5 Monitor Locations in the PM2.5 Nonattainment Areas................................... 2-1
Figure 2-3. Location of Power Plants in the Vicinity of the PM2.5 Nonattainment Areas .......... 2-8
Figure 3-1. North Carolina’s Inspection & Maintenance (I/M) Phase-In Map .......................... 3-5
Figure 4-1. Speciated Data for the Hickory area (left) and the Triad area (right) ....................... 4-3
Figure 4-2. North Carolina’s 2009 Statewide SO2 Emissions .................................................... 4-4
Figure 4-3. Hickory Area 2009 Primary PM2.5 Emissions ........................................................... 4-6
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 viii
Redesignation Demonstration and Maintenance Plan December 18, 2009
Acronym Definition
ºF Degrees Fahrenheit
CAA Clean Air Act
CAAA Clean Air Act Amendments of 1990
CERR Consolidated Emissions Reporting Rule
CFR Code of Federal Regulations
CO Carbon Monoxide
E-GAS 5.0 Economic Growth Analysis System version 5.0
FR Federal Register
FRM Federal Reference Method
GUAMPO Greensboro Urban Area Metropolitan Planning Organization
HC Hydrocarbons
I/M Inspection and Maintenance
MVEB Motor Vehicle Emission Budget
NAAQS National Ambient Air Quality Standard
NCCSA North Carolina Clean Smokestacks Act
NCDAQ North Carolina Division of Air Quality
NCDENR North Carolina Department of Natural Resources
NCDOT North Carolina Department of Transportation
NOx Nitrogen Oxides
PM Particulate Matter
PM2.5 Fine Particulate Matter
ppm Parts per million
QA Quality Assure
SAFETY-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for
Users
SIP State Implementation Plan
SO2 Sulfur Dioxide
SOx Sulfur Oxides
SUV Sports Utility Vehicle
TIP Transportation Improvement Program
TPD Tons per Day
TSP Total Suspended Particulates
USEPA U.S. Environmental Protection Agency
VMT Vehicle Miles Traveled
VOC Volatile Organic Compounds
μg/m3 Micrograms per cubic meter
μm Micrometer
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 1-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
Fine particulate matter, also known as fine particles and PM2.5, refers to airborne particles less
than or equal to 2.5 micrometers (μm) in diameter. Fine particles are treated as though they are a
single pollutant, but they come from many different sources and are composed of many different
compounds. PM2.5 exposure adversely affects human health, especially respiratory and
cardiovascular systems. Individuals particularly sensitive to PM2.5 exposure include children,
people with heart and lung disease, and older adults.
PM2.5 can be liquid, solid, or can have a solid core surrounded by liquid. PM2.5 can include
material produced by combustion, photochemical reactions, and can contain salt from sea spray
and soil-like particles. Particles are distinguished based on the method of formation. Primary
particles are particles directly emitted into the atmosphere and retain the same chemical
composition as when they were released. Secondary particles are those formed through chemical
reactions involving atmospheric oxygen, water vapor, hydroxyl radical, nitrates, sulfur dioxide
(SO2), oxides of nitrogen (NOx), and organic gases from natural and anthropogenic sources.
PM2.5 can therefore be composed of varying amounts of different species, including:
• Sulfates
• Nitrates (usually found in the form of ammonium nitrate)
• Ammonium
• Hydrogen ion
• Particle bound water
• Elemental carbon
• Organic compounds
Primary organic species (from cooking and combustion)
Secondary organic compounds
• Crustal material (includes calcium, aluminum, silicon, magnesium, and iron)
• Sea salt (generally only found at coastal monitoring sites)
• Transitional metals
• Potassium (generally from wood burning or cooking)
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 1-2
Redesignation Demonstration and Maintenance Plan December 18, 2009
The most significant sources of PM2.5 and its precursors are coal-fired power plants, industrial
boilers and other combustion sources. These emissions are often transported over large
distances. Other sources of PM2.5 emissions include mobile sources, area sources, fires,
windblown dust, and biogenic, i.e., naturally occurring emissions such as sea salt from oceans
and organics from trees.
A variety of meteorological and geographic factors influence the concentration levels of fine
particles, including both the regional and local distribution of urbanized areas, primary and
precursor emissions sources, and natural features such as oceans and forests. PM2.5
concentrations can also be high and exceed the national ambient air quality standards (NAAQSs)
for fine particulate matter at any time of the year. Therefore, the United States Environmental
Protection Agency (USEPA) mandates in the Code of Federal Regulations (CFR) the year round
monitoring of PM2.5 concentrations throughout the country (40 CFR 58.App. D, 4.7).
In 1997, the USEPA promulgated the primary (health) and secondary (welfare) NAAQSs for
PM2.5 (40 CFR 50.7), setting the standard at a 15.0 micrograms per cubic meter (μg/m3) annual
average and at a 65 μg/m3 daily or 24-hour average. A violation of the annual PM2.5 NAAQS
occurs when the annual average PM2.5 concentration averaged over a three consecutive year
period is equal to or greater than 15.1 μg/m3. A violation of the daily PM2.5 NAAQS occurs
when the annual 98th percentile of daily PM2.5 concentration averaged over a three consecutive
year period is equal to or greater than 66 μg/m3. The annual or daily PM2.5 design value for a
nonattainment area is the highest design value for any monitor in that area.
Since the 1977 amendments to the Clean Air Act (CAA), areas of the country that had not
attained the ambient standard for a particular pollutant were formally designated as
nonattainment for that pollutant. This formal designation concept was retained in the 1990 CAA
Amendments (CAAA). With the implementation of the PM2.5 standard, areas could be
designated under Section 172 of the CAAA (subpart 1) and have five years from designation to
attain the standard.
On January 5, 2005, the USEPA designated the Hickory area (Catawba County) and the
Greensboro/Winston-Salem/High Point area (referred to as the Triad area and consisting of
Davidson and Guilford Counties) as “subpart 1” nonattainment for the annual PM2.5 standard
based on the ambient data from 2001-2003 (Figure 1-1). At that time, the design values for the
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 1-3
Redesignation Demonstration and Maintenance Plan December 18, 2009
Hickory and Triad nonattainment areas were 15.6 μg/m3 and 15.9 μg/m3, respectively. The
official designation and classification was published in the Federal Register (FR) on
January 5, 2005 (70 FR 944) and became effective on April 5, 2005. Prior to the implementation
of the new PM2.5 standard, these areas had been in attainment of the coarse particulate matter
(PM10) and total suspended particulate matter (TSP) standards. All areas of North Carolina met
the 1997 daily PM2.5 standard.
All violating monitors were attaining the annual PM2.5 standard with the inclusion of the 2008
ambient data. The 2006-2008 design values for the Hickory and Triad nonattainment areas are
14.2 μg/m3 and 14.5 μg/m3, respectively. Both areas continue to attain the daily PM2.5 standard.
Section 107(d) (3) (E) of the CAA, as amended, states an area can be redesignated to attainment
if the following conditions are met:
1. The USEPA has determined that the NAAQS have been attained. For fine particulate
matter, the areas must show that the average of the annual average values from three (3)
consecutive calendar years of quality-assured air quality monitoring data must be
15.0 μg/m3 or lower.
2. The applicable implementation plan has been fully approved by the USEPA under section
110(k).
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 1-4
Redesignation Demonstration and Maintenance Plan December 18, 2009
3. The USEPA has determined that the improvement in air quality is due to permanent and
enforceable reductions in emissions. To demonstrate this, the State should estimate the
percent reduction (from the year used to determine the design value for designation and
classification) achieved from Federal, State, and local measures.
4. The State has met all applicable requirements for the area under Section 110 and Part D.
5. The USEPA has fully approved a maintenance plan, including a contingency plan, for the
areas under section 175A.
In the sections to follow, the North Carolina Department of Environment and Natural Resources,
Division of Air Quality (NCDAQ) will provide the technical data necessary to show that both the
Hickory and Triad nonattainment areas have attained and are expected to maintain the annual
fine particulate matter standard, and have met the requirements for redesignation set forth above.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
The NCDAQ has collected ambient monitoring data for Catawba, Davidson, and Guilford
Counties since 1999. At the time of fine particulate matter designations, there were three Federal
Reference Method (FRM) monitors for fine particulate matter in the three counties; Hickory,
Lexington, and Mendenhall (Figure 2-1). In late 2007, another PM2.5 FRM monitor was installed
in Guilford County, located in Colfax which is located just west of Greensboro. These monitors
were installed in accordance with the 40 CFR 58.
Data from the fourth quarter of 2006 at Mendenhall is incomplete due to construction at the
monitoring site and complications in relocating the site. The NCDAQ had to move the site since
the school where the monitoring site is located constructed a two-story field house immediately
adjacent to the monitoring site (letter to USEPA Region 4, Appendix D). The school had not
notified the NCDAQ of its intention to build the field house. During a routine site visit, the
NCDAQ discovered that construction had started within four meters of the monitoring site. At
that point, the monitor no longer met the ambient monitoring siting criteria and had to be shut
down and moved.
A new site was promptly found and appropriate permits were applied for. It took the NCDAQ
four months (instead of an estimated 3 weeks) to resolve all the necessary permits and complete
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-2
Redesignation Demonstration and Maintenance Plan December 18, 2009
the relocation of the monitor. This unfortunate circumstance resulted in most of the fourth
quarter to go unmonitored.
The USEPA guidance does not address missing monitoring data for an entire quarter. The
NCDAQ decided the best option was to develop regressive analysis between Mendenhall and
surrounding monitors. Data from surrounding monitors was incorporated into the regressive
analysis to obtain a best estimate for the fourth quarter at Mendenhall. Please see Appendix D
for more details.
The Mendenhall monitor has never violated the PM2.5 standards and has consistently had annual
averages that were 1 – 2 μg/m3 below the annual PM2.5 NAAQS. The NCDAQ is confident that
had the monitor been operating during the 2006 fourth quarter, the ambient air quality levels
would have been consistent with the estimated values the NCDAQ has developed. The USEPA
has also proposed to determine that the Greensboro/Winston-Salem/High Point nonattainment
area has attained the 1997 PM2.5 NAAQS (74 FR 51249).
Tables 2-1 and 2-2 below show the air quality data and corresponding design values,
respectively, for the monitors in the both the Hickory and Triad nonattainment areas from 1999
to 2006. Table 2-2 indicates that the Hickory and Lexington monitors were in violation of the
PM2.5 NAAQS for this period, while the Mendenhall monitor was consistently below the annual
PM2.5 standard.
Monitor Fine Particulate Matter Annual Average (μg/m3)
1999 2000 2001 2002 2003 2004 2005 2006 2007
Hickory Nonattainment Area
Hickory
AIRS ID #37-035-0004
Catawba County
17.42 17.63 15.98 15.36 15.04 15.00 15.95 15.17 14.54
Triad Nonattainment Area
Lexington
AIRS ID #37-057-0002
Davidson County
17.34 18.04 16.45 15.88 15.17 15.18 15.40 15.13 14.64
Mendenhall
AIRS ID #37-081-0013
Guilford County
13.72 13.32 13.97 14.01 14.06* 13.05
*Estimated fourth quarter data
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-3
Redesignation Demonstration and Maintenance Plan December 18, 2009
Monitor
Design Value (μg/m3)
99-01 00-02 01-03 02-04 03-05 04-06 05-07
Hickory Nonattainment Area
Hickory
AIRS ID #37-035-0004
Catawba County
Triad Nonattainment Area
Lexington
AIRS ID #37-057-0002
Davidson County
Mendenhall
AIRS ID #37-081-0013
Guilford County
13.7 13.8 14.0* 13.7*
Note: Bolded values represent violations of the annual fine particulate matter standard.
