UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 4 

Sam Nunn Atlanta Federal Center 

61 Forsyth Street, SW 

Atlanta, Georgia 30303-8960 

DATE: June 14, 2010 

SUBJECT: Technical Support Document for Notice of Proposed Rulemaking – Knoxville, 

Tennessee: Determination of Attaining Data for the 1997 8-Hour Ozone National 

Ambient Air Quality Standards 

FROM: Twunjala Bradley, Environmental Engineer /s/ 

Regulatory Development Section 

TO: EPA-R04-OAR-2007-0228-Knoxville, Tennessee 8-Hour Ozone 

 Clean Data Determination 

THRU: Lynorae Benjamin /s/ 

 Chief, Regulatory Development Section 

A. BACKGROUND 

 On July 18, 1997, (62 FR 38894), EPA promulgated a revised 8-hour ozone standard of 

0.08 parts per million (ppm) for both the primary and secondary National Ambient Air Quality 

Standards (NAAQS). Pursuant to EPA regulations 40 Code of Federal Regulations (CFR) part 

50, the 1997 8-hour ozone NAAQS is attained when the 3-year average of the annual fourthhighest daily maximum 8-hour average ambient air quality ozone concentration is less than or 

equal to 0.08 ppm (i.e. 0.084 ppm when rounding is considered). EPA established these 

standards based on significant evidence and numerous health studies demonstrating that serious 

health effects are associated with exposures to ozone precursors volatile organic compounds and 

nitrogen oxides. The process for designating areas following promulgation of a new or revised 

NAAQS is contained in section 107(d)(1) of the Clean Air Act. 

On April 30, 2004 (69 FR 23587), EPA published its air quality designations and 

classifications for the 1997 8-hour ozone NAAQS based upon air quality monitoring data from 

those monitors for calendar years 2001-2003. These designations became effective on June 15, 

2004. The Knoxville, Tennessee Area (comprised of the entire counties of Anderson, Jefferson, 

Blount, Knox, Loudon and Sevier and a portion of Cocke County) was designated nonattainment 

for the 1997 8-hour ozone NAAQS (see 40 CFR part 81). On February 19, 2010, the State of 

Tennessee submitted to EPA a request to make a determination that the Knoxville, Tennessee 

nonattainment area has attained the 1997 8-hour ozone NAAQS based on quality assured, quality 

controlled monitoring data from 2007 through 2009. This Technical Support Document (TSD) 
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summarizes the 2007-2009 data EPA is using to support its determination that the Knoxville, 

Tennessee area now has attaining data for the 1997 8-hour ozone NAAQS. 

B. EPA REQUIREMENTS 

A nonattainment area for the 1997 8-hour ozone NAAQS is determined to have attaining 

data when the design value1

 meets the requirements stipulated in 40 CFR Part 50, section 

50.10(b) as follows: 

The 8-hour primary and secondary ozone ambient air quality standards are met at an 

 ambient air quality monitoring site when the average of the annual fourth-highest daily 

 maximum 8-hour average ozone concentration is less than or equal to 0.08 ppm, as 

 determined in accordance with appendix I to this part. 

Ambient air quality monitoring data for the 3-year period must meet a data completeness 

requirement. The ambient air quality monitoring data completeness requirement is met when the 

average percent of days with valid ambient monitoring data is greater than 90 percent, and no 

single year has less than 75 percent data completeness as determined in Appendix I of part 50. 

Specifically, section 2.3 of 40 CFR part 50, Appendix I, “Comparisons with the Primary and 

Secondary Ozone Standards” states: 

“The primary and secondary ozone ambient air quality standards are met at an ambient 

air quality monitoring site when the 3-year average of the annual fourth-highest daily 

 maximum 8-hour average ozone concentration is less than or equal to 0.08 ppm. The 

 number of significant figures in the level of the standard dictates the rounding convention 

 for comparing the computed 3-year average annual fourth-highest daily maximum 8-hour 

 average ozone concentration with the level of the standard. The third decimal place of 

 the computed value is rounded, with values equal to or greater than 5 rounding up. Thus, 

 a computed 3-year average ozone concentration of 0.085 ppm is the smallest value that is 

 greater than 0.08 ppm.” 

