Attainment Demonstration 

Jackson County, Alabama 

Chattanooga 

PM2.5 Nonattainment Area 

Prepared by 

Alabama Department of Environmental Management 

Air Division 

August 2009 

Table of Contents 

Table of Contents............................................................................................................................. i 

List of Figures................................................................................................................................. ii 

List of Tables .................................................................................................................................. ii 

EXECUTIVE SUMMARY ............................................................................................................ 1 

1.0 Introduction......................................................................................................................... 2 

1.1 Fine Particulate Matter (PM2.5)....................................................................................... 2 

1.2 PM2.5 National Ambient Air Quality Standard ............................................................... 3 

2.0 Chattanooga, Tennessee-Georgia PM2.5 Nonattainment Area............................................ 4 

2.1 Nonattainment Area Designations .................................................................................. 4 

2.2 PM2.5 Monitoring Stations .............................................................................................. 5 

2.3 Trends Analysis .............................................................................................................. 6 

3.0 Attainment Modeling.......................................................................................................... 7 

4.0 Development of Emission Inventories................................................................................ 8 

4.1 Point Source Emissions................................................................................................... 8 

4.1.1 2002 Base Case....................................................................................................... 8 

4.1.2 2009 Future Year .................................................................................................... 8 

4.2 Area Source Emissions ................................................................................................... 9 

4.2.1 2002 Base Case....................................................................................................... 9 

4.2.2 2009 Future Year .................................................................................................... 9 

4.3 Onroad Mobile Source Emissions ................................................................................ 10 

4.3.1 2002 Base Case..................................................................................................... 10 

4.3.2 2009 Future Year .................................................................................................. 10 

4.4 Nonroad Mobile Source Emissions .............................................................................. 11 

4.4.1 2002 Base Case..................................................................................................... 11 

4.4.2 2009 Future Year .................................................................................................. 11 

4.5 Biogenic Source Emissions........................................................................................... 11 

4.6 Emissions Summary for the Partial Area of Jackson County....................................... 12 

5.0 Significance of Precursors Contributing to Fine Particulate Matter................................. 13 

5.1 Nitrogen Dioxides......................................................................................................... 13 

5.2 Sulfur Dioxides ............................................................................................................. 13 

5.3 Ammonia and Volatile Organic Compounds................................................................ 13 

6.0 RACT and RACM ............................................................................................................ 14

7.0 Contingency Measures...................................................................................................... 16 

8.0 Reasonable Further Progress............................................................................................. 17 

9.0 Permanent and Enforceable Improvements in Air Quality............................................... 18 

10.0 Insignificance Determination for Transportation Conformity.......................................... 19 

10.1 Nitrogen Oxides (NOX)................................................................................................. 19 

10.1.1 Analysis of motor vehicle NOX emissions in the Jackson County portion of the 

Chattanooga nonattainment area........................................................................................... 19 

10.1.2 The current state of the air quality in Jackson County.......................................... 20 

10.1.3 The absence of SIP motor vehicle controls for the area. ...................................... 20 

10.1.4 Historical trends and future projections of the growth of motor vehicle emissions.

 20 

i 
ii 

10.2 Direct PM2.5: ................................................................................................................. 21 

10.2.1 Analysis of motor vehicle PM2.5 emissions in the Jackson County portion of the 

Chattanooga nonattainment area........................................................................................... 21 

10.2.2 The current state of the air quality in Jackson County.......................................... 22 

10.2.3 The absence of SIP motor vehicle controls for the area. ...................................... 22 

10.2.4 Historical trends and future projections of the growth of motor vehicle emissions.

 22 

11.0 Summary and Conclusion................................................................................................. 23 

List of Figures

Figure 2-1 Chattanooga PM2.5 Nonattainment Area....................................................................... 4 

Figure 2.2-1 Locations of PM2.5 Monitors in the Chattanooga Nonattainment Area .................... 6 

Figure 6-1 Response to 30% reduction in 2009 Base D Emissions.............................................. 15 

List of Tables 

Table 1 2009 Modeled Annual PM2.5 Design Values..................................................................... 1 

Table 1.2-1 24-Hour PM2.5 Design Values for the Chattanooga NAA.......................................... 3 

Table 2.2-1 PM2.5 Annual PM2.5 Design Values............................................................................ 5 

Table 3-1 2009 Modeled Annual PM2.5 Design Values................................................................. 7 

Table 4.6-1 2002 Emissions for the Partial Nonattainment Area of Jackson County ................. 12 

Table 4.6-2 2009 Emissions for the Partial Nonattainment Area of Jackson County ................. 12 

Table 6-1 Controls at TVA Widows Creek .................................................................................. 14 

Table 10.1.1-1 2002 NOX (TPY) Emissions in the Nonattainment portion of Jackson County by 

Source Type .................................................................................................................................. 20 

Table 10.1.1-2 2002 NOX (TPY) On-road Mobile Source Emissions in the Nonattainment 

Portion of Jackson County Compared to Total On-road Mobile Source Emissions in the entire 

Chattanooga NAA......................................................................................................................... 20 

Table 10.1.4-1 Historical and Future Projections of NOX emissions from On-Road Mobile 

Sources in Jackson County ........................................................................................................... 21 

Table 10.2.1-1 2002 Direct PM2.5 (TPY) Emissions in the Nonattainment Portion of Jackson 

County by Source Type ................................................................................................................ 21 

Table 10.3.1-2 2002 Direct PM2.5 (TPY) On-road Mobile Source Emissions in the 

Nonattainment Portion of Jackson County Compared to Total On-road Mobile Source Emissions 

in the Entire Chattanooga NAA.................................................................................................... 22 

Table 10.2.4-1 Historical and Future Projections of PM2.5 emissions from On-Road Mobile 

Sources in Jackson County ........................................................................................................... 22 

Table 11-1 2001 – 2003 PM2.5 Design Values for Chattanooga Nonattainment Area Monitors 23 

Table 11-2 PM2.5 2009 Future (Modeled) Design Values.......................................................... 24 
EXECUTIVE SUMMARY 

On January 5, 2005, the United States Environmental Protection Agency (EPA) published the 

fine particulate matter (PM2.5) nonattainment designation for the Chattanooga nonattainment 

area (NAA). This area consists of Hamilton County in Tennessee, Catoosa and Walker 

Counties in Georgia, and the portion of Jackson County in Alabama that is described as U.S. 