*Estimated fourth quarter 2006 data used in Design Value calculation.
The most recent three years of PM2.5 monitoring data (2006-2008) for both the Hickory and
Triad nonattainment areas demonstrate compliance with the annual fine particulate matter
NAAQS. Table 2-3 is a summary of the annual averages for the monitors located in the
nonattainment areas for 2006-2008 and their respective design values. The Colfax monitor only
has data for 2008 and therefore does not have sufficient data to calculate a design value.
However, the 2008 annual average is significantly below the annual PM2.5 standard. Therefore,
the NCDAQ is confident the area is in compliance of the NAAQS. The 2008 PM2.5 monitoring
data for both the Hickory and the Triad areas have been fully quality assured and were officially
submitted to the USEPA on May 9, 2009.
As noted in the previous section, the fourth quarter data for 2006 at the Mendenhall monitoring
site is incomplete. After an extensive analysis, the NCDAQ is confident that the Mendenhall
monitor is not in violation of the PM2.5 NAAQS (see Appendix D). It should be noted that the
Mendenhall monitor has never violated the annual PM2.5 NAAQS in the history of its operation.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-4
Redesignation Demonstration and Maintenance Plan December 18, 2009
Monitor Year PM2.5 Annual Average
(μg/m3)
Design Value (μg/m3)
2006-2008
Hickory Nonattainment Area
Hickory
AIRS ID #37-035-0004
Catawba County
2006 15.17
2007 14.54 14.2
2008 12.85
Triad Nonattainment Area
Lexington
AIRS ID #37-057-0002
Davidson County
2006 15.13
2007 14.64 14.5
2008 13.66
Mendenhall
AIRS ID #37-081-0013
Guilford County
2006 14.06*
2007 13.05 12.9*
2008 11.45
Colfax
AIRS ID #37-081-0141
Guilford County
2006 N/A
2007 N/A N/A
2008 12.21
*Estimated fourth quarter 2006 data used in Design Value calculation.
There are several State and Federal measures that have been enacted in recent years that are
resulting in permanent emissions reductions. Most of these emission reductions are due to
regulations and thus are enforceable. However, a few measures are non-regulatory but will still
result in emission reductions. A list of those measures that contributed to the permanent
emission reductions are listed below and are more fully described in Section 3.2.
The federal measures that have been implemented include:
• Tier 2 vehicle standards: In addition to NOx controls, the Tier 2 rule also reduced the
sulfur content of gasoline to 30 parts per million (ppm) starting in January of 2006.
Most gasoline sold in North Carolina prior to January 2006 had a sulfur content of
about 300 ppm. These emission reductions are federally enforceable.
• Heavy-duty gasoline and diesel highway vehicle standards: Second phase of
standards and testing procedures, which began in 2007, will reduce particulate matter
from heavy-duty highway engines, and will also reduce highway diesel fuel sulfur
content to 15 ppm since the sulfur damages emission control devices. The total
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Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-7
Redesignation Demonstration and Maintenance Plan December 18, 2009
Year Annual SO2 Emissions
(Tons)
Annual NOx Emissions
(Tons)
2002 462,993 145,706
2003 462,041 135,879
2004 472,320 124,079
2005 500,936 114,300
2006 462,143 108,584
2007 370,827 64,770
2008* 227,030 61,669
*Data from 2008 is considered preliminary.
As mentioned in Section 1.1, PM2.5 is composed of many species from varying sources.
Figure 2-2 presents the North Carolina statewide averaged PM2.5 speciation data from the
speciation trends network (STN) monitors for the year 2004. The figure presents sulfates and
organic carbons as the main contributors to PM2.5, each with 29% of the total PM2.5 mass. The
“other” portion of the PM2.5 that accounts for 17% of the mass can be attributed to water, sea
salts, and other trace materials captured with the STN monitors.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-8
Redesignation Demonstration and Maintenance Plan December 18, 2009
Organic carbon is predominately attributed to biogenic emission sources and sulfate is associated
with SO2 emissions. When evaluated across North Carolina and also throughout both
nonattainment areas and surrounding regions, the SO2 is primarily from the point source sector.
For this reason, reductions in SO2 emissions will provide the greatest reductions in PM2.5
ambient concentrations. Figure 2-3 displays the location of the major power plants located near
the PM2.5 nonattainment areas. Table 2-5 presents the SO2 emissions from these nine power
plants as reported from the USEPA acid rain database. It is clearly demonstrated that the annual
emissions from these facilities have significantly decreased since 2005, with over 250,000 tons
of SO2 emission reduction in the 2008 compared to 2005. This is over a 50% reduction in utility
SO2 emissions that are permanent and enforceable. These reductions have taken place beginning
in 2006, which includes the first year of the attaining 3-year design value. Since the final
compliance date for the NCCSA SO2 emissions caps is 2013, future design values are expected
to continue to decline below the 2006-2008 attaining design values.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 2-9
Redesignation Demonstration and Maintenance Plan December 18, 2009
Facility County 2005 2006 2007 2008
Belews Creek Rockingham 96,813 95,290 86,388 17,252
Buck Rowan 9,582 9,560 10,261 7,353
Cliffside Rutherford 28,209 29,128 27,566 29,421
Dan River Stokes 4,248 7,068 7,672 6,687
Allen Gaston 45,424 45,395 50,550 49,578
Marshall Catawba 100,540 85,050 24,754 6,174
Mayo Person 27,076 24,499 22,811 20,072
Riverbend Gaston 13,964 15,148 15,907 15,942
Roxboro Person 101,444 94,627 65,247 24,436
Total 427,301 405,765 311,155 176,914
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
The State's plan for maintaining compliance with the ambient air quality standard for annual fine
particulate matter in the Hickory and Greensboro/Winston-Salem/High Point nonattainment
areas consists of three major parts: a foundation control program, a maintenance demonstration,
and a contingency plan. The foundation control program consists of the current Federal and
State control measures already in effect, as well as the future benefits of the federal cleaner
engine programs, and low sulfur gasoline and low sulfur diesel fuel programs. Additionally,
although the federal Clean Air Interstate Rule (CAIR) has been remanded back to the USEPA, a
replacement rule is expected to be promulgated in 2011. This new rule is expected to be as
stringent as CAIR.
The NCDAQ has implemented programs that will remain enforceable and are hereby submitted
as the plan to ensure that maintenance of the annual fine particulate matter standard will
continue. Sources are prohibited from reducing emission controls (anti-backsliding) following
the redesignation of the area unless such a change is first approved by the USEPA as a revision
to the North Carolina SIP that is consistent with Section 110(l) of the Clean Air Act.
For the maintenance demonstration, the base year of 2008 was chosen since it is a year that falls
within the attaining design value period of 2006-2008 and some emissions inventory data was
already developed for this year. The interim years chosen were: 2011, 2014, and 2017 since the
USEPA recommends three-year increments for interim years. The final year of the maintenance
demonstration is 2021, since the CAA requires maintenance for at least ten years after
redesignation. The maintenance demonstration consists of a comparison between the 2008
baseline emissions inventory and the projected emissions inventories (for 2011, 2014, 2017, and
2021), which consider economic and population growth as well as expected controls. The
comparison shows that the total emissions in each of the interim years and the final year will be
lower than in the base year, which demonstrates maintenance of the annual PM2.5 standard. The
reductions in emissions are due to the foundation control programs outlined below.
The North Carolina contingency plan involves tracking and triggering mechanisms to determine
when contingency measures are needed and a process of implementing appropriate control
measures. The primary trigger of the contingency plan will be a violation of the ambient air
quality standard for annual PM2.5. The secondary trigger will be a monitored air quality pattern
that suggests an actual annual PM2.5 NAAQS violation may be imminent, such as repeated
exceedances of the daily fine particulate matter standard.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-2
Redesignation Demonstration and Maintenance Plan December 18, 2009
The main element of the maintenance plan is the foundation control program. The foundation
control program contains the controls necessary to maintain the ambient air quality standards.
The purpose of the foundation control program is to prevent the ambient air quality standards
from being violated and thereby eliminate the need for more costly controls being imposed on
industry and the general public. Each component of the State's foundation control program is
essential in demonstrating maintenance of the air quality standards.
The foundation control program consists of Federal and State measures. The Federal measures
include the cleaner fuel programs and the federal highway motor vehicle and off-road equipment
control program and controls on power plants. State measures include the I/M program, the NOx
SIP Call rule, the NCCSA, and open burning and idle reduction regulations. The state measures
also include additional programs that support maintenance of the PM2.5 standard. Most of these
emission reductions are due to regulations and thus are enforceable. However, a few measures
are non-regulatory but will still result in emission reductions. All of these programs have already
been implemented or are in the process of being implemented.
Tier 2 Vehicle Standards
Federal Tier 2 vehicle standards require all passenger vehicles in a manufacturer’s fleet,
including light-duty trucks and Sport Utility Vehicles (SUVs), to meet an average standard of
0.07 grams of NOx per mile. Implementation began in 2004, with full compliance required by
2007. The Tier 2 standards also cover passenger vehicles over 8,500 pounds gross vehicle
weight rating (the larger pickup trucks and SUVs), which are not covered by the Tier 1
regulations. For these vehicles, the standards were phased in beginning in 2008, with full
compliance required by 2009. The new standards require vehicles to be 77% to 95% cleaner.
The Tier 2 rule also reduced the sulfur content of gasoline to 30 ppm starting in January of 2006.
Most gasoline sold in North Carolina prior to January 2006 had a sulfur content of about
300 ppm. Sulfur occurs naturally in gasoline and interferes with the operation of catalytic
converters on vehicles, which results in higher NOx emissions. Lower-sulfur gasoline is
necessary to achieve the Tier 2 vehicle emission standards. These emission reductions are
federally enforceable.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-3
Redesignation Demonstration and Maintenance Plan December 18, 2009
Heavy-Duty Gasoline and Diesel Highway Vehicles Standards
The USEPA standards designed to reduce NOx and VOC emissions from heavy-duty gasoline
and diesel highway vehicles began to take effect in 2004. The second phase of the standards and
testing procedures began in 2007 and will reduce particulate matter from heavy-duty highway
engines, and reduces highway diesel fuel sulfur content to 15 ppm since the sulfur damages
emission control devices. The total program is expected to achieve a 90% reduction in PM
emissions and a 95% reduction in NOx emissions for the new engines using low sulfur diesel,
compared to engines using higher-content sulfur diesel. These emission reductions are federally
enforceable.
Large Nonroad Diesel Engines Rule
In May 2004, the USEPA promulgated new rules for large nonroad diesel engines, such as those
used in construction, agricultural, and industrial equipment, to be phased in between 2008 and
2014. The nonroad diesel rules also reduce the allowable sulfur in nonroad diesel fuel by over
99%. Prior to the fuel standard change, nonroad diesel fuel averaged about 3,400 ppm sulfur.
The rule limits nonroad diesel sulfur content to 500 ppm by 2006 and 15 ppm by 2010. The
combined engine and fuel rules is expected to reduce NOx and PM emissions from large nonroad
diesel engines by over 90%, compared to current nonroad engines using higher-content sulfur
diesel. These emission reductions are federally enforceable.
