Office of Air & Radiation 

# Proposed Rule: Ozone Nonattainment 

# Area Classifications Approach, Attainment Deadlines, and Revocation of the 1997 Standards for Transportation Conformity Purposes

Summary for NACAA February 21, 2012Office of Air & Radiation



# Overview

• Proposed rule published in the Federal Register Feb.14, 2012 (77 FR 8197). Docket ID No. EPA- HQ -OAR- 201 0

- 0885.

• Public comment period closes March 15, 2012.

• EPA intends to finalize this rule no later than May 31, 2012.



### • What the proposed rule covers:

– Classification thresholds for designated nonattainment areas

– Reclassification of areas that have voluntarily requested higher 

### classifications

– Attainment deadlines for nonattainment areas

– Revocation of the 1997 ozone NAAQS for purposes of Transportation Conformity



### • All other implementation rule and guidance issues will be addressed in separate rulemaking that is targeted for proposal this spring, and final by end of 2012. 2Office of Air & Radiation 

# CAA Classification Scheme

• Table 1 in CAA section 181 specifies ozone design values associated with each classification, based on the standard that existed in 1990 (0.120 ppm 1

- hour exceedance

based NAAQS).

• Each classification has a specified attainment date tied to 

### a number of years after the CAA amendments were enacted.

• For subsequent 8

- hr standards, the Table 1 design values and 

### attainment dates are outdated, but the same basic classification structure applies.
3 Table 1 from CAA Section 181(a)(1)

Area classification Design value ( ppm ) Primary

standard attainment date

Marginal 0.121 up to 0.138 3 years after Nov 15, 1990

Moderate 0.138 up to 0.160 6 years after Nov 15, 1990

Serious 0.160 up to 0.180 9 years after Nov 15, 1990

Severe 0.180 up to 0.280 15 years after Nov 15, 1990

Extreme 0.280 and above 20 years after Nov 15, 1990Office of Air & Radiation 

# Classification Thresholds of NAAs

• EPA is proposing thresholds based on the “Percent

Above

- the

- Standard” method for translating the design values in CAA section 181, Table 1 (1

- hour thresholds) 

## into 8

- hour thresholds for the 2008 8

- hour NAAQS.

• The same methodology was used for classifying areas for the 1997 8

- hour NAAQS.



## • Upper thresholds for each classification are based on calculated percentages above the level of the NAAQS:

• 15% for Marginal (0.138

- 0.120)/0.120

• 33.33% for Moderate (0.160

- 0.120)/0.120

• 50% for Serious (0.180

- 0.120)/0.120

• 133.33% for Severe (0.280

- 0.120)/0.120 4Office of Air & Radiation 

# Calculation of Thresholds Using Percent
- Above
- the
- Standard Method

5 Classification Range ( ppm ) # Hypo. NAAs*
Marginal 0.076 up to 0.086 43

Moderate 0.086 up to 0.100 6

Serious 0.100 up to 0.113 3

Severe 0.113 up to 0.175 0

Extreme 0.175 and up 0 

### • The level of the 2008 NAAQS is multiplied by the percent above the standard for each classification threshold in 

### Table 1 of the CAA.

• The result is added to the level of the 2008 NAAQS to obtain the new threshold.

• For example, to calculate the upper threshold for the Moderate classification using 0.075 ppm : (0.075 ppm x 33.3%) + 0.075 ppm = 0.100 ppm * Estimated with 2010 Design ValuesOffice of Air & Radiation 

# Reclassification of areas that voluntarily requested higher classifications

• Under the 1997 ozone NAAQS, 7 areas requested a voluntary reclassification.

• EPA is proposing to apply 

### these voluntary reclassifications to the 2008 ozone NAAQS unless the state requests otherwise.



### • Texas has already indicated they do not wish to apply the previous reclassification to the Houston NAA.

6 Areas for which the State Requested a Voluntary Reclassification

Under the 1997 NAAQS

Nonattainment Area St. Original 1997

NAAQS Classification Voluntary

Reclassification Request 2008

NAAQS Potential Classification Los Angeles

South Coast Air Basin CA Severe Extreme Serious

San Joaquin Valley CA Serious Extreme Serious

Houston

Galveston

Brazoria TX Moderate Severe Marginal

Riverside County (Coachella Valley) CA Serious Severe Moderate

Sacramento Metro CA Serious Severe Serious Ventura County CA Moderate Serious Moderate Western Mojave (pending) CA Moderate Severe ModerateOffice of Air & Radiation 

# Proposed Attainment Deadlines

• CAA section 181 establishes attainment dates based on area classification.



### • EPA is requesting comment on 2 proposed options for establishing attainment dates for the 2008 NAAQS that are 

### consistent with the intent of the CAA.

• If designations are completed in 2012, attainment dates 

### would range from 2015 to 2032.

7 Area classification Attainment

deadline Attainment

Year

Marginal 3 years 2015

Moderate 6 years 2018

Serious 9 years 2021

Severe 15 years 2027

Extreme 20 years 2032Office of Air & Radiation 

# Proposed Attainment Deadlines

– Option 1: X years after Effective Date of Designations

• Under this option, EPA is proposing that the deadlines in the regulatory table would be established in terms of a specified number of years from the effective date of designation for the 2008 standard.



### • This is the same approach used for the 1997 NAAQS.

• Under Option 1, the term “years” in CAA Table 1 is interpreted to mean “rolling 365

- day periods” and the words “after the effective 

### date of designation” would be substituted for the CAA’s “after November 15, 1990” language.

• For example, if designations are effective on August 15, 2012, the attainment date for Moderate areas would be August 15, 2018.

– Under Option 1, the evaluation of attainment for Moderate areas in this example would be based on the 2017 design value (2015

- 2017 air quality data). Air quality data from 2018 would not be considered.
8Office of Air & Radiation 

# Proposed Attainment Deadlines

– Option 2:

End of Calendar Year

• Under this option, EPA is proposing that the deadlines in the regulatory table would be established as the number of CAA

- specified years from the end of the calendar year in which an area’s nonattainment designation is effective. This is EPA’s preferred option.

• This option assures each nonattainment area will be afforded 3, 6, 9, 15, or 20 full ozone seasons (per classification) after designation to attain.

• For example, if designations are effective on August 15, 2012, the attainment date for Moderate areas would be December 31, 2018.

• Under Option 2, the evaluation of attainment for Moderate areas in this example would be based on the 2018 design value (2016

- 2018 air quality data). This would allow air quality improvements due to emissions reductions occurring in the 2018 ozone season to inform attainment determinations.

• EPA believes this is consistent with the near end

- of

- year outcome (i.e., November 15) associated with the 1990 CAA amendments.

9Office of Air & Radiation 

# Revocation of the 1997 NAAQS for Transportation Conformity Purposes

• A conformity demonstration is intended to show that implementation of the metropolitan transportation plan, TIP, or project falls within an area’s mobile source emissions budget.

• Newly designated areas have a 1

- year grace period for transportation conformity. A conformity “lapse” occurs if a conformity determination has not been made by the end of the grace period.

• EPA is proposing to revoke the 1997 ozone NAAQS 1 year after the effective date of designation for the 2008 ozone NAAQS for purposes of transportation conformity only.

– This provides certainty for planning operations, and prevents areas from having to implement the transportation conformity program for two different NAAQS concurrently.

– Backsliding is prevented through the use of approved motor vehicle emissions budgets for a prior ozone NAAQS until new budgets are established for the 2008 ozone NAAQS. 10