Census 2000 block group identifier 01–071-9503–1. There are no PM2.5 monitors located in the 

Jackson County, Alabama, portion of the nonattainment area; however, the air quality 

monitoring data for 2001-2003 from monitors located in the Georgia and Tennessee portions of 

the nonattainment area indicated that the annual average PM2.5 concentrations (design values) 

exceeded the 15.0 μg/m3

 National Ambient Air Quality Standard (NAAQS). EPA included the 

above-mentioned portion of Jackson County, Alabama, in the Chattanooga nonattainment area 

because they concluded that the TVA Widows Creek Fossil Plant located in the county 

contributes to the nonattainment situation in the Chattanooga NAA. Subsequently, the Alabama 

Department of Environmental Management, the Chattanooga-Hamilton County Air Pollution 

Control Bureau, the Tennessee Division of Air Pollution Control and the Georgia Air Protection 

Branch have collaborated to develop a PM2.5 NAAQS State Implementation Plan (SIP) for each 

jurisdiction. This document contains the SIP for the Jackson County, Alabama, portion of the 

nonattainment area, which demonstrates attainment of the annual PM2.5 NAAQS, promulgated 

in 1997, in the Chattanooga NAA by April 5, 2010. 

Air quality modeling conducted for the State of Alabama, Hamilton County, Tennessee, and the 

State of Georgia by the Association for Southeastern Integrated Planning (ASIP) indicates that 

the nonattainment area will attain the annual PM2.5 NAAQS beginning in 2009. The model 

results are based upon projected 2002-2009 emissions reductions from sources within the area 

and are supported by downward trends in actual emissions. It is expected that the area will 

attain the PM2.5 NAAQS based upon implementation of Federal and regional measures. The 

2009 modeled PM2.5 design values are provided below. 

Table 1 2009 Modeled Annual PM2.5 Design Values 

Federal Reference Monitor 

PM2.5 Design Value 

(μg/m3) 

Siskin Drive/UTC (470654002), TN 13.6 

Maxwell Road/East Ridge 

(470650031), TN 14.4 

Soddy-Daisy High School 

(470651011), TN 12.3 

Walker County, GA (132950002) 13.9 

1 
1.0 Introduction 

1.1 Fine Particulate Matter (PM2.5) 

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), nitrogen oxides (NOX), and organic gases from natural and anthropogenic 

sources. PM2.5 can therefore be composed of varying amount of different species, including: 

• Sulfates 

• Nitrates (usually found in the form of ammonium nitrate) 

• Ammonium 

• Hydrogen ion 

• Particle bound water 

• Elemental carbon 

• Organic compounds 

o Primary organic species (from cooking and combustion) 

o 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) 

The most significant sources of PM2.5 and its precursors are coal-fired utilities, 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, biogenic sources, fires, 

wind blown dust, and oceans. 

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. Since PM2.5

concentrations can exceed the National Ambient Air Quality Standards (NAAQS) at any time of 

the year, the United States Environmental Protection Agency (EPA) mandates the year round 

monitoring of the pollutant throughout the country (40 CFR 58, App. D). 

2 
1.2 PM2.5 National Ambient Air Quality Standard 

In July 1997, the EPA established both annual and 24-hour fine particulate primary (healthbased) and secondary NAAQS for annual and 24-hour fine particulate (62 FR 38711 and 40 

CFR 50.7). The secondary PM2.5 standards, established for the protection of public welfare and 

the environment, were established at the same levels as the primary standards. After review, 

the EPA revised the 24-hour standard in October 2006, but the annual standard remained the 

same. The 24-hour standard (as revised in 2006) is met when the 3-year average of a 

monitoring site's annual 98th percentile value is 35 micrograms per cubic meter (μg/m3

) or less. 

The annual standard is met when the 3-year average of a monitoring site's annual mean 

concentration is 15.0μg/m3

 or less. The 3-year averages at each monitoring site (of annual 

means or 98th percentiles) are called design values. The design value for an entire area is the 

single highest design value among the monitoring sites located in the area. 

Since the 1977 amendments to the Clean Air Act (CAA), areas of the country that violated the 

ambient standard for a particular pollutant were formally designated as nonattainment for that 

pollutant. This formal designation concept was retained in the 1990 Amendments (CAAA). 

With the implementation of the PM2.5 standard, areas designated nonattainment under Section 

172 of the CAAA (Subpart 1) have five years from designation to attain the standard. 

Federal regulations require that in “any area designated as nonattainment for the PM2.5 NAAQS, 

the State must submit an attainment demonstration showing that the area will attain the annual 

and 24-hour standards as expeditiously as practicable.” [40 CFR 51.1007(a)] As seen in table 

1.2-1 below, all monitors in the Chattanooga NAA attain the 1997 24-hour PM2.5 standard of 65 

μg/m3

. While the Chattanooga area is in compliance with the 1997 24-hour PM2.5 NAAQS, 

measures implemented through this SIP for achieving attainment with the annual standard will 

have a co-benefit for the 24-hour standard. 

Table 1.2-1 24-Hour PM2.5 Design Values for the Chattanooga NAA 

PM2.5 Design Value (μg/m3) Federal Reference Monitor 

2001-2003* 2002-2004 2003-2005 2004-2006 

Siskin Drive/UTC (470654002), 

TN 35 33 34 32

Maxwell Road/East Ridge 

(470650031), TN 37 34 35 32

Soddy-Daisy High School 

(470651011), TN 34 30 31 28

Walker County, GA (132950002) 33 32 33 29

*Averaging period used by the EPA in the nonattainment area designation

3 
2.0Chattanooga, Tennessee-Georgia PM2.5 Nonattainment Area 

On January 5, 2005, EPA published the annual PM2.5 nonattainment designation for the 

Chattanooga, Tennessee-Georgia area. This area consists of Hamilton County in Tennessee, 

Catoosa and Walker Counties in Georgia, and the portion of Jackson County in Alabama that is 

described as U.S. Census 2000 block group identifier 01–071-9503–1. Figure 2-1 illustrates the 

nonattainment area boundaries. Although Jackson County is not contiguous to the rest of the 

nonattainment area, EPA concluded that a coal-fired power plant located in this census tract 

contributed to the PM2.5 problem in the Chattanooga area. The effective date of the 

nonattainment designation was April 5, 2005, and was based on air quality monitoring for the 

years 2001, 2002, and 2003. 

Figure 2-1 Chattanooga PM2.5 Nonattainment Area 

2.1 Nonattainment Area Designations 

EPA, based on monitoring data submissions from states and tribes, designates a county as 

attainment/unclassifiable or nonattainment. In addition, a county is designated as nonattainment 

if it is deemed to contain sources that contribute to the nonattainment status of a county. 

4 
Nonattainment counties are initially grouped based on presumptive boundaries. These 

boundaries are based metropolitan statistical areas (MSAs) or combined statistical areas 

(CSAs). If a county within a MSA or CSA possesses a violating monitor, the entire area is 

presumed to be in nonattainment of the NAAQS. The state(s) is given the opportunity to 

provide EPA with evidence indicating that certain counties in the CSA should be omitted from 

the nonattainment area using 9-factors specified by EPA. EPA made the initial nonattainment 

designation of the Chattanooga NAA for the annual PM2.5 NAAQS on January 5, 2005 (70 FR 

944), and amended the designations on April 5, 2005 (70 FR 19844). The Alabama portion of 

the Chattanooga NAA is made up of a single census block located in Jackson County. The 

designation of a portion of Jackson County as a part of the Chattanooga nonattainment area 

was based upon EPA’s conclusion that a power plant located in the county was contributing to 

the PM2.5 violations occurring in the Chattanooga NAA. 

