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Ohio

Area Designations for the

2008 Ozone National Ambient Air Quality Standards

SUMMARY

The table below identifies the areas and associated counties in 

Ohio that EPA intends to designate as nonattainment for the 2008 

ozone National Ambient Air Quality Standards (NAAQS).1

 In 

accordance with section 107(d) of the CAA, EPA must designate an 

area (county or part of a county) as “nonattainment” if it is 

violating the 2008 ozone NAAQS or if it is contributing to a 

violation of the 2008 ozone NAAQS in a nearby area. The 

technical analyses supporting the boundaries for the 

nonattainment areas are provided below.

Table 1. Intended Ozone Nonattainment Areas in Ohio

Area Ohio Recommended 

Nonattainment Counties

EPA’s Intended 

Nonattainment Counties

Nonattainment Areas †

Cincinnati-MiddletownWilmington, OH-KY-IN ‡Butler

Clermont

Clinton

Hamilton

Warren

Butler

Clermont

Clinton

Hamilton

Warren

Cleveland-Akron-Lorain, 

OH

Ashtabula

Cuyahoga

Geauga

Lake

Lorain

Medina

Portage

Summit

Ashtabula

Cuyahoga

Geauga

Lake

Lorain

Medina

Portage

Summit

Columbus, OH Delaware

Fairfield

Franklin

Knox

Licking

Madison

Delaware

Fairfield

Franklin

Knox

Licking

Madison

 1 The primary 8-hour hour ozone standard, set to protect human health, was 

revised on March 27, 2008 (73 FR 16436) from 0.08 parts per million (ppm) to 

0.075 ppm. The secondary ozone standard, set to protect human welfare and 

the environment, was revised to be consistent with the primary ozone standard 

in all respects. 
2

† Nonattainment for both primary and secondary 2008 8-hour 

ozone standards.

‡ Cincinnati-Middletown-Wilmington, OH-KY-IN is a multi-state 

nonattainment area. Table 2 below identifies the counties 

in Ohio and in other states that EPA intends to designate 

as part of the nonattainment area.

EPA intends to designate the remaining counties in Ohio that are 

not listed in Table 1 above as “unclassifiable/attainment” for 

the 2008 ozone NAAQS.

The analysis below provides the basis for the intended 

nonattainment area boundaries. It relies on our analysis of 

whether and which monitors are recording violations of the 2008 

ozone NAAQS, based on certified air quality monitoring data from 

2008-2010 and on an evaluation of whether nearby areas are 

contributing to such violations. EPA has evaluated 

contributions from nearby areas based on a weight-of-evidence 

analysis considering the factors identified below. EPA issued 

guidance on December 4, 2008 that identified these factors as 

ones EPA would consider in determining nonattainment area 

boundaries, and recommended that states consider these factors 

in making their designation recommendations to EPA.2

1. Air quality data (including the ozone design value 

calculated for each Federal Reference Method (FRM) or 

Federal Equivalent Method (FEM) monitor in the area);

2. Emissions and emissions-related data (including location of 

sources, population, amount of emissions and emission 

controls, and growth patterns);

3. Meteorology (weather/transport patterns);

4. Geography and topography (mountain ranges and other basin 

boundaries affecting ozone levels and ozone precursor 

transport); and,

5. Jurisdictional boundaries (e.g. counties, air districts, 

existing ozone nonattainment areas, Indian country, 

 2 The December 4, 2008 guidance memorandum, “Area Designations for the 2008 

Revised Ozone National Ambient Air Quality Standards,” refers to 9 factors. 

In this technical support document, we have grouped the emissions-related 

factors together under the heading of “Emissions-Related Data,” which results 

in 5 categories of factors.
3

Metropolitan Planning Organization (MPOs) and their covered 

area).

Ground-level ozone is generally not emitted directly into the 

air, but is created by chemical reactions involving Nitrogen 

Oxides (NOx) and Volatile Organic Compounds (VOC) in the 

presence of sunlight.3

 Because NOx and VOC emissions from a 

broad range of sources over a wide area typically contribute to 

violations of the ozone standards, EPA believes it is important 

to consider whether there are contributing emissions from a 

broad geographic area. Accordingly, EPA chose to examine the 5 

factors with respect to the larger of the Combined Statistical 

Area (CSA) or Core Based Statistical Area (CBSA) associated with 

the violating monitor(s).4 All data and information used by EPA 

in this evaluation are the latest available to EPA and/or 

provided to EPA by states or tribes.

In EPA’s designations guidance for the 2008 ozone NAAQS, EPA 

recommended examining CSA/CBSAs because certain factors used to 

establish CSAs and CBSAs are similar to the factors EPA is using 

in this technical analysis to determine if a nearby area is 

contributing to a violation of the 2008 ozone NAAQS. Congress 

required a similar approach in 1990 for areas classified as 

serious and above for the 1-hour ozone standard and EPA used the 

same approach in the designation process for the 1997 ozone 

NAAQS. Where a violating monitor is not located in a CSA or 

CBSA, EPA’s September 4, 2008 guidance recommends using the 

boundary of the county containing the violating monitor as the 

starting point for considering the nonattainment area’s 

boundary.

Technical Analysis for Cincinnati-Middletown-Wilmington, OH-KYIN

Figure 1 is a map of the Cincinnati-Middletown-Wilmington, OHKY-IN intended nonattainment area. The map provides other 

relevant information, including the locations and ozone design 

values (violating monitors only) of air quality monitors, county 

and other jurisdictional boundaries, existing maintenance 

boundary for the 1997 ozone NAAQS, Cincinnati-Middletown-

 3 Peak ozone concentrations generally occur downwind of source areas on 

relatively sunny days with high temperatures and relatively low wind speeds.

4 Lists of CBSAs and CSAs and their geographic components are provided at 

www.census.gov/population/www/metroareas/metrodef.html. The lists are 

periodically updated by the Office of Management and Budget. EPA used the 

most recent update, based on 2008 population estimates, issued on December 1, 

2009 (OMB Bulletin No. 10-02).
4

Wilmington, OH-KY-IN CSA boundary, and major transportation 

arteries. 

Figure 1. Cincinnati-Middletown-Wilmington, OH-KY-IN Area

For purposes of the 1997 ozone NAAQS, as noted in Figure 1, 

portions of this area were designated nonattainment and 

subsequently redesignated to attainment (maintenance). The 

boundary for the nonattainment area for the 1997 ozone NAAQS 

included the entire counties of Butler, Clermont, Clinton, 

Hamilton, and Warren in Ohio and Boone, Campbell, and Kenton in 

Kentucky and part of Dearborn County (Lawrenceburg Township) in 

Indiana.

In March 2009, Ohio recommended that Butler, Clermont, Clinton, 

Hamilton, and Warren Counties be designated as “nonattainment” 

for the 2008 ozone NAAQS based on air quality data from 2006-

2008. In March 2009, Kentucky recommended that Boone, Campbell, 

and Kenton Counties be designated as nonattainment for the 2008 

ozone NAAQS based on air quality data from 2006-2008. 
5

Additionally, Indiana, in March 2009, recommended that each 

county in the Indiana portion of the Cincinnati-MiddletownWilmington, OH-KY-IN CSA be designated as “attainment” for the 

2008 ozone NAAQS. In October 2011, Kentucky submitted an update 

to their 2009 recommendation, and revised their recommendation 

to “attainment” designations for each county in the State.5

The ozone data reflected in Figure 1 and summarized below are 

from FEM monitors sited and operated in accordance with 40 CFR 

part 58.

After considering these recommendations and based on EPA’s 

technical analysis described below, EPA intends to designate the 

counties in Ohio and Kentucky and the partial county in Indiana 

identified in Table 2 below as “nonattainment” for the 2008 

ozone NAAQS as part of the Cincinnati-Middletown-Wilmington, OHKY-IN nonattainment area.

Table 2. EPA’s Intended Nonattainment Counties for the 

Cincinnati-Middletown-Wilmington, OH-KY-IN Ozone Nonattainment 

Area

Cincinnati-MiddletownWilmington, OH-KY-INState-Recommended 

Nonattainment Counties

EPA Intended 

Nonattainment Counties

Indiana None Dearborn-Partial

Kentucky None Boone

Campbell

Kenton

Ohio Butler

Clermont

Clinton

Hamilton

Warren

Butler

Clermont

Clinton

Hamilton

Warren

Factor Assessment

Factor 1: Air Quality Data

 5 Letters from Leonard K, Peters, Kentucky Energy and Environmental Cabinet 

Secretary to A. Stanley Meiburg and Gwendolyn Keyes Fleming regarding the 

initial and updated nonattainment boundary recommendations for the 2008 8-

hour ozone standard for Kentucky(October 13, 2011 and March 12, 2009, 

respectively); Letter from Chris Korleski, Director, State of Ohio 

Environmental Protection Agency, to Lynn Buhl, Regional Administrator, U.S. 

Environmental Protection Agency, Region 5, regarding initial nonattainment 

boundary recommendations for Ohio for the 2008 ozone NAAQS (March 9, 2009); 

Letter from Thomas W. Easterly, Commissioner, Indiana Department of 

Environmental Management, to Bharat Mathur, Deputy Regional Administrator, 

U.S. Environmental Protection Agency, Region 5, regarding the initial 

nonattainment boundary recommendations for the 2008 ozone NAAQS for Indiana. 
6

For this factor, we considered 8-hour ozone design values (in 

ppm) for air quality monitors in counties in the CincinnatiMiddleton-Wilmington, OH-KY-IN CSA based on data for the 2008-

2010 period, which are the most recent years with fullycertified air quality data. A monitor’s design value is the 

metric or statistic that indicates whether that monitor attains 

a specified air quality standard. The 2008 ozone NAAQS are met 

at a monitor when the annual fourth-highest daily maximum 8-hour 

ozone concentrations, averaged over 3 years is 0.075 ppm or 

less. A design values is valid only if minimum data 

completeness requirements are met. See 40 CFR part 50 Appendix 

P. Where several monitors are located in a county (or a 

designated nonattainment area or maintenance area), the design 

value for the county or area is determined by the monitor with 

the highest individual design value.

