_________________________________________________________________________________________________________

Redesignation Request

and Maintenance Plan

For

The Tennessee Portion of the

Chattanooga, Tennessee-Georgia, PM2.5 Nonattainment Area

_________________________________________________________________________________________________________

Prepared by:

Chattanooga-Hamilton County Air Pollution Control Bureau

6125 Preservation Drive, Suite 140

Chattanooga, Tennessee 37416-3740

July 1, 2014
Redesignation Request and Maintenance Plan for the

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EXECUTIVE SUMMARY

The Chattanooga-Hamilton County Air Pollution Control Bureau (the Bureau) requests, by way 

of this document, that the United States Environmental Protection Agency (U.S. EPA) 

redesignate the Tennessee portion (Hamilton County) of the Chattanooga, Tennessee-Georgia,

PM2.5 (fine particulate matter) nonattainment area to attainment as a ―maintenance area.‖ This 

request is warranted because air monitoring data for the three-year period from 2007 through 

2009 was granted a ―clean data determination‖ by the U.S. EPA for demonstrating attainment 

with the 1997 annual national ambient air quality standard for PM2.5. Furthermore, evidence is 

presented in this document that attainment of the standard is attributable to permanent, 

enforceable reductions in emissions of PM2.5 and its significant precursors.

This document also includes the Bureau’s plan for maintaining attainment with the standard

through at least the year 2025. The plan includes contingency measures to be taken if the 

standard is either exceeded or at risk of being exceeded as indicated by ambient air monitoring 

or emissions inventory trends. This maintenance plan is supported by projections through 2025

that show decreases in emissions of PM2.5 and its significant precursors, nitrogen oxides (NOX) 

and sulfur dioxide (SO2), within Hamilton County. In addition, motor vehicle emissions budgets, 

in accordance with the U.S. EPA’s transportation ―conformity‖ rule, are presented for emissions 

of PM2.5 and NOX within Hamilton County.
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TABLE OF CONTENTS

Executive Summary .....................................................................................................................i

List of Tables ............................................................................................................................. iii

List of Figures ............................................................................................................................ iv

List of Appendices.......................................................................................................................v

1.0 Introduction.........................................................................................................................1

1.1 Fine Particulate Matter (PM2.5) ....................................................................................1

1.2 PM2.5 National Ambient Air Quality Standards.............................................................2

1.3 PM2.5 Federal Reference Method Monitors .................................................................2

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

1.5 Redesignation Request Requirements........................................................................5

1.6 Maintenance Plan Requirements ................................................................................6

2.0 Redesignation Request.......................................................................................................7

2.1 Attainment of the Annual PM2.5 NAAQS......................................................................7

2.2 Emissions Reduction Measures..................................................................................8

2.2.1 Speciated Ambient PM2.5 Concentrations ........................................................8

2.2.2 Source Apportionment of Ambient PM2.5 Concentrations.................................8

2.2.3 Industrial Source Emissions Reduction Measures.........................................10

2.2.4 Mobile Source Emissions Reduction Measures.............................................13

2.2.5 PM2.5 and Ozone Transport Rules .................................................................14

2.2.6 Other Emissions Reduction Measures...........................................................15

2.3 Requirements of Title I, Part A, Section 110 and Title I, Part D of the Clean Air Act..15

3.0 Maintenance Plan .............................................................................................................17

3.1 Maintenance Demonstration .....................................................................................17

3.1.1 Attainment Year Emissions Inventory............................................................17

3.1.2 Projected Emissions Inventory ......................................................................20

3.1.3 Safety Margins ..............................................................................................23

3.1.4 Regulatory Programs ....................................................................................24

3.2 Verification of Continued Attainment .........................................................................26

3.3 Contingency Measures .............................................................................................26

3.3.1 Contingency Measure Triggers......................................................................27

3.3.2 Procedures for Adoption and Implementation of Contingency Measures.......27

4.0 Motor Vehicle Emissions Budgets.....................................................................................29

4.1 Applicable Pollutants.................................................................................................29

4.2 Motor Vehicle Emissions Budgets Determination......................................................30

4.3 Safety Margin Allotments ..........................................................................................31

5.0 Conclusion........................................................................................................................33
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LIST OF TABLES

Table 1-1 Annual PM2.5 Design Values.....................................................................................4

Table 2-1 Monitored Annual Mean PM2.5 Concentrations .........................................................7

Table 2-2 Monitored Annual Mean Concentrations of Speciated PM2.5 Components................8

Table 2-3 Annual Industrial Point-Source Emissions of SO2 ...................................................10

Table 2-4 Annual Industrial Point-Source Emissions of NOX...................................................10

Table 3-1 Attainment Year Emissions from Sources in Hamilton County................................20

Table 3-2 Projected Annual Emissions of PM2.5 from Sources in Hamilton County .................21

Table 3-3 Projected Annual Emissions of NOX from Sources in Hamilton County...................22

Table 3-4 Projected Annual Emissions of SO2 from Sources in Hamilton County ...................22

Table 3-5 Projected Annual Emissions of VOCs and Ammonia from Sources in Hamilton

County....................................................................................................................23

Table 3-6 Projected Annual Emissions from Combined Sources in Hamilton County .............23

Table 3-7 Projected Annual Emissions from Combined Sources in the Chattanooga

Maintenance Area ..................................................................................................24

Table 4-1 Projected Annual Emissions from Onroad Sources in Hamilton County..................31

Table 4-2 Safety Margin Allotments to Proposed Motor Vehicle Emissions Budgets for

Onroad Sources in Hamilton County.......................................................................32
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LIST OF FIGURES

Figure 1-1 Locations of PM2.5 Federal Reference Method Monitors ..........................................3

Figure 1-2 Chattanooga, Tennessee-Georgia, PM2.5 Nonattainment Area................................5

Figure 2-1 2002–2006 Average Contributions to Ambient PM2.5 Concentrations ......................9

Figure 2-2 Annual SO2 Emissions and Energy Production from Combined Bowen and

Hammond Plants...................................................................................................12

Figure 2-3 Annual NOX Emissions and Energy Production from Combined Bowen and

Hammond Plants...................................................................................................12
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LIST OF APPENDICES

Appendix A ―Georgia’s Redesignation Request and Maintenance Plan for the Chattanooga 

Nonattainment Area for the 1997 PM2.5 NAAQS for Catoosa and Walker Counties‖ 

(narrative)

Appendix B ―Redesignation Request and Maintenance Demonstration — Jackson County, 

Alabama — Chattanooga Annual PM2.5 Nonattainment Area‖ (narrative)

Appendix C Annual PM2.5 Design Values and Annual Mean PM2.5 Concentrations

Applicable Portions of PM2.5 Design Value Reports from www.epa.gov/airtrends/values.

html and www.epa.gov/airtrends/values_previous.html

Appendix D ―Source Apportionment of PM2.5 in Georgia‖

Appendix E Power Plant Emissions Data

Facility Emissions Trends Reports from the U.S. EPA Clean Air Markets Division for 

Widows Creek, Bowen, and Hammond Power Plants

Appendix F Point Source Emissions Data

Chattanooga-Hamilton County Air Pollution Control Bureau 2003, 2004, 2005, 2006, 

2008, 2009, and 2010 Emissions Inventory System Reports

Appendix G 2007 Point Source Emissions Data

2005 National Emissions Inventory (NEI) Download for Hamilton County, Tennessee –

Updated to 2007

Appendix H Point Source Emission Calculation Spreadsheets

Appendix I 2007 Area Source Emissions Data

2005 National Emissions Inventory (NEI) Download for Hamilton County, Tennessee –

Updated to 2007

Appendix J 2005 Aircraft, Marine, and Railroad Source Emissions Data

2005 National Emissions Inventory (NEI) Download for Hamilton County, Tennessee

Appendix K Area Source Emission Calculation Spreadsheets

Appendix L Onroad Source Input Data

MOVES2010b (Motor Vehicle Emission Simulator) Input Data for Hamilton County, 

Tennessee

(provided electronically under folder names: 2007 MOVES Inputs, 2025 w.o. IM MOVES 

Inputs, 2025 Worst Case w.o. IM MOVES Inputs, 2040 w.o. IM MOVES Inputs, and 2040 

Worst Case w.o. IM MOVES Inputs)

Appendix M Onroad Source Emissions Data

MOVES2010b (Motor Vehicle Emission Simulator) Output for Hamilton County, 

Tennessee

Appendix N Onroad Source Emission Calculation Spreadsheets

Appendix O Nonroad Source Emissions Data

NONROAD2008a Emission Inventory Model Output for Hamilton County, Tennessee
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LIST OF APPENDICES (Continued)

Appendix P VOC and Ammonia Emissions Data

Applicable Portion of the Particulate Matter (PM) NAAQS Final Rule Regulatory Impact 

Assessment from ftp.epa.gov/EmisInventory/2007v5 (filename: 2007platform_county_

sector_emissions_2007re_2020re.zip)

Appendix Q Point Source Emission Growth Factors

Economic Growth Analysis System (EGAS) Version 5.0 Output by North American 

Industry Classification System (NAICS) Codes for Hamilton County, Tennessee – 2007 

Base Year

Appendix R Area Source Emission Growth Factors

Economic Growth Analysis System (EGAS) Version 5.0 Output by Source Classification 

Codes (SCC) for Hamilton County, Tennessee – 2007 Base Year
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1.0 INTRODUCTION

This document contains technical support for the request by the Chattanooga-Hamilton County 

Air Pollution Control Bureau (the Bureau) that the Tennessee portion (Hamilton County) of the 

Chattanooga, Tennessee-Georgia, PM2.5 nonattainment area be redesignated as an area that is 

in attainment with the 1997 annual PM2.5 national ambient air quality standard (NAAQS), 

pursuant to Title I, Part A, §107(d)(3)(D) and (E) of the Clean Air Act. A plan for maintaining

attainment with the standard is also included in this document. The redesignation request and 

maintenance plan were prepared in accordance with a September 4, 1992, guidance 

memorandum from the United States Environmental Protection Agency (U.S. EPA) entitled 

―Procedures for Processing Requests to Redesignate Areas to Attainment.‖ Furthermore, this 

document includes motor vehicle emissions budgets that are being proposed in accordance with 

the U.S. EPA’s transportation ―conformity‖ rule.