2.2 PM2.5 Monitoring Stations 

While there are no monitors currently located in Jackson County, AL, the observed annual PM2.5 

design values at three of the four nonattainment area monitors located in Georgia and 

Tennessee violated the annual standard for 2001 – 2003; the period on which nonattainment 

designations were based. Three of the monitors are located in Hamilton County, Tennessee, 

and one is located in Walker County, Georgia. 

Georgia currently has one ambient PM2.5 monitoring site in the Chattanooga, TennesseeGeorgia nonattainment area, as shown in Table 2.2-1 and Figure 2.2-1. The Rossville-Maple 

Street site is in Walker County, GA. 

Table 2.2-1 Annual PM2.5 Design Values 

PM2.5 Design Value (μg/m3) Federal Reference Monitor 

2001-2003* 2002-2004 2003-2005 2004-2006 

Siskin Drive/UTC (470654002), 

TN 15.2 14.7 15.0 15.1 

Maxwell Road/East Ridge 

(470650031), TN 16.1 15.7 16.1 15.5 

Soddy-Daisy High School 

(470651011), TN 14.1 13.8 13.8 13.5 

Walker County, GA (132950002) 15.5 15.2 15.8 15.2 

*Averaging period used by the EPA in the nonattainment area designation

For a full discussion of PM2.5 monitoring performed in the Georgia portion of the NAA, please 

see Section 2.2 of the Georgia SIP located in Appendix 2. For a full discussion of the PM2.5 

monitoring performed in the Tennessee portion of the NAA, please see Section 1.3 of the 

Tennessee SIP located in Appendix 1. 

5 
Figure 2.2-1 Locations of PM2.5 Monitors in the Chattanooga Nonattainment Area

2.3 Trends Analysis 

Overall, there has been a general downward long-term trend in PM2.5 concentrations at most 

monitors in the Chattanooga NAA. Detailed information regarding these trends can be found in 

Section 2.3.1 of the GA SIP located in Appendix 2. 

6 
3.0Attainment Modeling 

In 2001, the southeastern states formed the Visibility Improvement State and Tribal Association 

of the Southeast (VISTAS) to address compliance with the Regional Haze Rule that was 

published in 1999 (64 FR 35714). The member states are Alabama, Florida, Georgia, 

Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia. 

VISTAS found that the modeling requirements for the Regional Haze Rule were similar to the 

requirements for the modeled attainment demonstration for PM2.5 nonattainment areas. The 

member states formed a new organization, the Association for Southeastern Integrated 

Planning (ASIP), in order to conduct modeled attainment demonstrations for the PM2.5

nonattainment areas. VISTAS and ASIP used the same emissions inventory and model. 

A detailed description of the attainment modeling methodology used by Alabama, Georgia and 

Tennessee to evaluate the Chattanooga annual PM2.5 nonattainment area and the resulting 

conclusions can be found in Sections 2 and 3 of the TN SIP and Sections 3, 4 and 6 of the GA 

SIP located in Appendices 1 and 2, respectively. 

The results of the attainment demonstration modeling for the Chattanooga NAA are shown in 

the Table 3-1 below. All PM2.5 monitors in the NAA are expected to meet the annual PM2.5

NAAQS beginning in 2009. 

Table 3-1 2009 Modeled Annual PM2.5 Design Values 

Federal Reference Monitor 

PM2.5 Design Value 

(μg/m3) 

Siskin Drive/UTC (470654002), TN 13.6 

Maxwell Road/East Ridge 

(470650031), TN 14.4 

Soddy-Daisy High School 

(470651011), TN 12.3 

Walker County, GA (132950002) 13.9 

Control measures for attainment focus on control of SO2 (and therefore sulfates) from utilities. 

The most significant state-specific measure is the Georgia multi-pollutant rule. Federal 

measures include the following: 

• Clean Air Interstate Rule 

• Tier 2 Vehicle Standards 

• Heavy-duty Gasoline and Diesel Highway Vehicles Standards 

• Ultra Low Sulfur Diesel Fuel Rule 

• Large Non-road Diesel Engine and Fuel Standards 

• Non-road Spark Ignition Engines and Recreational Engines Standards 

• NOX SIP Call in Surrounding States 

7 
4.0Development of Emission Inventories 

This section describes the methodologies and data used to prepare the 2002 base case, and 

the 2009 and 2012 future year emissions inventories. 

4.1 Point Source Emissions 

4.1.1 2002 Base Case 

4.1.1.1 Non-EGU Point Sources 

The starting point for the 2002 Base G2 emission inventory was EPA’s 1999 National Emission 

Inventory (NEI). The 1999 data was supplemented with more recent inventories submitted by 

state and local agencies and was ultimately replaced with data submitted by VISTAS/ASIP 

States pursuant to the Consolidated Emissions Reporting Rule (CERR) and included in the 

2002 NEI. The 2002 Base G2 emission inventory was released in August 2006 and 

incorporated updates and corrections to the 2002 NEI inventory. Changes for Alabama 

included the correction of latitude and longitude values; identification of closed facilities with 

non-zero emissions reported in the NEI; and updating emissions for several facilities, based on 

the most recently reported information. 

4.1.1.2 EGU Point Sources 

For point sources, the 2002 base year inventory includes both actual emissions for coal-fired 

electric utilities and a “typical” year inventory. Actual emissions from 2002 were obtained from 

EPA’s Clean Air Markets Division (CAMD). The “typical year” point source inventory was 

developed to smooth out any anomalies in utility emissions due to meteorological, economic, 

and outage factors in 2002. The 2002 “typical” base year emissions inventory for EGUs was 

developed using CAMD data to develop normalization factors for the 2002 typical emissions 

inventory. VISTAS/ASIP used the actual 2002 heat input and the average heat input for the 5-

year period from 2000-2004 as the normalization factor, as follows: 

Normalization Factor = (2000-2004 average heat input)

 2002 actual heat input 

If the unit did not operate for all five years from 2000-2004, then the average heat input was 

calculated for the years in which the unit did operate. Actual emissions for 2002 were multiplied 

by the normalization factor to determine the typical emissions for 2002, as follows: 

 Typical Emissions = (2002 actual emissions)(Normalization Factor) 

For the entire VISTAS/ASIP region, actual 2002 SO2 emissions were about 0.5 percent higher 

than the typical year emissions. 

4.1.2 2009 Future Year 

Different approaches were used to develop the point source inventory for EGUs and non-EGUs. 