Note: Monitors that are eligible for providing design value data 

generally include State and Local Air Monitoring Stations 

(SLAMS) that are sited in accordance with 40 CFR Part 58, 

Appendix D (Section 4.1) and operating with a Federal Reference 

Method (FRM) or Federal Equivalent Method (FEM) monitor that 

meets the requirements of 40 CFR Part 58, Appendix A. All data 

from a Special Purpose Monitor (SPM) using an FRM or FEM which 

has operated for more than 24 months is eligible for comparison 

to the NAAQS unless the monitoring agency demonstrates that the 

data came from a particular period during which the requirements 

of Appendix A (quality assurance requirements) or Appendix E 

(probe and monitoring path siting criteria) were not met.

The 2008-2010 ozone design values for monitors and counties in 

the Cincinnati-Middletown-Wilmington, OH-KY-IN CSA are shown in 

Table 3.

Table 3. Ozone Air Quality Data for the Cincinnati-MiddletownWilmington, OH-KY-IN CSA

State/County Site Number 2008-2010 

8-hour 

Ozone 

Design 

Values 

(ppm)

Ohio:

Butler 390170018 0.078†

Butler 390170004 0.073

Clermont 390250022 0.071

Clinton 390271002 0.074

Hamilton 390610040 0.076†

Hamilton 390610010 0.073
7

Hamilton 390610006 0.079†

Warren 391650007 0.078†

Kentucky:

Boone 210150003 0.065

Campbell 210373002 0.072

† Monitored violation of the 2008 ozone NAAQS.

Butler, Hamilton, and Warren Counties in Ohio show violations of 

the 2008 ozone NAAQS. Therefore, these counties are included in 

the intended ozone nonattainment area. A county (or partial 

county) must also be designated nonattainment if it contributes 

to a violation in a nearby area. Each county without a 

violating monitor that is located near a county with a violating 

monitor has been evaluated based on the weight-of-evidence of 

the five factors and other relevant information to determine 

whether it contributes to the nearby violation.

Please note that the state of Ohio, in its March 9, 2009 area 

designation recommendations and accompanying technical support 

documentation, based its recommendations on 2006-2008 ozone 

data. Since these data no longer cover the most recent 3-year 

period with quality-assured, state-certified data and have been 

supplanted by the more current 2008-2010 ozone data, we are not 

reviewing the older ozone data covered by the state of Ohio.

Factor 2: Emissions and Emissions-Related Data

EPA evaluated emissions for ozone precursors (VOC and NOx) and 

other emissions-related data that provide information on area 

contributions to ozone standard violations.

Emissions Data

EPA evaluated county-level emission data for NOx and VOC derived 

from the 2008 National Emissions Inventory (NEI), version 1.5. 

These are the most recently available NEI emissions data. (See 

http://www.epa.gov/ttn/chief/net/2008inventory.html) 

Significant emission levels in a nearby area indicate the 

potential for the area to contribute to the observed ozone 

standard violation. 

Table 4 shows the 2008 emissions of VOC and NOx (tons per year 

(tpy)) for all counties in the Cincinnati-Middletown-Wilmington, 

OH-KY-IN CSA. This table also indicates which of the counties 

were recommended to be nonattainment for the 2008 ozone NAAQS by 

their respective states.
8

Table 4. Total 2008 VOC and NOx Emissions (tons/year) in the 

Cincinnati-Middletown-Wilmington, OH-KY-IN CSA

State/County State Recommended 

Nonattainment?

VOC Emissions

(tpy)

NOx Emissions

(tpy)

Indiana:

Dearborn No 3,572 11,637

Franklin No 1,097 862

Ohio No 210 259

Kentucky:

Boone No 4,332 8,848

Bracken No 361 760

Campbell No 2,260 2,697

Gallatin No 671 1,634

Grant No 1,148 1,623

Kenton No 3,901 4,095

Pendleton No 608 1,394

Ohio:

Brown No 1,720 1,430

Butler Yes 10,813 12,600

Clermont Yes 5,809 28,461

Clinton Yes 2,618 2,941

Hamilton Yes 26,816 38,664

Warren Yes 5,618 6,027

CSA Total 71,554 123,933

Emissions Observations By State

Ohio:

From the Ohio emissions data in Table 4, it can be seen that 

comparatively high 2008 VOC and NOx emissions in the vicinity of 

the violating counties originate in the following counties: 

Butler, Clermont, Hamilton, and Warren. Emissions from these 

counties in 2008 account for 68.6 percent of the VOC emissions 

and 69.2 percent of the NOx emissions for the entire CincinnatiMiddletown-Wilmington, OH-KY-IN CSA. 

The VOC and NOx emissions from Brown and Clinton Counties, Ohio 

are significantly smaller than those originating in the higher 

emitting counties elsewhere in the Cincinnati-MiddletownWilmington, OH-KY-IN CSA. This supports the exclusion of Brown 

County from the recommended ozone nonattainment area for the 

2008 8-hour ozone NAAQS, but not the exclusion of Clinton County 

based on consideration of jurisdictional boundaries (see the 

discussion of Factor 5 below).

Indiana:
9

From the Indiana emissions data in Table 4, it can be seen that 

comparatively high 2008 VOC and NOx emissions in the vicinity of 

the violating counties originate from Dearborn County. 

Emissions from this county in 2008 account for 5.0 percent of 

the VOC emissions and 9.4 percent of the NOx emissions for the 

entire Cincinnati-Middletown-Wilmington, OH-KY-IN CSA. The 

majority of these emissions come from the American Electric 

Power (AEP) - Tanner’s Creek Generating Station located in the 

Lawrenceburg Township, adjacent to the recommended nonattainment 

area. 

The VOC and NOx emissions from Franklin and Ohio Counties in 

Indiana are comparatively smaller than those originating in the 

higher emitting counties elsewhere in the Cincinnati-MiddletownWilmington, OH-KY-IN CSA. This supports the exclusion of these 

counties from the recommended ozone nonattainment area for the 

2008 8-hour ozone NAAQS.

Kentucky:

Based on the 2008 NEI, 62 percent of Boone County’s NOx 

emissions are from point sources, and 21 percent of Boone 

County’s NOx emissions from mobile sources. Less than 5 percent 

of Campbell County’s NOx emissions are from point sources, and 

57 percent of Campbell County’s NOX emissions are from mobile 

sources. Kenton County also has less than 5 percent of its NOx 

emission from point sources, but 63 percent of Kenton County’s 

NOX emissions are from mobile sources. Boone County has 29 

percent of its VOC emission coming from area sources and 23 

percent of its VOC emissions from mobile sources. Campbell 

County has 35 percent of its VOC emissions coming from area 

sources and 43 percent of VOC emissions from mobile sources. 

Kenton County has 38 percent of its VOC emission coming from 

area sources and 41 percent of its VOC emissions from mobile 

sources. 

The VOC and NOx emissions from Bracken, Gallatin, Grant, and 

Pendleton Counties, Kentucky are considerably less than those 

originating in the higher emitting counties elsewhere in the 

Cincinnati-Middletown-Wilmington, OH-KY-IN CSA. This would 

support the exclusion of these counties from the recommended 

ozone nonattainment area for the 2008 8-hour ozone NAAQS.

Population, Population Density, and Degree of Urbanization

EPA evaluated the population and vehicle use characteristics and 

population trends of the area as indicators of the probable 
10

location and magnitude of non-point source emissions. These 

include ozone-creating emissions from on-road and off-road 

vehicles and engines, consumer products, residential fuel 

combustion, and consumer services. Areas of dense population or 

commercial development are an indicator of area source and 

mobile source NOx and VOC emissions that may contribute to 

violating ozone monitors. Rapid population or Vehicle Miles 

Traveled (VMT) growth in a county on the urban perimeter 

signifies increasing integration with the urban core area, and 

indicates that it may be appropriate to include this county in 

the ozone nonattainment area, particularly if this county 

already has moderate or higher VOC and/or NOx emissions. Table 

5 shows the 2010 population, population density, and population 

growth information for each county in the Cincinnati-MiddletownWilmington, OH-KY-IN CSA.

Table 5. Population and Population Growth in the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA

State/County State 

Recommended 

Nonattainment

2010 

Population

2010 

Population 

Density

(1,000 per 

square 

mile)

Change in 

Population 

(2000-

2010)

Population 

Percent 

Change 

(2000-

2010)

Indiana:

Dearborn No 50,047 0.16 3,702 +8

Franklin No 23,087 0.06 866 +4

Ohio No 6,128 0.07 492 +9

Kentucky:

Boone No 118,811 0.46 31,811 +37

Bracken No 8,488 0.04 211 +3

Campbell No 90,336 0.57 1,680 +2

Gallatin No 8,589 0.08 705 +9

Grant No 24,662 0.09 2,115 +9

Kenton No 159,720 0.97 8,032 +5

Pendleton No 14,877 0.05 389 +3

Ohio:

Brown No 44,846 0.09 2,263 +5

Butler Yes 368,130 0.78 34,447 +10

Clermont Yes 197,363 0.43 18,733 +10

Clinton Yes 42,040 0.10 1,378 +3

Hamilton Yes 802,374 1.94 -41,916 -5

Warren Yes 212,693 0.52 52,006 +32

Area-wide 2,172,191 0.45 116,914 +6

Sources: U.S. Census Bureau population estimates for 2010 as of 

August 4, 2011. 

(http://factfinder2.census.gov/faces/tableservices/jsf/pages/pro

ductview.xhtml?pid=DEC_10_PL_GCTPL2.STO5&prodType=table)
11

Population Observations By State

Ohio:

For Ohio, the population data show that Butler, Clermont, 

Hamilton, and Warren Counties have comparatively large 

populations and population densities and are densely populated. 