A redesignation request and maintenance plan for the Georgia portion (Catoosa and Walker 

Counties) of the Chattanooga nonattainment area was prepared by the Air Protection Branch of 

the Environmental Protection Division (EPD) of the Georgia Department of Natural Resources. 

The narrative of this document is provided in Appendix A. Similarly, the Air Division of the 

Alabama Department of Environmental Management (DEM) prepared a redesignation request 

and maintenance plan, the narrative of which is provided in Appendix B, for the Alabama portion 

(part of Jackson County) of the nonattainment area.

1.1 Fine Particulate Matter (PM2.5)

PM2.5, or fine particulate matter, refers to airborne particles that have an aerodynamic diameter

of 2.5 micrometers (μm) or less. These particles are treated as a single air pollutant, but they

are composed of various compounds and come from many different sources. Inhalation of 

PM2.5 can result in adverse respiratory and cardiovascular health effects. Children, older adults, 

and people with a chronic disease of the lungs or heart are particularly sensitive to PM2.5

exposure.

PM2.5 can be a solid, liquid, or solid core surrounded by liquid. Primary PM2.5 is directly emitted 

to the atmosphere and retains the same chemical composition after it is released. Secondary 

PM2.5 is formed through chemical reactions in the atmosphere involving precursors such as 

sulfur dioxide (SO2), nitrogen oxides (NOX), ammonia, and volatile organic compounds (VOCs)

from biogenic or anthropogenic sources. PM2.5 constituents include:

 Sulfates;

 Nitrates;

 Ammonium ion;

 Elemental carbon;
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 Primary organic compounds (generally from combustion);

 Secondary organic aerosols (SOA); and

 Inorganic crustal material (e.g., dust, metals, and sea salt).

Coal-fired power plants, other fuel combustion sources, motor vehicles, and industrial processes 

are among the most significant sources of emissions of PM2.5 and its precursors. PM2.5 can also 

be emitted into the air as windblown dust. These emissions are often transported over long 

distances. PM2.5 concentration levels in the ambient air are influenced by both meteorological 

conditions and geographic factors.

1.2 PM2.5 National Ambient Air Quality Standards

The U.S. EPA promulgated both 24-hour and annual NAAQS for PM2.5 on July 18, 1997

(Federal Register Vol. 62, No. 138, pp. 38652–38760). The 24-hour standard was set at 65

micrograms per cubic meter (μg/m3) and the annual standard was set at 15.0 μg/m3. The 

24-hour PM2.5 NAAQS was subsequently revised to 35 μg/m3on October 17, 2006 (Federal 

Register Vol. 71, No. 200, pp. 61144–61233). The 2006 24-hour standard is met when the 98th 

percentile daily PM2.5 monitored concentration (the value below which 98% of the values in a 

calendar year fall), as averaged over three consecutive years, is less than or equal to 35 μg/m3. 

The U.S. EPA designated Hamilton County as being in attainment with this 24-hour standard on 

November 13, 2009 (Federal Register Vol. 74, No. 218, pp. 58688–58781). The 1997 annual 

standard is met when the annual mean of daily PM2.5 monitored concentrations (average of 

quarterly-average values in a calendar year), as averaged over three consecutive years, is less 

than or equal to 15.0 μg/m3.

1.3 PM2.5 Federal Reference Method Monitors

Daily concentrations of PM2.5 in the ambient air, which are used in determining attainment with 

the 24-hour and annual PM2.5 NAAQS, are obtained from data that is collected by Federal 

Reference Method (FRM) monitors. The Bureau operates three PM2.5 FRM monitors in 

Hamilton County, Tennessee. A PM2.5 FRM monitor in nearby Walker County, Georgia, is 

operated by the Georgia EPD. The locations of these four monitors are mapped in Figure 1-1, 

which follows. (The Hamilton County monitor that is identified in the figure as being on Maxwell 

Road in East Ridge was relocated a distance of less than one mile to Tombras Avenue in East 

Ridge in 2007.)
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Figure 1-1. Locations of PM2.5 Federal Reference Method Monitors 

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1.4 Chattanooga, Tennessee-Georgia, PM2.5 Nonattainment Area

The annual mean PM2.5 concentration (average of quarterly-average concentrations), based on 

quality-assured and certified data from an FRM monitor as averaged over three consecutive 

calendar years, is referred to as the monitor’s annual PM2.5 ―design value‖ for that three-year 

period. Annual design values for each PM2.5 FRM monitor are given below in Table 1-1. 

Exceedances of the 1997 annual PM2.5 NAAQS of 15.0 μg/m3are demarcated in bold font in 

this table. The design values in the table are from PM2.5 design value reports that are available 

at the U.S. EPA websites www.epa.gov/airtrends/values.html and www.epa.gov/airtrends/

values_previous.html. Applicable portions of these reports are provided in Appendix C.

Table 1-1. Annual PM2.5 Design Values

Annual PM2.5 Design Value (μg/m3)

PM2.5 Federal Reference 

Method Monitor

2001–

2003

2002–

2004

2003–

2005

2004–

2006

2005–

2007

2006–

2008

2007–

2009

2008–

2010

2009–

2011

2010–

2012

Siskin Drive (UTC)

(ID #470654002) 15.2 14.7 15.0 15.0 15.2 14.3 12.7 11.6 11.1 10.9

Tombras Avenue, East Ridge

(ID #470650031) 16.1 15.7 16.1 15.3 15.1 13.8 12.6 11.6 11.2 11.1

Soddy-Daisy High School

(ID #470651011) 14.1 13.8 13.8 13.4 13.7 12.9 11.7 11.4 11.0 11.2

Maple Street, Rossville, GA

(ID #132950002) 15.5 15.2 15.8 15.2 14.9* 13.5* 12.3* 10.6 10.1* 10.0*

*Data from the Rossville, Georgia, monitor for 2007 and 2011 did not meet completeness criteria

Data from three of the four PM2.5 FRM monitors in the Chattanooga area for the period from 

2001 through 2003 showed an exceedance of the 1997 annual PM2.5 NAAQS. Based on the 

2001–2003 monitoring data, the U.S. EPA designated the Chattanooga, Tennessee-Georgia,

area as being in nonattainment with the annual standard on January 5, 2005 (Federal Register

Vol. 70, No. 3, pp. 944–1019). The U.S. EPA readdressed this designation on April 14, 2005 

(Federal Register Vol. 70, No. 71, pp. 19846 and 19847), but made no change to it. The 

Chattanooga nonattainment area consists of Hamilton County in Tennessee, Catoosa and 

Walker Counties in Georgia, and an interior portion of Jackson County in Alabama that is 

described as U.S. Census 2000 Block Group Identifier 01-071-9503-1. The nonattainment area 

is depicted in Figure 1-2, which follows. (PM2.5 FRM monitor locations that are shown in this 

figure are approximate and are less precise than those indicated in the preceding Figure 1-1.)
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Figure 1-2. Chattanooga, Tennessee-Georgia, PM2.5 Nonattainment Area

1.5 Redesignation Request Requirements

Title I, Part A, §107(d)(3)(E) of the Clean Air Act requires that the following conditions be met in 

order for the Tennessee portion of the Chattanooga nonattainment area to be redesignated as

an area in attainment with the 1997 annual PM2.5 NAAQS:
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 A determination by the U.S. EPA that the annual PM2.5 NAAQS has been attained;

 A determination by the U.S. EPA that the improvement in air quality that resulted in 

attainment of the standard is due to permanent and enforceable reductions in emissions;

 Full approval by the U.S. EPA of the state implementation plan (SIP) for the Tennessee 

portion of the nonattainment area under Title I, Part A, §110(k) of the Clean Air Act;

 Attainment of all applicable requirements for the Tennessee portion of the nonattainment 

area under Title I, Part A, §110 and Title I, Part D of the Clean Air Act; and

 Full approval by the U.S. EPA of a maintenance plan, including contingency measures, 

for the Tennessee portion of the nonattainment area as required by Title I, Part D, §175A 

of the Clean Air Act.

1.6 Maintenance Plan Requirements

The required maintenance plan must provide for the continued attainment of the 1997 annual 

PM2.5 NAAQS for a period of at least ten years after the U.S. EPA has formally redesignated the

Tennessee portion of the Chattanooga nonattainment area to attainment as a ―maintenance 

area.‖ The plan must demonstrate that future attainment of the standard is expected to 

continue, it must indicate how continued attainment of the standard will be verified, and it must 

include contingency measures to be implemented if the standard is either exceeded or 

determined to be at risk of being exceeded.
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2.0 REDESIGNATION REQUEST

The Bureau formally requests that the U.S. EPA redesignate the Tennessee portion of the 

Chattanooga, Tennessee-Georgia, PM2.5 nonattainment area to a maintenance area in 

attainment with the 1997 annual PM2.5 NAAQS, pursuant to Title I, Part A, §107(d)(3)(D) and (E)

of the Clean Air Act. Technical support for the request is provided in this section of the 

document, including demonstrations that the standard has been met as a result of permanent 

and enforceable emissions reductions and that applicable requirements of the Clean Air Act 

have been complied with.

2.1 Attainment of the Annual PM2.5 NAAQS

Annual mean PM2.5 concentrations (averages of quarterly-average concentrations) for each 

PM2.5 FRM monitor, based on quality-assured and certified data, are given below in Table 2-1. 

The concentrations in the table are from PM2.5 design value reports that are available at the U.S. 

EPA websites www.epa.gov/airtrends/values.html and www.epa.gov/airtrends/values_previous.

html. Applicable portions of these reports are provided in Appendix C.