Nonroad Spark-Ignition Engines and Recreational Engines Standard
The nonroad spark-ignition and recreational engine standards, effective in July 2003, regulates
NOx, hydrocarbons (HC) and CO for groups of previously unregulated nonroad engines. These
engine standards apply to all new engines sold in the United States and imported after these
standards began and applies to large spark-ignition engines (forklifts and airport ground service
equipment), recreational vehicles (off-highway motorcycles and all-terrain-vehicles), and
recreational marine diesel engines. The regulation varies based upon the type of engine or
vehicle.
The large spark-ignition engines contribute to ozone formation and ambient CO and PM levels in
urban areas. Tier 1 of this standard was implemented in 2004 and Tier 2 started in 2007. Like
the large spark-ignition, recreational vehicles contribute to ozone formation and ambient CO and
PM levels. For the off-highway motorcycles and all-terrain-vehicles, the exhaust emissions
standard was phased-in. Fifty percent of model year 2006 engines had to meet the standard and
for model years 2007 and later, all engines must meet the standard. Recreational marine diesel
engines over 37 kilowatts are used in yachts, cruisers, and other types of pleasure craft.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-4
Redesignation Demonstration and Maintenance Plan December 18, 2009
Recreational marine engines contribute to ozone formation and PM levels, especially in marinas.
Depending on the size of the engine, the standard began phasing-in in 2006.
When all of the nonroad spark-ignition and recreational engine standards are fully implemented,
an overall 72% reduction in HC, 80% reduction in NOx, and 56% reduction in CO emissions are
expected by 2020. These controls will help reduce ambient concentrations of ozone, CO, and
PM2.5. These emission reductions are federally enforceable.
NOx SIP Call in Surrounding States
In October 1998, the USEPA made a finding of significant contribution of NOx emissions from
certain states and published a rule that set ozone season (May to September) NOx budgets for the
purpose of reducing regional transport of ozone (63 FR 57356). This rule, referred to as the NOx
SIP Call, required ozone season controls to be put on utility and industrial boilers, as well as
internal combustion engines, in 22 states in the Eastern United States. A NOx emissions budget
was set for each state and the states were required to develop rules that would assure that each
state met its budget. A NOx trading program was established, allowing sources to buy credits to
meet their NOx budget as opposed to actually installing controls. The emission budgets were to
be met by the beginning of 2004. Even with the trading program, the amount of ozone season
NOx emissions has decreased significantly in and around North Carolina. These emission
reductions are federally enforceable.
Clean Air Interstate Rule
On May 12, 2005, the USEPA promulgated the “Rule To Reduce Interstate Transport of Fine
Particulate Matter and Ozone (Clean Air Interstate Rule); Revisions to Acid Rain Program;
Revisions to the NOx SIP Call”, referred to as CAIR. This rule established the requirement for
States to adopt rules limiting the emissions of NOx and SO2 and a model rule for the states to use
in developing their rules. The purpose of the CAIR is to reduce interstate transport of precursors
of fine particulate and ozone.
This rule provides annual state caps for NOx and SO2 for large fossil-fuel-fired electric
generating units in two phases, with the Phase I caps for NOx and SO2 starting in 2009 and 2010,
respectively. Phase II caps become effective in 2015. The USEPA is allowing the caps to be
met through a cap and trade program if a state so chooses to participate in the program. These
emission reductions are federally enforceable.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-5
Redesignation Demonstration and Maintenance Plan December 18, 2009
Due to court challenges of CAIR in 2008, the USEPA will be making changes to the program by
2011. However, the existing CAIR rules will remain in place until the USEPA promulgates
changes to the program. Additionally, the revisions to the CAIR program are expected to be as
stringent as the existing program.
North Carolina has adopted a number of regulations, legislation, and voluntary programs to
address pollution issues across the State. These are summarized below.
Clean Air Bill
The 1999 Clean Air Bill expanded the vehicle emissions I/M program in North Carolina from 9
counties to 48 counties, between July 1, 2002 through January 1, 2006 (Figure 3-1). Vehicles are
tested using the onboard diagnostic system (OBDII), an improved method of testing, which
ensures proper emission system operation for vehicles and light trucks during their lifetime by
monitoring emission-related components and systems for malfunction and/or deterioration. An
important aspect of OBDII is its ability to notify the driver of malfunction and/or deterioration
by illuminating the "check engine light". If the vehicle is taken to a repair shop in a timely
fashion, it can be properly repaired before any significant and prolonged emission increase
occurs. The previously used tailpipe test (i.e., idle test) did not measure NOx emissions; it only
tested for VOC and CO emissions. By utilizing the OBDII test method, the NOx emissions as
well as other pollutants from motor vehicles are reduced. The effective dates for the counties in
the PM2.5 nonattainment area are listed below.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-8
Redesignation Demonstration and Maintenance Plan December 18, 2009
the Triad area are subject to this rule Alamance Caswell Davidson Davie Forsyth Guilford
Randolph Rockingham and Stokes.
The open burning regulation reduces PM, NOx, SO2, VOC, and CO emissions and are state
enforceable. The estimated emission reductions through the attainment and maintenance period
are presented in Table 3-3. For a full explanation of how these emission reductions were
estimated, please refer to Appendix C.2, the Area Source Emissions Inventory Documentation.
Hickory Area
Catawba 56 66 76 85 100
Triad Area
Davidson 94 109 126 141 167
Guilford 79 91 105 119 140
Triad Total 173 200 231 260 307
Hickory Area
Catawba 10 11 12 14 17
Triad Area
Davidson 16 18 21 23 28
Guilford 13 15 17 20 23
Triad Total 29 33 38 43 51
Hickory Area
Catawba 326 380 438 493 581
Triad Area
Davidson 541 632 729 819 965
Guilford 454 530 612 688 809
Triad Total 995 1162 1341 1507 1774
Idle Reduction Regulation
The EMC adopted the Heavy-Duty Vehicle Idling Restrictions rule to reduce unnecessary idling
of heavy-duty trucks on July 9, 2009. This rule has received several letters of objection and will
undergo a legislative review in the Spring of 2010 before becoming effective. Once in effect,
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-9
Redesignation Demonstration and Maintenance Plan December 18, 2009
this rule will be state enforceable and generally prevent any person who operates a heavy-duty
vehicle to cause, let, permit, suffer or allow idling for a period of time in excess of 5 consecutive
minutes in any 60 minute period. The expected emissions from this regulation were not
included in the mobile source emissions estimated for this maintenance plan because of the
uncertainty of the regulations.
Air Awareness Program
The North Carolina Air Awareness Program is a public outreach and education program of the
NCDAQ. The goal of the program is to reduce air pollution though voluntary actions by
individuals and organizations. The program seeks to educate individuals about (1) the sources of
air pollution; (2) the health effects of air pollution and how these effects can be mitigated by
modification of outdoor activities on air quality action days; and (3) simple "action tips", such as
carpooling, vehicle maintenance, and energy conservation, that reduce individual contributions
to air pollution. One of the major program components is the year round daily air quality
forecast. The NCDAQ produces a daily fine particulate matter forecasts and corresponding air
quality index for the Hickory forecast area, while the Forsyth County Environmental Affairs
Department provides daily fine particulate matter forecasts and the corresponding air quality
index for the Triad region.
Transportation Conformity
The NCDAQ works closely with the North Carolina Department of Transportation (NCDOT)
and local transportation agencies to assure that Transportation Improvement Programs (TIPs) in
the nonattainment areas are consistent with and conform to the State's air quality program,
including the SIP, and meet the Federal requirements on transportation conformity. This
conformity review is performed for all federally funded and all other major projects contained in
TIPs, regardless of source of funding. Technical analysis of transportation plans, programs, and
projects for conformity are done cooperatively by the Statewide Planning Branch of the NCDOT
and the NCDAQ. In the event that the NCDAQ disagrees with the NCDOT on a conformity
determination or other conformity related issue, the NCDAQ and the NCDOT will present the
issue to the Governor for resolution.
The public and interested parties are given an early and reasonable opportunity to comment on
transportation plans, programs, projects and proposed conformity determinations in accordance
with procedures adopted by metropolitan planning organizations pursuant to the requirements of
•
•
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-18
Redesignation Demonstration and Maintenance Plan December 18, 2009
will be a rolling 12 quarter average that exceeds the annual PM2.5 NAAQS. The tertiary trigger
will be a monitored annual average that exceeds the annual PM2.5 NAAQS. Upon either the
primary or secondary triggers being activated, the NCDAQ will commence analyses to
determine what additional measures, if any, will be necessary to attain or maintain the annual
PM2.5 standard. If activation of either the primary or secondary triggers occurs, this plan
provides a regulatory adoption process for revising emission control strategies. Activation of the
tertiary trigger will result in an analysis to understand the cause of the exceedance and to identify
voluntary measures if needed.
In addition, there will be a tracking mechanism that requires a comparison of the actual
emissions inventory submitted under the Federal Consolidated Emissions Reporting Rule
(CERR) and Air Emissions Reporting Rule (AERR) to the projected inventory, and to the
attainment year inventory contained in this maintenance plan. The CERR and AERR reporting
years coincide with the baseline, interim and final years of the emission inventory in this
maintenance demonstration.
The primary trigger of the contingency plan will be a violation of the annual PM2.5 standard, or
when the three-year average of the average annual ambient concentration is greater than
15.0 μg/m3 at any monitor in the PM2.5 nonattainment areas. The trigger date will be 60 days
from the date that the State observes an annual average concentration that, when averaged with
the two previous annual average PM2.5 concentrations, would result in a three-year average
greater than 15.0 μg/m3.
The secondary trigger will apply where no actual violation of the annual PM2.5 standard has
occurred, but where the State finds that the rolling 12-quarter average monitored PM2.5 levels
exceed the PM2.5 NAAQS. A pattern will be deemed to exist when the average PM2.5
concentrations of any 12 consecutive quarters is greater than 15.0 μg/m3 at any monitor within
the PM2.5 nonattainment areas. The trigger date will be 60 days from the date that the State
observes a rolling 12-quarter average greater than 15.0 μg/m3 at any monitor.
Similarly, the tertiary trigger will not be an actual violation of the annual PM2.5 standard. This
trigger will be a first alert as to a potential air quality problem on the horizon. The trigger will be
activated when a monitor in either of the PM2.5 nonattainment areas has an annual average
greater than 15.0 μg/m3, starting the first year after the maintenance plan has been approved.
The trigger date will be 60 days from the date that the State observes an annual average greater
than 15.0 μg/m3 at any monitor.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-19
Redesignation Demonstration and Maintenance Plan December 18, 2009
There are a number of programs that are still being implemented in North Carolina that will
continue to reduce fine particulate matter and its precursors. The NCCSA has a final compliance
year of 2013 by which the public utilities in North Carolina must meet their SO2 emissions caps.
It is estimated that an additional 133,320 tons of SO2 will be reduced from the 2008 emission
levels for the sources subject to the NCCSA. Additionally, the NCDAQ is still awarding grants
for retrofits, replacement or repowering of diesel engines for on-road and nonroad mobile
sources. Since it is possible that the speciation composition of fine particulate matter may
change in the future years, it is important that the NCDAQ identify the pollutant or pollutants for
which further reductions are needed in order to maintain the annual PM2.5 NAAQS.