This implies that the population-related VOC and NOx emissions 

in these counties are relatively high. In addition, the 

population change percentages in Butler, Clermont, and Warren 

Counties between 2000 and 2010 exceed the population change 

percentage for the entire Cincinnati-Middletown-Wilmington, OHKY-IN area, implying that the population-related emission 

contributions from these counties are increasing compared to 

those from other counties in the Cincinnati-MiddletownWilmington, OH-KY-IN area.

Indiana:

The populations of the Indiana counties in the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA are smaller than those of 

the Ohio counties and larger Kentucky counties in this CSA, but 

Dearborn County has a moderate population implying moderate 

population-related VOC and NOx emissions. In addition, the 

population change percentage change from 2000 to 2010 in 

Dearborn County is greater than the population change percentage 

for the entire Cincinnati-Middletown-Wilmington, OH-KY-IN CSA, 

implying that the population-related emission contribution from 

this county may be increasing relative to those from other 

counties in the Cincinnati-Middletown-Wilmington, OH-KY-IN area. 

Ohio County, Indiana also has a greater population change 

percentage as well, but the lower population in this county 

causes this change to be less significant.

Kentucky:

For Kentucky, Boone, Campbell, and Kenton Counties have 

relatively high populations and population densities when 

compared to the rest of the CSA. Bracken, Gallatin, Grant and 

Pendleton Counties are smaller when compared to the counties 

included in the non-attainment recommendation. Boone County at 

37 percent growth and Warren County at 32 percent growth had the 

highest percentage of population growth for any of the counties 

in the Cincinnati-Middletown-Wilmington CSA. Other counties in 

this CSA did not have as large of a population percentage 

change, with their growth rates ranging from a 2 to 10 percent 
12

increase. Hamilton County population decreased by 5 percent 

from 2000-2010.

Traffic and Commuting Patterns

EPA evaluated the total VMT for each county in the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA. In combination with the 

population/population density data and the location of main 

transportation arteries (see above area map), this information 

helps identify the probable location of non-point source 

emissions. A county with high VMT is generally an integral part

of an urban area and indicates the presence of relatively high 

motor vehicle emissions that may significantly contribute to 

ozone formation and transport that contributes to nonattainment 

in the urban area. Rapid population or VMT growth in a county 

on the urban perimeter signifies increasing integration with the 

core urban area, and suggests that this county should be 

included in the ozone nonattainment area, particularly if the 

VOC and/or NOx emissions in this county are a significant 

portion of the total emissions in the nonattainment area.

Table 6 shows the traffic levels, total 2008 VMT, in each county 

in the Cincinnati-Middletown-Wilmington, OH-KY-IN CSA.

Table 6. Traffic Levels in the Cincinnati-MiddletownWilmington, OH-KY-IN CSA

State/County State 

Recommended 

Nonattainment

2008 VMT*

(million 

miles)

Indiana:

Dearborn No 904

Franklin No 316

Ohio No 63

Kentucky:

Boone No 1,095

Bracken No 89

Campbell No 1,005

Gallatin No 278

Grant No 432

Kenton No 1,669

Pendleton No 182

Ohio:

Brown No 413

Butler Yes 2,469

Clermont Yes 1,464

Clinton Yes 655

Hamilton Yes 7,391

Warren Yes 1,640
13

Area-wide 20,063 * MOBILE model VMT are those input into the NEI version 1.5 use 

to compute the mobile source portion of the NEI emissions 

summarized above in Table 4.

VMT Observations By State

Ohio:

For Ohio, the VMT data show that VMT levels in Butler, Clermont, 

Hamilton, and Warren Counties are comparatively higher than 

those in Brown and Clinton Counties and, accumulatively, are a 

significant portion of the total VMT for the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA.

Indiana:

For Indiana, the data show that VMT level in Dearborn County is 

a comparatively high portion of the total VMT for the 

Cincinnati-Middletown-Wilmington, OH-KY-IN CSA.

Kentucky:

The VMT data show that VMT levels in Boone, Campbell, and Kenton 

Counties are larger than those in Bracken, Gallatin, Grant, and 

Pendleton Counties and, accumulatively, are a large portion of 

the total VMT for the Cincinnati-Middletown-Wilmington, OH-KY-IN 

CSA.

Additional Emissions-Related Data Discussed in Ohio’s March 9, 

2009 Designation Recommendation Submittal

The State of Ohio, through the Ohio Environmental Protection 

Agency (OEPA), has provided a detailed discussion of the countyspecific VOC and NOx emissions, populations, and traffic and 

commuting patterns for the Ohio counties in the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA. These data support our 

conclusions discussed above, but also allow us to further refine 

our decisions for Factor 2 for the Ohio portion of the CSA. 

This is particularly true for growth in county populations and 

traffic levels and the inter-county impact of commuter traffic.

With regard to emissions, Ohio clearly shows that both VOC and 

NOx daily emissions in Brown County are considerably lower than 

many other counties in the Cincinnati-Middletown-Wilmington, OHKY-IN CSA. This confirms our conclusions that Brown County 
14

emissions are relatively low and would not support inclusion of 

this county in the ozone nonattainment area.

Ohio has projected county-populations through 2030. These 

population projections show that populations in Clinton and 

Brown Counties will remain comparatively low through 2030. 

Whereas, the populations of Butler, Clermont, Hamilton, and 

Warren Counties will either significantly increase or will 

remain relatively high through 2030.

Estimated daily VMT in Brown County are shown to be largely 

unchanged beginning in 2001 through 2007, and daily VMT in 

Hamilton County are estimated to be similarly unchanged between 

1990 and 2007. In contrast, daily VMT levels have shown 

significant growth trends in Butler, Clinton, Clermont, and 

Warren Counties between 1990 and 2007.

The State of Ohio notes that the vast majority of workers 

traveling out of county from Butler, Warren, and Clermont 

Counties commute to Hamilton County. This conclusion is 

supported by tabulated inter-county commuter numbers and 

percentages in Ohio’ March 9, 2009 submittal. It is also noted 

that approximately 15 percent of the Hamilton County workers 

commute outside of the county, with the majority traveling to 

Butler County, with significant numbers of commuters also 

traveling from Hamilton County to Warren and Clermont Counties. 

The commuter numbers for Brown County show a much smaller number 

commuters traveling to or from other counties in the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA.

Considering all of the information provided by the State of Ohio 

supports the conclusion that there is strong urban integration 

of Butler, Clermont, Hamilton, and Warren Counties. In 

contrast, Clinton and Brown Counties are not significantly 

integrated with the Cincinnati urban area. This favors the 

exclusion of Brown County from the Cincinnati-MiddletownWilmington, OH-KY-IN ozone nonattainment area for the 2008 ozone 

NAAQS. Clinton County, however, cannot be excluded from the 

ozone nonattainment area due to jurisdictional boundary 

considerations, as discussed for Factor 5 below.

Factor 3: Meteorology (Weather/Transport Patterns)

EPA evaluated available meteorological data to help determine 

how meteorological conditions, particularly transport 

conditions, affect the fate and transport of ozone and ozone 

precursors contributing to ozone formation in the Cincinnati-
15

Middletown-Wilmington, OH-KY-IN CSA. The wind direction 

percentages show that there is no “preferred” wind direction 

during the summertime. Transport winds can and do blow from all 

directions into the counties with the recorded violations of the 

2008 ozone NAAQS. There is, however, an indication that winds 

from south-southwest and west-southwest (collectively, the 

southwest quadrant) may be more prevalent than winds from other 

wind directions during the summertime in all three ozone 

standard violation counties.

Factor 4: Geography/Topography (Mountain Ranges or Other Air 

Basin Boundaries)

The geography/topography analysis evaluates the physical 

features of the land that might affect the airshed and, 

therefore, the distribution of ozone over the area.

The Cincinnati-Middletown-Wilmington, OH-KY-IN CSA does not have 

any geographical or topographical barriers significantly 

limiting air pollution transport within its air shed. 

Therefore, this factor did not play a significant role in this 

evaluation.

Factor 5: Jurisdictional Boundaries

Once we identified the general area that we anticipated we would 

recommend as nonattainment for the 2008 ozone NAAQS, we then 

considered existing jurisdictional boundaries for the purposes 

of providing a clearly defined legal boundary and to help 

identify the area appropriate for carrying out the air quality 

planning and enforcement functions for an ozone nonattainment 

area. Examples of jurisdictional boundaries include 

existing/prior nonattainment boundaries for ozone or other 

urban-scale pollutants, county boundaries, air district 

boundaries, township boundaries, areas covered by metropolitan 

planning organizations, state lines, and Reservation boundaries. 

Where existing jurisdictional boundaries are not adequate or 

appropriate to describe the nonattainment area, other clearly 

defined and permanent landmarks or geographic coordinates may be 

considered.

The Cincinnati-Middletown-Wilmington, OH-KY-IN area has 

previously established nonattainment boundaries associated with 

the both the 1-hour ozone and 1997 8-hour ozone NAAQS. The 

Cincinnati nonattainment boundary for the 1-hour ozone NAAQS 

included Boone, Campbell and Kenton Counties in their entireties 

in Kentucky; Butler, Clermont, Hamilton and Warren Counties in 
16

their entireties in Ohio. Whereas the Cincinnati nonattainment 

boundary for the 1997 8-hour ozone NAAQS included Boone, 

Campbell and Kenton Counties in their entireties in Kentucky, 

Butler, Clermont, Clinton, Hamilton and Warren Counties in their 

entireties in Ohio, and a portion of Dearborn County

(Lawrenceburg Township) in Indiana. Kentucky and Indiana have 

recommended a different nonattainment boundary for the 2008 

ozone NAAQS for their portion of this area. Ohio recommended 

the same boundary as the 1997 ozone NAAQS nonattainment boundary 

for their portion of this area. With the exception of those 

counties (and partial county) that comprise the 1997 8-hour 

ozone boundary for this area, we believe that the remainder of 

the counties in the CSA do not contribute to the violations at 

the monitors in this area and, therefore, are not necessary for 

consideration as part of the nonattainment area.