Table 2-1. Monitored Annual Mean PM2.5 Concentrations

PM2.5 Federal Reference

Method Monitor

Annual Mean PM2.5 Concentration (μg/m3)

2006 2007 2008 2009 2010 2011 2012

Siskin Drive (UTC)

(ID #470654002) 15.039 15.046 12.707 10.471 11.726 11.073 10.010

Tombras Avenue, East Ridge

(ID #470650031) 14.258 14.933 12.289 10.475 12.025 11.056 10.073

Soddy-Daisy High School

(ID #470651011) 13.081 14.222 11.388 9.520 13.290 10.290 9.992

Maple Street, Rossville, GA

(ID #132950002) 14.453 13.689* 12.482 10.704 8.690 10.772* 10.541

*Data from the Rossville, Georgia, monitor for 2007 and 2011 did not meet completeness criteria

The annual mean PM2.5 concentration, as rounded to one decimal place, from any of the four 

monitors in the Chattanooga area has been no greater than 15.0 μg/m3from 2006 onwards. 

Furthermore, the annual PM2.5 design value for each monitor and for each three-year period,

beginning with 2006–2008, has been below the annual PM2.5 NAAQS of 15.0 μg/m3, as shown 

in the preceding Table 1-1. Accordingly, the U.S. EPA granted a ―clean data determination‖ to 

the ambient air monitoring data from the four PM2.5 FRM monitors for the period from 2007

through 2009 and determined, as of the publication date of May 31, 2011 (Federal Register Vol. 
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76, No. 104, pp. 31239–31241), that the Chattanooga nonattainment area has attained the 1997 

annual PM2.5 NAAQS.

2.2 Emissions Reduction Measures

In order for the Chattanooga nonattainment area to be redesignated to attainment, the decrease 

in monitored ambient PM2.5 concentrations through 2009, which resulted in a clean data 

determination for monitoring data for the three-year period ending in 2009, must be 

demonstrated to be due to permanent and enforceable reductions in emissions of PM2.5 and/or 

its significant precursors. These reductions are required to have resulted from measures 

implemented after 2003 since the nonattainment designation was based upon monitoring data 

for the three-year period that continued through 2003.

2.2.1 Speciated Ambient PM2.5 Concentrations

PM2.5 constituents include many components from varying sources. A PM2.5 speciation monitor

is located adjacent to the PM2.5 FRM monitor at the Siskin Drive (UTC) site in Hamilton County 

and is a part of the U.S. EPA speciation trends network (STN). It provides ambient air 

concentrations of sulfates, nitrates, ammonium ion, potassium, sodium, elemental carbon, 

organic carbon, and specific metals, all of which are speciated PM2.5 components. Annual 

mean concentrations of major components of PM2.5 from the STN monitor are from U.S. EPA Air 

Quality System raw data reports and are given below in Table 2-2.

Table 2-2. Monitored Annual Mean Concentrations of Speciated PM2.5 Components

Speciated PM2.5

Component

Annual Mean Concentration (μg/m3)

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Sulfates 5.2 5.2 4.9 5.4 4.0 4.8 4.0 2.4 3.1 2.8 2.1

Nitrates 1.0 1.2 1.0 1.0 1.0 1.1 0.8 0.7 0.9 0.5 0.7

Ammonium Ion 1.7 1.8 1.6 1.9 1.5 1.9 1.5 0.9 1.1 0.8 0.6

2.2.2 Source Apportionment of Ambient PM2.5 Concentrations

The Georgia EPD conducted a source apportionment analysis of speciated PM2.5 component 

concentrations that were obtained from the Hamilton County PM2.5 STN monitor from 2002 

through 2006. The analysis was conducted using EPA-PMF1.1 (Positive Matrix Factorization), 

which is the U.S. EPA’s model for distinguishing correlation patterns among speciated PM2.5

concentrations in a given location. The results of the analysis are included in a document 
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entitled ―Source Apportionment of PM2.5 in Georgia,‖ which is provided in Appendix D, and are 

diagrammed below in Figure 2-1.

Figure 2-1. 2002–2006 Average Contributions to Ambient PM2.5 Concentrations (μ/m3)

According to the source apportionment analysis, the greatest contribution to ambient PM2.5 

concentrations in the Chattanooga area is from secondary sulfates, which are formed from 

atmospheric reactions with SO2. Three coal (fossil fuel)-fired electric power plants are the 

largest industrial point-sources of SO2 emissions that significantly impact the area. These three 

plants also result in considerable emissions of NOX. One of these plants, the Tennessee Valley 

Authority (TVA) Widows Creek power plant, is located in the Alabama portion of the 

Chattanooga nonattainment area in Jackson County. The other two facilities are located nearby 

in Northwest Georgia — Georgia Power’s Bowen power plant in Bartow County and Hammond 

power plant in Floyd County. Bartow County is a part of the extensive Atlanta PM2.5

nonattainment area, and Floyd County comprises a separate PM2.5 nonattainment area.

Secondary organic aerosols are shown to be the second largest contributor to ambient PM2.5 in 

the Chattanooga area, but precursor emissions for these aerosols are considered to mostly 

result from biogenic sources and are thus not readily controlled. Primary PM2.5 emissions from 

mobile sources and from biomass burning also significantly affect area PM2.5 concentrations, as 

indicated by the analysis. Most industrial sources of primary PM2.5 emissions within Hamilton 

County have long been controlled or subject to emission limitations. Contributions to PM2.5 in 

the ambient air from all other source categories appear to be of less consequence.
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2.2.3 Industrial Source Emissions Reduction Measures

Annual emissions of SO2 and NOX from each of the Widows Creek, Bowen, and Hammond 

power plants, along with those from the combined industrial point sources within Hamilton 

County, are given below in Tables 2-3 and 2-4, respectively. The emissions from the three 

power plants are from U.S. EPA Clean Air Markets Division facility emissions trends reports and 

are provided in Appendix E. The emissions from the combined Hamilton County point sources 

are from annual reports generated from the Bureau’s Emissions Inventory System for all 

applicable years except 2007. These reports are provided in Appendix F. Point source

emissions for 2007 are from the 2005 National Emissions Inventory (NEI) download for 

Hamilton County, updated to 2007, that is provided in Appendix G, and these emissions are 

tabulated in spreadsheets provided in Appendix H.

Table 2-3. Annual Industrial Point-Source Emissions of SO2

SO2 Emissions (tons/year)

Source 2003 2004 2005 2006 2007 2008 2009 2010

Hamilton County 

Point Sources 1,920 1,788 1,779 1,397 919 892 559 788

Widows Creek

Plant (Alabama) 44,046 31,396 34,380 33,507 32,723 27,903 12,861 10,982

Bowen Plant 

(Georgia) 164,884 165,914 186,470 206,442 196,841 148,149 54,811 7,618

Hammond Plant 

(Georgia) 35,923 37,696 39,548 40,579 47,809 12,465 894 2,427

Table 2-4. Annual Industrial Point-Source Emissions of NOX

NOX Emissions (tons/year)

Source 2003 2004 2005 2006 2007 2008 2009 2010

Hamilton County

Point Sources 2,841 2,758 2,748 2,653 2,437 2,140 1,716 1,738

Widows Creek

Plant (Alabama) 24,615 19,843 18,154 17,184 17,620 15,100 3,526 2,996

Bowen Plant 

(Georgia) 24,960 24,770 26,246 28,636 18,478 24,070 6,947 7,257

Hammond Plant 

(Georgia) 7,437 6,183 6,750 5,783 7,782 6,096 3,164 3,163
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As shown in the preceding tables, annual emissions of both SO2 and NOX from each of the 

three power plants are considerably greater than the respective emissions from all of the 

industrial point sources in Hamilton County combined prior to 2009. In 2003, emissions from 

the Widows Creek, Bowen, and Hammond power plants combined were greater than emissions 

from the combined Hamilton County point sources by factors of 127.5 times for SO2 and 20.1 

times for NOX. Furthermore, emissions from the three power plants combined were reduced 

from 2003 to 2009 by 72.0% for SO2 and 76.1% for NOX.

While flue-gas desulfurization scrubbers for each of the eight coal-fired units at the Widows 

Creek power plant were installed prior to 2002, the scrubber controlling SO2 emissions from Unit 

8 was upgraded in 2004. In addition, selective catalytic-reduction equipment to control NOX

emissions was installed in 2003 for Unit 7 and in 2004 for Unit 8 in accordance with Federal 

Facilities Compliance Agreement, Docket No. CAA-04-2010-1760, between the U.S. EPA and 

TVA. This agreement is both permanent and enforceable. Furthermore, Units 1–6 at the 

Widows Creek plant were permanently removed from service as of October 1, 2011, in early 

compliance with the agreement. Operation of Units 1–6 began to be scaled back in 2009.

The Bowen and Hammond power plants are both subject to ―Multipollutant Control of Electric 

Utility Steam Generating Units‖ [Georgia Rule 391-3-1-.02(2)(sss)], which requires flue gas 

desulfurization to control SO2 emissions and selective catalytic reduction for the control of NOX

emissions. The rule was promulgated in 2007 to reduce mercury deposition and to lower 

ambient ozone and PM2.5 concentrations through the control of precursor emissions. Although

the rule’s compliance date was December 31, 2008, the required controls at both facilities 

began to be used in the first half of 2008. ―SO2 Emissions from Electric Utility Steam 

Generating Units‖ [Georgia Rule 391-3-1-.02(2)(uuu)] is a companion rule that requires a 95% 

reduction in SO2 emissions from the majority of Georgia’s coal-fired power plants. This 

requirement is being phased in from 2010 through 2016.

Annual emissions of SO2 and NOX from the Bowen and Hammond power plants combined, 

along with the annual quantity of electrical energy generated from the two combined plants, are 

graphically presented in the following Figures 2-2 and 2-3, respectively. The energy production 

data was furnished by the Georgia EPD.
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Figure 2-2. Annual SO2 Emissions and Energy Production from Combined Bowen and

Hammond Plants

Figure 2-3. Annual NOX Emissions and Energy Production from Combined Bowen and

Hammond Plants
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The preceding figures indicate that annual energy generation from the Bowen and Hammond 

power plants combined was stable. In fact, electrical energy production from the combined 

plants was 26.7 megawatt hours (MWh) in 2003 and 26.6 MWh in 2009, which is relatively 

unchanged. This demonstrates that the reductions in SO2 and NOX emissions from the two 

plants are due to the implementation of permanent and enforceable regulations rather than to 

any decrease in energy output.