For EGUs, Integrated Planning Model® (IPM®) results were used to project future generation 

and to calculate the impact of future emission control programs. IPM results were adjusted as 

necessary to account for planned emission controls at specific EGUs. For non-EGUs, the 2009 

inventory was based on updated growth and control data, supplemented with State/Local 

agency input and updated fuel use forecast data from the U.S. Department of Energy. Post2002 facility shutdowns were also noted in the 2009 inventory. 

8 
For both sectors, 2009 inventories were generated using a combined on-the-books (OTB) and 

on-the-way (OTW) control scenario. The OTB/OTW control scenario accounted for post-2002 

emission reductions from promulgated and proposed Federal, State, local and site specific 

control programs as of July 1, 2004. 

4.2 Area Source Emissions 

4.2.1 2002 Base Case 

The area source sector of the emissions inventory consisted of three components: development 

of a typical-year fire inventory; incorporation of data submitted by states to EPA pursuant to the 

CERR; and development of NH3 emission estimates for livestock and fertilizers and paved road 

PM emissions. 

Development of a typical-year fire inventory provided the capability of using a comparable data 

set for both the base year and future years. Since fire emissions are not easily grown or 

projected, VISTAS determined that a typical-year fire inventory was needed to effectively 

represent fires in the base and future year inventories. Development of the typical-year fire 

inventory covered wildfire, prescribed burning, agricultural fires and land clearing fires. Typicalyear fire emissions were developed from actual fire acreage data and emissions were 

calculated for each state in the VISTAS/ASIP region. 

The second component of the area source inventory was the incorporation of CERR data 

submitted by states to EPA. The CERR data work involved: 1) obtaining data from EPA; 2) 

evaluating reported pollutants and emissions to avoid double-counting; and 3) adding missing 

sources/pollutants, as necessary. 

The final component of the area source inventory was related to the development of ammonia 

emission estimates for livestock and fertilizers and the estimate(s) of paved road PM emissions. 

Version 3.6 of the Carnegie Mellon University (CMU) ammonia model was used to estimate 

livestock and fertilizer emissions. For paved road PM estimates, VISTAS/ASIP used the most 

recent EPA estimates developed in the 2002 NEI. 

4.2.2 2009 Future Year 

The 2002 base year inventory was used as the starting point for projections. For nonagricultural sources, the VISTAS/ASIP contractor worked with states to obtain state-specific 

growth factors and future control requirements. Uncontrolled emissions were obtained from the 

2002 inventory and control requirements were then added to calculate controlled emissions. 

Growth factors were obtained from states or from EPA’s CAIR1

 emission projections, and these 

factors were applied to project the controlled emissions to the future year. If no state or CAIR 

growth factor was available, then EGAS Version 5 growth factors were used. The final 

inventory was then submitted to the VISTAS/ASIP States for review and comment. 

To calculate projected emissions for agricultural area sources (predominantly ammonia), 

VISTAS/ASIP used the 2002 base year inventory data and obtained state-specific growth 

factors from individual states. Since base year emissions were uncontrolled, and no future 

controls were identified for agricultural sources, VISTAS/ASIP projected the agricultural 

 

1 On December 23, 2008, the United States Court of Appeals for the District of Columbia Circuit 

remanded CAIR to EPA without vacatur, directing the Agency to remedy the rule’s flaws in accordance 

with the Court’s July 11, 2008, opinion in the case of North Carolina v. EPA, 531 F. 3d 896, 901 (D.C. Cir. 

2008). When EPA responds to the Court’s remand, the SIP may need to be revised to be consistent with 

the Agency’s new final action.

9 
emissions using state-specific growth or U.S. EPA’s Interstate Air Quality Transport Rule 

(IAQTR) ammonia inventory. The final inventory was submitted to the VISTAS/ASIP States for 

review and comment. 

The 2009 emissions inventory for fires was updated to account for increased prescribed fire 

burning by federal agencies in future years. VISTAS/ASIP developed an updated Base G2 fire 

inventory for 2009 to capture the projected increases. 

4.3 Onroad Mobile Source Emissions 

4.3.1 2002 Base Case 

The MOBILE6 module of the Sparse Matrix Operator Kernel Emissions (SMOKE) model was 

used to develop the onroad mobile source emissions estimates for CO, NOX, NH3, SO2, PM, 

and VOC emissions. The MOBILE6 parameters, vehicle fleet descriptions, and Vehicle Miles 

Traveled (VMT) estimates were combined with gridded, episode-specific temperature data to 

calculate the gridded, temporalized emission estimates. The emission factors model included 

the following variables: 

• Hourly and daily minimum/maximum temperatures; 

• Facility speeds; 

• Inspection/maintenance (I/M) control programs, if any; 

• Adjustments for running losses; 

• Splitting of evaporative and exhaust emissions into separate source categories; 

• VMT, fleet turnover, and changes in fuel composition and Reid Vapor Pressure. 

The primary input to MOBILE6 was the MOBILE shell file, which contained the various options 

to direct the calculation of the MOBILE6 emissions factors (e.g., type of inspection and 

maintenance program, oxygenated fuel program in effect, alternative vehicle mix profiles, Reid 

Vapor Pressure of in-use fuel, operating mode). Onroad mobile source emissions were 

produced using selected weeks (seven days) of each month and using these days as 

representative of the entire month. This selection criterion allowed for the representation of dayof-the-week variability in the onroad motor vehicles, and models a representation of the 

meteorological variability in each month. The modeled weeks were selected from mid-month, 

avoiding inclusion of major holidays. 

4.3.2 2009 Future Year 

To develop the future year projections, VISTAS/ASIP assembled data to develop 2009 future 

year inventories from: 1) an inventory that included all OTB control programs; and 2) an 

inventory that included controls that were likely to be OTW. For the 2009 emission forecasts to 

the mobile source sector, OTB and OTW were defined with the same strategies; therefore, only 

a single projection scenario was developed for the forecast year. To ensure consistency across 

evaluation years, the 2009 inventory was developed, to the maximum extent practical, using 

methodologies identical to those employed in developing the 2002 onroad portion of the revised 

2002 base year inventory. 

The methodology used to generate the 2009 VMT for use in estimating onroad mobile source 

emissions was as follows: 

1. All estimates started from the final VMT estimates used for the 2002 revised base 

year inventory; 

10 
2. Initial 2009 VMT estimates were based on linear growth rates for each state, county, 

and vehicle type, as derived from the VMT data assembled by EPA for the most recent 

HDD (heavy duty diesel) rulemaking. 

4.4 Nonroad Mobile Source Emissions 

4.4.1 2002 Base Case 

Emissions from nonroad sources were estimated in two steps. First, emissions for nonroad 

sources that were included in the NONROAD model were developed. Second, emissions from 

sources not included in the NONROAD model were estimated. An initial 2002 base year 

emissions inventory for nonroad engines and equipment covered by the EPA NONROAD model 

was prepared for VISTAS in early 2004. Revisions to the emissions inventory were 

implemented to ensure that the latest state and local data were considered and to accurately 

reflect gasoline sulfur contents for 2002. 

