DRAFT

Pre-Hearing Draft

Redesignation Request and

Maintenance Demonstration

For

The Tennessee Portion of the 

Chattanooga Tennessee-Georgia

Annual PM2.5 Nonattainment Area

Prepared by:

Chattanooga-Hamilton County Air Pollution Control Bureau

6125 Preservation Drive

Chattanooga, Tennessee 37416-3638

January 16, 2013
Preface: This document contains the technical support for the Chattanooga-Hamilton 

County Air Pollution Control Bureau’s request that Hamilton County Tennessee be 

redesignated to attainment for the annual fine particulate matter national ambient 

standard pursuant to §§ 107(d)(3)(D) and (E) of the Clean Air Act, as amended.
DRAFT

Table of Contents

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

1.0 INTRODUCTION ........................................................................................................ 3

1.1 Maintenance Plan Requirements .............................................................................. 3

1.2 Request for Redesignation........................................................................................ 4

1.3 Description of Fine Particulate ................................................................................. 4

1.4 Clean Air Act Redesignation Criteria....................................................................... 5

Air Quality .......................................................................................................................... 6

2.1 Monitor Locations..................................................................................................... 6

3.0 PERMANENT AND ENFORCEABLE EMISSIONS REDUCTIONS ...................... 8

3.1 Power Plants ............................................................................................................. 8

4.0 EMISSION REDUCTIONS FROM GEORGIA.......................................................... 9

5.0 CONCLUSION AND REQUEST FOR REDESIGNATION.................................... 11

5.1 1990 Clean Air Act Amendment ........................................................................... 11

5.2 Air Quality History ................................................................................................. 11

5.3 Clean Air Act Redesignation Criteria......................Error! Bookmark not defined.

6.0 Air Quality .................................................................................................................. 12

6.1 Air Quality (1999-2009)......................................................................................... 12

6.2 Recent Design Values (2007-2009, 2008-2010 and 2009-2011) ........................... 12

8.0 Maintenance Plan........................................................................................................ 14

8.1 Hamilton County Maintenance Plan....................................................................... 14

8.2 Existing Emissions Controls................................................................................... 15

8.3 Federal Motor Vehicle Standards........................................................................... 15

8.3.1 Tier 2 Passenger Vehicle Standards................................................................. 15

8.3.2 Heavy Duty Gasoline and Diesel Highway Vehicle Standards....................... 15

8.3.3 Large Non-road Diesel Engines Rule .............................................................. 16

8.3.4 Non-road Spark-Ignition Engines and Recreational Engines Standard........... 16

8.4 TRANSPORT RULES ........................................................................................... 16

8.5 ADDITIONAL PROGRAMS SUPPORTING MAINTENANCE......................... 17
9.0 Emissions Inventories and Maintenance Demonstration............................................ 17

9.1.2 Emission Inventories............................................................................................ 17

9.1.3 Safety Margin................................................................................................... 19

10.0 Plan to Maintain Air Quality..................................................................................... 20

List of Tables

Table 2-1 Annual PM2.5 Design Values for all monitors................................12

Table 4-1 2012 SO2 Reductions from Bowen and Hammond Power Plants..........14

Table 4-2 2002 and 2009 SO2 Reductions from Bowen and Hammond Plants......14

Table 4-3 Annual Sulfate Concentration at the Chattanooga Speciation Monitor...15

Table 6-1 FRM Monitors in the Tennessee-North Georgia PM2.5 

Nonattainment Area Annual Mean PM2.5 Concentrations ..................17

Table 9-1 NOx Inventory by Year..............................................................22

Table 9-2 SO2 Inventory by Year...............................................................22

Table 9-3 PM2.5 Inventory by Year..........................................................23

Table 10-4 Safety Margin......................................................................23
List of Figures

Figure 2-1 Locations of Federal Reference Monitors..........................................11
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, TennesseeGeorgia 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. The Alabama portion of the nonattainment 

area contains a coal-fired power plant and a paper plant. Large coal-fired power plants are 

located in Georgia between the nonattainment area and Atlanta. 

The Chattanooga-Hamilton County Air Pollution Control Bureau, the Tennessee Division of Air 

Pollution Control, the Georgia Air Protection Branch, and the Alabama Department of 

Environmental Management have developed PM2.5 National Ambient Air Quality Standard 

(NAAQS) State Implementation Plans (SIP) for each jurisdiction. 

Reductions in PM2.5 precursors and direct PM2.5 resulted in monitor readings that demonstrate 

attainment. 

Monitored PM2.5 Weighted Mean Values (μg/m3

)

For Determination of Design Value

Federal Reference Monitor 2009 2010 2011

Siskin Drive/UTC 

(470654002) 10.5 11.7 11.1

Tombras Avenue

(470650031) 10.5 12.0 11.1

Soddy-Daisy High School

(470651011) 9.5 13.3 10.3

Rossville, Georgia 

(132950002) 10.7 8.7 10.8*

*Did not meet completeness criteria.