2.2.4 Mobile Source Emissions Reduction Measures

―Control of Emissions from New and In-Use Highway Vehicles and Engines‖ (the Tier 2

standards, Title 40 Code of Federal Regulations Part 86) was initiated in 2004 and were mostly

phased in by 2007. For passenger vehicles with a gross weight of over 8,500 pounds, the Tier 

2 standards were phased in beginning in 2008 with full compliance in 2009. The standards 

require all passenger vehicles in a manufacturer’s fleet, including light-duty trucks and sport 

utility vehicles, to emit no more than 0.07 grams of NOX per mile, on average. The standards 

also require that subject vehicles emit at least 77% less NOX than passenger vehicles in 

operation prior to the standards adoption. A second phase of these standards, which began to 

be implemented in 2007, resulted in an estimated 90% reduction in particulate matter emissions 

from heavy-duty engines used in highway vehicles.

In addition, the Tier 2 standards required a lowering of the sulfur content of gasoline to 30 parts 

per million (ppm), beginning in January of 2006. Prior to this, the typical sulfur content of 

gasoline available in the Chattanooga area was about 340 ppm. Furthermore, ―Regulation of 

Fuels and Fuel Additives‖ (Title 40 Code of Federal Regulations Part 80) became effective in 

2004. This rule required sulfur content reductions to 15 ppm for onroad diesel fuel, 500 ppm for 

nonroad diesel fuel by 2006, and 15 ppm for nonroad diesel fuel by 2010. Nonroad diesel fuel 

in the area had an average sulfur content of about 3,400 ppm before 2006. Sulfur, which occurs 

naturally in gasoline and diesel fuel, interferes with the operation of catalytic converters that are 

used on vehicles to control NOX emissions. Reducing the content of sulfur in these fuels also 

served to proportionally decrease motor vehicle emissions of SO2.

―Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines‖ (Title 40 

Code of Federal Regulations Part 1039) was promulgated in 2004 with a phase-in period from

2008 to 2014. This regulation applies to emissions of particulate matter and NOX from engines 

used in construction, agricultural, and industrial equipment. Full implementation of the rule is 

anticipated to reduce particulate matter emissions from large nonroad diesel-fuel engines by 

over 90%.

―Control of Emissions from New, Large Nonroad Spark-Ignition Engines,‖ (Title 40 Code of 

Federal Regulations Part 1048) regulates NOX and other pollutants emitted from engines that 

are used in vehicles such as forklift trucks and airport ground service equipment. The first 
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phase of this rule was implemented in 2004 and the second phase commenced in 2007. 

―Control of Emissions from Recreational Engines and Vehicles‖ (Title 40 Code of Federal 

Regulations Part 1051) pertains to emissions of NOX and other pollutants from such sources as 

off-highway motorcycles, all-terrain-vehicles, and recreational motor boats, and phase-in of this 

rule commenced in 2006. It is estimated that these two rules will result in an 80% overall 

reduction in NOX emissions from subject sources when fully implemented.

2.2.5 PM2.5 and Ozone Transport Rules

In October 1998, the U.S. EPA made a finding of significant contribution to ozone formation due 

to NOX emissions from certain states and published the ―NOX Budget Trading Program for State 

Implementation Plans‖ (the NOX SIP Call, Title 40 Code of Federal Regulations Part 96, 

Subparts A–I), which set ozone-season NOX emission budgets for the purpose of reducing 

regional transport of ozone. This rule called for NOX emission budgets to be established for 

twenty-two eastern states (and the District of Columbia), including Tennessee, Georgia, and 

Alabama. Each subject state was required to develop rules requiring the control of NOX

emissions from utility and industrial boilers that would allow the state to meet its budget by 

2004. Furthermore, a NOX emission trading program was established that allows sources to 

buy credits to meet the applicable budget as opposed to installing NOX emission control 

equipment.

The U.S. EPA promulgated the ―Rule to Reduce Interstate Transport of Fine Particulate Matter 

and Ozone [Clean Air Interstate Rule (CAIR)]‖ on May 12, 2005 (Federal Register Vol. 70, No.

91, pp. 25162–25405). This rule established a requirement for states to regulate emissions of 

NOX and SO2 from fossil-fuel fired electric generation units with capacities in excess of 25 

megawatts. Annual limits on state-wide emissions of NOX and SO2 were to be set in phases 

beginning in 2009 and continuing through 2015.

On July 11, 2008, the U.S. Court of Appeals for the District of Columbia Circuit vacated CAIR 

and remanded it to the U.S. EPA. A rehearing of the Court’s decision was requested and 

granted. On December 23, 2008, the Court remanded CAIR to the U.S. EPA without vacatur 

(i.e., the rule was still in place). The U.S. EPA was directed to correct the deficiencies in CAIR 

that were identified in the Court’s decision.

To replace CAIR, the U.S. EPA promulgated the ―Transport Rule‖ [Cross-State Air Pollution 

Rule (CSAPR)] on August 8, 2011 (Federal Register Vol. 76, No. 152, pp. 48208–48483). This

rule was to impose restrictions on emissions of NOX and SO2 from states identified as having 

significant impacts on ozone and/or PM2.5 NAAQS attainment or as interfering with maintenance 

of these standards in downwind states. The requirements of CSAPR were to become effective 

in 2012 and 2014. However, the U.S. Court of Appeals for the District of Columbia Circuit 

issued respective rulings on December 30, 2011, and August 21, 2012, at first to stay CSAPR,
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pending judicial review, and then to vacate it. Regardless of the timing of any transition from 

CAIR to a replacement transport rule, emissions of NOX and SO2 affecting the Chattanooga 

nonattainment area have declined significantly and are expected to continue to decrease due, in 

large part, to the continuation of the Federal Facilities Compliance Agreement between the U.S. 

EPA and TVA and Georgia Rules 391-3-1-.02(2)(sss) and (uuu) that apply to coal-fired electric 

power plants.

2.2.6 Other Emissions Reduction Measures

In 2005, a seasonal open-burning ban was instituted in Hamilton County. Furthermore, the City 

of Chattanooga no longer operates an air-curtain destructor for brush burning, with the 

exception of operation to dispose of debris from major storms. Permits issued for open burning 

in Hamilton County numbered 7,131 in calendar year 1994 and 5,510 during the open burning 

season from October 1, 2006, through April 30, 2007, a decrease of 22.7%. Emissions from 

open burning include elemental carbon, organic carbon, and direct PM2.5.

―Pollution Solution‖ is a public outreach and education program of the Bureau. The goal of the 

program is to reduce air pollution by voluntary actions. The program is activated on air quality 

alert days when the concentration of either PM2.5 or ozone in the ambient air is projected to be 

above the ―moderate‖ range for health effects. On such days, pertinent information is sent to 

select individuals, government employees, hospitals, health care facilities, child daycare

centers, schools, gyms, and emergency responders, in addition to television, radio, and print 

media outlets.

2.3 Requirements of Title I, Part A, Section 110 and Title I, Part D of the Clean Air Act

Title I, Part A, §110 of the Clean Air Act contains requirements for SIPs that provide for the 

implementation, maintenance, and enforcement of applicable NAAQS. Title I, Part D, Subpart 1

(§171–179) of the Clean Air Act contains general requirements for areas that have been 

designated as nonattainment for a NAAQS. Following designation by the U.S. EPA of the 

Chattanooga area as being in nonattainment with the 1997 annual PM2.5 NAAQS in 2005, the 

Bureau submitted a PM2.5 NAAQS SIP for the Tennessee portion of the Chattanooga 

nonattainment area in accordance with Part D.

With the determination by the U.S. EPA in 2011 that the Chattanooga nonattainment area has 

attained the 1997 annual PM2.5 NAAQS, the area is no longer subject to nonattainment

requirements of Part A, §110 and Part D. Accordingly, the following was published on May 31, 

2011 (Federal Register Vol. 76, No. 104, p. 31241):

―EPA has determined, as of May 31, 2011, the Chattanooga, Tennessee, nonattainment 

area has attaining data for the 1997 annual PM2.5 NAAQS. This determination, in 
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accordance with 40 CFR 52.1004(c), suspends the requirements for this area to submit 

an attainment demonstration, associated reasonably available control measures, a 

reasonable further progress plan, contingency measures, and other planning SIPs 

related to attainment of the standard for as long as this area continues to meet the 1997 

annual PM2.5 NAAQS.‖

All other requirements of Part A, §110 and Part D pertaining to the Chattanooga area have 

previously been approved or are currently subject to approval by the U.S. EPA.
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3.0 MAINTENANCE PLAN

The Bureau’s plan for maintaining attainment with the 1997 annual PM2.5 NAAQS within the 

Tennessee portion of the Chattanooga, Tennessee-Georgia, PM2.5 maintenance area is detailed 

in this section of the document. The maintenance plan demonstrates continued attainment of 

the standard and includes procedures for verification of future attainment. In addition, this plan 

incorporates contingency measures to be implemented if the verification procedures indicate 

that the standard is no longer being attained or close to not being attained.

3.1 Maintenance Demonstration

The Bureau is demonstrating maintenance of the 1997 annual PM2.5 NAAQS by showing that 

future annual emissions of PM2.5, its significant precursors of NOX and SO2, and its precursors 

of VOCs and ammonia from all sources combined within the Tennessee portion (Hamilton 

County) of the Chattanooga maintenance area will not exceed the respective emissions for the 

―attainment year.‖ Maintenance of the annual PM2.5 NAAQS has been similarly demonstrated 

for the Georgia portion (Catoosa and Walker Counties) of the maintenance area by the Georgia 

EPD and for the Alabama portion (part of Jackson County) of the maintenance area by the 

Alabama DEM. These respective demonstrations are included in redesignation request and 

maintenance plan documents that were prepared by the Georgia EPD and by the Alabama 

DEM, the narratives of which are provided in Appendices A and B, correspondingly.