Conclusion

Ohio:

Based on the assessment of factors described above, EPA has 

preliminarily concluded that the following Ohio counties should 

be included in the Cincinnati-Middletown-Wilmington, OH-KY-IN 

ozone nonattainment area because they are either violating the 

2008 ozone NAAQS or contributing to a violation of the 2008 

ozone NAAQS within this preliminary nonattainment area: Butler; 

Clermont; Clinton; Hamilton; and, Warren.

Table 8a summarizes which factors, discussed above, support the 

inclusion of each Ohio county in the intended nonattainment area 

for the 2008 ozone NAAQS. Note that Table 8a covers all Ohio 

counties in the Cincinnati-Middletown-Wilmington, OH-KY-IN CSA, 

but that not all of these counties are included in the 

preliminary nonattainment area for the 2008 ozone NAAQS.

Table 8a. Factors Supporting Inclusion of Ohio Counties in the 

Cincinnati-Middletown-Wilmington, OH-KY-IN Ozone Nonattainment 

Area for the 2008 Ozone NAAQS

County Violates 

Ozone 

Standard

High 

Emissions 

Population 

and Traffic 

Levels 

Meteorology

Favors 

Emissions 

Impact on 

Violating 

Monitor

Geography 

Favors 

High Ozone 

or 

Emissions 

Impact on 

Violating 

Monitor

Jurisdictional

Basis for 

Inclusion In 

Nonattainment 

Area

Butler X X X NA X

Clermont X X NA X
17

Clinton X NA X

Hamilton X X X NA X

Warren X X X NA X

The results in the above table show that Butler, Hamilton, and 

Warren Counties, at minimum, should be included in the ozone 

nonattainment area based on air quality data. In addition, 

these counties also have comparatively high VOC and NOx 

emissions, populations (high population-related emissions), and 

traffic levels (traffic-related emissions), which favor their 

inclusion in the ozone nonattainment area.

Clermont County has comparatively high VOC and NOx emissions and 

relatively high populations and traffic levels, which, based on 

meteorological considerations, can also contribute to the 

monitored ozone standard violations in EPA’s intended ozone 

nonattainment area. Therefore, Clermont County should also be 

included in the preliminary ozone nonattainment area.

Clinton County has no monitored ozone standard violations and 

generally lacks the higher VOC and NOx emissions and high 

population and traffic levels of the other Ohio counties 

discussed above. Therefore, these factors do not favor the 

inclusion of Clinton County in the intended ozone nonattainment 

area. However, it is noted that Clinton County has historically 

been included in the Cincinnati ozone nonattainment area for the 

1997 ozone NAAQS. In addition, the State of Ohio, in its March 

9, 2009 ozone designation submittal, has recommended that 

Clinton County should be included in the ozone nonattainment 

area for the 2008 ozone NAAQS. Based on the jurisdictional 

factor and the State’s recommendation, we are including Clinton 

County in the intended, preliminary Cincinnati-MiddletownWilmington, OH-KY-IN ozone nonattainment area for the 2008 ozone 

NAAQS.

Finally, it is noted Brown County lacks ozone standard 

violations, and the comparatively high emissions, populations, 

and traffic levels of other Ohio counties in the CincinnatiMiddletown-Wilmington, OH-KY-IN CSA. In addition, this county 

was not included in the nonattainment area for the 1997 ozone 

NAAQS and Ohio has not recommended the inclusion of this county 

in the ozone nonattainment area for the 2008 ozone NAAQS. Based 

on all of these factors and facts, we are not including Brown 

County in the intended Cincinnati-Middletown-Wilmington, OH-KYIN ozone nonattainment area for the 2008 ozone NAAQS.

Indiana:
18

Based on the assessment of factors described above, EPA has 

preliminarily concluded that the following Indiana county should 

be included in the Cincinnati-Middletown-Wilmington, OH-KY-IN 

ozone nonattainment area because they are either violating the 

2008 ozone NAAQS or contributing to a violation of the 2008 

ozone NAAQS within this preliminary nonattainment area: Lawrence 

Township in Dearborn County.

Table 8b summarizes which factors, discussed above, support the 

inclusion of each Indiana county in the intended nonattainment 

area for the 2008 ozone NAAQS. Note that Table 8b covers all 

Indiana counties in the Cincinnati-Middletown-Wilmington, OH-KYIN CSA, but that not all of these counties are included in the 

preliminary nonattainment area for the 2008 ozone NAAQS.

Table 8b. Factors Supporting Inclusion of Indiana Counties in 

the Cincinnati-Middletown-Wilmington, OH-KY-IN Ozone 

Nonattainment Area for the 2008 Ozone NAAQS

County Monitored 

Violation for 

Ozone 

Standard

High 

Emissions 

Population and 

Traffic Levels 

Meteorology

Favors Emissions 

Impact on 

Violating Monitor

Geography Favors 

High Ozone or 

Emissions Impact on 

Violating Monitor

Jurisdictional

Basis for Inclusion 

In Nonattainment 

Area

Dearborn 

- Partial X X NA X

EPA has preliminarily concluded that Franklin and Ohio Counties 

are not expected to contribute to the ozone standard violations 

in the recommended Cincinnati-Middletown-Wilmington, OH-KY-IN

ozone nonattainment area. The areas are mostly rural with no 

point source emissions and minimal amounts of nonpoint source 

and mobile emissions. Franklin and Ohio Counties were not 

included in the Cincinnati ozone nonattainment area for the 1997 

ozone NAAQS. EPA has preliminarily concluded that Franklin and 

Ohio Counties are to be excluded from the proposed nonattainment 

area. 

Lawrenceburg Township in Dearborn County contains the American 

Electric Power (AEP) – Tanner’s Creek Generating Station and has 

high NOx and VOC emissions. Dearborn County also has the 

potential to have moderate mobile source and population related 

VOC and NOx emissions. The inclusion of Lawrenceburg Township 

in the Cincinnati-Middletown-Wilmington, OH-KY-IN ozone 

nonattainment area would be consistent with the ozone 

nonattainment area for the 1997 ozone NAAQS. Lawrenceburg 

Township contains the only major stationary source in the 

Indiana portion of Cincinnati-Middletown-Wilmington, OH-KY-IN 

CSA and accounts for the majority of the VOC and NOx emissions 
19

in the Indiana portion of this area. The remainder of Dearborn 

County is fairly rural and is similar to Franklin and Ohio 

Counties. The inclusion of the Lawrenceburg Township portion of 

Dearborn County, Indiana in the intended Cincinnati-MiddletownWilmington, OH-KY-IN nonattainment area for the 2008 ozone NAAQS 

is sufficient to account for the contribution of this county.

Kentucky:

Table 8c summarizes which factors discussed above support the 

inclusion of Kentucky counties in the intended nonattainment 

area for the 2008 ozone NAAQS. Note that Table 8c covers all 

Kentucky counties in the Cincinnati-Middletown-Wilmington, OHKY-IN CSA, but that not all of these counties are included in 

the preliminary nonattainment area for the 2008 ozone NAAQS.

Table 8c. Factors Supporting Inclusion of Kentucky Counties in 

the Cincinnati-Middletown-Wilmington, OH-KY-IN Ozone 

Nonattainment Area for the 2008 Ozone NAAQS

County Monitored 

Violation 

for Ozone 

Standard

High 

Emissions 

Population and 

Traffic Levels 

Meteorology

Favors Emissions 

Impact on 

Violating Monitor

Geography Favors 

High Ozone or 

Emissions Impact on 

Violating Monitor

Jurisdictional

Basis for Inclusion 

In Nonattainment 

Area

Boone X X NA X

Campbell X X NA X

Kenton X X NA X

For Kentucky, based on the assessment of factors described 

above, EPA has preliminarily concluded that the following 

counties, Boone, Campbell and Kenton, should be included as part 

of the Cincinnati-Middletown-Wilmington nonattainment area 

because they are contributing to a violation in a nearby area. 

Source category emissions data indicate that mobile sources and 

area sources are not the primary contributors of NOx to ozone 

formation in the Cincinnati-Middletown -Wilmington area. The 

analysis reveals that mobile emissions make up approximately 28 

percent of the total NOx in the Cincinnati-Middletown-Wilmington

area, and area sources make up approximately 12 percent of the 

total NOx emissions in the Cincinnati-Middletown -Wilmington

area. The total of mobile sources and area sources make up 

approximately 40 percent of the total NOx emissions in the 

Cincinnati area. However, VOC emissions in CincinnatiMiddletown-Wilmington area are high for area and mobile sources. 

The analysis reveals that mobile emissions make up approximately 

37 percent of the total VOC in the Cincinnati-MiddletownWilmington area, and area sources make up approximately 38 

percent of the total VOC emissions in the Cincinnati area. The 
20

total of mobile sources and area sources make up approximately 

75 percent of the total VOC emissions in the CincinnatiMiddletown-Wilmington area. Point sources in the area make up 

approximately 50 percent of the total NOx emissions and 

approximatley10 percent of the total VOC emissions in the 

Cincinnati-Middletown-Wilmington Area.

Boone, Campbell, and Kenton counties’ NOx and VOC precursor 

emissions, high VMT along with population growth suggest that 

these counties should be considered for inclusion in the 

Cincinnati-Middletown-Wilmington, OH-KY-IN ozone nonattainment 

area. 

Technical Analysis for Cleveland-Akron-Elyria, OH

Figure 2 is a map of the intended Cleveland-Akron-Elyria, OH 

ozone nonattainment area for the 2008 ozone NAAQS. The map 

provides other relevant information, including the locations and 

ozone design values of air quality monitors recording violations 

of the 2008 ozone NAAQS, county and other jurisdictional 

boundaries, existing maintenance boundary for the 1997 ozone 

NAAQS, Cleveland-Akron-Elyria, OH CSA boundary and major 

transportation arteries.