4.4.2 2009 Future Year 

Nonroad mobile source emissions were developed for 2009 in the same fashion as they were 

developed for 2002. The final version of the NONROAD2005 model was used for the 2009 

projections. Other specific updates for the projection years for NONROAD model sources 

consisted of: 

1. Changes to the emissions inventory year in the model to be reflective of the projection 

year; 

2. Revisions to the fuel sulfur content for gasoline- and diesel-powered equipment; and 

3. Implementation of a limited number of local control program changes (most national 

control program changes are handled internally within the NONROAD model, so explicit 

input file changes are not required). 

All equipment, population growth and fleet turnover impacts are also handled internally within 

the NONROAD model, so that explicit changes to the input files are not required. To correctly 

account for diesel fuel sulfur content differences between the base and projection years, two 

sets of input and output files were prepared for each forecast year, one set for land-based 

equipment and one set for marine equipment. 

To correctly account for the national reduction in gasoline sulfur content (a national control not 

explicitly handled by the NONROAD model), all NONROAD input files for 2009 were revised to 

reflect a gasoline fuel sulfur content of 30 ppm. 

Those sources requiring emissions estimated outside the NONROAD model (locomotives, 

airplanes and commercial marine vessels) were projected through a combination of applied 

technological reductions and growth due to increased demand on these sectors. Further details 

are contained in Appendices G and H of Georgia’s SIP, located in Appendix 2. 

4.5 Biogenic Source Emissions 

Biogenic emissions were prepared with the SMOKE-BEIS3 (Biogenic Emission Inventory 

System 3 version 0.9) preprocessor. SMOKE-BEIS3 is a modified version of the Urban Airshed 

Model (UAM)-BEIS3 model. Modifications include use of MM5 data, gridded land-use data, and 

improved emissions characterization. The emission factors that were used in SMOKE-BEIS3 

were the same as the emission factors in UAM-BEIS3. The basis for the gridded land-use data 

used by BEIS3 is the county land-use data in the Biogenic Emissions Landcover Database 

11 
version 3 (BELD3) provided by EPA. A separate land classification scheme, based upon 

satellite (AVHRR, 1 km spatial resolution) and census information, aided in defining the forest, 

agriculture and urban portions of each county. 

4.6 Emissions Summary for the Partial Area of Jackson County 

Table 4.6-1 2002 Emissions for the Partial Nonattainment Area of Jackson County 

2002 Jackson County -Partial (TPY) 

Sector VOC NOX SO2 PM2.5 NH3

Point 144 26,337 44,080 933 2 

Area 33 3 17 12 14

Non-road 16 14 5 1 0

Mobile 18 7 6 0 0

Total 211 26,361 44,108 946 16

Table 4.6-2 2009 Emissions for the Partial Nonattainment Area of Jackson County 

2009 Jackson County -Partial (TPY) 

Sector VOC NOX SO2 PM2.5 NH3

Point 177 5,157 45,356 1,124 8

Area 24 3 16 12 14

Non-road 13 13 2 2 0

Mobile 11 5 1 0 1

Total 252 5,178 45,375 1,138 23 

12 
5.0Significance of Precursors Contributing to Fine Particulate Matter 

EPA, in 72 FR 20586, requires states to “evaluate and consider control strategies for sources of 

SO2, direct PM2.5 and NOX emissions in all nonattainment areas.” However, the rule does allow 

states to make technical demonstrations to reverse the inclusion of NOX as precursor of PM2.5, 

or deem the precursor insignificant, based on geographical regions, emissions, etc. 

The two remaining precursor species that contribute to PM2.5 formation, ammonia (NH3) and 

volatile organic carbons (VOCs), have been deemed as insignificant contributors to the total 

mass of PM2.5 by EPA. With regards to NH3, 72 FR 20586 states NH3 “is presumed not to be a 

PM2.5 attainment plan precursor, meaning that the State is not required to address [NH3] in its 

attainment plan or evaluate sources of [NH3] emissions for reduction measures.” Likewise, the 

final rule for VOCs states that “States are not required to address VOC in PM2.5 implementation 

plans and evaluate control measures for such pollutants unless the State or EPA makes a 

technical demonstration that emissions of VOCs from sources in the State significantly 

contribute to PM2.5 concentrations in a given nonattainment area.” 

5.1 Nitrogen Dioxides 

Analysis performed by both the Chattanooga-Hamilton County Air Pollution Control Bureau and 

Georgia Department of Natural Resources Environmental Protection Division indicate that 

control of NOX in the Chattanooga nonattainment area would be expected to result in an 

insignificant reduction in PM2.5 levels. Please see Appendices 1 and 2 for the analyses 

performed by these agencies. These analyses further support ADEM’s conclusion that no 

additional reductions in NOX emissions in the Jackson County, Alabama, partial NAA are 

warranted or reasonable beyond the reductions resulting from national programs such as CAIR 

and mobile source control programs. Additional information concerning NOX emissions can be 

found in the RACT analyses in Section 6. 

5.2 Sulfur Dioxides 

As discussed previously, SO2 is an important precursor to the formation of PM2.5 and has a 

strong regional impact on PM2.5 concentrations. The RACT/RACM analysis for SO2 can be 

found in Section 6. 

5.3 Ammonia and Volatile Organic Compounds 

The State of Alabama agrees with EPA’s presumptive exclusion of NH3 and VOC with regards 

to this PM2.5 SIP. Therefore, emission controls for NH3 and VOC were not considered part of 

Alabama’s PM2.5 attainment demonstration plan. 

13 
6.0RACT and RACM 

Section 172 (c)(1) of the CAA requires SIPS to provide for the implementation of all reasonably 

available control measures (RACM) that contribute to attainment as “expeditiously as 

practicable” in the specific nonattainment area. The EPA has consistently interpreted RACM as 

a collection of measures that would advance the attainment date by at least 1 year. This 

requirement also applies to emissions reductions from existing stationary sources through the 

adoption of reasonably available control technology (RACT). “Reasonably available” allows the 

state to consider both the cost and benefits of applying the measure and whether the measure 

can be readily and effectively implemented without undue administrative burden. 

EPA included one Jackson County, Alabama, census block in the Chattanooga NAA because 

they concluded that the TVA Widows Creek utility contributes to nonattainment of the annual 

PM2.5 NAAQS in the Chattanooga NAA. The TVA Widows Creek facility is subject to CAIR. 

Table 6-1 lists the controls as well as installation dates of current control equipment for the TVA 

Widows Creek facility. SCRs were installed on the two largest units in 2003 and 2004. Also, 

since 2002, FGD was upgraded in efficiency on one of the two largest units. 