This document contains the Chattanooga-Hamilton County’s demonstration under the Federal 

Clean Air Act Amendments of 1990 that the Tennessee portion of the Chattanooga, TennesseeGeorgia PM2.5 Nonattainment Area should be redesignated from nonattainment to attainment 

with respect to the 1997 National Ambient Air Quality Standard (NAAQS) for annual PM2.5

particulate. The nonattainment area consists of Hamilton County in Tennessee, Walker and 

Catoosa Counties in Georgia, as well as the portion of Jackson County in Alabama that is 

described as U.S. 2000 block group identifier 01-071-9503-1.
This area is requesting to be redesignated to attainment for PM2.5. Attainment is based on the 

design values for 2007-2009, for 2008-2010, and for 2009-2011. On May 31, 2011, the 

Environmental Protection Agency published “Approval and Promulgation of Implementation 

Plans and Designations of Areas for Air Quality Planning Purposes; Alabama, Georgia, and

Tennessee: Chattanooga; Determination of Attaining Data for the 1997 Annual Fine Particulate 

Standard”. The Chattanooga Area has attained the 1997 annual average PM2.5. EPA has 

determined that the Tennessee-Georgia, fine particulate (PM2.5) nonattainment area has attained 

the 1997 annual average PM2.5 National Ambient Air Standard. This determination of attainment 

is based upon quality-assured and certified ambient air monitoring data for the 2007-2009 period 

showing that the area has monitored attainment of the 1997 annual PM2.5 NAAQS.
1.0 INTRODUCTION

1.1 Maintenance Plan Requirements

The United States EPA, the State of Tennessee, the State of Georgia, the State of Alabama, and 

the Chattanooga-Hamilton County Air Pollution Control Bureau implemented permanent and 

enforceable reductions in emissions of fine particulate matter, sulfur dioxide, and nitrogen 

oxides. Sulfur dioxide and nitrogen oxides are precursors for PM2.5 particulate matter. These

emissions reductions demonstrate the PM2.5 monitors show attainment with the annual PM2.5 

standard. This document contains the technical support for the Hamilton County Tennessee 

portion of the Chattanooga nonattainment area to be redesignated as an area attaining the 1997

annual fine particulate matter (PM2.5) standard pursuant to Sections 107(d)(3)(D) and (E) of the 

Clean Air Act (CAA) as amended. This redesignation request was prepared in accordance with 

US EPA Guidance issued in 1992 (Memorandum dated September 4 1992 from John Calcagni). 

The United States EPA, Hamilton County Tennessee, the State of Georgia, the State of 

Tennessee, and the State of Alabama have implemented permanent and enforceable reductions in 

fine particulate matter, sulfur dioxide (SO2), and nitrogen oxide (NOx). SO2 and NOx are 

precursors for fine particulate matter. Actions by the Chattanooga-Hamilton County Air 

Pollution Control Bureau, The Tennessee Department of Environmental Quality, the Georgia Air 

Protection Branch, and federal actions have resulted in cleaner air in the PM2.5 nonattainment 

area. The future benefits from these programs are expected to result in continued maintenance of 

the 1997 annual PM2.5 NAAQS. 

The redesignation applies to Hamilton County Tennessee. 

Local measures include the implementation of rules that apply to industrial sources. The state of 

Tennessee implemented an annual motor vehicle inspection and maintenance program. Georgia 

implemented Georgia Rule 391-3-1-.02(2)(SSS) which reduced emissions from power plants. 

Several actions at the federal level contributed to the reductions in PM2.5. The federal effort 

involved reducing the sulfur content of diesel fuel and gasoline, reducing NOx from on-road and 

non-road mobile sources, and reducing power plant emissions. 

The stationary emissions inventory was developed for the 2007 baseline year. The area source 

emissions inventory was also developed for 2007. Future emission inventories were developed 

for years 2010, 2013, 2016, 2019, 2022 and a final emission inventory for 2025. The future 

emissions were less than the 2007 emissions in all cases.

This demonstrates that the PM2.5 nonattainment area is expected to continue to maintain the 1997 

annual PM2.5 NAAQS through 2025 since in no future year emissions are expected to be greater 

than they were in the baseline year. The area is in compliance with Section 110 and Part D 

requirements of the Clean Air Act. INVISTA is subject to a Federal Consent Decree. To comply 

with this requirement, INVISTA has removed their coal fired boilers and now uses natural gas
The backup fuel is now No 2 oil. These changes will reduce 157.015 tons/year of NOx. SO2 

reductions will 502.803tons per year. These reductions are used for the contingency provisions.

1.2 Request for Redesignation 

Based on the information above and criteria established in Section 107(d)(3)(E) of the CAA, 

Tennessee is requesting that the USEPA redesignate the Tennessee portion of the Chattanooga, 

Tennessee-Georgia PM2.5 fine particulate nonattainment area to attainment. The monitoring data 

shows that the region has attained the annual fine particulate matter standard, and the 

maintenance demonstration shows that future emission inventories are expected to be lower than 

the attainment year through the implementation of the various controls discussed in this 

document.

1.3 Description of Fine Particulate

Fine particulate matter, also known as PM2.5, refers to airborne particles less than or equal to 2.5 

micrograms per cubic meters (μgm) 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 and elements. 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 a solid core surrounded by liquid. PM2.5 can include material 

produced by combustion, photochemical reactions, and salt from sea spray and soil like particles. 