Once the primary or secondary trigger is activated, the Planning Section of the NCDAQ shall
commence analyses including trajectory analyses of high PM2.5 days, and emissions inventory
assessment to determine those emission control measures that will be required for attaining or
maintaining the annual PM2.5 standard. Additionally, the PM2.5 speciation data from the STN
monitors will be reviewed to determine which species are the more predominant components for
the period where a violation or exceedance of the NAAQS was observed.
If it is determined that the cause of the violation or exceedance of the PM2.5 NAAQS is due to
sources outside of North Carolina, then the NCDAQ will commence discussion with regulatory
authorities responsible for upwind sources to determine additional actions to be implemented.
The State of North Carolina has already filed a Section 126 petition in order to ensure that
neighboring states reduce their utility emissions in a timely manner. As a result of the recent
court decision in the State of North Carolina vs. Tennessee Valley Authority, additional
emissions reductions are anticipated for upwind TVA sources.
If it is determined that the violation or exceedance occurred due to sources within North
Carolina, then by November 1 of the year following the year in which the primary or secondary
trigger has been activated, North Carolina will complete sufficient analyses to begin adoption of
necessary rules for ensuring attainment and maintenance of the annual PM2.5 NAAQS. If the
rules are still needed, then rules would become State effective by the following July 1, unless
legislative review is required. Each adopted rule will include a schedule that will require
compliance with the rule no later than 2 years after adoption of the rule.
The measures that will be considered for adoption upon a trigger of the contingency plan
include: Reasonably Available Control Technology on stationary sources in the PM2.5
nonattainment area counties, diesel inspection and maintenance program, implementation of
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 3-20
Redesignation Demonstration and Maintenance Plan December 18, 2009
diesel retrofit programs, including incentives for performing retrofits, and additional controls in
upwind areas.
Once the tertiary trigger is activated, the Planning Section of the NCDAQ shall commence
analyses including meteorological evaluation, trajectory analyses of high PM2.5 days, and
emissions inventory assessment to understand why an annual exceedance of the standard has
occurred. Once the analyses are completed, the NCDAQ will work with the local air awareness
program and develop an outreach plan to identify any additional voluntary measures that can be
implemented. NCDAQ will work with the local air awareness coordinator to implement the plan
for the following summer.
In addition to the measures listed above, emissions inventory comparisons will be carried out.
The large stationary sources are required to submit an emissions inventory annually to the
NCDAQ. The NCDAQ will commit to review these emissions inventories to determine if an
unexpected growth in NOx, SO2 or primary particulate matter emissions in the PM2.5
nonattainment areas may endanger the maintenance of the annual PM2.5 standard. Additionally,
as new VMT data is provided by the North Carolina Department of Transportation (NCDOT),
the NCDAQ commits to review this data and determine if any unexpected growth in VMT may
endanger the maintenance of the annual PM2.5 standard.
Additionally, under the CERR and AERR the NCDAQ is required to develop a comprehensive,
annual, statewide emissions inventory every three years and is due twelve to eighteen months
after the completion of the inventory year. The CERR and AERR inventory years coincide with
the baseline, interim and final years of the maintenance plan. Therefore, the NCDAQ commits
to compare these inventories as they are developed with the maintenance plan to determine if
additional steps are necessary for continued maintenance of the annual PM2.5 standard in this
area.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
The purpose of transportation conformity is to ensure that Federal transportation actions
occurring in nonattainment and maintenance areas do not hinder the area from attaining and
maintaining the annual fine particulate matter standard. This means that the level of emissions
estimated by the NCDOT or the metropolitan planning organizations for the TIP and Long
Range Transportation Plan must not exceed the motor vehicle emission budgets (MVEBs) as
defined in this maintenance plan.
40 CFR 93.119(f)(7) through (10) identifies the pollutants for PM2.5 that regional emissions
analysis needs to be performed for transportation conformity purposes. These parts of the rule
are listed below:
Only primary, or direct PM2.5, tailpipe emissions must be considered for transportation
conformity regional emissions analysis. The other precursor pollutants and reentrained road dust
only need to be considered if the State air agency and/or the USEPA have deemed the pollutant
as a significant contributor to the PM2.5 nonattainment problem. The following sections discuss
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-2
Redesignation Demonstration and Maintenance Plan December 18, 2009
the significance of the precursor pollutants and reentrained road dust to the PM2.5 nonattainment
problem.
The PM2.5 precursor NOx is presumed to be a significant contributor to the PM2.5 nonattainment
problem by the USEPA. The NCDAQ has determined that NOx is a relatively minor contributor
to the PM2.5 concentrations in North Carolina. However, the NCDAQ is not asserting that NOx
is an insignificant precursor for the 1997 PM2.5 standard. Therefore, the NCDAQ will establish
county level MVEBs for NOx for all three PM2.5 nonattainment counties.
For the purpose of this attainment demonstration, VOC and ammonia are presumed to be
insignificant contributors to the PM2.5 nonattainment problem by the USEPA. The NCDAQ
agrees with the USEPA that both VOC and ammonia are insignificant contributors to the PM2.5
nonattainment problem in North Carolina. Since these precursors have been deemed
insignificant, no MVEBs are being established for VOC or ammonia.
An affirmative insignificance finding from the USEPA only relieves the transportation partners
from a regional emissions analysis for PM2.5 emissions for these areas and does not relieve them
of the other transportation conformity requirements. The transportation partners will need to
note the VOC and Ammonia insignificance finding (if found adequate and approved by the
USEPA) in future conformity determinations.
The majority of the roads in North Carolina are paved so there is minimum road dust due to the
paved roads. The factor to calculate reentrained road dust on paved roads is very small. What
dust is generated, has been shown in the literature,
, to be inconsequential.
This fact is affirmed by the small crustal component in the PM2.5 speciated data which measures
only 3% at Hickory monitoring site (Catawba County) in 2002 and only 2% at Lexington
monitoring site (Davidson County) in 2004 (see Figure 4-1 below).
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-3
Redesignation Demonstration and Maintenance Plan December 18, 2009
Since the reentrained road dust is not a significant contributor to the PM2.5 nonattainment
problem, the NCDAQ will not be establishing MVEBs for this source category. An affirmative
insignificance finding from the USEPA only relieves the transportation partners from a regional
emissions analysis for reentrained road dust emissions for these areas and does not relieve them
of the other transportation conformity requirements. The transportation partners will need to
note the reentrained road dust insignificance finding (if found adequate and approved by the
USEPA) in future conformity determinations.
The PM2.5 precursor SO2 could not be deemed insignificant to the PM2.5 nonattainment problem.
However, the NCDAQ has determined that SO2 emitted by the mobile source sector is
insignificant. The USEPA in its Federal Register notice for PM2.5 does not address the mobile
sector in its listing of significant emissions. North Carolina agrees with the following statements
addressing SO2 from on-road mobile emissions as published in the May 6, 2005, Federal
Register, (70 FR 24283):
Nitrate
6%
Sulfate
30%
Ammonium
10%
Organic carbon
32%
Elemental carbon
4%
Crustal component
3%
Other
15%
Nitrate
7%
Sulfate
29%
Ammonium
10%
Organic carbon
28%
Elemental carbon
4%
Crustal component
2%
Other
20%
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-4
Redesignation Demonstration and Maintenance Plan December 18, 2009
Although sulfate is a significant component to the PM2.5 nonattainment problem in North
Carolina, the majority of the SO2 emissions in 2009 come from the stationary point source sector
(see Figure 4-2). The mobile source sector only contributes one half of one percent (0.5 %) of
the 2009 statewide SO2 emissions. This is consistent with what the USEPA stated above.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-5
Redesignation Demonstration and Maintenance Plan December 18, 2009
Since the mobile source SO2 contribution is insignificant, the NCDAQ is not establishing
MVEBs for this precursor. An affirmative insignificance finding from the USEPA only relieves
the transportation partners from a regional emissions analysis for SO2 emissions for these areas
and does not relieve them of the other transportation conformity requirements. The
transportation partners will need to note the SO2 insignificance finding (if found adequate and
approved by the USEPA) in future conformity determinations.
40 CFR 93.109(k) in the Transportation Conformity Rule Amendments for the new 8-hour ozone
and fine particulate matter NAAQSs addresses areas with insignificant motor vehicle emissions
as follows,
The rule suggests that such a finding would be based on a number of factors, including the
percentage of motor vehicle emissions in the context of the total SIP inventory, the current state
of air quality as determined by monitoring data for that NAAQS, the absence of SIP motor
vehicle control measures, and historical trends and future projections of the growth of motor
vehicle emissions. Although there is an inspection and maintenance program in the
nonattainment areas, this control measure does not control primary PM2.5, but rather is in place to
reduce the ozone precursors.
The NCDAQ believes strongly that the primary PM2.5 emissions from mobile sources do not
contribute significantly to the PM2.5 nonattainment problem. However, the USEPA has indicated
they will not approve a SIP that does not set MVEBs for primary PM2.5 for the Triad
nonattainment area. Therefore, the NCDAQ will establish county level MVEBs for primary
PM2.5 for the Triad area. The sections that follow discuss the insignificance of PM2.5 emissions.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-6
Redesignation Demonstration and Maintenance Plan December 18, 2009
The attainment modeling for the Hickory and the Triad PM2.5 nonattainment areas was submitted
to the USEPA on August 21, 2009. In conjunction with that modeling the NCDAQ examined
the sources of PM2.5 emissions and their contribution to PM2.5 formation in the nonattainment
counties. This was accomplished using the 2009 emissions inventories developed for the
attainment demonstration modeling. Figure 4-3 provides the percent contributions from point,
area, nonroad mobile and on-road mobile source sectors for the Hickory nonattainment area.
The 2009 on-road mobile PM2.5 emissions contributed only 1.6% of the total PM2.5 emissions for
the Hickory area. Therefore, it is demonstrated that the PM2.5 emissions compared to the total
PM2.5 emissions are insignificant. It should be noted that the mobile source PM2.5 emissions
slightly decrease from 2002 to 2009 despite an increase in VMT.
The NCDAQ performed sensitivity modeling in order to address the challenge of Section
93.109(k) in the Transportation Conformity Rule Amendments,
The sensitivity modeling showed that
with a doubling of the mobile source PM2.5 emissions there was no change in the air quality
modeling results. This sensitivity modeling is discussed in more detail in Appendix C.3.
Based on the information discussed above, the NCDAQ believes that the on-road mobile PM2.5
emissions are insignificant contributors to the PM2.5 nonattainment problem. Emission estimates
indicate that the on-road mobile PM2.5 emissions are a small percentage of the total PM2.5
emissions in the Hickory nonattainment area. On-road mobile PM2.5 emissions are projected to
1.59%
68.70%
1.49%
28.22%
Mobile
Point
Area
Nonroad
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 4-7
Redesignation Demonstration and Maintenance Plan December 18, 2009
decrease into the future notwithstanding VMT increases. Air quality modeling sensitivities show
that doubling the mobile source PM2.5 emissions has very little effect on the future design values.
The NCDAQ considers it unreasonable to expect that the Hickory PM2.5 nonattainment area will
experience enough motor vehicle PM2.5 emissions growth for a future PM2.5 violation to occur
due to mobile sources.