Upon determination by EPA that an area designated nonattainment for the 1997 8-hour 

ozone NAAQS has attained the standard, 40 CFR 51.918 provides that the requirement for such 

an area to submit attainment demonstrations and associated reasonably available control 

measures, reasonable further progress plans, contingency measures, and other planning State 

Implementation Plans related to attainment of the 8-hour ozone NAAQS shall be suspended until 

the area is redesignated to attainment, at which time the requirement no longer applies. 

1 Design values are the metrics that are compared to the NAAQS levels to determine 

attainment. The 8-hour ozone design value is calculated as the 3-year average annual fourthhighest daily maximum 8-hour average ozone concentration recorded at a monitoring site. (See 

40 CFR part 50 Appendix I.) 
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However, if EPA subsequently determines that the area has violated the 8-hour ozone NAAQS, 

the requirement to submit such plans is reinstated. 

C. EPA’S ANALYSIS OF MONITORED DATA 

EPA’s determination that the Knoxville nonattainment area has attaining data for the 

1997 8-hour ozone NAAQS is based upon complete, quality assured, quality controlled and 

certified ambient air monitoring data for the 2007-2009 period, as measured by Federal reference 

method described in 40 CFR Part 50, Appendix D. The monitors and data used to determine the 

2007-2009 8-hour ozone design value for the Knoxville nonattainment area are included in the 

table below. 

Table 1. Design Value for Counties in the Knoxville, Tennessee Nonattainment Area for the 1997 

8-hour Ozone NAAQS 

Location AQS site ID 2007 

(ppm) 

2008 

(ppm) 

2009 

(ppm) 

2007-2009 

Design Value (ppm) 

Anderson County Freels Bend Study Area 

(470010101-1) 

0.080 0.073 0.065 0.072 

Look Rock, GSMNP 

(470090101-1) 

Blount County 0.088 0.082 0.069 0.079 

Cades Cove, GSMNP 

(470090102-1) 

0.074 0.071 0.062 0.069 

Jefferson County 1188 Lost Creek Road 

(470890002-1) 

0.085 0.075 0.068 0.076 

9315 Rutledge Pike 

(470930021-1)) 

Knox County 0.087 0.079 0.066 0.077 

4625 Mildred Drive 

(470931020-1) 

0.092 0.086 0.068 0.082 

Loudon County 130 Webb Drive 

(471050109-1) 

0.088 0.077 0.067 0.077 

Sevier County2 Cove Mountain, GSMNP 

(471550101-1) 

0.088 0.079 0.070 0.079 

A preliminary 2008-2010 design value of 0.076 ppm for the Knoxville Area indicates continued 

 

2 In addition to the Cove Mountain monitor, there is the Clingman’s Dome ozone monitoring site in Sevier County. 

 The Clingman’s Dome monitor does not meet siting criteria listing in 40 CFR 58, and thus is not appropriate to be 

used for the determination of attainment on nonattainment for the ozone NAAQS. 
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attainment of the 1997 8-hour ozone NAAQS3

. 

D. CONCLUSIONS AND RECOMMENDED AGENCY ACTION

 Quality assured, quality controlled, and certified ambient air monitoring data for 2007-

2009 shows that the design value for the Knoxville 8-hour ozone nonattainment area is 0.082 

ppm. This design value is less than the 1997 8-hour ozone NAAQS 0.080 ppm (i.e., 0.084 ppm 

when rounding is considered), demonstrating that the Knoxville Area has monitored attainment 

for this NAAQS. EPA concludes that the Knoxville Area indeed has quality assured, quality 

controlled attaining the 1997 8-hour ozone NAAQS with 2007-2009 monitoring data. 

3 The 2008-2010 design value is considered preliminary data, based on the current 2010 annual fourth-highest daily 

maximum 8-hour average ozone concentration in the Knoxville, TN ozone nonattainment area.