Particles are distinguished based on the method of formation. Primary particles are directly 

emitted into the atmosphere and retain the same chemical composition as when they were 

released. Secondary particles are those formed through chemical reactions involving atmospheric 

oxygen, water vapor, hydroxyl radical, nitrates, sulfur dioxide (SO2), oxides of nitrogen (NOx), 

and organic gases from natural and anthropogenic sources. PM2.5 can be composed of varying 

amounts of different species including:

• Sulfate

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

• Ammonium

• Hydrogen ion

• Particle bound water

• Elemental Carbon

• Organic compounds

• Primary organic species (from cooking and combustion)

• Secondary organic compounds

• Crustal Material (includes calcium, aluminum, silicon, magnesium, and iron

• Sea Salt (generally only at costal monitoring sites)

• Transitional metals
• Potassium (generally from wood burning or cooking)

The most significant sources of PM2.5 and its precursors are coal-fired power plants, industrial 

boilers, and other combustion sources. These emissions are often transported over long distances. 

Other sources of PM2.5 emissions include on-road and non-road mobile sources, area sources, 

fires, windblown dust, and biogenic, i.e., naturally occurring emissions such as organics from 

trees.

A variety of meteorological and geographic factors influence the concentration levels of fine 

particles. Regional and local distribution of PM2.5 comes from urbanized areas as primary and 

precursor emissions sources. PM2.5 concentrations can also be high and exceed the national 

ambient air quality standards (NAAQS) for fine particulate at any time of the year. Therefore 

year around monitoring is required. 

In 1997, the USEPA promulgated the annual and daily NAAQS for PM2.5. The annual standard 

was set at 15 micrograms per cubic meter and the daily standard was set at 65 micrograms per 

cubic meter. However, the daily standard has been revised to 35 micrograms per cubic meters. 

The Chattanooga area is in attainment with the revised daily standard and has never been in non 

attainment of the daily standard. 

A violation of the annual PM2.5 standard occurs when the annual average PM2.5 concentration, 

averaged over a three consecutive year period, is equal or greater than 15.1 micrograms per cubic 

meter. The annual PM2.5 design value for a nonattainment area is the highest design value for any 

monitor in that area. 

1.4 Clean Air Act Redesignation Criteria

Since the 1977 amendments of the Clean Air Act (CAA), areas that had not attained the ambient 

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

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

implementation of the PM2.5 standard, areas could be designated under Section 172 of the CAAA 

(Subpart 1) and have five years from designation to attain the standard. The effective date of the 

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

the years 2001, 2002, and 2003. 

Section 107(d)(3)(E) of the CAA, as amended, states that an area can be redesignated to 

attainment if the following conditions are met:

The US EPA has determined that the NAAQS have been attained. For fine particulate matter, the 

area must show that the average of the annual average values from three consecutive calendar 

years of quality-assured air quality monitoring data must be 15 micrograms per cubic meter or 

lower.
The applicable implementation plan has been fully approved by the USEPA under section 

110(k).

The US EPA has determined that the improvement in air quality is due to permanent and 

enforceable reductions in emissions. To demonstrate this, the reduction (from the year used to 

determine the designation and classification) achieved from Federal, State, and local measures.

The State has met all applicable requirements for the area under Section 110 and Part D.

The US EPA has fully approved a maintenance plan, including a contingency plan, for the areas 

under Section 175A.

The following will provide the technical data necessary to show that the Chattanooga area has 

attained and is expected to maintain the annual fine particulate matter standard. This area meets 

the requirements for redesignation as described.

Air Quality

2.1 Monitor Locations

Four PM2.5 federal reference monitors are located in the nonattainment area. Three monitors are 

located in Hamilton County Tennessee and one monitor is located in Walker County Georgia. 

Federal reference monitors (FRM) collect samples that are used to determine if an area is in 

attainment with the PM2.5 NAAQS. A list of the monitors and associated design values are 

shown in Table 1-1. The FRM located at Soddy-Daisy High School is the most rural site of the 

three Hamilton County FRMs and has always shown attainment. The other three monitors 

showed exceedences of the annual standard for the 2001-2003 averaging period, which is the 

period the EPA used in the designation of the nonattainment area. Monitor locations are show in 
Figure 2-1. 

Figure 2-1 Monitor Locations 

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Design values for all monitors are shown below in Table 2-1.

Table 2-1. Design Values for All Monitors for all years

 (EPA Concurred Exceptional Events Excluded)

Monitor 2002-

2004*

2003-

2005

2004-

2006

2005-

2007

2006-

2008

2007-

2009

2008-

2010

2009-

2011

Siskin 

Drive/UTC 

(470654002)

14.7 15.0 15.1 15.3 14.3 12.7 11.6 11.1

Tombras 

Avenue/

East Ridge 

(470650031)

15.7 16.1 15.5 15.3 14.0 12.6 11.6 11.2

Soddy-Daisy 

High School 

(470651011)

13.8 13.8 13.5 13.8 13.0 11.7 11.4 11.0

Walker 

County, GA

(132950002)

15.5 15.5 15.2 15.8 15.2 13.0 10.7 *10.1

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

Design values show attainment with the annual standard for 2007 through 2009, 2008 through 

2010, and 2009 through 2011. 

3.0 PERMANENT AND ENFORCEABLE EMISSIONS REDUCTIONS

In order to meet the standard, permanent and enforceable reductions of precursors for PM2.5 and 

of direct PM2.5 were required. The major precursors of PM2.5 in this area are sulfur dioxide, 

organic carbon, and nitrogen oxides. 