Due to above analysis and agreement from the USEPA, budgets for direct PM2.5 will not be set
for the Hickory nonattainment area. An affirmative insignificance finding from the USEPA only
relieves the transportation partners from a regional emissions analysis for PM2.5 emissions for
this area and does not relieve them of the other transportation conformity requirements. The
transportation partners will need to note the PM2.5 insignificance finding (if found adequate and
approved by the USEPA) in future conformity determinations.
As stated in Section 3.3.4, a safety margin is the difference between the attainment level of
emissions from all source categories (i.e., point, area, on-road mobile and nonroad mobile) and
the projected level of emissions from all source categories. The safety margins for both the
Hickory and Triad areas are listed in Table 3-21 and 3-22. The State may choose to allocate
some of the safety margin to the MVEB, for transportation conformity purposes, so long as the
total level of emissions from all source categories remains below the attainment level of
emissions.
The NCDAQ has decided to allocate a portion of the safety margin to the MVEB to allow for
unanticipated growth in VMT, changes to vehicle mix assumptions, etc. that will influence the
emission estimations. Since NOx is a precursor to ozone, the NCDAQ has decided to limit the
amount of the safety margin allocated to the MVEBs. For 2011 and 2021, the NCDAQ has
added an additional 10% and 20%, respectively, to the NOx MVEBs. This is consistent with
how the NCDAQ has handled NOX MVEBs in ozone maintenance plans.
Since the NCDAQ does not believe that mobile source PM2.5 emissions are a significant
contributor to PM2.5 nonattainment, the 2011 and 2021 MVEBs for the Triad nonattainment area
will be set at the 2008 mobile source PM2.5 emission levels.
As part of the consultation process on setting MVEBs, the NCDAQ sent out a request for
comment on setting the geographic extent of the MVEBs to all of the transportation partners. A
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 5-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
For an area to be redesignated and have an approved maintenance plan, the SIP must include
evidence of compliance with the rules relied on to show maintenance of the standard. This
section provides the evidence of compliance with such rules for the Hickory and Triad PM2.5
nonattainment area.
The following rules regulating emissions of SO2 and/or NOx in PM2.5 nonattainment area
counties have been approved, or have been submitted with a request to be approved, as part of
the SIP:
15A NCAC 2D .0530, Prevention of Significant Deterioration
15A NCAC 2D .1000, Motor Vehicle Emission Control Standards
15A NCAC 2D .1200, Control and Emissions from Incinerators
15A NCAC 2D .1409(b), Stationary Internal Combustion Engines
15A NCAC 2D .1416 - .1423, NOx SIP rules
15A NCAC 2D .1600, General Conformity
15A NCAC 2D .1900, Open Burning
15A NCAC 2D .2000, Transportation Conformity
15A NCAC 2D .2400 Clean Air Interstate Rules
Section 15A NCAC 2D .1000 also regulates emissions from motor vehicles in the counties near
the Hickory and Triad nonattainment area and requires the use of the on board diagnostic system,
which will indicate NOx emissions as well as other pollutants.
Section 15A NCAC 2D .1200 regulates the controls and emissions from incinerators. Part of this
rule has been submitted as part of the SIP, while .1205, .1206 and .1210 are part of the CAA
Section 111(d) plans.
Two rules are conformity related, 15A NCAC 2D .1600 and .2000. General conformity related
projects are covered under Section .1600, while transportation conformity related projects are
covered under Section .2000. Although neither of these rules require reduction in emissions, they
do ensure that federal actions do not hinder attainment or maintenance of the NAAQS.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 5-2
Redesignation Demonstration and Maintenance Plan December 18, 2009
North Carolina has adopted an open burning rule, 15A NCAC 2D .1900, which prohibits open
burning of vegetative material during Air Quality Action Days of Code Orange or higher in
forecasted areas of the State. Particle pollution forecasts are issued for the Hickory and Triad
areas year-round; therefore this area is covered by this rule.
Section 15A NCAC 2D .2400 regulates nitrogen oxide emissions from electric generating units
with a nameplate capacity of 25 megawatts or more producing electricity for sale. Section 15A
NCAC 2D .2400 also covers industrial boilers that are covered under the NOx SIP Call rules.
This Section replaces the NOx SIP Call rules beginning January 1, 2009.
Another important set of rules that may result in control of some particulates that are air toxics in
North Carolina in these counties is Section 15A NCAC 2D .1100, Control of Toxic Air
Pollutants. These rules, however, have not been submitted to the USEPA to be approved as part
of the SIP.
There are two other rules that control emissions of some particulates in these areas. They are
15A NCAC 2D .0524, New Source Performance Standards. Also, rule 2D.1111, Maximum
Achievable Control Technology applies to control of emissions of HAP, some of which are
particulates. They are not part of the SIP, but the USEPA has delegated the State enforcement
authority for standards that have been adopted by the State. (The standards adopted by the State
are state-enforceable regardless of the USEPA delegation.)
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 6-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
Section 107(d)(3)(E)(v) of the CAA requires that the provisions of Section 110 and Part D of the
Act be met within the area to be redesignated. This means that North Carolina must meet all
requirements, if any, that had come due as of the date of the redesignation request.
The USEPA in its latest guidance on meeting redesignation requirements as contained in a
memorandum from John Calcagni, Director, Air Quality Management Division, Office of Air
Quality Planning and Standards to the USEPA Regional Offices dated September 4, 1992, (See
Appendix A), states that "For the purposes of redesignation, a State must meet all requirements
of Section 110 and Part D that were applicable prior to submittal of the complete redesignation
request. When evaluating a redesignation request, Regions should not consider whether the State
has met requirements that come due under the Act after submittal of a complete redesignation
request."
Monitoring is one of the requirements of Section 110. The NCDAQ commits to continue
operating the current fine particulate matter monitors in the Hickory and Triad nonattainment
areas, providing sufficient funding is available for continued operation. Any monitor shutdowns
or relocations will only be made with the approval of the USEPA. No plans are underway to
discontinue operation, relocation or otherwise affect the integrity of the ambient monitoring
network in place. The current monitors are operated consistent with 40 CFR Part 58 and any
changes will only be made if they are consistent with 40 CFR Part 58.
NCDAQ believes that North Carolina has met all of the requirements of Section 110 and Part D.
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5 7-1
Redesignation Demonstration and Maintenance Plan December 18, 2009
The most recent three years of fine particulate matter monitoring data for the both the Hickory
and Greensboro/Winston-Salem/High Point (Triad) nonattainment areas demonstrate compliance
with the NAAQS for annual fine particulate matter. Since the 1990’s, there have been major
programs enacted in North Carolina that have led to significant actual, enforceable emissions
reductions, which have led to improvements in the air quality in both the Hickory and Triad
areas. Additionally, the maintenance plan demonstrates that the projected emissions inventories
for 2021, the final year of the maintenance plan and ten years beyond the expected redesignation
year, as well as the interim years, are all less than the base year emissions inventory. Therefore,
maintenance of the annual fine particulate matter NAAQS has also been demonstrated.
This redesignation demonstration and maintenance plan has been prepared to meet the
requirements of the 1990 Clean Air Act Amendments.
Point Source Emission Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Errata to the Redesignation Demonstration and Maintenance Plan
10
Appendix C.1
December 22, 2010
Point Source Emission Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Errata to the Redesignation Demonstration and Maintenance Plan
11
Appendix C.1
December 22, 2010
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
12
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
13
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
14
Appendix C.1
December 18, 2009
13310 6976 6189 10549 6975 6187 10548 6975 6186 10548 6973 6184 10548 6971 6183
Point Source Emission Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Errata to the Redesignation Demonstration and Maintenance Plan
15
Appendix C.1
December 22, 2010
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
16
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
17
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
18
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
19
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
20
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
21
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
22
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
23
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
24
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
25
Appendix C.1
December 18, 2009
Point Source Emissions Inventory Documentation
Hickory and Greensboro/Winston Salem/High Point Annual-PM2.5
Redesignation Demonstration and Maintenance Plan
26
Appendix C.1
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
3
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
4
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
5
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
6
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
7
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
8
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
9
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
10
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
11
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
12
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
13
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Redesignation Demonstration and Maintenance Plan
14
Appendix E
December 18, 2009
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
17
Appendix E
December 22, 2010
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
18
Appendix E
December 22, 2010
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
19
Appendix E
December 22, 2010
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
20
Appendix E
December 22, 2010
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
21
Appendix E
December 22, 2010
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
22
Appendix E
December 22, 2010
Public Notice Report, Comments Received, and Responses
Hickory and Greensboro/Winston-Salem/High Point Annual PM2.5
Supplement to the Redesignation Demonstration and Maintenance Plan
23
Appendix E
December 22, 2010
On-road Mobile Source Emission Inventory Documentation i
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
1.0 INTRODUCTION AND SCOPE ............................................................................................. 1
2.0 OVERALL METHODOLOGY ................................................................................................ 1
2.1 Emission Estimation Approach ........................................................................................... 1
3.0 QUALITY ASSURANCE MEASURES .................................................................................. 2
4.0 DISCUSSION OF ON-ROAD MOBILE SOURCES .............................................................. 3
4.1 Introduction and Scope ........................................................................................................ 3
4.2 MOVES Input Assumptions ................................................................................................ 4
4.2.1 Speed Assumptions ........................................................................................................ 4
4.2.2 Vehicle Age Distribution ............................................................................................. 10
4.2.3 Vehicle Mix Assumptions ............................................................................................ 11
4.2.4 Disaggregating State Specific Information .................................................................. 12
4.2.5 Vehicles/Equipment: On-Road Vehicle Equipment ................................................... 16
4.2.6 Road Type ................................................................................................................... 17
4.2.7 Pollutants and Processes ............................................................................................. 18
4.2.8 Temperature, Relative Humidity and Barometric Pressure Assumptions ................... 18
4.2.9 Source Type Population .............................................................................................. 18
4.2.10 Vehicle Inspection and Maintenance Program Assumptions .................................... 21
4.2.11 Reid Vapor Pressure (RVP) Assumptions ................................................................. 21
4.2.12 Diesel Sulfur Content Assumptions ........................................................................... 22
4.2.13 Fuel (Formulation and Supply) ................................................................................. 22
4.3 VMT Assumptions .............................................................................................................. 22
4.4 Estimated Emissions From Mobile Sources ...................................................................... 25
4.5 Motor Vehicle Emissions Budget for Conformity ............................................................. 26
4.5.1 Transportation Conformity .......................................................................................... 26
4.5.2 Pollutants to be Considered ......................................................................................... 26
4.5.3 Safety Margin ............................................................................................................... 33
4.5.4 Motor Vehicle Emission Budgets ................................................................................ 35
5.0 DATA USED ......................................................................................................................... 39
5.1 North Carolina’s Vehicle Mix ........................................................................................... 39
5.1.1 2008 State Vehicle Mix .............................................................................................. 39
5.1.2 2011 State Vehicle Mix .............................................................................................. 40
5.1.3 2014 State Vehicle Mix .............................................................................................. 41
5.1.4 2017 State Vehicle Mix .............................................................................................. 42
5.1.5 2021 State Vehicle Mix .............................................................................................. 43
On-road Mobile Source Emission Inventory Documentation ii
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
5.2 Meteorology ........................................................................................................................ 44
5.2.1 Catawba County Temperature and Relative Humidity ................................................ 44
5.2.2 Davidson and Guilford County Temperature and Relative Humidity ......................... 50
Table 4.2.1-1 Modeled Area Speeds for Davidson County (miles/hour) ...................................... 5
Table 4.2.1-2 Rural Area Speeds for Davidson County (miles/hour) ............................................ 5
Table 4.2.1-3 Modeled Area Speeds for Guilford County (miles/hour) ........................................ 6
Table 4.2.1-4 Modeled Area Speeds for Catawba County (miles/hour) ........................................ 6
Table 4.2.1-5 Rural Area Speeds for Catawba County (miles/hour) ............................................. 7
Table 4.2.4-1 Mapping of HPMS data to MOBILE6.2 Categories .............................................. 12
Table 4.2.4-2 Calculation of New 2008 Statewide Rural Interstate Vehicle Mix ....................... 14
Table 4.2.4-3 Calculation of 2008 Statewide Rural Interstate Vehicle Mix ................................ 16
Table 4.3-1 Modeled Vehicle Miles Traveled for Davidson County ........................................... 23
Table 4.3-2 Vehicle Miles Traveled for Davidson County Rural Donut Area ............................. 23
Table 4.3-3 Vehicle Miles Traveled for Guilford County ............................................................ 24
Table 4.3-4 Vehicle Miles Traveled for Catawba County Modeled Portion ................................ 24
Table 4.3-5 Vehicle Miles Traveled for Catawba County Rural Donut Area .............................. 25
Table 4.4-1 Emissions by County and year .................................................................................. 25
Table 4.5.3-1 Safety Margin for Hickory PM2.5 Nonattainment Area ......................................... 34
Table 4.5.3-2 Safety Margin for Triad PM2.5 Nonattainment Area ............................................. 34
Table 4.5.4-1 On-Road Mobile Source PM2.5 Emissions ............................................................ 35
Table 4.5.4-2 On-Road Mobile Source NOx Emissions............................................................... 36
Table 4.5.4-3 Catawba County MVEB ........................................................................................ 36
Table 4.5.4-4 Davidson County MVEB ...................................................................................... 36
Table 4.5.4-5 Guilford County MVEB ........................................................................................ 37
Table 4.5.4-6 County Level PM2.5 MVEB Safety Margin for 2011 and 2021 ............................ 37
Table 4.5.4-7 County Level NOx MVEB Safety Margin for 2011 and 2021 .............................. 37
Table 4.5.4-8 New Safety Margins for the Hickory PM2.5 nonattainment area ........................... 38
Table 4.5.4-9 New Safety Margins for the Triad PM2.5 nonattainment area ............................... 38
Figure 4.5.2-2. North Carolina’s 2009 Statewide SO2 Emissions .............................................. 30
Figure 4.5.2-3. Hickory Area 2009 Primary PM2.5 Emissions ..................................................... 31
Figure 4.5.2-4. Catawba County Hourly PM2.5 Emissions ........................................................... 33
On-road Mobile Source Emission Inventory Documentation 1
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
This fine particulate matter (PM2.5) on-road mobile source documentation covers the Hickory
PM2.5 nonattainment area (Catawba County) and the Greensboro/Winston Salem/High Point
PM2.5 nonattainment area (referred to as the Triad area and consisting of Davidson and Guilford
Counties). On-road mobile sources produce nitrogen oxides (NOx), particles less than 2.5
micrometers in diameter (PM2.5), and sulfur dioxide (SO2), along with a host of other pollutants.