3.1.1 Attainment Year Emissions Inventory

Ambient air monitoring data from all four FRM monitors in the Chattanooga area indicated 

attainment with the 1997 annual PM2.5 NAAQS for the three-year period from 2007 through 

2009, and this data was accordingly granted a clean data determination by the U.S. EPA. 

Furthermore, the annual mean PM2.5 concentration (average of quarterly-average 

concentrations), rounded to one decimal place, from each monitor was no greater than 15.0

μg/m3for each of the three years in this period, based on quality-assured and certified 

monitoring data. These concentrations were previously given in Table 2-1. The Bureau has

therefore chosen to use 2007, the first year of the three-year attainment period, as the 

attainment, or base, year for Hamilton County. 2007 was also selected as the attainment year 

by the Georgia EPD for the Georgia portion of the maintenance area and by the Alabama DEM 

for the Alabama portion of the maintenance area.

Emissions of PM2.5, its significant precursors of NOX and SO2, and its precursors of VOCs and 

ammonia occur from point, area, onroad mobile, and nonroad mobile sources within Hamilton 

County. Emissions of these pollutants that occurred during 2007 from the combined sources 

within Hamilton County represent emission levels that are consistent with attainment of the 

standard.
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Point sources are certain industrial, commercial, and institutional stationary sources. Attainment 

year emissions of PM2.5, NOX, and SO2 from point sources were obtained from the 2005 NEI 

download for Hamilton County, updated to 2007, that is provided in Appendix G. These 

emissions are tabulated in spreadsheets provided in Appendix H. The original source for most 

of these emissions is the Bureau’s Emissions Inventory System, which is a database wherein 

annual emissions from sources that are permitted by the Bureau are recorded. These

emissions were determined from direct measurement, calculated using material balances,

estimated using emission factors from sources such the U.S. EPA’s Compilation of Air Pollutant 

Emission Factors (AP-42), or estimated by other methods. The PM2.5 emissions include any 

condensable portion that could be determined. The Emissions Inventory System is updated 

continually and archived for each calendar year. The updated emissions, predominately from 

industrial fuel-combustion sources, were obtained from the Emissions Inventory System for 

2007 and are either higher or lower than what was reported in the 2005 NEI.

Area (nonpoint) sources are residential stationary sources and those industrial, commercial, and 

institutional stationary sources that are not classified as point sources. Emissions from area 

sources are estimated for entire source categories (e.g., residential natural-gas combustion) 

rather than for individual emission points. Attainment year emissions of PM2.5, NOX, and SO2

from area sources were obtained from the 2005 NEI download for Hamilton County, updated to 

2007, that is provided in Appendix I. Emissions were updated by subtracting out emissions from 

certain fuel-combustion source categories that were found either to not actually be performed 

within Hamilton County or to also be included in the NEI as point sources.

Attainment year emissions of PM2.5, NOX, and SO2 from aircraft, marine vessels, and railroads 

are also being listed as area source emissions. These emissions were determined by the U.S. 

EPA and were obtained from the 2005 NEI download for Hamilton County that is provided in 

Appendix J. Emissions from aircraft were based on airport-specific landing and take-off data 

provided by the Federal Aviation Administration of the U.S. Department of Transportation (U.S. 

DOT). Emissions from marine vessels are given for both ―port‖ and ―underway‖ categories. 

Emissions from marine vessels while in port were based on cargo tonnage handled at specific 

river port facilities, and emissions from vessels while underway were based on cargo tonnage 

transported along lengths of waterway segments as established by the U.S. Army Corps of 

Engineers. Emissions from railroads are given for both ―yard‖ and ―line haul‖ categories. 

Emissions from both switchyard and line haul locomotives were based on fuel use data from the 

Energy Information Administration of the U.S. Department of Energy and on Geographic 

Information System rail tonnage data provided by the Bureau of Transportation Statistics of the 

U.S. DOT. No updates were made to these emissions, which are more conservative than what 

was reported in the 2008 NEI. An economic downturn that was ongoing in 2008 makes the 

2005 data more appropriate to use. All of the area source emissions are tabulated in 

spreadsheets provided in Appendix K.
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Onroad mobile sources include passenger cars and trucks, commercial trucks, buses, 

motorcycles, and motor homes. Attainment year emissions of PM2.5, NOX, and SO2 from onroad 

sources within Hamilton County were determined by using MOVES2010b (Motor Vehicle 

Emission Simulator), dated March 2012, which is the U.S. EPA’s current model for estimating 

emissions from onroad sources. The model was run in ―inventory‖ mode, and the hourly ―time 

aggregation level‖ was used in order to obtain the greatest precision. Input data for the model 

includes the number of vehicles of each type, ―vehicle miles travelled‖ by vehicle type and hour 

of day, vehicle age distribution, and road type distribution. In addition, since the Tennessee 

Automobile Inspection and Maintenance (I/M) Program has been in effect in Hamilton County 

since April 1, 2005, the model input option for an I/M program was selected. The model input

data was supplied by the Chattanooga Metropolitan Planning Organization (MPO) as ten 

spreadsheets. The input spreadsheet files and the ―run specification‖ file (.mrs extension) that 

was used to set up the model run are provided electronically in Appendix L under the folder 

name ―2007 MOVES Inputs.‖ The resulting emissions from the model are provided in Appendix 

M and are tabulated in spreadsheets provided in Appendix N.

Nonroad mobile sources include construction equipment, agricultural equipment, and lawn care 

equipment. Attainment year emissions of PM2.5, NOX, and SO2 from nonroad sources within 

Hamilton County were determined by using NONROAD2008a, dated 2009, which is the U.S. 

EPA’s current model for estimating emissions from nonroad sources. Input data for this model 

was supplied by the U.S. EPA. The resulting emissions from the model are provided in 

Appendix O.

Attainment year emissions of VOCs and ammonia from point, area, onroad mobile, and nonroad 

mobile sources within Hamilton County were obtained from a county-level emissions summary 

that is a part of the Particulate Matter (PM) NAAQS Final Rule Regulatory Impact Assessment. 

It is available from the U.S. EPA Emissions Modeling Clearinghouse at the website ftp.epa.gov/

EmisInventory/2007v5 (filename: 2007platform_county_sector_emissions_2007re_2020re.zip). 

The applicable portion of the emissions summary is provided in Appendix P.

The emissions of PM2.5, NOX, SO2, VOCs, and ammonia from the various source types within 

Hamilton County during the attainment year are given in Table 3-1, which follows.
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Table 3-1. Attainment Year Emissions from Sources in Hamilton County

2007 Emissions (tons/year)

Source Type PM2.5 NOX SO2 VOCs Ammonia

Point 160.2 2,437.2 919.2 1,047.0 12.5

Area 875.4 3,415.1 332.6 5,338.9 194.2

Onroad 395.1 11,465.2 87.6 4,797.5 161.6

Nonroad 153.6 1,792.1 99.3 2,383.3 2.7

Total 1,584.3 19,109.5 1,438.8 13,566.6 370.9

3.1.2 Projected Emissions Inventory

Demonstration of future maintenance of the 1997 annual PM2.5 NAAQS is required for a period 

of ten years following the presumed date of redesignation, which should end no later than 2025. 

This demonstration is being made by showing that projected emissions of PM2.5 and its 

significant precursors of NOX, and SO2 for each of the years 2010, 2013, 2016, 2019, 2022, and 

2025 from all sources combined within Hamilton County will not exceed the respective 

emissions for the attainment year of 2007.

Projected annual emissions of PM2.5, NOX, and SO2 from point sources were determined by 

applying Economic Growth Analysis System (EGAS) Version 5.0 factors for Hamilton County to 

the respective attainment year emissions. These growth factors are for point sources as 

grouped by North American Industry Classification System (NAICS) codes and are provided in 

Appendix Q. The resulting emissions are tabulated in spreadsheets provided in Appendix H.

Three coal-fired boilers at the INVISTA, S.à r.l., LLC, plant in Hamilton County are subject to 

Consent Decree, Case No. 1:09-cv-00244-GMS, between the U.S. et al. and INVISTA. This 

consent decree established emission limitations for the combined boilers of at most 194 tons of 

NOX per year and 530 tons of SO2 per year with an effective date of January 28, 2015. As a 

result, these maximum emissions are being ascribed to the boilers for years following 2015. 

Emissions of PM2.5 were unaffected by the consent decree. During 2007, the combined boilers 

resulted in point source emissions of 24.3 tons of PM2.5, 280.1 tons of NOX, and 566.8 tons of 

SO2.

Caraustar Mill Group, Inc., (doing business as Chattanooga Paperboard) previously operated 

two residual-oil-fired boilers and one natural-gas-fired boiler at their plant in Hamilton County. 

All operations at this plant ceased on July 22, 2008, and the operating permit for the plant was 

withdrawn. No emissions are therefore being ascribed to the boilers for years following 2008. 
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During 2007, the combined boilers resulted in point source emissions of 4.6 tons of PM2.5, 41.6 

tons of NOX, and 122.5 tons of SO2.

Projected annual emissions of PM2.5, NOX, and SO2 from area sources were determined by 

applying EGAS Version 5.0 factors for Hamilton County to the respective attainment year 

emissions. These growth factors are for area sources as grouped by source classification 

codes (SCC) and are provided in Appendix R. The resulting emissions are tabulated in 

spreadsheets provided in Appendix K.

Projected emissions of PM2.5, NOX, and SO2 from onroad mobile sources within Hamilton 

County for 2025 were determined by using the MOVES2010b model. The model was run in 

inventory mode using the hourly time aggregation level. In addition, the model input option for 

an I/M program was not selected since the future status of the Tennessee I/M Program cannot 

be known. (Not selecting the I/M program option for the 2025 model run resulted in 6.0% 

greater emissions of NOX and no change in the emissions of PM2.5 and SO2.) Input data for the 

model was supplied by the Chattanooga MPO as thirteen spreadsheets. The input spreadsheet 

files and the run specification file that was used to set up the model run are provided 

electronically in Appendix L under the folder name ―2025 w.o. IM MOVES Inputs.‖ The resulting 

emissions from the model are provided in Appendix M and are tabulated in spreadsheets 

provided in Appendix N. Emissions for the years 2010, 2013, 2016, 2019, and 2022 were 

calculated by linear interpolation between the respective emissions for 2007 and 2025.