Hamilton County industrial sources base year was 2007. All stationary sources are shown below:

3.1 Power Plants

Area wide power plants are major sources of PM2.5, Nitrates, and Sulfates. Emissions from 

Georgia Power plants are subject to Georgia Rule 391-3-1.02(2)(sss) which require reductions of 

SO2 and NOx as well as direct PM2.5. The closest Tennessee coal-fired power plants are the 

Widows Creek plant and the Kingston Steam plant. These plants are required to control both 

Sulfate and Nitrate PM2.5. 
Industrial sources in the Hamilton County portion of the nonattainment area are subject to at 

least RACT level controls for direct PM2.5 and PM2.5 precursors. Many of the industrial sources 

are subject to requirements of BACT. Industrial sources are regulated by existing local rules, 

Tennessee rules, and federal rules. 

Automobiles and light trucks registered in Hamilton County are subject to the State of Tennessee 

Automobile Inspection and Maintenance Program. This rule requires annual vehicle inspections. 

The Inspection and Maintenance Program insures that high-emitting vehicles are promptly 

repaired so that they meet the emissions standards for the specific vehicle. Annual On-Board 

Diagnostic (OBD) testing is required for model years 2006 and newer. Older vehicles are subject 

to a tail pipe test. Open burning is also restricted by Rule 6 of the Chattanooga Air Pollution 

Control Ordinance. No open burning is allowed between May 1 and September 30. 

The following Federal actions contribute to the improvement in air quality.

Tier 2 vehicle standards: In addition to NOx controls, the Tier 2 rule also reduced the sulfur 

content of gasoline to thirty parts per million (30 ppm) starting in January 2006. Most gasoline 

sold in Tennessee prior to January of 2006 had a sulfur content of about 300 ppm.

Heavy-duty diesel and gasoline vehicle standards: The second phase of standards and testing 

procedures, which began in 2007, will reduce particulate matter from heavy-duty highway 

engines and will reduce highway diesel fuel sulfur content to 15ppm to avoid damage to 

emission control devices. This program is expected to reduce particulate emissions by 90%.

Non-road spark-ignition engine and recreational engine standards: Tier 1 of this standard was 

implemented in 2004 and Tier 2 started in 2007, and will reduce particulate matter emissions. 

Large nonroad diesel engine standards: This standard was promulgated in 2004 and is being 

phased in between 2008 and 2014. This rule will also reduce sulfur content in nonroad diesel 

fuel. When fully implemented, this rule will also reduce NOx and direct PM2.5 emissions by over 

90%.

As on road and non-road vehicles are replaced, emissions from motor vehicles will continue to 

decrease since newer vehicles are subject to more stringent standards than older vehicles. 

The combination of local, state, and federal actions resulted in the monitors demonstrating 

attainment today and in the future.

4.0 EMISSION REDUCTIONS FROM GEORGIA 

Table 4-1 shows the Georgia counties 2012 SO2 emissions for this Area. The Georgia SIP 

showed the following quantities of SO2 emissions from power plants located between Hamilton

County and Atlanta. Georgia Rule 391-3-1-.02(2)(sss) required reductions of SO2 from the 

Bowen and Hammond coal-fired power plants as shown in Table 4-1.
Table 4-1 2002 and 2009 SO2 Reductions from Bowen and Hammond Power Plants in Georgia

Power Plants 2002

SO2 tpy

2009

SO2 tpy

2002-2009

SO2 tpy

Reductions

Bowen 153,848.8 83,349.3 70,499.7

Hammond 30,376.2 1,857.9 28,518.3

Total 184,225.0 85,207.2 99,017.8

The Hammond plant is located 55 miles from the Chattanooga speciation monitor which is 

located at 35.050 degrees north and 85.2929 degrees west. The Bowen plant is located 67 miles 

from the speciation monitor. The speciation monitor is collocated with the Federal Reference 

Monitor at the Siskin Drive/UTC site. 

Effective December, 2008, reductions of SO2 were required by Georgia Rule SSS. Both the 

Hammond and Bowen plants were required to significantly reduce SO2. Reductions in SO2

resulted in reductions of Sulfates. The speciation monitor located at the University of Tennessee 

at Chattanooga at 35.050 degrees north and 85.2929 degrees west shows a decrease in sulfates at 

the University of Tennessee at Chattanooga after the sulfur reductions occurred at the power 

plant.

The Widows Creek Power Plant is located in Jackson County Alabama. The power plant is 28.26

located miles from the speciation monitor. Emissions of SO2 and NOx are as follows:

Table 4-2 Emissions from Widows Creek

2007 2017 2025

SO2 32,803 10,515 10,515

NOx 18,591 3,468 3,607

PM2.5 755.49 534.89 534.89
Table 4-3 Annual Sulfate Concentration at the Chattanooga Speciation Monitor

Year μgram/m3

2006 4.997

2007 5.532

2008 4.266

2009 2.816

2010 2.570

The speciation monitor shows a decrease in concentration of sulfate for 2009 and 2010, 

compared with 2006 and 2007 as a component of PM2.5. All of the FRM monitors also show 

reductions of PM2.5.

5.0 CONCLUSION AND REQUEST FOR REDESIGNATION

Based on the information presented in this document and in criteria established in Section 

107(d)(3)(E) of the Clean Air Act, Tennessee is requesting that USEPA redesignate Hamilton 

County to attainment. The monitors show that this area has attained the standard and the 

maintenance demonstration shows that the future inventories are expected to be lower than the 

attainment year inventory through the implementation of the various national, regional, and local 

efforts.