Emissions of these pollutants are estimated in the mobile source inventory required for the
maintenance plan. Mobile sources comprise about 74% of the NOx emissions in the Hickory
and Triad fine particulate matter nonattainment areas. The scope of this document covers only
the procedures associated with on-road mobile sources.
Mobile source emissions are estimated by the methodologies suggested in the United States
Environmental Protection Agency (USEPA) documents Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards
(NAAQS) and Regional Haze Regulations, Policy Guidance on the Use of MOVES2010 for
State Implementation Plan Development, Transportation Conformity, and Other Purposes EPA-
420-B-09-046, December 2009), and Technical Guidance on the Use of MOVES2010 for
Emission Inventory Preparation in State Implementation Plans and Transportation Conformity
EPA-420-B-10-023, April 2010).
In December 2009, the USEPA released a new model for mobile sources. MOVES (MOtor
Vehicle Emissions Simulator) is a computer program designed by the USEPA to estimate air
pollution emissions from mobile sources. MOVES2010 (hereafter referred to as MOVES)
replaces the USEPA’s previous emissions model for on-road mobile sources, MOBILE6.2.
MOVES is used to estimate exhaust and evaporative emissions as well as brake and tire wear
emissions from all types of on-road vehicles.
Compared to MOBILE6.2, MOVES incorporates substantial new emissions test data and
accounts for changes in vehicle technology and regulations as well as improved understanding of
in-use emission levels and the factors that influence them. Also, MOVES has a completely new
database-centered software framework.
On-road Mobile Source Emission Inventory Documentation 2
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
There is currently a two year grace period for transportation conformity purposes for use of
MOVES as the new regulatory model. However, the North Carolina Division of Air Quality
(NCDAQ) committed to provide supplemental data to the Annual PM2.5 Redesignation
Demonstration and Maintenance Plan when MOVES was released and approved for regulatory
purposes.
The estimation of emissions from mobile sources involves multiplying an activity level by an
emission factor. Previously this was done using MOBILE6.2 to calculate an emissions factor
and multiplying it by the vehicle miles travelled (VMT). One important new feature of MOVES is
the option to calculate emissions either as inventory estimates (total emissions in units of mass) or,
emission rates (emissions per unit of distance for running emissions or per vehicle for starts,
extended idle and resting evaporative emissions) in a look-up table format.
Use of the inventory option simplifies the post-processing of MOVES output compared to
MOBILE6.2, but it requires VMT and vehicle population data as an input to MOVES. When using
the emission rates option, VMT and vehicle population are applied during post-processing external to
MOVES. Either approach can be used to develop emissions estimates for state implementation plans
(SIPs) and regional conformity analyses. If inventory option is selected, MOVES provides emissions
estimates as mass, using VMT and vehicle population entered by the user. If emission rate option is
selected, MOVES provides emission rates as mass per unit of activity. The emission rates option
produces a look-up table of emission rates that must be post-processed to produce an inventory. The
NCDAQ is electing to run the model in the inventory mode due to faster model run times and fewer
post-processing requirements.
The USEPA has performed preliminary comparison of MOVES2010 to MOBILE6.2 using local
data for several different urban areas, varying the local data used by fleet distribution, fraction of
light- and heavy-duty VMT, local fuel specifications, meteorology, and other input factors. In
general, volatile organic carbon (VOC) emissions are lower when using MOVES2010 when
compared to MOBILE6.2, while NOx and particulate matter (PM) emissions are higher.
The quality assurance (QA) for the highway mobile source category can be broken into two
components: 1) input files and 2) MOVES outputs/summaries. Each of these components is
detailed in the paragraphs below.
After the speed and VMT information is acquired from the North Carolina Department of
Transportation (NCDOT), the speed information is checked for reasonableness against previous
On-road Mobile Source Emission Inventory Documentation 3
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
sets of speeds for the areas. Once the speeds are deemed reasonable, the NCDAQ enters the
speed information into MOVES input files. In addition to the speed information, the user enters
data to characterize local meteorology, fleet and activity information. All input files are checked
against a “key” with the original source of the information. This QA step is always performed
by a person other than the one who generated the input files. If any discrepancies are found, they
are noted back to the person who generated the input files for correction.
Once the input files have passed through the QA procedure, MOVES is run to generate
emissions.
On-road mobile sources produce NOx, PM2.5, and SO2, along with a host of other pollutants.
Emissions of these three pollutants are estimated in the on-road mobile source inventory for the
maintenance plan. The objective of the following section is to describe the source category, the
input files, and the emissions estimation procedures. This section also includes tables
summarizing the estimated emissions for the projection years by county.
On-road mobile sources are considered as those vehicles that travel on the roadways. On-road
mobile sources are a major contributor to NOx emissions in North Carolina and a less significant
contributor to primary PM2.5 and SO2. Emissions from motor vehicles occur throughout the day
while the vehicle is in motion, at idle, parked, and during refueling. All of these emissions
processes need to be estimated in order to properly reflect the total emissions from this source
category.
On-road mobile source emissions comprise a small percentage of the total fine particulate matter
emissions for all of North Carolina. Particulate emissions from motor vehicles only occur while
the vehicle is moving or idling. These emissions are direct tailpipe (from both gas and diesel
fuel vehicles), sulfate, tire wear, and brake wear. Only direct particulate emissions processes
will be estimated in order to properly reflect the total fine particulate matter emissions from this
source category.
A very important component of the highway mobile emission estimation process is interagency
consultation. The primary transportation partners involved in the Hickory and Triad
redesignation interagency consultation process included: NCDOT, USEPA, Federal Highway
Administration (FHWA), Greensboro Urban Area Municipal Planning Organization (MPO),
On-road Mobile Source Emission Inventory Documentation 4
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
High Point Urban Area MPO, Piedmont Triad Rural Planning Organization (RPO), and Greater
Hickory MPO. Specifically the NCDOT was consulted for input data such as speeds and VMT
for the rural counties where the Hickory and Triad Urban Travel Demand Models (TDMs) did
not cover. An interagency call was held April 19, 2010 to discuss the need to update the motor
vehicle emission budgets (MVEBs) for the Greater Hickory and Triad areas. The NCDAQ had
the data originally provided for the redesignation for the years 2008, 2011, 2014, 2017, and
2021. The NCDAQ received updated speeds and VMT for the Triad (Davidson and Guilford
Counties), in February 2009, as well as, updated speeds and VMT for Catawba County from
NCDOT in April 2009. The NCDAQ discussed the differences anticipated in the emissions by
running the MOVES model and the possible necessity to update the MVEBs in the
Redesignation Package before the MOVES model would be required to be used for conformity
purposes. The interagency partners agreed that the activity data that the NCDAQ had were the
latest and should be used as inputs to the MOVES model.
Due to the size and the complexity of the MOVES input and output files, the MOVES input files
and output files will be provided electronically.
Vehicle power, speed, and acceleration have a significant effect on vehicle emissions. MOVES
models those emission effects by assigning activity to specific drive cycles or operating mode
distributions. The distribution of vehicle hours traveled (VHT) by average speed is used to determine
an appropriate operating mode distribution. The Average Speed Distribution importer in MOVES
calls for a speed distribution in VHT in 16 speed bins, by each road type, source type, and hour of the
day included in the analysis. The methodology used to develop the average speed distribution inputs
is documented below.
The speeds for the urban areas covered by a TDM were provided by the MPOs. Piedmont
Authority for Regional Transportation (PART) provided modeled speeds for the entire county of
Guilford and the modeled portion of Davidson County for the desired maintenance plan years.
Speeds for rural areas in Davidson and the urban and rural areas in Catawba were generated by
NCDOT. Modeled speeds for urban areas of Catawba County were received for the years 2007,
2015, 2025, and 2035, and interpolated to the years needed. Tables 4.2.1-1 through 4.2.1-5
provide a summary of the average speeds in miles per hour (mph).