Figure 2. Cleveland-Akron-Elyria, OH Area
21

For purposes of the 1997 ozone NAAQS, as noted in Figure 2, 

portions of this area were designated nonattainment and 

subsequently redesignated to attainment (maintenance). The 

boundary for the nonattainment area for the 1997 ozone NAAQS 

included all Ohio counties in the Cleveland-Akron-Elyria, OH 

CSA. In March 2009, Ohio recommended that the same counties in 

Ohio be designated as nonattainment for the 2008 ozone NAAQS 

based on air quality data from 2006-2008. These data are from 

monitors sited and operated in accordance with 40 CFR part 58.

After considering these recommendations and based on EPA’s 

technical analysis described below, EPA intends to designate the 

same 8 counties in Ohio (identified in Table 9 below) as 

“nonattainment” for the 2008 ozone NAAQS for the ClevelandAkron-Elyria, OH nonattainment area.

Table 9. EPA’s Intended Nonattainment Counties for the 

Cleveland-Akron-Elyria, OH Ozone Nonattainment Area

State-Recommended Nonattainment EPA Intended Nonattainment Counties
22

Counties in Ohio in Ohio

Ashtabula

Cuyahoga

Geauga

Lake

Lorain

Medina

Portage

Summit

Ashtabula

Cuyahoga

Geauga

Lake

Lorain

Medina

Portage

Summit

Factor Assessment

Factor 1: Air Quality Data

For this factor, we considered 8-hour ozone design values (in 

ppm) for air quality monitors in counties in the ClevelandAkron-Elyria, OH CSA based on data for the 2008-2010 period, 

which are the most recent years with fully-certified air quality 

data. As discussed above, a monitor’s design value is the 

metric or statistic that indicates whether that monitor attains 

a specified air quality standard. The 2008 ozone NAAQS are met 

at a monitor when the annual fourth-highest daily maximum 8-hour 

ozone concentrations, averaged over 3 years is 0.075 ppm or 

less. A design value is valid only if minimum data completeness 

requirements are met. See 40 CFR part 50 Appendix P. Where 

several monitors are located in a county (or a designated 

nonattainment area or maintenance area), the design value for 

the county or area is determined by the monitor with the highest 

individual design value.

The 2008-2010 ozone design values for ozone monitors in the 

Cleveland-Akron-Elyria, OH CSA are shown in Table 10.

Table 10. Ozone Air Quality Data for the Cleveland-AkronElyria, OH CSA

County Site Number 2008-2010 

8-Hour 

Ozone 

Design 

Values 

(ppm)

Ashtabula 390071001 0.077†

Cuyahoga 390350064 0.068

Cuyahoga 390350034 0.075

Cuyahoga 390355002 0.075

Geauga 390550004 0.077†

Lake 390850003 0.076†

Lorain 390930018 0.070

Medina 391030004 0.070
23

Portage 391331001 0.067

Summit 391530020 0.075

† Monitored violation of the 2008 ozone NAAQS.

From Table 10, it can be seen that Ashtabula, Geauga, and Lake 

Counties in Ohio show violations of the 2008 ozone NAAQS for the 

period of 2008-2010. Therefore, these counties must be included 

in the ozone nonattainment area. As noted above, a county (or 

partial county) must also be designated nonattainment if it 

contributes to an air quality standard violation in a nearby 

area. Each county in the Cleveland-Akron-Elyria, OH CSA has 

been evaluated, as discussed below, based on the five factors 

summarized above and other relevant information to determine 

whether it contributed to the violations of the 2008 ozone NAAQS 

in Ashtabula, Geauga, and Lake Counties.

Please note that the State of Ohio, in its March 9, 2009 area 

designation recommendations and accompanying technical support 

documentation, based its area recommendations on 2006-2008 ozone 

data. Since these data no longer cover the most recent 3-year 

period with quality-assured, state-certified data and have been 

supplanted by the more current 2008-2010 ozone data, we are not 

reviewing the older ozone data covered by the state of Ohio.

Factor 2: Emissions and Emissions-Related Data

EPA evaluated emissions for VOC and NOx and other emissionsrelated data (primarily county population, population density, 

and traffic levels, and projected growth rates for county 

populations) that provide information on area contributions to 

local ozone standard violations.

Emissions Data

EPA evaluated county-level emission data for NOx and VOC derived 

from the 2008 NEI, version 1.5. These are the most recently 

available NEI emissions data. (See

http://www.epa.gov/ttn/chief/net/2008inventory.html) 

Significant emission levels in a nearby area indicate the 

potential for the area to contribute to the observed ozone 

standard violation. 

Table 11 shows the 2008 emissions of NOx and VOC (tons per year) 

for all counties in the Cleveland-Akron-Elyria, OH CSA. This 

table also indicates which of the counties were recommended to 

be nonattainment for the 2008 ozone NAAQS by the State of Ohio.
24

Table 11. Total 2008 VOC and NOx Emissions (tons/year) in the 

Cleveland-Akron-Elyria, OH CSA

State/County State Recommended 

Nonattainment?

VOC Emissions

(tpy)

NOx Emissions

(tpy)

Ohio:

Ashtabula Yes 10,411 9,860

Cuyahoga Yes 42,981 38,698

Geauga Yes 3,891 2,237

Lake Yes 10,382 19,286

Lorain Yes 11,646 15,261

Medina Yes 5,918 5,101

Portage Yes 6,137 5,656

Summit Yes 18,699 14,924

CSA Total 110,065 111,022

From the emissions data in Table 11, it can be seen that 

comparatively high 2008 VOC and NOx emissions in the vicinity of 

the violating counties originate in the following counties: 

Ashtabula, Cuyahoga, Lake, Lorain, and Summit. Emissions from 

these counties in 2008 account for 85.5 percent of the VOC 

emissions and 88.3 percent of NOx emissions for the entire 

Cleveland-Akron-Elyria, OH CSA.

The VOC and NOx emissions from Geauga, Medina, and Portage 

Counties are significantly smaller than those originating in the 

higher emitting counties within the Cleveland-Akron-Elyria, OH 

CSA. Note, however, that the collective emissions from these 

“lower emission” counties does constitute 12 to 15 percent of 

the CSA total emissions. So, even though individual VOC and NOx 

emissions are relatively low in the low emissions counties, 

their collective emission levels are equivalent to the emission 

levels for counties we are intending to include in the

nonattainment area for the 2008 ozone NAAQS. On this basis, we 

conclude that these counties may have the potential to 

contribute to ozone standard violations in the Cleveland-AkronElyria, OH area. 

Population, Population Density, and Degree of Urbanizaion

EPA evaluated the population and vehicle use characteristics and 

population trends of the area as indicators of the probable 

location and magnitude of non-point source emissions. These 

include ozone-creating emission from on-road and off-road 

vehicles and engines, consumer products, residential fuel 

combustion, and consumer services. Areas of dense population or 

commercial development are an indicator of area source and 

mobile source NOx and VOC emissions, which can contribute to 

local and downwind high ozone concentrations. Rapid population 
25

or VMT growth in a county on the urban perimeter signifies 

increasing integration with the urban core area, and indicates 

that it may be appropriate to include this county in the ozone 

nonattainment area, particularly if this county already has 

moderate or higher VOC and/or NOx emissions.

Table 12 shows the 2010 population, population density, and 

population growth information for each county in the ClevelandAkron-Elyria, OH CSA.

Table 12. Population and Population Growth in the ClevelandAkron-Elyria, OH CSA

State/County State 

Recommended 

Nonattainment?

2010 

Population

2010 

Population 

Density 

(1,000 per 

square 

mile)

Change in 

Population 

(2000-

2010)

Population 

Percent 

Change 

(2000-

2010)

Ohio:

Ashtabula Yes 101,497 0.14 -1,249 -1

Cuyahoga Yes 1,280,122 2.79 -111,989 -8

Geauga Yes 93,389 0.23 2,180 2

Lake Yes 230,041 0.99 2,385 1

Lorain Yes 301,356 0.61 16,224 6

Medina Yes 172,332 0.41 20,496 13

Portage Yes 161,419 0.32 9,036 6

Summit Yes 541,781 1.29 -1,797 0

Area Totals 2,881,937 0.79 -64,714 -2

Sources: U.S. Census Bureau population estimates for 2010 as of 

August 4, 2011.

(http://factfinder2.census.gov/faces/tableservices/jsf/pages/pro

ductview.xhtml?pid=DEC_10_PL_GCTPL2.STO5&proType=table)

The population data show that Cuyahoga, Lake, Lorain, Medina, 

Portage, and Summit Counties have comparatively high populations 

and population densities. This implies that these counties are 

generally urbanized and relatively integrated with the urban 

core of the Cleveland-Akron-Elyria, OH CSA. It also implies 

that the population-related VOC and NOx emissions in these 

counties are comparatively high and contribute to the ozone 

standard violations in the Cleveland-Akron-Elyria, OH CSA. 

The counties that experienced the largest population growth for 

the 2000-2010 period are Lorain and Medina. As noted above, 

this implies an increasing integration of these counties with 

the urban core of the Cleveland-Akron-Elyria, OH CSA, and favors 

the inclusion of these counties in the ozone nonattainment area.
26

Although some counties, to the contrary are experiencing 

population declines (Cuyahoga and Summit Counties), their base 

populations remain high, implying that they should not be 

excluded from the ozone nonattainment area.

Traffic and Commuting Patterns

EPA evaluated the total VMT for each county in the ClevelandAkron-Elyria, OH CSA. In combination with the county-specific 

population/population density data and the locations of the main 

transportation arteries (see above), this information helps 

identify the probable locations of non-point source emissions. 

A county with high VMT is generally an integral part of an urban 

area and indicates the presence of relatively high motor vehicle 

emissions that may significantly contribute to ozone formation 

and transport that contributes to ozone standard violations in 

or downwind of the urban area. Rapid population or VMT growth 

in a county on the urban perimeter signifies increasing 

integration with the urban core area, and indicates that this 

county should be included in the ozone nonattainment area, 

particularly if the VOC and/or NOx emissions in this county are 

a significant portion of the total emissions in the 

nonattainment area.