In 1997, the US EPA promulgated the primary and secondary NAAQS for PM2.5. The annual 

standard was set at 15 micrograms per cubic meter and the daily standard was set at 65 

micrograms per cubic meter. However, the daily standard was revised to 35 μgrams per cubic 

meters. The Chattanooga area is in attainment with the revised daily standard and has never been 

in nonattainment of the daily standard.

A violation of the annual PM2.5 standard occurs when the annual average PM2.5 concentration 

averaged over a three consecutive year period is equal or greater than 15.1 micrograms per cubic 

meter. The annual PM2.5 design value for a nonattainment area is the highest design value for any 

monitor in that area. 

5.1 1990 Clean Air Act Amendment 

Since the 1977 amendments of the Clean Air Act (CAA), areas that had not attained the ambient 

standard, for a particular pollutant were formally designated as nonattainment for that pollutant. 

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

implementation of the PM2.5 standard, areas could be designated under Section 172 of the CAAA 

(subpart 1) and have five years from designation to attain the standard. The effective date of the 

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

the years 2001, 2002, and 2003
5.2 Air Quality History

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

Chattanooga-Tennessee-Georgia area. The 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. Although Jackson County 

is not contiguous to the rest of the nonattainment area, a coal-fired power plant located in this 

census tract is a major contributor to the PM2.5 problem. 

6.0 Air Quality

6.1 Air Quality (1999-2009)

There are 4 Federal Reference Monitors in the nonattainment area. Locations of the monitors in 

the nonattainment area are shown in Figure 2-1. The speciation monitor is 67 miles from the 

Bowen coal-fired power plant and 55 miles from the Hammond coal- fired power plant. The 

speciation monitor is located at the Siskin Drive/UTC site. 

6.2 Recent Design Values (2007-2009, 2008-2010 and 2009-2011)

As shown in Table 2-1, the most recent three year design values of PM2.5 monitoring data (2007-

2009) as well as (2008-2010) demonstrate attainment with the annual fine particulate standard at 

all of the monitors in this nonattainment area.

Permanent and Enforceable Emissions Reductions

Local, State, and Federal measures have been enacted that provide for permanent and 

enforceable emissions reductions to ensure that the PM2.5 will continue to meet the standard at all 

monitors in the area. 

The federal measures that have been implemented include:

• Tier 2 vehicle standards: In addition to NOx controls, the Tier 2 rule also reduced the 

sulfur content of gasoline to 30 parts per million (ppm) starting in January of 2009. Prior to the 

implementation of the low sulfur gasoline, the sulfur content of gasoline was 340 ppm in this 

area. 

• Heavy-duty gasoline and heavy diesel highway vehicles standards: The second phase of 

standards and testing procedures, which will reduce particulate matter from heavy-duty highway 

engines, and will also reduce highway diesel fuel sulfur content to 15 ppm since sulfur damages 
the emissions control devices. The total program is expected to achieve a 90% reduction in 

particle from diesel vehicles. 

• Non-road spark-ignition engines and recreational engine standards: Tier 1 of the standard was 

implemented in 2004 and Tier 2 started in 2007, and will continue to reduce particulate matter 

emissions.

• Large non-road diesel engine standards: Promulgated in 2004, this rule is being phased in 

between 2008 and 2014. The rule will also reduce sulfur content in non-road diesel fuel. When 

fully implemented, this rule will reduce NOx and direct PM2.5 emissions by over 90%. 

Georgia Power Plant Reductions

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

of Electric Steam Generating Units” required the following reductions of NOx and SO2. By 

December 2008 emission controls were required to be installed and operational at the Bowen 

Plant in Bartow County and the Hammond Plant near Rome Georgia. Emissions of SO2 were 

required to be reduced by 92,104 tons per year. An additional reduction of 19,328 tons of SO2 

reductions were achieved during the last 7 months of 2010. Further reductions of SO2 and NOx

will continue through 2015 from Georgia power plants. 

Tennessee Valley Authority

• The Kingston Steam Plant has been equipped with SO2 scrubbers. This scrubber installation 

was operational in 2009 but was not modeled. Additional scrubbers were installed on 9 units in 

2010.

Boiler Changes July 28, 2009 Federal Consent Order for INVISTA

• A Federal Consent order of July 28, 2009 required INVISTA to reduce emissions of SO2 by 

783 tons per year and 167 tons per year of NOx. The reduction was implemented in a 2009 

Consent Decree and has been incorporated in a Title 5 Air Permit issued April 19, 2010.

• To meet the requirements of the consent agreement, INVISTA elected to replace the coal fired 

boilers with natural gas fired boilers. These emissions reductions were not modeled because the 

emissions were not recognized prior to the modeling. These allowable emissions were as 

follows:

2007 SO2 Emissions 566.81 TPY

2007 NOx Emissions 316.67 TPY

2014 SO2 Allowable Emissions 75.889 TPY

2014 NOx Allowable Emissions 151.757 TPY
The 2009 emissions inventory was adjusted to reflect the consent decree requirements to reduce 

SO2 and NOx totals above.

8.0 Maintenance Plan

8.1 Hamilton County Maintenance Plan

Hamilton County Tennessee’s plan for maintaining compliance with the ambient air quality 

standard for fine particulate consists of three components. The Chattanooga Air Pollution 

Control ordinance established local air pollution control rules, and local adoption of existing 

federal requirements. Both Tennessee and Georgia have adopted rules in surrounding 

jurisdictions that are not in Hamilton County which will provide reductions of pollutants that will 

contribute to attainment in both the Tennessee and the Georgia portion of the nonattainment area. 