On-road Mobile Source Emission Inventory Documentation 5
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Functional Class 2008 2011 2014 2017 2021
Urban Interstate 68 68 68 68 67
Urban Freeway or Expressway 57 57 56 56 55
Urban Other Principal Arterial 39 39 38 38 39
Urban Minor Arterial 40 40 40 40 39
Urban Collector 42 41 42 42 41
Urban Local 46 45 45 45 44
Rural Interstate 69 68 68 68 68
Rural Other Principal Arterial --- --- --- 35 35
Rural Minor Arterial 51 51 51 51 50
Rural Major Collector 43 43 42 42 41
Rural Minor Collector 49 48 48 48 48
Rural Local 49 49 48 48 48
Functional Class 2008 2011 2014 2017 2021
Urban Interstate 62 63 62 62 62
Urban Freeway or Expressway 56 56 56 56 56
Urban Other Principal Arterial 28 29 28 28 29
Urban Minor Arterial 32 32 32 32 32
Urban Collector 31 31 31 31 31
Urban Local 31 31 31 31 31
Rural Interstate 65 66 65 65 65
Rural Other Principal Arterial 45 46 45 45 45
Rural Minor Arterial 44 44 44 44 44
Rural Major Collector 43 43 43 43 43
Rural Minor Collector 42 42 42 42 42
Rural Local 42 42 42 42 42
On-road Mobile Source Emission Inventory Documentation 6
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Functional Class 2008 2011 2014 2017 2021
Urban Interstate 55 55 56 56 55
Urban Freeway or Expressway 51 51 50 50 51
Urban Other Principal Arterial 39 39 39 39 39
Urban Minor Arterial 37 37 38 38 38
Urban Collector 37 37 37 37 37
Urban Local 34 34 34 34 34
Rural Interstate 60 59 58 58 57
Rural Other Principal Arterial 47 48 50 50 49
Rural Minor Arterial 43 42 44 44 46
Rural Major Collector 46 46 46 46 45
Rural Minor Collector 47 47 47 47 46
Rural Local 43 42 46 46 45
Functional Class 2008 2011 2014 2017 2021
Urban Interstate 60 59 57 55 52
Urban Freeway or Expressway 46 46 45 45 44
Urban Other Principal Arterial 34 33 32 31 30
Urban Minor Arterial 34 33 32 31 30
Urban Collector 36 35 34 33 32
Urban Local 38 37 36 35 33
Rural Interstate 64 63 62 60 56
Rural Other Principal Arterial 59 59 58 58 57
Rural Minor Arterial 42 41 40 39 38
Rural Major Collector 43 43 42 42 41
Rural Minor Collector 37 36 35 35 34
Rural Local 42 42 41 41 40
On-road Mobile Source Emission Inventory Documentation 7
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Functional Class 2008 2011 2014 2017 2021
Urban Interstate 63 63 63 63 63
Urban Freeway or Expressway 56 56 56 56 56
Urban Other Principal Arterial 29 29 29 29 29
Urban Minor Arterial 32 32 32 32 32
Urban Collector 31 31 31 31 31
Urban Local 31 31 31 31 31
Rural Interstate 63 63 63 63 63
Rural Other Principal Arterial 46 46 46 46 46
Rural Minor Arterial 44 44 44 44 44
Rural Major Collector 43 43 43 43 43
Rural Minor Collector 42 42 42 42 42
Rural Local 42 42 42 42 42
MOVES uses four different roadway type categories that are affected by the average speed
distribution input: rural restricted access, rural unrestricted access, urban restricted access, and
urban unrestricted access (these road types are discussed in more detail in Section 4.2.6). In
MOVES, local roadways are included with arterials and collectors in the urban and rural
unrestricted access roads category. In MOBILE6.2, local roadways were a separate category with
a fixed speed of 12.9 mph. For MOVES, the USEPA recommends that the average speed
distribution for local roadway activity be included as part of a weighted distribution of average
speed across all unrestricted roads along with the distribution of average speeds for arterials and
connectors.
When only a single average speed is available for a specific road type and that average speed is
not identical to the average speed in a particular speed bin, MOVES guidance stipulates that
users should apply the following formula for creating the appropriate speed distribution among
two adjacent speed bins.
The general formula is:
VHT Fraction A in Speed Bin with closest average speed lower than observed average speed +
VHT Fraction B in Speed Bin with closest average speed higher that observed average speed = 1
On-road Mobile Source Emission Inventory Documentation 8
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
VHT Fraction A(low bin) = 1 – [(observed average speed – average speed of lower speed bin) /
(average speed of higher speed bin – average speed of lower speed bin)]
VHT Fraction B(high bin) = 1- [(average speed of higher speed bin – observed average speed) /
(average speed of higher speed bin – average speed of lower speed bin)]
Or more simply: VHT Fraction B = 1 – VHT fraction A
The following is an example of applying the above equations. If the single average speed for a
roadway is 58 miles per hour, the average speed distribution will be split between the 55 and 60
mph speed bins. The appropriate VHT fractions are found with the following equations:
VHT fraction A(low bin) = 1 – [(58 mph Avg. Speed – 55 mph (Bin Speed)) / (60 mph (Bin Speed)
– 55 mph (Bin Speed)] = 0.4
VHT fraction B(high bin) = 1 – [(60 mph (Bin Speed) – 58 mph Avg. Speed) / (60 mph (Bin Speed)
– 55 mph (Bin Speed)] = 0.6
VHT Fraction A(low bin) + VHT Fraction B(high bin) = 1
0.4 + 0.6 = 1
As stated above, MOVES uses only four different roadway types: rural restricted access, rural
unrestricted access, urban restricted access and urban unrestricted access. This means that the
speeds for multiple roadway types need to be combined into the appropriate speed bins. To
create the speed bin fractions for combined roadways the VMT for each road way is used to
weight the speed bin fraction. For example, below are speeds and VMT for urban restricted
access road types:
Road type Speed
(miles/hour)
VMT
(hourly miles)
Urban Interstate 63 250,000
Urban Freeway 56 100,000
The first step is to determine the speed bin fractions for each road type separately. For the urban
interstate road type, the speed 63 is split between the MOVES speed bins of 60 and 65 as
described above, which results in the VHT fractions of 0.4 and 0.6 for speed bins 60 and 65,
respectively. Similarly, the speed for the urban freeway road type (56 miles/hour) is split
On-road Mobile Source Emission Inventory Documentation 9
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
between the MOVES speed bins of 55 and 60 and results in the VHT fractions of 0.8 and 0.2,
respectively.
The next step requires road type VMT to weigh the VHT Fractions so that the final MOVES
speed bin fractions can be developed. The VHT Fraction, specific to the road type and speed
bin, are multiplied by the corresponding hourly VMT. These hourly totals are divided by the
total VMT for that hour for the road type category (in this example, urban restricted access
includes urban interstate and urban freeway). The following equation is used to calculate the
combined speed bin fractions:
Where:
RT = the HPMS road type
In this example, the HPMS road types are urban interstate (UI) and urban freeway (UF) and the
speed bins are 55, 60 and 65. The table below summarizes the speed bin fractions for this
example.
HPMS Road Type Speed Bin 55 Speed Bin 60 Speed Bin 65
Urban Interstate 0.0 0.4 0.6
Urban Freeway 0.8 0.2 0.0
Using the equation below, the final MOVES speed bin fractions are calculated for the urban
restricted access road type.
VHT(Speed Bin X) = [(VHT Fraction(UI) * hourly VMT(UI)) + (VHT Fraction(UF) * hourly VMT(UF))]
(hourly VMT(UI) + hourly VMT(UF))
VHT(Speed Bin 55) = [(0.0 * 250,000) + (0.8 * 100,000)]
(250,000 + 100,000)
VHT(Speed Bin 55) = 0.2286
VHT(Speed Bin 60) = [(0.4 * 250,000) + (0.2 * 100,000)]
(250,000 + 100,000)
VHT(Speed Bin 60) = 0.3428
On-road Mobile Source Emission Inventory Documentation 10
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
VHT(Speed Bin 65) = [(0.6 * 250,000) + (0.0 * 100,000)]
(250,000 + 100,000)
VHT(Speed Bin 65) = 0.4286
The sum of the VHT fractions for all speed bins within a road type category must add up to 1.0.
The hourly VHT fractions by speed bin and road type are then processed through a MOVES
supplied converter to develop the speed distribution file by hour and road type.
The age distribution of vehicle fleets can vary significantly from area to area. Fleets with a
higher percentage of older vehicles will have higher emissions for two reasons. Older vehicles
have typically been driven more miles and have experienced more deterioration in emission
control systems. Additionally, a higher percentage of older vehicles also implies that there are
more vehicles in the fleet that do not meet newer, more stringent emissions standards. Surveys of
registration data indicate considerable local variability in vehicle age distributions.
For SIP and conformity purposes, the USEPA recommends and encourages states to develop
local age distributions. The MOVES model categorizes the vehicle fleet into different vehicle
classes and more model years than MOBILE6.2. A typical vehicle fleet includes a mix of
vehicles of different ages. MOVES covers a 31 year range of vehicle ages, with vehicles 30 years
and older grouped together. MOVES allows the user to specify the fraction of vehicles in each of
30 vehicle ages for each of the 13 source types in the model.
Local age distributions can be estimated from local vehicle registration data. The vehicle age
distribution comes from annual registration data for North Carolina from the NCDOT. For this
analysis, the age distribution was generated based on 2008 data, the latest available count data at
the time. The NCDOT provided the data based on the number of vehicle types per year from
1975 through 2008. The data obtained from the NCDOT has the vehicles greater than 25 years
old combined and included as the 25th model year. Additionally, the NCDOT data has the
vehicle count information provided for nine vehicle types; light duty gas vehicles (LDGV), light
duty diesel vehicles (LDDV), light duty gas trucks 1 (LDGT1), light duty gas trucks 2 (LDGT2),
light duty diesel trucks 1 (LDDT1), light duty diesel trucks 2 (LDDT2), heavy duty gas vehicles
(HDGV), heavy duty diesel vehicles (HDDV) and motorcycles (MC). LDDT1 and LDDT2 are
combined and labeled as light duty diesel trucks (LDDT). Since MOVES categorizes the vehicle
fleet into different vehicle classes and more model years, the USEPA has created data converters
On-road Mobile Source Emission Inventory Documentation 11
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
that take registration distribution input files created for MOBILE6.2 and converts them to the
appropriate age distribution input tables for MOVES.
Vehicle mix or VMT mix is used by MOVES to convert annual VMT to VMT by HPMS class,
VMT fractions by hour, and VMT by road type distribution. The vehicle mix is developed by
the same method used in MOBILE6.2, as outlined below. The resulting file is then used in a
MOVES supplied converter to develop the VMT by HPMS class, VMT fractions by hour, and
VMT by road type distribution.
The vehicle mix refers to the percentage of different vehicle types on each of the 12 FHWA road
types. These road types are listed above in the speed assumptions section. It is critical for
estimating on-road mobile source emissions in an area to use data that accurately reflects the
vehicles types traveling on each of these different road types.
In August 2004, the USEPA released the guidance document EPA420-R-04-013 Technical
Guidance on the Use of MOBILE6.2 for Emission Inventory Preparation, which outlines how to
convert the Highway Performance Monitoring System (HPMS) traffic count data to MOBILE6.2
vehicle mix data Outlined below is the methodology used to convert the 13 HPMS vehicle
types count data reported to FHWA and generate a state specific vehicle mix.