Table 6-1 Controls at TVA Widows Creek 

Rated Initial Initial Initial

Capacity NOx Service SO2 Service PM Service

(MW) Strategy Year Strategy Year Strategy Year

Tennessee Valley Authority

Widows Creek WCF U1-6 141 each LLNB 2004 FS CS-ESPs

WCF U7 575

SCR 

(LNB) 2003 FGD 1984 CS-ESP

WCF U8 550

SCR 

(LNB) 2004 FGD 1977*

*-The FGD installed on unit 8 was upgraded in efficiency in 2004. 

Units 7 and 8 are base load units and units 1-6 are peaking units. As shown in the table, 100% 

of the base load generating capacity of this facility has SCR and FGD controls. 

The attainment demonstrations that have been prepared by the State of Georgia and the 

Chattanooga local program indicate that the area will attain the annual fine particle NAAQS at 

the 2009 emissions levels projected from Widows Creek and all other sources in the area. 

Since the 2009 emissions levels reflect the implementation of the Clean Air Interstate Rule and 

other National emissions reductions programs, ADEM concludes that currently no additional 

controls are needed at the Widows Creek facility and that CAIR equals RACT for SO2 and NOX. 

In the CAIR rule, EPA determined "that the earliest reasonable deadline for compliance with the 

final highly cost effective control levels for reducing emissions was 2015..." (70 FR 25197-

25198, May 12, 2005). ADEM believes the cost of compliance and the time necessary for 

compliance are the dominant factors for determining if additional reductions would be 

reasonable from CAIR-subject EGUs. Based on the detailed analyses in the May 12, 2005, 

CAIR rule, ADEM concludes that CAIR controls satisfy RACT for SO2 and NOX for utilities. 

Sensitivity modeling performed by ASIP indicates that if ground-level and point source 

emissions of particulate in Alabama are reduced by 30%, annual PM2.5 concentrations in the 

Chattanooga NAA would not be significantly affected (See Figure 6-1). Therefore, ADEM 

14 
concludes that no additional reductions in emissions of particulate are needed to attain the 

annual PM2.5 NAAQS in the Chattanooga NAA. 

Figure 6-1 Response to 30% reduction in 2009 Base D Emissions 

15 
7.0 Contingency Measures 

The PM2.5 Implementation Rule requires contingency measures that would take effect in the 

event that a nonattainment area fails to meet the PM2.5 NAAQS. These contingency measures 

must be fully adopted rules or control measures that are ready to be implemented quickly upon 

failure of an area to meet the standard by the attainment date. 

Georgia Rules for Air Quality Control Chapter 391-3-1 Rule (sss) “Multipollutant Control of 

Electric Steam Generating Units” requires additional power plant SO2 emission reductions after 

the end of 2008. Bowen Plant Unit 1 is required to be equipped with flue gas desulfurization by 

June 1, 2010. The SO2 emissions reductions expected from this unit are 33,135 tons per year 

or 19,328 tons reduction in the last seven months of 2010. These reductions were not modeled 

for 2009. The reductions are not required to demonstrate attainment of the annual PM2.5 

standard, but constitute contingency measures. 

16 
8.0Reasonable Further Progress 

Clean Air Act §172(c)(2) requires plans for nonattainment areas to require “reasonable further 

progress,’’ (RFP) as defined in CAA §171(1). The Act requires nonattainment areas to make 

“such annual incremental reductions in emissions of the relevant air pollutant as are required by 

this part or may reasonably be required by the Administrator for the purpose of ensuring 

attainment of the applicable national ambient air quality standard by the applicable date.” In 

general terms, the goal of RFP is to allow areas to achieve generally linear progress toward 

attainment. The RFP requirements were included in the CAA to assure steady progress toward 

attaining air quality standards, as opposed to deferring implementation of all measures until the 

end date by which the standard is to be attained. 

40 CFR §51.1009 states that, consistent with CAA §172(c)(2), SIPs for PM2.5 nonattainment 

areas must demonstrate reasonable further progress as provided in §51.1009(b) through (h). 

Paragraph (b) of that section states that “If the State submits to EPA an attainment 

demonstration and State implementation plan for an area which demonstrates that it will attain 

the PM NAAQS within five years of the date of designation, the State is not required to submit a 

separate RFP plan. Compliance with the emission reduction measures in the attainment 

demonstration and State implementation plan will meet the requirements for achieving 

reasonable further progress for the area.” 

Consistent with the provisions of §51.1009(b), Hamilton County, TN, the State of Georgia and 

ADEM have submitted SIPs that demonstrate that the Chattanooga nonattainment area will 

attain the annual PM2.5 NAAQS within five years of designation. Therefore, no additional 

provisions for RFP are required. Compliance with the emission reduction measures in the AL, 

TN and GA SIPs will meet the requirements for achieving reasonable further progress for the 

Chattanooga nonattainment area. 

17 
9.0Permanent and Enforceable Improvements in Air Quality 

Since 2000, there have been several major federal programs enacted that have led to 

significant actual, enforceable PM2.5 and PM2.5 precursor emission reductions. These programs 

were established to provide reductions in emissions from the mobile source and industrial 

sectors. These programs are listed below. A more detailed discussion can be found in Section 

5.1 of the Georgia SIP located in Appendix 2. 

1. Tier II Motor Vehicle Emissions Standards 

2. Federal Onroad Diesel Engine Standards 

3. Federal Nonroad Diesel Engine Standards 

4. Federal Marine Engine Requirements 

5. Federal Locomotive Requirements 

6. The New Source Performance Standards under Section 111 (42 U.S.C 7411) 

7. The National Emission Standards for Hazardous Air Pollutants (NESHAP) under Section 

112 (42 U.S.C. 7412) 

8. The NOX SIP Call 

9. The Clean Air Interstate Rule (CAIR) 

After December 1, 2014, all onroad, nonroad, locomotive and marine diesel fuel produced and 

imported will be Ultra-Low Sulfur Diesel (ULSD-15 ppm). 

18 
10.0 Insignificance Determination for Transportation Conformity 

This section demonstrates that emissions of nitrogen oxides (NOX), and direct fine particles 

(PM2.5) from mobile sources in the small portion of Jackson County designated by EPA as 

nonattainment for the annual fine particle NAAQS, are an insignificant contributor to 

nonattainment of the annual PM2.5 NAAQS. 

EPA designated a small portion of Jackson County, Alabama, as nonattainment for the annual 

PM2.5 NAAQS on December 17, 2004. Jackson County was designated as part of the 

Chattanooga, Tennessee, annual PM2.5 nonattainment area. According to EPA, the small 

portion of Jackson County, which includes the Widows Creek Steam Plant, was included in the 

Chattanooga nonattainment area because they believed that emissions from this utility 

contribute to nonattainment in Chattanooga. The technical support document for the December 

17, 2004, designations states “Additionally we have included in our recommended 

nonattainment area Jackson County, AL, that is adjacent to the Chattanooga MSA, that is 

generally rural in character, and that contains an identifiable large emitting facility or facilities 

(e.g., power plants) which we believe contribute to the nearby nonattainment problem.” 