Table 13 show the traffic levels, 2008 VMT, in each county in 

the Cleveland-Akron-Elyria, OH CSA. 

Table 13. Traffic Levels in the Cleveland-Akron-Elyria, OH CSA

State/County State Recommended 

Nonattainment?

2008 VMT (million miles)

Ohio:

Ashtabula Yes 1,039

Cuyahoga Yes 10,148

Geauga Yes 736

Lake Yes 2,111

Lorain Yes 2,359

Medina Yes 1,532

Portage Yes 1,651

Summit Yes 5,471

Area Total 25,048

The VMT data show that VMT levels in all counties, with the 

exception of Geauga County, are relatively high. This implies 

that mobile source emissions in these counties are comparatively 

high and contribute to ozone standard violations in the 

Cleveland-Akron-Elyria, OH area.
27

VMT in Geauga County are comparatively lower than those in other 

counties in this area. This, however, does not imply that this 

county should be excluded from the ozone nonattainment area 

since this county has a monitored violation of the 2008 ozone 

NAAQS.

Additional Emissions-Related Data Discussed in Ohio’s March 9, 

2009 Designation Recommendation Submittal

OEPA has provided typical daily, county-specific total VOC and 

NOx emissions for 2005 and 2009 for each of the counties in the 

Cleveland-Akron-Elyria, OH CSA. These data confirm the 

conclusions we have drawn above using county-specific annual 

emissions. 

OEPA has provided population projections through 2030 for each 

of the counties in the CSA. These data show significant 

population growth trends in Geauga, Lake, Lorain, Medina, 

Portage, and Wayne Counties. Populations are projected to be 

substantially unchanged in Ashtabula and Summit Counties through 

2030. Populations are projected to decline over time in 

Cuyahoga County, however, the population in this county is 

projected to remain above 1 million through 2030.

OEPA provided graphs of daily VMT levels plotted for the period 

of 1990-2007 for each of the counties in the CSA. This visual 

VMT trend information shows that daily VMT grew moderately 

during the 1990-2007 period for Ashtabula, Cuyahoga, Geauga, 

Lake, Lorain, Medina, Portage, and Summit Counties.

OEPA provided inter-county commuter numbers and percentages for 

each of the counties in the Cleveland-Akron-Elyria, OH CSA. 

These numbers show a strong inter-county commuting pattern 

throughout the CSA.

Collectively, the OEPA-supplied population and traffic data 

support the conclusion that all of the counties in the 

Cleveland-Akron-Elyria, OH CSA, with the exception of Ashtabula 

County, are relatively integrated with the urban, industrial 

core of this area. Therefore, these data support including 

Cuyahoga, Geauga, Lake, Lorain, Medina, Portage, and Summit 

Counties in the Cleveland-Akron-Elyria, OH ozone nonattainment 

area. As noted elsewhere in this technical review, Ashtabula 

County must be included in this ozone nonattainment area as the 

result of its monitored violation of the 2008 ozone NAAQS.

Factor 3: Meteorology (Weather/Transport Patterns)
28

EPA evaluated available meteorological data to help determine 

how meteorological conditions, particularly transport 

conditions, affect the fate and transport of ozone and ozone 

precursors contributing to ozone formation in the ClevelandAkron-Elyria, OH CSA. EPA examined the frequency distribution 

of wind directions for the four seasons of the year by averaging 

National Weather Service direction-sorted wind directions for 

each county for a 30 year period. To apply the results of this 

data analysis to the Cleveland-Akron-Elyria, OH CSA, we have 

considered the wind direction (direction from which winds are 

blowing, reflecting directions to potential source areas) 

frequencies during the summer months (June-August) for the three 

Ohio counties with recorded violations of the 2008 ozone NAAQS 

(See Table 10). Therefore, we have considered wind direction 

distributions for Ashtabula, Cuyahoga, and Geauga Counties in 

Ohio.

Table 14 shows the summertime 30-year averaged percentages of 

wind directions (winds blowing into the subject county from the 

specified wind direction sector) for the three ozone standard 

violation counties in the Cleveland-Akron-Elyria, OH CSA.

Table 14. Averaged Summertime Wind Direction Percentages for 

Ozone Standard Violation Counties in the Cleveland-Akron-Elyria, 

OH CSA

Wind Direction Ashtabula County Geauga County Lake County

North-Northeast 10.1 13.4 14.8

East-Northeast 7.1 6.1 5.5

East-Southeast 8.5 8.3 6.9

South-Southeast 10.1 9.5 9.7

South-Southwest 25.1 24.8 26.8

West-Southwest 15.8 16.6 16.2

West-Northwest 13.2 10.9 10.2

North-Northwest 10.1 10.3 10.0

The wind direction percentages show that there is no single 

“preferred” wind direction during the summertime, when the 

highest ozone concentrations are generally monitored. Transport 

winds can and do blow from all directions in the counties with 

the recorded violations of the 2008 ozone NAAQS. There is, 

however, an indication that winds from the south-southwest and 

west-southwest may be more prevalent than winds from other wind 

directions during the summertime in all three ozone standard 

violation counties.
29

Unfortunately, EPA’s wind direction percentage data do little to 

shed light on which counties in the Cleveland-Akron-Elyria, OH 

CSA are the most important from an ozone and ozone precursor 

transport standpoint. The wind directions considered have not 

been sorted based on peak ozone concentrations or specifically 

for high ozone days, the timing of peak ozone concentrations, 

wind speeds, or other factors that could have been used to 

isolate the most critical ozone precursor source areas. 

Factor 4: Geography/Topography (Mountain Ranges or Other Air 

Basin Boundaries)

The geography/topography analysis evaluates the physical 

features of the land that might affect the airshed and, 

therefore, the distribution of ozone over the area.

The Cleveland-Akron-Elyria, OH CSA does not have any 

geographical or topographical barriers significantly limiting 

air pollution transport within its air shed. Therefore, this 

factor did not play a significant role in this evaluation.

Factor 5: Jurisdictional Boundaries

Once we identified the general area that we anticipated we would 

recommend as nonattainment for the 2008 ozone NAAQS, we then 

considered existing jurisdictional boundaries for the purposes 

of providing a clearly defined legal boundary and to help 

identify the area appropriate for carrying out the air quality 

planning and enforcement functions for an ozone nonattainment 

area. Examples of jurisdictional boundaries include 

existing/prior nonattainment boundaries for ozone or other 

urban-scale pollutants, county boundaries, air district 

boundaries, township boundaries, areas covered by metropolitan 

planning organizations, state lines, and Reservation boundaries. 

Where existing jurisdictional boundaries are not adequate or 

appropriate to describe the nonattainment area, other clearly 

defined and permanent landmarks or geographic coordinates may be 

considered.

The portion of the Cleveland-Akron-Elyria, OH CSA that we are 

considering as designating as nonattainment for the 2008 ozone 

NAAQS has a previously established nonattainment boundary 

associated with the 1997 8-hour ozone NAAQS. The State of Ohio 

has recommended the same counties (as included in the 1997 8-

hour ozone nonattainment area) in Ohio to be included in the 

boundary of the nonattainment area for the 2008 ozone NAAQS. 

The prior inclusion of these counties in the ozone nonattainment 
30

area for the 1997 ozone NAAQS forms the primary jurisdictional 

basis for the inclusion of these counties in the nonattainment 

area for the 2008 ozone NAAQS.

Conclusion

Based on the assessment of factors described above, EPA has 

preliminarily concluded that the following Ohio counties should 

be included in the Cleveland-Akron-Elyria, OH ozone 

nonattainment area because they are either violating the 2008 

ozone NAAQS or are contributing to a violation of the 2008 ozone 

NAAQS within this preliminary nonattainment area: Ashtabula; 

Cuyahoga; Geauga; Lake; Lorain; Medina; Portage; and, Summit.

Table 15 summarizes which factors discussed above support the 

inclusion of each Ohio county in the preliminary nonattainment 

area for the 2008 ozone NAAQS. 

Table 15. Factors Supporting Inclusion of Ohio Counties in the 

Cleveland-Akron-Elyria, OH Ozone Nonattainment Area for the 2008 

Ozone NAAQS

County Violates 

Ozone 

Standard

High 

Emissions 

Population 

and Traffic 

Levels 

Meteorology

Favors 

Emissions 

Impact on 

Violating 

Monitor

Geography 

Favors 

High Ozone 

or 

Emissions 

Impact on 

Violating 

Monitor

Jurisdictional

Basis for 

Inclusion In 

Nonattainment 

Area

Ashtabula X X X NA X

Cuyahoga X X NA X

Geauga X X NA X

Lake X X X NA X

Lorain X X NA X

Medina X X NA X

Portage X X NA X

Summit X X NA X

The results in the above table show that all counties in the 

Cleveland-Akron-Elyria, OH CSA should be included in the 

Cleveland-Akron-Elyria, OH nonattainment area for the 2008 ozone 

NAAQS. Ashtabula, Geauga, and Lake Counties have monitored 

violations of the 2008 ozone NAAQS. All counties, except Geauga 

County, have high emissions or emissions-related data 

(population, population growth, and/or traffic levels) that 

support inclusion in the nonattainment area. Finally, all of 

these counties are recommended for inclusion in the ozone 

nonattainment area by the State of Ohio and were included in the 

ozone nonattainment area for the 1997 ozone NAAQS.
31

Based on these factors, we conclude that the entire ClevelandAkron-Elyria, OH CSA should be included in the Cleveland-AkronElyria, OH nonattainment area for the 2008 ozone NAAQS.

Technical Analysis for Columbus-Marion-Chillicothe, OH

Figure 3 is a map of the intended Columbus, OH ozone 

nonattainment area for the 2008 ozone NAAQS. The map provides 

other relevant information, including the locations and ozone 

design values of air quality monitors recording violations of 

the 2008 ozone NAAQS, county and other jurisdictional 

boundaries, existing maintenance boundary for the 1997 ozone 

NAAQS, Columbus-Marion-Chillicothe, OH CSA boundary and major 

transportation arteries.