The North Carolina HPMS data used to generate the new statewide vehicle mix was based on
2008 data counts. This is the latest available statewide count information at the time of the
modeling. Table 4.2.3-1 shows the percent of vehicles per vehicle type for each of the 12 road
classes.
On-road Mobile Source Emission Inventory Documentation 12
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Section 4.1.5 of Technical Guidance on the Use of MOBILE6.2 for Emission Inventory
Preparation, illustrates how to map the HPMS statewide vehicle data to general MOBILE6.2
vehicle categories. This mapping is outlined in Table 4.2.4-1 below:
Motorcycle Motorcycle (MC)
Passenger Car Passenger Car (LDV)
Other 2-Axel, 4-Tire Vehicles Light Truck (LDT)
Busses Bus (HDB)
All Other Trucks:
Single unit, 2-axel, 6-tire
Single unit, 3-axel
Single unit, 4 or more axel
Single trailer, 4 or fewer axel
Single trailer, 5-axel
Single trailer, 6 or more axel
Multi-trailer, 5 or fewer axel
Multi-trailer, 6-axel
Multi-trailer, 7 or more axel
Heavy Duty Truck (HDV)
The HPMS data in Table 4.2.3-1 was grouped into these five general categories for each road
type. In order to expand the five general categories to the 16 vehicle types used in MOBILE6.2,
the national average VMT fractions by each vehicle class were used. The 2008 fractions were
used since the state specific data is from 2008. The national average data was obtained from
Table 4.1.2 in Technical Guidance on the Use of MOBILE6.2 for Emission Inventory
Preparation. An example for rural interstates is illustrated below:
From Table 4.2.3-1 above:
Passenger Cars = 60.13% 5 axel Trailer = 17.65%
Pickup Trucks = 13.72% 6 axel Trailer = 0.66%
Bus = 1.04% 5 axel Multi Trailer = 0.51%
2 axel Trucks = 2.86% 6 axel Multi Trailer = 0.23%
3 axel Trucks = 0.75% 7 axel Multi Trailer = 0.15%
4 axel Trucks = 0.05% Motorcycles = 0.38%
4 axel Trailer = 1.86%
On-road Mobile Source Emission Inventory Documentation 13
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Therefore, the five general categories are:
Motorcycles = 0.38%
Light Duty Vehicles = 60.13%
Light Duty Trucks = 13.72%
Heavy Duty Buses = 1.04%
Heavy Duty Vehicles = 24.73%
From Table 4.1.2 in Technical Guidance on the Use of MOBILE6.2 for Emission Inventory
Preparation, the 2008 national average vehicle mix for light duty trucks, buses and heavy duty
trucks are:
Light Duty Trucks Heavy Duty Trucks
LDT1 = 0.0846
LDT2 = 0.2817
LDT3 = 0.0868
LDT4 = 0.0399
Buses
Using the methodology described in Section 4.1.5 in Technical Guidance on the Use of
MOBILE6.2 for Emission Inventory Preparation the new 2008 North Carolina statewide mix
was developed. The basic formula for developing the mix is shown below,
Vehicle Type = (2008 M6.2 fraction for vehicle) X (2008 State total for group) .
(2008 M6.2 total for subcategory)
Table 4.2.4-2 displays the calculation for each vehicle type for the 2008 rural interstate vehicle
mix.
HDV2B = 0.0388
HDV3 = 0.0038
HDV4 = 0.0031
HDV5 = 0.0024
HDV6 = 0.0087
HDV7 = 0.0102
HDV8A = 0.0111
HDBS = 0.0020 HDV8B = 0.0397
HDBT = 0.0009
On-road Mobile Source Emission Inventory Documentation 14
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Vehicle
Type Calculation New
2008 Mix
LDV = LDV = 0.6013
MC = MC = 0.0038
Light Duty Trucks
LDT1 = 0.0846 x (0.1372/0.4930) = 0.0235
LDT2 = 0.2817 x (0.1372/0.4930) = 0.0784
LDT3 = 0.0868 x (0.1372/0.4930) = 0.0242
LDT4 = 0.0399 x (0.1372/0.4930) = 0.0111
Heavy Duty Vehicles
HDV2B = 0.0388 x (0.2473/0.1178) = 0.0815
HDV3 = 0.0038 x (0.2473/0.1178) = 0.0080
HDV4 = 0.0031 x (0.2473/0.1178) = 0.0065
HDV5 = 0.0024 x (0.2473/0.1178) = 0.0050
HDV6 = 0.0087 x (0.2473/0.1178) = 0.0183
HDV7 = 0.0102 x (0.2473/0.1178) = 0.0214
HDV8A = 0.0111 x (0.2473/0.1178) = 0.0233
HDV8B = 0.0397 x (0.2473/0.1178) = 0.0833
Buses
HDBS = 0.0020 x (0.0104/0.0029) = 0.0072
HDBT = 0.0009 x (0.0104/0.0029) = 0.0032
2008, 2011, 2014, 2017 and 2021 Statewide Vehicle Mix
Once the 2008 new vehicle mix was generated, the other years were created using the
methodology described in Section 4.1.4 in Technical Guidance on the Use of MOBILE6.2 for
Emission Inventory Preparation. This method grouped light duty vehicles, light duty trucks and
motorcycles together and heavy duty buses, heavy duty trucks and heavy duty vehicles together.
The combined percentages for these groupings are listed below.
Light Duty Vehicles = 74.23%
Heavy Duty Vehicles = 25.77%
On-road Mobile Source Emission Inventory Documentation 15
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
The MOBILE6.2 vehicle mix fractions for the year being developed were obtained from
Table 4.1.2 in Technical Guidance on the Use of MOBILE6.2 for Emission Inventory
Preparation. The MOBILE6.2 vehicle fractions for 2008 are listed below.
Light Duty Vehicles Heavy Duty Vehicles
The North Carolina 2008 vehicle mix was normalized to the MOBILE6.2 fractions using the
following formula:
Vehicle Type = (2008 M6 fraction for vehicle) X (2008 State total for group)
(2008 M6 total for group)
Table 4.2.4-3 below displays the calculations used to generate the 2008 North Carolina vehicle
mix for rural interstate.
LDV = 0.3807
LDT1 = 0.0846
LDT2 = 0.2817
LDT3 = 0.0868
LDT4 = 0.0399
MC = 0.0056
HDV2B = 0.0388
HDV3 = 0.0038
HDV4 = 0.0031
HDV5 = 0.0024
HDV6 = 0.0087
HDV7 = 0.0102
HDV8A = 0.0111
HDV8B = 0.0397
HDBS = 0.0020
HDBT = 0.0009
On-road Mobile Source Emission Inventory Documentation 16
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
Vehicle
Type
Calculation 2008 State Mix
Light Duty Vehicles
LDV = 0.3807 x (0.7386/0.8737) = 0.3219
LDT1 = 0.0846 x (0.7386/0.8737) = 0.0715
LDT2 = 0.2817 x (0.7386/0.8737) = 0.2381
LDT3 = 0.0868 x (0.7386/0.8737) = 0.0734
LDT4 = 0.0399 x (0.7386/0.8737) = 0.0337
MC = 0.0038
Heavy Duty Vehicles
HDV2B = 0.0388 x (0.2472/0.1178) = 0.0814
HDV3 = 0.0038 x (0. 2472/0.1178) = 0.0080
HDV4 = 0.0031 x (0. 2472/0.1178) = 0.0065
HDV5 = 0.0024 x (0. 2472/0.1178) = 0.0050
HDV6 = 0.0087 x (0. 2472/0.1178) = 0.0183
HDV7 = 0.0102 x (0. 2472/0.1178) = 0.0214
HDV8A = 0.0111 x (0. 2472/0.1178) = 0.0233
HDV8B = 0.0397 x (0. 2472/0.1178) = 0.0833
HDBS = 0.0020 x (0.0104/0.0029) = 0.0072
HDBT = 0.0009 x (0.0104/0.0029) = 0.0032
This method was used to generate all of the future year vehicle mixes that were needed to
compute the emission factors. The North Carolina transportation partners consider the statewide
vehicle mix to be the best representation of the vehicle population in the Hickory and Triad
nonattainment area. The vehicle mixes for all years can be found in Section 5.1 of this appendix.
As stated earlier in this section, vehicle mix or VMT mix is used in MOVES converters to
develop VMT by HPMS class, VMT fractions by hour, and VMT by road type distribution,
which are inputs to the model.
The Vehicles/Equipment menu item and panel is used to specify the vehicle types that are
included in the MOVES run. MOVES allows the user to select from among 13 “source use
On-road Mobile Source Emission Inventory Documentation 17
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
types” (the terminology that MOVES uses to describe vehicle types), and four different fuel
types (gasoline, diesel, compressed natural gas (CNG), and electricity).
For SIP and regional conformity analyses, users must select the appropriate fuel and vehicle type
combinations in the On Road Vehicle Equipment panel to reflect the full range of vehicles that
will operate in the county. For this analysis all valid diesel, gasoline, and CNG (only transit
buses) vehicle and fuel combinations were selected.
The Road Type Panel is used to define the types of roads that are included in the run. MOVES
defines five different Road Types:
• Off-Network (roadtype 1) – all locations where the predominant activity is vehicle starts,
parking and idling (parking lots, truck stops, rest areas, freight or bus terminals)
• Rural Restricted Access (2) – rural highways that can only be accessed by an on-ramp
• Rural Unrestricted Access (3) – all other rural roads (arterials, connectors, and local
streets)
• Urban Restricted Access (4) – urban highways or freeways that can only be accessed by
an on-ramp
• Urban Unrestricted Access (5) – all other urban roads (arterials, connectors, and local
streets)
Users should select the road types present in the area being analyzed. The determination of rural
or urban road types should be based on the HPMS classification of the roads in the county being
analyzed.
The NCDAQ followed the USEPA guidance that states that all SIP and regional conformity
analyses must include the Off-Network road type in order to account for emissions from vehicle
starts, extended idle activity, and evaporative emissions (for hydrocarbons). The Off-Network
road type is automatically selected when start or extended idle pollutant processes are chosen and
must be selected for all evaporative emissions to be quantified. Off-Network activity in MOVES
is primarily determined by the Source Type Population input, which is described in Section 4.2.9
of this document. Some evaporative emissions are estimated on roadways (i.e., roadtypes 2, 3, 4,
and 5) to account for evaporative emissions that occur when vehicles are driving. All roads types
are automatically selected when Refueling emission processes are selected.
On-road Mobile Source Emission Inventory Documentation 18
Hickory and Greensboro/Winston-Salem/Highpoint Annual PM2.5 Appendix C.3
Supplement to the Redesignation Demonstration and Maintenance Plan December 22, 2010
MOVES uses Road Type to assign default drive cycles to activity on road types 2, 3, 4, and 5.
For example, for unrestricted access road types, MOVES uses drive cycles that assume stop and
go driving, including multiple accelerations, decelerations, and short periods of idling. For
restricted access road types, MOVES uses drive cycles that include a higher fraction of cruise
activity with less time spent accelerating or idling, although some ramp activity is also included.
In MOVES, pollutant refers to particular types of pollutants or precursors of the pollutant, such as
PM or NOx, while process refers to the mechanism by which emissions are created, such as running
exhaust or start exhaust. Users must select all processes associated with a particular pollutant in order
to account for all emissions of that pollutant. For example, there are 11 separate pollutant processes
in MOVES fo