Projected annual emissions of PM2.5, NOX, and SO2 from nonroad mobile sources within 

Hamilton County were determined by using the NONROAD2008a model. Input data for this 

model was supplied by the U.S. EPA. The resulting emissions from the model are provided in 

Appendix O.

The projected annual emissions of PM2.5, NOX, and SO2 from the various source types within 

Hamilton County are given in the following Tables 3-2, 3-3, and 3-4, respectively.

Table 3-2. Projected Annual Emissions of PM2.5 from Sources in Hamilton County

PM2.5 Emissions (tons/year)

Source Type 2007 2010 2013 2016 2019 2022 2025

Point 160.2 156.3 158.2 169.2 180.7 193.1 205.8

Area 875.4 916.6 955.8 1,001.2 1,042.6 1,083.6 1,121.9

Onroad 395.1 342.0 288.9 235.8 182.7 129.6 76.5

Nonroad 153.6 141.6 123.7 101.0 82.4 70.4 63.5

Total 1,584.3 1,556.5 1,526.6 1,507.3 1,488.4 1,476.7 1,467.8
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Table 3-3. Projected Annual Emissions of NOX from Sources in Hamilton County

NOX Emissions (tons/year)

Source Type 2007 2010 2013 2016 2019 2022 2025

Point 2,437.2 2,484.1 2,575.6 2,650.6 2,811.6 2,982.2 3,154.6

Area 3,415.1 3,638.0 3,835.2 4,089.8 4,348.5 4,609.0 4,880.6

Onroad 11,465.2 9,972.4 8,479.7 6,986.9 5,494.2 4,001.5 2,508.7

Nonroad 1,792.1 1,562.6 1,264.3 1,003.4 833.6 730.8 675.2

Total 19,109.5 17,657.2 16,154.7 14,730.8 13,487.9 12,323.4 11,219.1

Table 3-4. Projected Annual Emissions of SO2 from Sources in Hamilton County

SO2 Emissions (tons/year)

Source Type 2007 2010 2013 2016 2019 2022 2025

Point 919.2 797.5 808.1 798.0 819.4 842.1 865.6

Area 332.6 346.7 363.2 382.9 401.1 420.6 441.1

Onroad 87.6 77.1 66.5 56.0 45.5 34.9 24.4

Nonroad 99.3 25.9 15.2 14.2 14.7 15.3 15.9

Total 1,438.8 1,247.2 1,253.2 1,251.1 1,280.7 1,312.9 1,346.9

On January 4, 2013, the U.S. Court of Appeals for the District of Columbia Circuit remanded to 

the U.S. EPA both the ―Clean Air Fine Particle Implementation Rule‖ (Federal Register Vol. 72, 

No. 79, pp. 20586–20667, April 25, 2007) and ―Implementation of the New Source Review 

(NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM2.5)‖ (Federal Register Vol. 

73, No. 96, pp. 28321–28350, May 16, 2008). A consequence of this decision is that, in 

accordance with Title I, Part D, Subpart 4 (§188–190) of the Clean Air Act, future PM2.5

precursor emissions of VOCs and ammonia can no longer be presumed to have a limited 

impact on the maintenance of the annual PM2.5 NAAQS. Therefore, a demonstration is also 

being made that available future year (2020) emissions of VOCs and ammonia from the 

combined sources within Hamilton County are below the respective attainment year emissions.

As with the attainment year emissions, emissions of VOCs and ammonia from point, area, 

onroad mobile, and nonroad mobile sources within Hamilton County, projected to 2020, were 

obtained from the county-level emissions summary that is a part of the Particulate Matter (PM) 

NAAQS Final Rule Regulatory Impact Assessment and that is available from the U.S. EPA 

Emissions Modeling Clearinghouse at the website ftp.epa.gov/EmisInventory/2007v5 (filename: 
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2007platform_county_sector_emissions_2007re_2020re.zip). The applicable portion of the 

emissions summary is provided in Appendix P.

The 2020 projected emissions of VOCs and ammonia from the various source types within 

Hamilton County are given below in Table 3-5.

Table 3-5. Projected Annual Emissions of VOCs and Ammonia from Sources in Hamilton

County

VOC Emissions (tons/year) Ammonia Emissions (tons/year)

Source Type 2007 2020 2007 2020

Point 1,047.0 1,038.1 12.5 12.5

Area 5,338.9 5,372.1 194.2 202.0

Onroad 4,797.5 1,541.8 161.6 92.5

Nonroad 2,383.3 1,213.3 2.7 3.1

Total 13,566.6 9,165.4 370.9 310.1

3.1.3 Safety Margins

For PM2.5 and its significant precursors of NOX and SO2, the ―safety margin‖ is the difference 

between the attainment year (2007) emissions from all sources (i.e., point, area, onroad mobile,

and nonroad mobile) combined and the respective 2025 projected emissions from the combined 

sources. Since projected emissions for PM2.5 precursors of VOCs and ammonia are only 

provided for 2020, the difference between the attainment year emissions from the combined 

sources and the 2020 projected emissions from all sources combined is being used as the 

safety margin for each of these two pollutants. The PM2.5, NOX, SO2, VOC, and ammonia safety 

margins for Hamilton County are given below in Table 3-6.

Table 3-6. Projected Annual Emissions from Combined Sources in Hamilton County

Emissions (tons/year)

Pollutant 2007 2020 2025 Safety Margin

PM2.5 1,584.3 -- 1,467.8 116.4

NOX 19,109.5 -- 11,219.1 7,890.4

SO2 1,438.8 -- 1,346.9 91.8

VOCs 13,566.6 9,165.4 -- 4,401.2

Ammonia 370.9 310.1 -- 60.9
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The projected emission decreases from 2007 to 2025 are 7.4% for PM2.5, 41.3% for NOX, and 

6.4% for SO2. VOC and ammonia emissions are projected to decrease by 32.4% and 16.4%, 

respectively, from 2007 to 2020.

The Georgia EPD and Alabama DEM also determined both attainment year emissions and 2025 

projected emissions for PM2.5 and its significant precursors of NOX and SO2 from point, area, 

onroad mobile, and nonroad mobile sources combined within the Georgia portion and Alabama 

portion, respectively, of the Chattanooga maintenance area. The resulting PM2.5, NOX, and SO2

safety margins for the entire maintenance area are given below in Table 3-7. The emissions 

that were used for the Georgia and Alabama portions of the maintenance area are from

narratives of the applicable redesignation request and maintenance plan documents that are 

provided in Appendices A and B, respectively.

Table 3-7. Projected Annual Emissions from Combined Sources in the Chattanooga

Maintenance Area

PM2.5 Emissions (tons/year) NOX Emissions (tons/year) SO2 Emissions (tons/year)

Maintenance 

Area Portion 2007 2025

Safety 

Margin 2007 2025

Safety 

Margin 2007 2025

Safety 

Margin

Tennessee 1,584 1,468 116 19,109 11,219 7,890 1,439 1,347 92

Georgia 1,733 2,056 -323 5,482 1,806 3,676 404 394 10

Alabama 785 565 220 18,654 3,634 15,020 32,805 10,518 22,287

Total 4,102 4,089 13 43,245 16,659 26,586 34,648 12,259 22,389

Significant decreases from 2007 to 2025 are projected for NOX emissions from the Georgia 

portion of the maintenance area and for emissions of PM2.5, NOX, and SO2 from the Alabama 

portion. SO2 emissions from the Georgia portion are projected to decrease only slightly from 

2007 to 2025, and PM2.5 emissions from the Georgia portion are projected to show a moderate 

increase over this period. The Georgia EPD used PM2.5 speciation data to show that the 

projected PM2.5 emissions increase within the Georgia portion of the maintenance area should 

be fully offset by the corresponding large decrease in NOX emissions. This explanation is 

contained in the redesignation request and maintenance plan for the Georgia portion, the 

narrative of which is provided in Appendix A. Overall, emissions from the entire Chattanooga 

maintenance area are projected to decrease by 0.3% for PM2.5, 61.5% for NOX, and 64.6% for 

SO2 from 2007 to 2025.

3.1.4 Regulatory Programs

The Bureau, the Tennessee Department of Environment and Conservation, the Georgia EPD, 

and the U.S. EPA have previously implemented enforceable requirements that will facilitate
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maintenance of the annual PM2.5 NAAQS. Regulatory programs that will remain in place for the 

Chattanooga maintenance area and nearby areas include the following:

 Chattanooga Air Pollution Air Pollution Control Ordinance;

 Hamilton County Air Pollution Control Regulation;

 Collegedale Air Pollution Control Ordinance;

 East Ridge Air Pollution Control Ordinance;

 Lakesite Air Pollution Control Ordinance;

 Lookout Mountain Air Pollution Control Ordinance;

 Red Bank Air Pollution Control Ordinance;

 Ridgeside Air Pollution Control Ordinance;

 Signal Mountain Air Pollution Control Ordinance;

 Soddy-Daisy Air Pollution Control Ordinance;

 Walden Air Pollution Control Ordinance;

 Seasonal open burning ban;

 ―Standards of Performance for New Stationary Sources,‖ Title 40 Code of Federal 

Regulations Part 60;

 ―National Emission Standards for Hazardous Air Pollutants,‖ Title 40 Code of Federal 

Regulations Part 61;

 ―National Emission Standards for Hazardous Air Pollutants for Source Categories,‖ Title 

40 Code of Federal Regulations Part 63;

 ―Regulation of Fuels and Fuel Additives,‖ Title 40 Code of Federal Regulations Part 80;

 ―Control of Emissions from New and In-Use Highway Vehicles and Engines‖ (Tier 2 

standards), Title 40 Code of Federal Regulations Part 86;

 ―NOX Budget Trading Program for State Implementation Plans‖ (NOX SIP Call), Title 40 

Code of Federal Regulations Part 96, Subparts A–I;

 ―Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines,‖

Title 40 Code of Federal Regulations Part 1039;

 ―Control of Emissions from New, Large Nonroad Spark-Ignition Engines,‖ Title 40 Code 

of Federal Regulations Part 1048;

 ―Control of Emissions from Recreational Engines and Vehicles,‖ Title 40 Code of Federal 

Regulations Part 1051;

 Consent Decree, Case No. 1:09-cv-00244-GMS, between the U.S. et al. and INVISTA, 

S.à r.l., LLC

 Federal Facilities Compliance Agreement, Docket No. CAA-04-2010-1760, between the 

U.S. EPA and TVA;

 ―Multipollutant Control of Electric Utility Steam Generating Units,‖ Georgia Rule 391-3-1-

.02(2)(sss); and

 ―SO2 Emissions from Electric Utility Steam Generating Units,‖ Georgia Rule 391-3-1-

.02(2)(uuu).
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3.2 Verification of Continued Attainment

Continued attainment of the Chattanooga maintenance area with the 1997 annual PM2.5 NAAQS

shall be verified through operation of the four existing PM2.5 FRM monitors in the area and 

through periodic emissions inventory updates. The three such monitors in Hamilton County are 

maintained and operated by the Bureau, and maintenance and operation of the monitor in 

Walker County is performed by the Georgia EPD. All of these monitors are operated in 

accordance with applicable provisions of ―Ambient Air Quality Surveillance‖ (Title 40 Code of 

Federal Regulations Part 58). Required data from the four PM2.5 FRM monitors is submitted

quarterly to the U.S. EPA pursuant to §58.16 of Part 58.