Figure 3. Columbus-Marion-Chillicothe, OH Area

For purposes of the 1997 ozone NAAQS, as noted in Figure 3, 

portions of this area were designated nonattainment and 

subsequently redesignated to attainment (maintenance). The 
32

boundary for the nonattainment area for the 1997 ozone NAAQS 

included only a portion of the Columbus-Marion-Chillicothe, OH 

CSA. In March 2009, Ohio recommended that the same counties 

(the same counties included in the nonattainment area for the 

1997 ozone NAAQS) in Ohio be designated as nonattainment for the 

2008 ozone NAAQS based on air quality data from 2006-2008 and 

other considerations. The 2006-2008 ozone data are from 

monitors sited and operated in accordance with 40 CFR part 58.

After considering these recommendations and based on EPA’s 

technical analysis described below, EPA intends to designate the 

same 6 counties in Ohio (identified in Table 16 below) as 

“nonattainment” for the 2008 ozone NAAQS as part of the 

Columbus, OH nonattainment area.

Table 16. EPA’s Intended Designated Nonattainment Counties for 

the Columbus, OH Ozone Nonattainment Area

State-Recommended Nonattainment 

Counties in Ohio

EPA Intended Nonattainment Counties

in Ohio

Delaware

Fairfield

Franklin

Knox

Licking

Madison

Delaware

Fairfield

Franklin

Knox

Licking

Madison

Factor Assessment

Factor 1: Air Quality Data

For this factor, we considered 8-hour ozone design values (in 

ppm) for air quality monitors in counties in the ColumbusMarion-Chillicothe, OH CSA based on data for the 2008-2010 

period, which are the most recent years with fully-certified air 

quality data. As discussed above, a monitor’s design value is 

the metric or statistic that indicates whether that monitor 

attains a specified air quality standard. The 2008 ozone NAAQS 

are met at a monitor when the annual fourth-highest daily 

maximum 8-hour ozone concentrations, averaged over 3 years is 

0.075 ppm or less. A design value is valid only if minimum data 

completeness requirements are met. See 40 CFR part 50 Appendix 

P. Where several monitors are located in a county or area (or a 

designated nonattainment area or maintenance area), the design 

value for the county or area is determined by the monitor with 

the highest individual design value.

The ozone design values for ozone monitors in the ColumbusMarion-Chillicothe, OH CSA are shown in Table 17.
33

Table 17. Ozone Air Quality Data for the Columbus-MarionChillicothe, OH CSA

State/County Site Number 2008-2010 

8-Hour 

Ozone 

Design 

Values 

(ppm)

Delaware 390410002 0.073

Franklin 390490081 0.069

Franklin 390490037 0.071

Franklin 390490029 0.078†

Knox 390830002 0.071

Licking 390890005 0.072

Madison 390970007 0.070

† Monitored violation of the 2008 ozone NAAQS.

From Table 17, it can be seen that Franklin County is the only 

county in the Columbus-Marion-Chillicothe, OH CSA with a 

monitored violation of the 2008 ozone NAAQS for the period of 

2008-2010. Therefore, at minimum, Franklin County must be 

included in the ozone nonattainment area. As noted above, a 

county (or partial county) must also be designated nonattainment 

if it contributes to an air quality violation in a nearby area 

(to the violation of the 2008 ozone NAAQS recorded in Franklin 

County). Each county in the Columbus-Marion-Chillicothe, OH CSA 

has been evaluated, as discussed below, based on the five 

factors discussed above and other relevant information to 

determine whether it contributed to the violation of the 2008 

ozone NAAQS in Franklin County.

Please note that the State of Ohio, in its March 9, 2009 area 

designation recommendations and accompanying technical support 

documentation, based its area recommendations on 2006-2008 ozone 

data. Since these data no longer cover the most recent 3-year 

period with quality-assured, state-certified data and have been 

supplanted by the more current 2008-2010 ozone data, we are not 

reviewing the older ozone data covered by the state of Ohio.

Factor 2: Emissions and Emissions-Related Data

EPA evaluated emissions for VOC and NOx and other emissionsrelated data (primarily county population, population density, 

and traffic levels, and projected growth rates for these 

emissions-related data) that provide information on area 

contributions to local ozone standard violations.
34

EPA’s Accumulated Emissions and Emissions-Related Data

Emissions Data

EPA evaluated county-level emission data for NOx and VOC derived 

from the 2008 NEI, version 1.5. These are the most recently 

available NEI emissions data. (See 

http://www.epa.gov/ttn/chief/net/2008inventory.html) 

Significant emission levels in a nearby area (in a county near 

to a county with a violating ozone monitor) indicate the 

potential for the area to contribute to the observed ozone 

standard violation. 

Table 18 shows the 2008 emissions of NOx and VOC (in tons per 

year) for all counties in the Columbus-Marion-Chillicothe, OH 

CSA. This table also indicates which of the counties were 

recommended to be nonattainment for the 2008 ozone NAAQS by the 

State of Ohio.

Table 18. Total 2008 VOC and NOx Emissions (tons/year) in the 

Cleveland-Akron-Elyria, OH CSA

State/County State Recommended 

Nonattainment?

VOC Emissions

(tpy)

NOx Emissions

(tpy)

Ohio:

Delaware Yes 5,686 5,655

Fairfield Yes 4,459 4,915

Fayette No 1,887 1,981

Franklin Yes 38,690 32,092

Knox Yes 2,324 1,539

Licking Yes 7,016 6,008

Madison Yes 2,373 2,809

Marion No 3,588 3,509

Morrow No 1,983 2,190

Pickaway No 2,969 3,919

Ross No 3,292 5,010

Union No 3,404 2,413

CSA Total 77,671 72,041

From the emissions data in Table 18, it can be seen that the VOC 

and NOx emissions in the Columbus-Marion-Chillicothe, OH CSA are 

dominated by those in Franklin County. The VOC emissions in 

Franklin County are 49.8 percent of the CSA total, and the NOx 

emissions in Franklin County are 44.5 percent of the CSA total. 

All other counties in this CSA have significantly lower and 

similar (to each other) VOC and NOx emissions. However, the 

accumulative VOC and NOx emissions in these remaining counties 

is a significant portion of the total VOC and NOx emissions in 

the CSA. 
35

The high emissions in Franklin County, along with the monitored 

violation of the 2008 ozone NAAQS in this county, implies that 

Franklin County should be part of the nonattainment area for the 

2008 ozone NAAQS. The VOC and NOx emissions for the remaining 

counties in the Columbus-Marion-Chillicothe, OH CSA do not 

provide a definitive basis for inclusion or exclusion from the 

nonattainment area. Note that the counties Ohio is recommending 

for exclusion from the nonattainment area have similar VOC and 

NOx emissions to many of the Ohio-recommended nonattainment 

counties in the Columbus-Marion-Chillicothe, OH CSA.

Population, Population Density, and Degree of Urbanization

EPA evaluated the population and vehicle use characteristics and 

trends of the area as indicators of the probable location and 

magnitude of non-point source emissions. These include ozonecreating emissions from on-road and off-road vehicles and 

engines, consumer products, residential fuel combustion, and 

consumer services. Areas of dense population or commercial 

development are an indicator of area source and mobile source 

NOx and VOC emissions, which can contribute to local and

downwind high ozone concentrations. Rapid population or VMT 

growth in a county on the urban perimeter signifies increasing 

integration with the urban core area, and indicates that it may 

be appropriate to include this county in the ozone nonattainment 

area, particularly if this county already has moderate or higher 

VOC and/or NOx emissions.

Table 19 shows the 2010 population, population density, and 

population growth information for each county in the ColumbusMarion-Chillicothe, OH CSA.

Table 19. Population and Population Growth in the ColumbusMarion-Chillicothe, OH CSA

State/County State 

Recommended 

Nonattainment?

2010 

Population

2010 

Population 

Density 

(1,000 per 

square 

mile)

Change in 

Population 

(2000-

2010)

Population 

Percent 

Change 

(2000-

2010)

Ohio:

Delaware Yes 174,214 0.38 62,504 56

Fairfield Yes 146,156 0.29 22,736 18

Fayette No 29,030 0.07 595 2

Franklin Yes 1,163,414 2.14 91,127 8

Knox Yes 60,921 0.12 6,278 11

Licking Yes 166,492 0.24 20,421 14

Madison Yes 43,435 0.09 3,223 8
36

Marion No 66,501 0.16 351 1

Morrow No 34,827 0.09 3,033 10

Pickaway No 55,698 0.11 2,882 5

Ross No 78,064 0.11 4,614 6

Union No 52.300 0.12 11,105 27

CSA Totals 2,071,052 0.34 228,869 12

Sources: U.S. Census Bureau population estimates for 2010 as of 

August 4, 2011.

(http://factfinder2.census.gov/faces/tableservices/jsf/pages/pro

ductview.xhtml?pid=DEC_10_PL_GCTPL2.STO5&proType=table)

The population data show that half of the 2010 population and 

almost half of the 2000-2010 population growth in the ColumbusMarion-Chillicothe, OH CSA can be found in Franklin County. 

Comparatively large 2010 populations and 2000-2010 population 

growths can also be found in Delaware, Fairfield, and Licking 

Counties. The 2010 populations in the remaining counties in the 

CSA are comparatively smaller. Union County has a comparativley 

high population growth percentage, however, its 2010 population 

is small compared to those of Delaware, Fairfield, Franklin, and 

Licking Counties. Finally, the 2010 populations and 2000-2010 

population growths of Fayette and Marion Counties are 

comparatively lower than those of other counties in the 

Columbus-Marion-Chillicothe, OH CSA.