A maintenance plan and a contingency plan are also in place to insure that attainment is 

maintained. Federal and State rules that are implemented in Tennessee and Georgia that are 

already in effect, as well as the future benefits of the federal engine programs, low sulfur 

gasoline, and low sulfur diesel fuel insure that attainment is maintained. 

The Tennessee Department of Environment and Conservation, the Chattanooga-Hamilton 

County Air Pollution Control Bureau, and the Georgia EPD have implemented enforceable 

requirements as well as contingency measures to ensure that maintenance with the standard will 

continue. Each jurisdiction that has contributed to attainment has developed enforceable rules 

that will ensure that the standard continues to be met. Sources are prohibited from increasing 

emissions (anti-backsliding) following the redesignation of the area unless such a change is first 

approved by USEPA as a revision of the appropriate SIP that is consistent with Section 110(l) of 

the Clean Air Act. 

For the maintenance demonstration, the base year of 2009 was chosen since it falls within the 

attaining design value period of 2007-2009 and emission inventory data was developed for these 

years. The interim years that were chosen were 2010, 2013, 2016, 2019, 2022, and 2025 since 

the USEPA recommends three-year increments. The final year of the maintenance demonstration 

is 2025, since the Clean Air Act requires maintenance for at least ten years after redesignation. 

The maintenance demonstration consists of a comparison between the 2007 baseline emissions 

inventory and the projected emissions inventories (for 2010, 2013, 2016, 2019, 2022, 2025), 

which consider economic and population growth as well as expected controls. The comparison 

shows that the total emissions in each of the interim years and the final year will be lower than 

the base year and therefore demonstrates maintenance of the annual PM2.5 standard. The 

reductions in emissions are due to the emissions control programs discussed.
8.2 Existing Emissions Controls 

The main element of the maintenance plan is the existing emission control program. This 

program implements the controls necessary to maintain the ambient air quality standards.

The purpose of the control program is to maintain the ambient air quality standards from being 

violated. Each component of the control program is essential to maintain the air quality 

standards. 

The control program consists of federal, state, and local measures. The federal measures include 

cleaner fuels, on and off road programs, and controls on power plants. State measures include the 

Tennessee Inspection and Maintenance program, and the CAIR rule. Georgia Air Pollution 

Controls including Georgia Rule SSS which requires reductions of NOx and SO2. Local measures 

include open burning restrictions, gasoline station requirements for Stage 1 Vapor Recovery, 

VOC limiting rules, NOx limiting rules, and SO2 limits. All of these programs have been 

implemented.

8.3 Federal Motor Vehicle Standards

8.3.1 Tier 2 Passenger Vehicle Standards

Federal Tier 2 vehicle standards require all passenger vehicles in a manufacture’s fleet, including 

light-duty trucks and sport utility vehicles (SUVs) to meet an average standard of 0.07 grams per 

NOx. Implementation began in 2004, with full compliance required by 2007. Tier 2 Standards 

also apply to passenger vehicles over 8,500 pounds gross vehicle weight that are not covered by 

Tier 1 rules. For these vehicles, the standards were phased in beginning in 2008 with full 

compliance required by 2009. Sulfur in gasoline has also been reduced from approximately 350 

ppm to 30 ppm starting in January 2006. Lower sulfur gasoline is necessary to achieve the Tier 2 

vehicle emission standards. 

8.3.2 Heavy Duty Gasoline and Diesel Highway Vehicle Standards

Implementation of USEPA standards designed to reduce NOx and VOC emissions from heavyduty gasoline and diesel vehicles began in 2004. The second phase of the standards and testing 

procedures began to take effect in 2007 and reduces particulate from heavy duty highway 

engines. Diesel fuel with a sulfur content of 15 ppm will be required for these vehicles. Use of 

the new low sulfur diesel fuel compared to emissions from engines using diesel fuel with higher 

sulfur levels will achieve a 90% reduction in PM emissions and a 95% reduction in NOx

emissions.
8.3.3 Large Non-road Diesel Engines Rule 

In May 2004, the USEPA promulgated new rules for large non-road diesel engines, such as those 

used in construction, agricultural, and industrial equipment, to be phased in between 2008 and 

2014. The non-road diesel rules also reduce the allowable sulfur in non-road diesel fuel by more 

than 99%. Prior to the fuel standard change, nonroad diesel fuel averaged about 3400 ppm sulfur. 

The rule limited nonroad diesel fuel sulfur content to 500 ppm by 2006 and requires the sulfur 

content to be limited to 15 ppm by 2010. The combined engine and fuel rules are expected to 

reduce NOx and PM emissions from large nonroad diesel engines by more than 90% compared 

to current nonroad engines using higher-content sulfur diesel.

8.3.4 Non-road Spark-Ignition Engines and Recreational Engines Standard

The non-road spark-ignition and recreational engine standards, effective in July 2003, regulates 

NOx, hydrocarbons and CO for groups of previously unregulated nonroad engines. These 

standards apply to all new engines sold in the United States and imported after these standards 

began and applies to large spark-ignition engines (forklifts and ground service equipment) 

recreational vehicles (off-highway motorcycles and all terrain vehicles) and recreational marine 

diesel engines. The regulation varies based upon the type of engine or vehicle. 