Emissions from industrial, commercial, and institutional point sources that are permitted by the 

Bureau are updated continually and archived annually in the Bureau’s Emissions Inventory 

System. The emissions that are tracked in this system include PM2.5, NOX, SO2, VOCs, and 

ammonia. The PM2.5 emissions include any condensable portion that can be determined. 

These emissions from point and nonpoint sources, as applicable, are reported to the NEI in 

accordance with the submittal schedule outlined in the ―Air Emissions Reporting Requirements

(AERR)‖ [Title 40 Code of Federal Regulations Part 51, Subpart A (§51.1–50)]. In addition, 

emissions of area, onroad mobile, and nonroad mobile sources are updated in the NEI every 

three years as required by the AERR. The most recent complete emissions inventory was 

submitted to the NEI in 2012 for calendar year 2011. The next complete emissions inventory, 

which will cover calendar year 2014, is due for submittal to the NEI in 2015.

3.3 Contingency Measures

§175A(d) of the Clean Air Act requires that the maintenance plan include contingency measures 

to be implemented, as necessary, to promptly correct any exceedance of the applicable NAAQS

that might occur in the maintenance area. The Bureau has identified the following possible 

means for providing further reductions in emissions of PM2.5 and/or its significant precursors as 

contingency measures for emission sources within Hamilton County:

 Reasonably available control technology (RACT) for point sources of PM2.5 emissions 

not already covered by RACT, best available control technology (BACT), or reasonable 

and proper emission limitations;

 Reasonably available control measures (RACM) for area sources of PM2.5 emissions;

 RACT for major point-sources of NOX emissions;

 RACT for minor point-sources of NOX emissions;

 RACM for area sources of NOX emissions;

 RACT for major point-sources of SO2 emissions;

 RACT for minor point-sources of SO2 emissions;
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 RACM for area sources of SO2 emissions; and

 Additional PM2.5, NOX, and/or SO2 emissions reduction measures yet to be identified.

Additional control measures for mobile sources of NOX emissions are not specifically listed as a 

possible contingency measure because the local agency and its legislative bodies do not have 

authority to adopt any such additional measures outside of Hamilton County.

3.3.1 Contingency Measure Triggers

An exceedance of the 1997 annual PM2.5 NAAQS of 15.0 μg/m3at any FRM monitor in the 

Chattanooga maintenance area, based on quality-assured and certified monitoring data as 

averaged over three consecutive calendar years, will ―trigger‖ a comprehensive evaluation by 

the Bureau to determine if contingency measures should be implemented. Furthermore, such 

an evaluation will also be triggered by the occurrence of any of the following conditions that may 

forewarn of a potential exceedance of the annual PM2.5 NAAQS:

 An annual mean PM2.5 concentration (average of quarterly-average concentrations) of

greater than or equal to 16.5 μg/m3for the previous calendar year at any FRM monitor 

in the Chattanooga maintenance area, based on quality-assured and certified monitoring 

data;

 An annual mean PM2.5 concentration (average of quarterly-average concentrations) of

greater than or equal to 15.5 μg/m3for each of the previous two consecutive calendar 

years at any FRM monitor in the Chattanooga maintenance area, based on qualityassured and certified monitoring data;

 Total emissions of PM2.5 in the most recent NEI for Hamilton County of greater than

2,059 tons, which is thirty percent more than the corresponding emissions for 2007 (the 

attainment year);

 Total emissions of NOX in the most recent NEI for Hamilton County of greater than 

24,842 tons, which is thirty percent more than the corresponding emissions for 2007;

and

 Total emissions of SO2 in the most recent NEI for Hamilton County of greater than

1,870 tons, which is thirty percent more than the corresponding emissions for 2007.

3.3.2 Procedures for Adoption and Implementation of Contingency Measures

Upon occurrence of a contingency measure trigger, the required comprehensive evaluation will 

be conducted to determine the cause(s) of the elevated ambient PM2.5 concentrations or 

emissions inventory increase, to determine if an exceedance of the annual PM2.5 NAAQS is 

likely to occur or continue, and to determine whether or not the adoption and implementation of
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appropriate contingency measures is required for the further reduction of emissions of PM2.5

and/or its significant precursors within Hamilton County. The evaluation will examine:

 Severity of the trigger condition;

 Potentially contributing emissions from sources within Hamilton County;

 Potentially contributing emissions resulting from regional or long-range transport;

 Potentially contributing meteorological conditions, if applicable;

 Emission trends for all source types;

 Future emissions reductions from any adopted or planned regulations or initiatives;

 Current and recently identified emission control technologies applicable to considered 

contingency measures;

 Emissions reduction potential of considered contingency measures;

 Technical and economic feasibility of considered contingency measures;

 Possible geographic limitations of considered contingency measures; and

 Implementation timeline of considered contingency measures.

The comprehensive evaluation will be completed by the Bureau and submitted to the U.S. EPA 

as expeditiously as practical, but no later than nine (9) months after the contingency measure 

trigger occurs. Any contingency measures that are needed for reattainment or maintenance of 

the annual PM2.5 NAAQS will be identified through the evaluation. The Bureau commits to 

pursue adoption of any rules that are necessary for the implementation of such measures within 

eighteen (18) months following the date on which the trigger condition occurs. Furthermore, the 

appropriate contingency measures will be implemented within twenty-four (24) months after the 

occurrence of the trigger condition. The Bureau will submit a revised implementation schedule 

to the U.S. EPA if it is determined that technical or economic considerations warrant additional 

time to fully implement the contingency measures. Adoption of any rules for the implementation 

of contingency measures is subject to necessary administrative and legal processes. No such 

rule will be adopted without providing an opportunity for full public participation through the 

issuance of public notices, the solicitation of input from interested and affected persons in the

area, and the holding of a public hearing.
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4.0 MOTOR VEHICLE EMISSIONS BUDGETS

―Conformity to State or Federal Implementation Plans of Transportation Plans, Programs, and 

Projects Developed, Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws‖ 

[the transportation conformity rule, Title 40 Code of Federal Regulations Part 93, Subpart A 

(§93.100–129)] requires that proposed, non-exempt highway and transit projects within the 

maintenance area conform to air quality goals before they can be federally funded. One 

requirement for a determination of conformity to be made is that, for each applicable pollutant,

an intended project cannot result in annual emissions in excess of a pertinent motor vehicle 

emissions budget (MVEB). The MVEB for each pollutant applies to the final year covered by 

the maintenance plan and subsequent years. The Bureau is proposing MVEBs, applicable to

2025 and later, for all onroad mobile sources combined within Hamilton County. Similarly, 

MVEBs for the combined onroad mobile sources within Catoosa and Walker Counties have

been proposed by the Georgia EPD that also cover years commencing with 2025. The 

Alabama DEM was not required to develop MVEBs for onroad mobile sources within the portion 

of Jackson County that is included in the Chattanooga maintenance area because emissions 

from these sources are very minimal and have been determined to not be significant

contributors to PM2.5 nonattainment.

4.1 Applicable Pollutants

Pollutants that must be addressed for transportation conformity purposes in PM2.5 maintenance 

areas are identified in §93.119(f)(7) through (10) of the transportation conformity rule. These 

pollutants are:

 PM2.5 [§93.119(f)(7)];

 Reentrained road dust if the U.S. EPA Regional Administrator or the director of the State 

air agency has made a finding that emissions from reentrained road dust within the area 

are a significant contributor to PM2.5 nonattainment and has so notified the pertinent 

MPO and Department of Transportation (DOT) [§93.119(f)(8)];

 NOX unless the U.S. EPA Regional Administrator and the director of the State air agency 

have made a finding that emissions of NOX within the area are not a significant 

contributor to PM2.5 nonattainment and have so notified the MPO and DOT

[§93.119(f)(9)]; and

 VOCs, SO2, and/or ammonia if the U.S. EPA Regional Administrator or the director of 

the State air agency has made a finding that emissions of any such precursor within the 

area are a significant contributor to PM2.5 nonattainment and has so notified the MPO 

and DOT [§93.119(f)(10)].

NOX must be addressed because no finding has been made that emissions of NOX are not a 

significant contributor to PM2.5 nonattainment in the Chattanooga maintenance area. 
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Reentrained road dust, VOCs, and ammonia are not required to be addressed because no 

finding has been made that emissions from reentrained road dust, emissions of VOCs, or 

emissions of ammonia are a significant contributor to PM2.5 nonattainment in the maintenance 

area. Although SO2 is a significant PM2.5 precursor, it is not required to be addressed because 

onroad mobile sources result in only 1.8% (24.4 tons) of the total projected SO2 emissions for 

2025 within Hamilton County.