Traffic and Commuting Patterns

EPA evaluated the commuting patterns of residents in the 

Columbus-Marion-Chillicothe, OH CSA. In combination with the 

county-specific population/population density data and the 

locations of the main transportation arteries (see above), this 

information helps identify the probable locations of non-point 

source emissions. A county with high VMT and/or a high number 

of commuters is generally an integral part of an urban area and 

indicates the presence of relatively high motor vehicle 

emissions that may significantly contribute to ozone standard 

violations in or downwind of the urban area. Rapid population 

or VMT growth in a county on the urban perimeter signifies 

increasing integration with the urban core area, and indicates 

that this county should be included in the ozone nonattainment 

area, particularly if the VOC and/or NOx emissions in this 

county are a significant portion of the total emissions in the 

nonattainment area.

Table 20 shows the traffic levels, 2008 VMT, in each county in 

the Columbus-Marion-Chillicothe, OH CSA.
37

Table 20. Traffic Levels in the Columbus-Marion-Chillicothe, OH 

CSA

State/County State Recommended 

Nonattainment?

2008 VMT (million miles)

Ohio:

Delaware Yes 1,530

Fairfield Yes 1,035

Fayette No 505

Franklin Yes 10,645

Knox Yes 397

Licking Yes 1,780

Madison Yes 704

Marion No 629

Morrow No 605

Pickaway No 648

Ross No 772

Union No 630

CSA Total 19,881

The VMT data show that county-specific VMT levels are the 

highest in Delaware, Franklin, Fairfield, and Licking Counties. 

These VMT account for 75.4 percent of the total VMT in the 

Columbus-Marion-Chillicothe, OH CSA. 

The VMT data plus the population data in Table 19 indicate that 

Delaware, Fairfield, Franklin, and Licking Counties are 

relatively urbanized with significant population- and trafficrelated emissions that contributed to the ozone standard 

violation in Franklin County. This contribution is much smaller

for the remaining counties in the Columbus-Marion-Chillicothe, 

OH CSA.

Additional Emissions-Related Data Discussed in Ohio’s March 9, 

2009 Designation Recommendation Submittal

OEPA has provided typical daily, county-specific total VOC and 

NOx emissions for 2005 and 2009 for each of the counties in the 

Columbus-Marion-Chillicothe, OH CSA. These data confirm the 

conclusions we have drawn above using county-specific annual 

emissions. 

OEPA has provided population projections through 2030 for each 

of the counties in the CSA. Populations are projected to 

increase significantly in Delaware, Fairfield, Franklin, 

Licking, Medina, Morrow, Pickaway, Ross, and Union Counties. 

Populations are projected to increase moderately in Fayette and 

Marion Counties. Populations are expected to decline in Knox 

County.
38

OEPA provided graphs of daily VMT levels plotted for the period 

of 1990-2007 for each of the counties in the CSA. This visual 

VMT trend information shows that daily VMT grew significantly 

during the 1990-2007 period for Delaware, Fairfield, Franklin, 

Licking and Morrow Counties. The VMT trend information shows 

that daily VMT grew moderately during the 1990-2007 period for 

Knox, Marion, Pickaway (VMT levels remained substantially 

unchanged after 1999 in this county), and Ross Counties.

OEPA provided inter-county commuter numbers and percentages for 

each of the counties in the Columbus-Marion-Chillicothe, OH CSA. 

These numbers show a moderate to high inter-county commuting 

pattern between Franklin County and other counties (with the 

exceptions of Fayette, Knox, Ross, Marion, and Morrow Counties) 

in the Columbus-Marion-Chillicothe, OH CSA. Inter-county 

commuter numbers between other counties (other than Franklin 

County) in the CSA are moderate to small.

Collectively, the OEPA-supplied population and traffic/commuter 

data show moderate integration between Franklin, Delaware, 

Fairfield, Licking, Medina, Morrow, Pickaway, Ross, and Union 

Counties. Less integration is apparent between Franklin, 

Fayette, Knox, and Marion Counties. This implies that, from an 

emissions standpoint, the Columbus, OH ozone nonattainment area 

should include Delaware, Fairfield, Franklin, Licking, Medina, 

Morrow, Pickaway, Ross, and Union Counties. Remaining counties 

in the CSA could be excluded on the basis that their emissions 

are not significant contributors to the monitored violations of 

the 2008 ozone NAAQS in Franklin County.

Factor 3: Meteorology (Weather/Transport Patterns)

EPA’s Accumulated Meteorological Data

EPA evaluated available meteorological data to help determine 

how meteorological conditions, particularly transport 

conditions, affect the fate and transport of ozone and ozone 

precursors contributing to ozone formation in the ColumbusMario-Chillicothe, OH CSA. EPA examined the frequency 

distribution of wind directions for the four seasons of the year 

by averaging National Weather Service direction-sorted wind 

directions for each county for a 30-year period. To apply the 

results of this data analysis to the Columbus-MarionChillicothe, OH CSA, we have considered the wind direction 

(direction from which winds are blowing, reflecting directions 

to potential source areas) frequencies during the summer months 

(June-August) for Franklin County, which is the only county in 
39

the CSA with a monitored violation of the 2008 ozone NAAQS (See 

Table 17). 

Table 21 shows the summertime 30-year averaged percentages of 

wind directions (winds blowing into the subject county from the 

specified wind direction sector) for Franklin County.

Table 21. Averaged Summertime Wind Direction Percentages For 

Franklin County

Wind Direction Franklin County

North-Northeast 15.3

East-Northeast 9.6

East-Southeast 11.4

South-Southeast 12.0

South-Southwest 22.0

West-Southwest 11.0

West-Northwest 9.7

North-Northwest 9.0

The wind direction percentages show that there is no single 

“preferred” wind direction during the summertime, when the 

highest ozone concentrations are generally monitored. Winds 

from south-southwest may be more prevalent than the winds from 

other wind directions during the summertime.

Unfortunately, EPA’s wind direction percentage data do little to 

shed light on which counties in the Columbus-Marion-Chillicothe, 

OH CSA are the most important from an ozone and ozone precursor 

transport standpoint. The wind directions considered have not 

been sorted based on peak ozone concentrations or specifically 

for high ozone days, the timing of peak ozone concentrations, 

wind speeds, or other factors that could have been used to 

isolate the most critical ozone precursor source areas. 

Factor 4: Geography/Topography (Mountain Ranges or Other Air 

Basin Boundaries)

The geography/topography analysis evaluates the physical 

features of the land that might affect the airshed and, 

therefore, the distribution of ozone over the area.

The Columbus-Marion-Chillicothe, OH CSA does not have any 

geographical or topographical barriers significantly limiting 

air pollution transport within its air shed. Therefore, this 

factor did not play a significant role in this evaluation.

Factor 5: Jurisdictional Boundaries
40

Once we identified the general area that we anticipated we would 

recommend as nonattainment for the 2008 ozone NAAQS, we then 

considered existing jurisdictional boundaries for the purposes 

of providing a clearly defined legal boundary and to help

identify the area appropriate for carrying out the air quality 

planning and enforcement functions for an ozone nonattainment 

area. Examples of jurisdictional boundaries include 

existing/prior nonattainment boundaries for ozone or other 

urban-scale pollutants, county boundaries, air district 

boundaries, township boundaries, areas covered by metropolitan 

planning organizations, state lines, and Reservation boundaries. 

Where existing jurisdictional boundaries are not adequate or 

appropriate to describe the nonattainment area, other clearly 

defined and permanent landmarks or geographic coordinates may be 

considered.

The portion of the Columbus-Marion-Chillicothe, OH CSA that we 

are considering for designation as nonattainment for the 2008 

ozone NAAQS has a previously established nonattainment boundary 

associated with the 1997 8-hour ozone NAAQS. The State of Ohio 

has recommended the same counties (as included in the 1997 8-

hour ozone nonattainment area) in Ohio be included in the 

boundary of the nonattainment area for the 2008 ozone NAAQS. 

The prior inclusion of these counties in the ozone nonattainment 

area for the 1997 ozone NAAQS forms the primary jurisdictional 

basis for the inclusion of these counties in the nonattainment 

area for the 2008 ozone NAAQS.

Conclusion

Based on the assessment of factors described above, EPA has 

preliminarily concluded that the following Ohio counties should 

be included in the Columbus, OH ozone nonattainment area because 

they are either violating the 2008 ozone NAAQS or are 

contributing to a violation of the 2008 ozone NAAQS within this 

intended ozone nonattainment area: Delaware; Fairfield; 

Franklin; Knox; Licking; and, Madison.

Table 22 summarizes which factors discussed above support the 

inclusion of each Ohio county in the Columbus, OH preliminary 

nonattainment area for the 2008 ozone NAAQS.

Table 22. Factors Supporting Inclusion of Ohio Counties in the 

Columbus, OH Ozone Nonattainment Area for the 2008 Ozone NAAQS

County Violates High Meteorology Geography Jurisdictional
41

Ozone 

Standard

Emissions 

Population 

and Traffic 

Levels 

Favors 

Emissions 

Impact on 

Violating 

Monitor

Favors 

High Ozone 

or 

Emissions 

Impact on 

Violating 

Monitor

Basis for 

Inclusion In 

Nonattainment 

Area

Delaware X X NA X

Fairfield X X NA X

Franklin X X X NA X

Knox X NA X

Licking X X NA X

Madison X NA X

The results in the above table show that Delaware, Fairfield, 

Franklin and Licking Counties should be included in the 

Columbus, OH ozone nonattainment area on the bases of a 

violation of the 2008 ozone NAAQS and/or significant emissions 

that contribute to the violation of the 2008 ozone NAAQS.

The issue is less clear for Knox and Madison Counties due to the 

lack of a monitored ozone standard violation and relatively low 

VOC and NOx emissions, populations, and traffic levels in these 

counties. The only bases for including these counties in the 

intended, preliminary ozone nonattainment area for the 2008 

ozone NAAQS are the facts that the State of Ohio has recommended 

their inclusion in the nonattainment area and that these 

counties were included in the nonattainment area for the 2007 

ozone NAAQS. Based on these facts, we agree with the State of 

Ohio that these counties should also be included in the 

Columbus, OH nonattainment area.