Emissions from large spark-ignition engines contribute to ozone formation and ambient CO and 

PM levels in urban areas. Tier 1 of this standard was implemented in 2004 and Tier 2 started in 

2007. Like the large spark-ignition engines, recreational vehicles contribute to ozone formation 

and ambient CO and PM levels. For the off-highway motorcycles and all-terrain-vehicles, the 

exhaust emissions standard was phased in. Fifty percent of model year 2006 engines had to meet 

the standard. All engines from model year 2007 and newer must meet the standard. Recreational 

marine diesel engines over 37 kilowatts are used in yachts, cruisers, and other types of pleasure 

craft. Recreational marine engines contribute to ozone formation and PM levels, especially in 

marinas. Depending on the size of the size of the engine, the standard began phasing-in in 2006. 

When all of the nonroad spark-ignition and recreational engine standards are fully implemented, 

an overall 72% reduction in HC, 80% reduction in NOx, and a 56%reduction in CO emissions are 

expected by 2020. These controls will help reduce ambient concentration of ozone, CO, and 

PM2.5

8.4 TRANSPORT RULES

In October 1998, the USEPA made a finding of significant contribution of NOx emissions from 

Tennessee and other South Eastern States and published a rule that set ozone season (May to 

September) NOx budgets to reduce regional ozone transport. Reductions of NOx, which is a PM2.5

precursor, were 59,414 tons per ozone season in Tennessee between 2003 and 2005.
8.5 ADDITIONAL PROGRAMS SUPPORTING MAINTENANCE

The Chattanooga Air Pollution Control Ordinance prohibits open burning between May 1 and 

September 30 and when air quality is forecasted to be Code Orange or higher.

Pollution Solution is a public outreach and education program of the Hamilton County Air 

Pollution Control Bureau. The goal of the program is to reduce air pollution by voluntary 

actions. The program is activated when the Air Quality Index is predicted to be greater than 100. 

On air quality alert days, information is sent to more than 80 individuals, government employees, 

daycares, gyms, hospitals, health care facilities, schools and police and fire departments. 

Information is communicated to 6 TV stations, 21 radio stations and 4 print publications. In 

addition, 15 billboards are located throughout the county to make people aware of high levels of 

ozone and PM2.5

Through the Chamber of Commerce, and the Chattanooga Manufacturing Association employers 

also are notified of high pollution levels. 

9.0 Emissions Inventories and Maintenance Demonstration

To demonstrate continued maintenance the projected emissions inventory is compared to the 

baseline emissions inventory. The approach used for this demonstration is the comparison of 

emissions inventories for the years 2007 and 2025. 

For the maintenance demonstration, the base year of 2007 was chosen and emissions inventory 

data was developed for this year. The maintenance demonstration is made by comparing the 

2007 emissions inventory to the 2025 projected emissions inventory. If the projected emissions 

remain at or below baseline emissions, then the ambient air quality standard will not be violated 

in the future. In addition to comparing the final year of the plan, all of the interim years are 

compared to the 2007 baseline to demonstrate that these years are also expected to show 

continued maintenance of the fine particulate matter standard. 

Section 175A(d) of the Clean Air Act requires contingency provisions. The contingency 

provisions are available to provide 157 tons per year and for 503 tons per year.

The emissions inventories are comprised of four major types of sources: point, area, on-road 

mobile, and nonroad mobile. The projected emissions inventories have been estimated using 

projected rates of growth in population, traffic, economic activity, expected control programs, 

and other parameters. Naturally occurring, or biogenic, emissions are not included in the 

emissions inventory comparison, as these emissions are out of the agency span of control.

9.1 Emission Inventories and Motor Vehicle Emissions Budget

The baseline year is 2007. Three year emissions were developed for 2007(baseline), 2010, 2013, 

2016, 2019, 2022, and 2025. 
Stationary source emissions were grown using EGAS 5.0 factors. EGAS factors were also used 

for area sources. Nonroad emissions were derived from running the nonroad model. 

There are four different man-made emission inventory classifications: (1) stationary point, (2) 

area, (3) on road mobile and (4) nonroad mobile sources. 

Stationary Point sources are those sources that require an air permit to operate. In general, these 

sources have a significant potential to emit NOx, PM2.5, and SO2 from a single facility. The 

source emissions are tabulated from data collected by direct measurement of emissions or mass 

balance calculation utilizing emission factors from the USEPA’s AP-42 or other calculation 

methods. Several emission sources are often located at an industrial facility. Emissions data is 

collected for each point source at a facility and the data is entered into an in-house database 

system.

Area Sources are facilities that are smaller sources such as dry cleaners, automobile repair 

facilities, small machine shops etc. The facility usually totals the facilities. 

Nonroad road sources are construction equipment, railroads, boats, lawn equipment, etc. Most 

nonroad equipment emissions are calculated from the non-road model. EPA Nonroad2008 is the 

current EPA nonroad model. The model is EPA-420-F-09-F-09-021 dated 2009. 

MOVES 2010b is the current version of MOVES EPA model dated March 2012. The MPO 

provided inputs to the MOVES model. 

The following shows emissions from Point Sources, Area Sources, Nonroad Sources, and 

Onroad sources for NOx, and PM2.5. The SO2 is less than 60 tons per year in any year. Also SO2 

continues to decrease each year. By 2025, SO2 shows only 20 tons per year. 