Therefore, it should be noted that the small portion of Jackson County was included in the 

Chattanooga nonattainment area because of EPA concerns related to utility emissions and not 

because of concerns related to mobile source emissions in the county. 

According to 40 CFR 93.109(k), there are several factors that are used to support a finding of 

insignificance for these transportation-related PM2.5 precursor pollutants. The first factor is the 

percentage of motor vehicle emissions in the context of the total SIP inventory. The second 

factor is the current state of the air quality in the area. The third factor is the absence of SIP 

motor vehicle emission control measures. Lastly, historical trends and future projections of the 

growth of motor vehicle emissions are reviewed. These factors are discussed in detail in the 

sections to follow. Each section supports the insignificance of NOX and direct PM2.5 emissions 

from mobile sources in the Jackson County portion of the nonattainment area under the 

transportation conformity rule for the PM2.5 NAAQS. 

10.1 Nitrogen Oxides (NOX) 

10.1.1 Analysis of motor vehicle NOX emissions in the Jackson County portion of the 

Chattanooga nonattainment area. 

Only a small portion of Jackson County, Alabama, was included in the Chattanooga PM2.5

nonattainment area. The small portion of the county designated nonattainment contains a 

limited number of roads. In order to determine the on-road emissions of NOX from motor 

vehicles in that portion of Jackson County, the document titled “Chattanooga Nonattainment 

Area Year 2030 Conformity Determination Report for Particulate Matter (PM2.5)” was used to 

determine how emissions were calculated for Jackson County and the same methodology was 

applied in this analysis. In order to estimate on-road mobile source emissions for the 

nonattainment portion of Jackson County, a ratio of the size of the nonattainment portion of 

Jackson County in square miles to the size of the entire county in square miles was calculated. 

The nonattainment portion of Jackson County was determined to be only about one percent of 

the total area of the entire county. The same ratio was applied to obtain area and non-road 

mobile source emissions for the nonattainment portion of the county. The following table shows 

the small percentage of NOX emissions from on-road mobile sources as compared to NOX

emissions from all other sources in the Jackson County portion of the nonattainment area. 

Emission data were obtained from the VISTAS 2002 “best and final” emissions inventory. 

19 
Table 10.1.1-1 2002 NOX (TPY) Emissions in the Nonattainment portion of Jackson County 

by Source Type 

Source Emissions (TPY) Percentage of Total 

Area 3.1 <1% 

Point 26337.4 99.9% 

Non-Road Mobile 14.18 <1% 

On-Road Mobile 6.97 <1% 

Total 26361.65 

As the above table demonstrates, NOX emissions from on-road mobile sources in the 

nonattainment portion of Jackson County are less than 1% of the total NOX emissions from all 

source categories in the same area. 

In the table below, a comparison is made of the mobile source NOX emissions from the 

nonattainment portion of Jackson County to total mobile source NOX emissions for the entire 

Chattanooga nonattainment area. 

Table 10.1.1-2 2002 NOX (TPY) On-road Mobile Source Emissions in the Nonattainment 

Portion of Jackson County Compared to Total On-road Mobile Source Emissions in the 

entire Chattanooga NAA 

Emissions (TPY) Percentage of Total 

Jackson County NAA 

Portion 

6.97 <1% 

Chattanooga NAA 13977.73 

As the table above demonstrates, NOX emissions from on-road mobile sources in the Jackson 

County portion of the nonattainment area are less than 1% of the total NOX emissions from onroad mobile sources in the entire Chattanooga nonattainment area. 

10.1.2 The current state of the air quality in Jackson County. 

As stated earlier in this document, the small portion of Jackson County, Alabama, was included 

in the Chattanooga PM2.5 nonattainment area due to the fact that a power plant is located in that 

area and it was thought by EPA to contribute to the PM2.5 problem in Chattanooga. There are 

no PM2.5 monitors located in Jackson County. Monitors in Alabama near Jackson County have 

monitored values below the annual PM2.5 NAAQS. Other counties surrounding the county are 

either in attainment or unclassifiable. 

10.1.3 The absence of SIP motor vehicle controls for the area. 

There are no SIP motor vehicle controls for Jackson County. 

10.1.4 Historical trends and future projections of the growth of motor vehicle emissions. 

The “Chattanooga Non-Attainment Area Year 2030 Conformity Determination Report for 

Particulate Matter (PM2.5)” was used to obtain past and future projections of the growth in NOX

emissions from on-road mobile sources. As demonstrated in the table below, future emissions 

of NOX are expected to decrease. 

20 
Table 10.1.4-1 Historical and Future Projections of NOX emissions from On-Road Mobile 

Sources in Jackson County 

Year Emissions (TPY) 

2002 6.97 

2010 3.40 

2020 1.35 

2030 0.96 

10.2 Direct PM2.5: 

10.2.1 Analysis of motor vehicle PM2.5 emissions in the Jackson County portion of the 

Chattanooga nonattainment area 

Only a small portion of Jackson County, Alabama, was included in the Chattanooga PM2.5

nonattainment area. The portion designated as nonattainment contains a limited number of 

roads. In order to determine the on-road emissions of PM2.5 from motor vehicles in that portion 

of Jackson County, the document titled “Chattanooga Non-Attainment Area Year 2030 

Conformity Determination Report for Particulate Matter (PM2.5)” was used to determine how 

emissions were calculated for Jackson County and the same methodology was applied in this 

analysis. In order to estimate on-road mobile source emissions for the nonattainment portion of 

Jackson County, a ratio of the size of the nonattainment portion of Jackson County in square 

miles to the size of the entire county in square miles was calculated. The nonattainment portion 

of Jackson County was determined to be only about one percent of the total area of Jackson 

County. The same ratio was applied to obtain area and non-road mobile source emissions for 

the nonattainment portion of the county. The following table shows the small percentage of 

PM2.5 emissions from on-road mobile sources as compared to PM2.5 emissions from all other 

sources in the nonattainment portion of Jackson County. Emission data were obtained from the 

VISTAS 2002 best and final inventory. 

Table 10.2.1-1 2002 Direct PM2.5 (TPY) Emissions in the Nonattainment Portion of 

Jackson County by Source Type 

Source Emissions (TPY) Percentage of Total 

Area 12.09 <1% 

Point 932.51 98.6% 

Non-Road Mobile 0.882 <1% 

On-Road Mobile 0.145 <1% 

Total 945.63 

As the above table demonstrates, direct PM2.5 emissions from on-road mobile sources in the 

nonattainment portion of Jackson County are less than 1% of the total direct PM2.5 emissions 

from all source categories in the same area. 

In the table below, a comparison is made of the mobile source direct PM2.5 emissions from the 

nonattainment portion of Jackson County to total mobile source PM2.5 emissions for the entire 

Chattanooga nonattainment area. 