Accordingly, the pollutants for which MVEBs will be established for onroad mobile sources 

within Hamilton County are PM2.5 and NOX. These are also the two pollutants for which MVEBs 

were proposed by the Georgia EPD for onroad mobile sources within Catoosa and Walker 

Counties.

4.2 Motor Vehicle Emissions Budgets Determination

The MOVES2010b model was run in inventory mode using the hourly time aggregation level in 

order to estimate emissions of PM2.5 and NOX from onroad mobile sources within Hamilton 

County for 2025 and 2040 using both normal and ―worst case‖ input scenarios. The model input 

option for an I/M program was not selected for any of these four model runs since the future 

status of the Tennessee I/M program cannot be known. The worst-case input assumptions that 

were employed are:

 A ten percent increase in vehicle miles traveled for all vehicle types;

 A doubled rate of increase in population (and corresponding number of vehicles) from 

the population in 2010; and

 A two-year increase in the age of all vehicles.

Input data was supplied by the Chattanooga MPO as thirteen spreadsheets for the 2025 model 

run, thirteen spreadsheets for the 2025 worst case model run, thirteen spreadsheets for the 

2040 model run, and thirteen spreadsheets for the 2040 worst case model run. The input 

spreadsheet files and run specification files for the 2025, 2025 worst case, 2040, and 2040 

worst case model runs are provided electronically in Appendix L under the folder names ―2025 

w.o. IM MOVES Inputs,‖ ―2025 Worst Case w.o. IM MOVES Inputs,‖ ―2040 w.o. IM MOVES 

Inputs,‖ and ―2040 Worst Case w.o. IM MOVES Inputs,‖ respectively. The resulting emissions 

from the model runs are provided in Appendix M, tabulated in spreadsheets provided in 

Appendix N, and summarized in Table 4-1, which follows. The listed emissions for 2025, using 

normal input conditions, were previously included in Tables 3-2 (for PM2.5) and 3-3 (for NOX).
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Table 4-1. Projected Annual Emissions from Onroad Sources in Hamilton County

Emissions (tons/year)

Pollutant 2025 2025 Worst Case 2040 2040 Worst Case

PM2.5 76.5 95.8 81.2 97.4

NOX 2,508.7 3,198.5 2,343.4 2,771.1

For 2025, using the worst-case input scenario rather than the normal input conditions results in 

emissions that are greater by 19.3 tons/year (25.2%) for PM2.5 and 689.8 tons/year (27.5%) for 

NOX. These substantial differences between worst case and normal case emissions are much 

less than the respective safety margins, which were previously given in Table 3-6.

The worst case emissions of PM2.5 for 2025 are only 1.6 tons/year lower than the worst-case 

PM2.5 emissions for 2040 and are higher than the corresponding normal-case emissions for 

2040 by 18.0% (14.6 tons/year). For NOX, the 2025 worst case emissions are both higher than 

the worst case emissions for 2040 by 15.4% (427.4 tons/year) and considerably higher than the 

normal case emissions for 2040 by 36.5% (855.1 tons/year). In addition, demonstration of 

future maintenance of the annual PM2.5 NAAQS is required for a period of ten years following 

the presumed date of redesignation, which should end no later than 2025. Therefore, the 

projected 2025 worst case emissions of 100.0 tons/year for PM2.5 and 3,200.0 tons/year for 

NOX, as rounded to the nearest ―ten‖ with two significant figures then added, are being 

proposed as MVEBs for onroad mobile sources within Hamilton County. Incidentally, the 

projected 2040 worst case emissions for PM2.5 also round to 100.0 tons/year, with the 

subsequent addition of significant figures.

The Chattanooga MPO has concurred that the proposed MVEBs for onroad mobile sources 

within Hamilton County of 100.0 tons/year for PM2.5 and 3,200.0 tons/year for NOX are sufficient 

and acceptable. For comparison, the Georgia EPD has proposed MVEBs for onroad mobile 

sources within Catoosa and Walker Counties combined of 44.2 tons/year for PM2.5 and 1,386.5 

tons/year for NOX.

4.3 Safety Margin Allotments

The safety margin for each applicable pollutant (PM2.5 and NOX) is the quantitative decrease in 

the combined point, area, onroad mobile, and nonroad mobile source emissions from 2007 (the 

attainment year) to 2025. For each pollutant, the amount of the proposed MVEB that exceeds 

the 2025 (normal case) emissions from onroad sources must be provided by the available 

safety margin. The portion of each safety margin that is being allocated for its respective MVEB

is given in Table 4-2, which follows.
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Table 4-2. Safety Margin Allotments to Proposed Motor Vehicle Emissions Budgets for

Onroad Sources in Hamilton County

Proposed 

MVEB

Safety 

Margin

Portion of Safety Margin 

Allocated for Proposed MVEB

Pollutant tons/year tons/year tons/year percentage

PM2.5 100.0 116.4 23.5* 20.2%

NOX 3,200.0 7,890.4 691.3† 8.8%

*100.0 tons/year (proposed MVEB) – 76.5 tons/year (normal 2025 onroad source emissions) = 23.5 tons/year

†3,200.0 tons/year (proposed MVEB) – 2,508.7 tons/year (normal 2025 onroad source emissions) = 691.3 tons/year

Allocating 23.5 tons/year of the PM2.5 safety margin to the proposed MVEB for PM2.5 emissions 

from onroad mobile sources still leaves 92.9 tons/year, or 79.8%, of the safety margin available 

to allow for potential PM2.5 emission increases from other source types. The situation is even 

better for NOX, in which designating 691.3 tons/year of its safety margin to its proposed MVEB 

sets 7,199.1 tons/year, or 91.2%, of the NOX safety margin in reserve for potential increases 

from other sources of NOX emissions.
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5.0 CONCLUSION

This document demonstrates that all requirements have been achieved in order for the 

Tennessee portion (Hamilton County) of the Chattanooga, Tennessee-Georgia, PM2.5

nonattainment area to be redesignated by the U.S. EPA to attainment of the 1997 annual PM2.5

NAAQS as a maintenance area. The U.S. EPA determined, as of May 31, 2011, that the 

Chattanooga area has attained the 1997 annual PM2.5 NAAQS, based on quality-assured and 

certified monitoring data for the 2007–2009 period. Ample evidence is given in this document 

that attainment of the standard is due to permanent and enforceable reductions in emissions of 

PM2.5 and its significant precursors, NOX and SO2. The Bureau’s plan for maintaining 

attainment of the standard within Hamilton County is also presented in the document. This plan 

uses projected emissions to demonstrate future attainment, and it makes use of ambient air 

monitoring and emission inventories to verify continued attainment. Included in the plan are 

contingency measures for emission sources within Hamilton County that can be implemented, if 

necessary, to preclude the maintenance area exceeding the standard or to return the area to 

attainment. In addition, motor vehicle emissions budgets, as required by the U.S. EPA’s 

transportation conformity rule, are contained in this document for onroad mobile source 

emissions of PM2.5 and NOX within Hamilton County.
Appendix A

“Georgia’s Redesignation Request and Maintenance Plan

for the Chattanooga Nonattainment Area for the 1997 PM2.5 NAAQS

for Catoosa and Walker Counties” (narrative)
Appendix B

“Redesignation Request and Maintenance Demonstration

— Jackson County, Alabama

— Chattanooga Annual PM2.5 Nonattainment Area” (narrative)
Appendix C

Annual PM2.5 Design Values and Annual Mean PM2.5 Concentrations

Applicable Portions of PM2.5 Design Value Reports

from www.epa.gov/airtrends/values.html

and www.epa.gov/airtrends/values_previous.html
Appendix D

“Source Apportionment of PM2.5 in Georgia”
Appendix E

Power Plant Emissions Data

Facility Emissions Trends Reports

from the U.S. EPA Clean Air Markets Division

for Widows Creek, Bowen, and Hammond Power Plants
Appendix F

Point Source Emissions Data

Chattanooga-Hamilton County Air Pollution Control Bureau

2003, 2004, 2005, 2006, 2008, 2009, and 2010 Emissions Inventory System Reports
Appendix G

2007 Point Source Emissions Data

2005 National Emissions Inventory (NEI) Download

for Hamilton County, Tennessee – Updated to 2007
Appendix H

Point Source Emission Calculation Spreadsheets
Appendix I

2007 Area Source Emissions Data

2005 National Emissions Inventory (NEI) Download

for Hamilton County, Tennessee – Updated to 2007
Appendix J

2005 Aircraft, Marine, and Railroad Source Emissions Data

2005 National Emissions Inventory (NEI) Download

for Hamilton County, Tennessee
Appendix K

Area Source Emission Calculation Spreadsheets
Appendix L

Onroad Source Input Data

MOVES2010b (Motor Vehicle Emission Simulator) Input Data

for Hamilton County, Tennessee

(provided electronically under folder names:

2007 MOVES Inputs,

2025 w.o. IM MOVES Inputs,

2025 Worst Case w.o. IM MOVES Inputs,

2040 w.o. IM MOVES Inputs,

and 2040 Worst Case w.o. IM MOVES Inputs)
Appendix M

Onroad Source Emissions Data

MOVES2010b (Motor Vehicle Emission Simulator) Output

for Hamilton County, Tennessee
Appendix N

Onroad Source Emission Calculation Spreadsheets
Appendix O

Nonroad Source Emissions Data

NONROAD2008a Emission Inventory Model Output

for Hamilton County, Tennessee
Appendix P

VOC and Ammonia Emissions Data

Applicable Portion of the Particulate Matter (PM) NAAQS Final Rule

Regulatory Impact Assessment

from ftp.epa.gov/EmisInventory/2007v5

(filename: 2007platform_county_sector_emissions_2007re_2020re.zip)
Appendix Q

Point Source Emission Growth Factors

Economic Growth Analysis System (EGAS) Version 5.0 Output

by North American Industry Classification System (NAICS) Codes

for Hamilton County, Tennessee – 2007 Base Year
Appendix R

Area Source Emission Growth Factors

Economic Growth Analysis System (EGAS) Version 5.0 Output

by Source Classification Codes (SCC)

for Hamilton County, Tennessee – 2007 Base Year