Table 9-1

Projected NOX (tons/year)

2007 2010 2013 2016 2019 2022 2025

Point 2,437 2,484 2,576 2,651 2,812 2,982 3,155

Area 3,415 3,638 3,835 4,090 4,349 4,609 4,881

Nonroad 1,792 1,563 1,264 1,003 834 731 675

Onroad 8,308 7,390 6,472 5,554 4,635 3,717 2,799

Total 15,952 15,075 14,147 13,297 12,629 12,039 11,509
Table 9-2

Projected SO2 (tons/year)

2007 2010 2013 2016 2019 2022 2025

Point 919 798 808 798 819 842 866

Area 333 347 363 383 401 421 441

Nonroad 99 26 15 14 15 15 16

Onroad 59 54 49 43 38 33 28

Total 1,410 1,224 1,235 1,238 1,273 1,311 1,350

Table 9-3

Projected PM2.5 (tons/year)

2007 2010 2013 2016 2019 2022 2025

Point 160 156 158 169 181 193 206

Area 875 917 956 1,001 1,043 1,084 1,122

Nonroad 154 142 124 101 82 70 64

Onroad 255 229 203 117 151 124 98

Total 1,444 1,443 1,440 1,448 1,456 1,472 1,490

Safety Margin

A safety margin is the difference between the attainment level of emissions from all categories 

(i.e., point, area, onroad mobile, nonroad) and the projected level of emissions from all source 

categories. The safety margins are as shown in Table 9-4.

Table 9-4

Safety Margin (tons/year)

Year NOX SO2 PM2.5

2007 15,952 1,410 1,444

2010 15,075 1,224 1,443

2013 14,147 1,235 1,440

2016 13,297 1,238 1,448

2019 12,629 1,273 1,457

2022 12,039 1,311 1,472

2025 11,509 1,350 1,490

Differences from 

2007 to 2025 

(Safety Margin) 4,443 60 46
The projected NOX emissions reduction is 4,443 tons from 2007 to 2002. In addition, overall 

SO2 emissions are projected to decrease by 60 tons for this period, and the slight projected 

increase in PM2.5 emissions over this period is 46 tons.

10-1 Motor Vehicle Emissions Budget

Pursuant to the EPA transportation conformity rule at 40 CFR Part 93, specific emission budgets 

are hereby defined for the on-road mobile source portion of the emissions inventory. These 

budgets are to be used by the transportation authorities to assure that transportation plans,

programs, and projects are consistent with, and conform to, the maintenance of acceptable air 

quality in the Hamilton County maintenance plan is 2025. Motor Vehicle Emissions Budgets 

(MVEB) for 2007 and 2025 will be set for PM2.5 and NOx by the Air Pollution Board.

Table 10-1

Total Motor Vehicle Emissions 

In tons per year

2007 2025

NOx 8308 2799

PM2.5 255 98

The MVEB reflects the total on-road emissions for the MVEB years 2007 and 2025, plus an 

allocation from the available NOx and PM2.5. The Air Pollution Control Board will determine 

Mobile Vehicle Emissions budgets. A portion of the safety margin may be allocated for 

transportation emissions.

The MVEB are consist with the plan for maintaining total emissions from all source categories 

at or below the 2007 NOx and PM2.5 emissions levels through the year 2025. For future 

conformity determinations, transportation authorities should rely on the above MVEB unless the 

maintenance plan is revised. 

10-2 Contingency Measures

The contingency requirement is met by replacing the coal boilers with natural gas boilers that 

will use No. 2 fuel oil as a backup. The new boilers are projected to reduce the NOX and SO2

emissions by 157.0 tons per year and 502.8 tons per year. The new boilers are projected to emit 

37.0 tons per year of NOX and 27.2 tons per year of SO2. These are surplus and available to use 

for use as the contingency measure. 

10-3 Plan to Maintain Air Quality

The Chattanooga-Hamilton County Air Pollution Control Bureau, the state of Alabama, the state 

of Georgia, and the state of Tennessee have implemented programs that will remain enforceable 

and are submitted as the plan to ensure that maintenance of the annual PM2.5 standard will 
continue. Sources are prohibited from reducing emission controls (“anti-backsliding”) following 

the redesignation of the area unless such a change is first approved by the EPA as a revision to 

the Hamilton County SIP, the state of Alabama SIP, the state of Georgia SIP, and the state of 

Tennessee that is consistent with Section 110(l) of the CAA. 

The following regulatory programs will remain in place in the Chattanooga Non-attainment 

Area:

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 Ordince

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

Federal Tier II Motor Vehicle Emissions Standards

Federal On-road Diesels Engine Diesel Engine Standards

Federal Non-road Diesel Engine Standards

Federal Marine Engine Requirements

Federal Locomotive Requirements 

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

The Federal NOx SIP Call
Georgia Rules for Air Quality Control Chapter 391-3-1 Rule (sss) “

Multipollutant Control of 

Electric Steam Generating Units”

The federal facilities compliance agreement between EPA and the Tennessee Valley Authority, 

Docket No. CAA-04-2010-1760 requiring TVA Widows Creek to retire Units 1-6. The 

compliance dates for this action are staggered as follows:

2 units by July 31, 2013;

2 units by July 31, 2014;

2 units by July 31, 2015.

The overall expected reductions are 15,111 tons per year of NOx and 28,192 tons per year of 

SO2. The consent decree further required year-round operation of the SCRs on Units 7 and 8.