21 
Table 10.2.1-2 2002 Direct PM2.5 (TPY) On-road Mobile Source Emissions in the 

Nonattainment Portion of Jackson County Compared to Total On-road Mobile Source 

Emissions in the Entire Chattanooga NAA 

Jackson County NAA 

Portion 

0.145 <1% 

Chattanooga NAA 264.97 

As the table above demonstrates, direct PM2.5 emissions from on-road mobile sources in the 

Jackson County portion of the nonattainment area are less than 1% of the total direct PM2.5

emissions from on-road mobiles sources in the entire Chattanooga NAA. 

10.2.2 The current state of the air quality in Jackson County. 

The small portion of Jackson County, Alabama, was included in the Chattanooga PM2.5

nonattainment area due to the fact that a power plant is located in that area and it was thought 

by EPA to contribute to the PM2.5 problem in Chattanooga. There are no PM2.5 monitors located 

in Jackson County. Monitors in Alabama near Jackson County have monitored values below the 

annual PM2.5 NAAQS. Other counties surrounding the county are either in attainment or 

unclassifiable. 

10.2.3 The absence of SIP motor vehicle controls for the area. 

There are no SIP motor vehicle controls for Jackson County. 

10.2.4 Historical trends and future projections of the growth of motor vehicle emissions. 

The “Chattanooga Non-Attainment Area Year 2030 Conformity Determination Report for 

Particulate Matter (PM2.5)” was used to obtain past and future projections of the growth in direct 

PM2.5 emissions from on-road mobile sources. As demonstrated in the table below, future 

emissions of direct PM2.5 are expected to decrease. 

Table 10.2.4-1 Historical and Future Projections of PM2.5 emissions from On-Road Mobile 

Sources in Jackson County 

2002 0.145 

2010 0.072 

2020 0.041 

2030 0.039 

Each of the factors set forth in 40 CFR 93.109(k) were reviewed for the transportation-related 

PM2.5 precursor pollutants NOX, SOX, and direct PM2.5. These reviews support the conclusion 

that mobile source emissions of NOX, SOX, and direct PM2.5 in the Jackson County portion of the 

Chattanooga annual PM2.5 nonattainment area are insignificant under the transportation 

conformity rule for the annual PM2.5 NAAQS. 

22 
11.0 Summary and Conclusion 

This section summarizes and concludes the results of the modeled attainment test referenced in 

this SIP, which covers the Jackson County, AL, portion of the Chattanooga annual PM2.5

nonattainment area. EPA designated the Chattanooga area as nonattainment for the PM2.5

NAAQS on January 5, 2005, and confirmed the designation on April 5, 2005. The Chattanooga 

PM2.5 nonattainment area is made up of Catoosa and Walker Counties in Georgia, Hamilton 

County in Tennessee, and the portion of Jackson County in Alabama that is described as U.S. 

Census 2000 block group identifier 01–071-9503–1. While there are currently no monitors in 

Jackson County, AL, the observed PM2.5 design value at three of the four nonattainment area 

monitors in TN and GA violated the annual standard from 2001- 2003, as shown in Table 11-1 

below. 

Table 11-1 2001 – 2003 PM2.5 Design Values for Chattanooga Nonattainment Area 

Monitors 

Site name Monitor 

ID

PM

2.5 Design Value 

(μg/m

3

)

PM

2.5 

Standard 

(μg/m

3

)

Siskin Drive/UTC, Tennessee 470654002 15.2 15.0

Maxwell Road/East Ridge, 

Tennessee 470650031 16.1 15.0

Soddy-Daisy High School, 

Tennessee 470651011 14.1 15.0

Rossville-Maple St., Georgia 132950002 15.5 15.0

Speciated monitoring data from the Rossville-Maple St. site in Georgia and the Siskin 

Drive/UTC site in Tennessee have shown that the most significant components of PM2.5 are 

sulfates and organic carbon. Sulfates are formed primarily from sulfur dioxide emissions from 

coal-fired electric generating units (EGUs), including EGUs located inside the nonattainment 

area and EGUs located outside the nonattainment area boundary. 

Control measures that may be credited in the SIP toward attainment are those that have been 

or will be implemented after 2002 but before 2009 (the modeled attainment year). Because of 

the large contribution of sulfates to the ambient PM2.5 problem in the nonattainment area, the 

most important measures for achieving attainment are those that reduce SO2 emissions from 

coal-fired EGUs. Georgia’s Multipollutant Rule (391-3-1-.02 (2) (sss)), enacted in 2007, is 

expected to achieve most of the needed reductions by reducing SO2 emissions from EGUs. 

Other modeled state and federal control measures such as CAIR, as well as unmodeled 

measures, will contribute to PM2.5 reduction to a smaller extent. 

Models were used to demonstrate attainment of the PM2.5 standard and the modeling was 

performed per EPA guidance. The modeling was performed in conjunction with the regional 

haze modeling being done by VISTAS and the PM2.5 and ozone modeling being done by ASIP. 

The models used were as follows: 

• Meteorology: MM5 

• Emissions: SMOKE 

• Air Quality: CMAQ 

23 
24 

An emissions inventory for the modeling was developed for the baseline year 2002 and 

projected to 2009. The pollutants inventoried include VOC, NOX, PM2.5, coarse particulate 

(PM10), NH3, and SO2. The projection to 2009 accounted for control measures expected to be 

implemented. 

The CMAQ modeling performance was measured by accepted methods. Overall, it is believed 

that the model predictions can be used to form the scientific foundation for proposed control 

options because its performance is well within the limits of acceptable performance criteria 

established in the Attainment Modeling Guidance. 

To demonstrate attainment, the models were used to perform the SMAT test at both of the 

federal reference monitor sites. The SMAT test projects future concentrations of individual PM 

species and then sums the results to project total PM2.5. The 2009-modeled PM2.5 design values 

are provided in Table 11-2. Since each of the modeled design values is less than 15.0 μg/m3

, 

modeled attainment is demonstrated. 

Table 11-2 PM2.5 2009 Future (Modeled) Design Values 

Federal Reference Monitor Monitor ID

2009 Annual Design 

Value (DVF) 

(μg/m

3

)

PM

2.5 

Standard 

(μg/m

3

)

Siskin Drive/UTC, Tennessee 470654002 13.6 15.0

Maxwell Road/East Ridge, Tennessee 470650031 14.4 15.0

Soddy-Daisy High School, Tennessee 470651011 12.3 15.0

Rossville-Maple St., Georgia 132950002 13.9 15.0

In conclusion, this SIP, which covers the Jackson County, AL, portion of the Chattanooga 

annual PM2.5 nonattainment area, is in accordance with regulatory requirements and guidance 

provided by EPA. It provides a comprehensive technical analysis that demonstrates that the 

Chattanooga PM2.5 nonattainment area will attain the annual PM2.5 NAAQS beginning in 2009. 

This demonstration is based upon implementation of the control measures described previously 

in this narrative, and will demonstrate attainment at the FRM monitors located in the 

Chattanooga nonattainment area.