1. Ozone Redesignation Substitutes for the HGB and DFW Areas
Walker Williamson
Air Quality Division
Texas Commission on Environmental Quality
Advanced Air Permitting Seminar 2016
HGB = Houston/Galveston/Brazoria
DFW = Dallas/Fort Worth

2. Overview Classifications What is a redesignation substitute?
Texas Redesignation Substitutes
Effects of Final EPA Approval
EPA = Environmental Protection Agency

3. Classifications
Classifications are important because they drive the SIP requirements for a nonattainment area, including nonattainment new source review tons per year (tpy) major source emissions thresholds and offset ratios.
Marginal:
100 tpy
1.1:1
Moderate:
1.15:1
Serious:
50 tpy
1.2:1
Severe:
25 tpy
1.3:1
Classifications also determine how much time a nonattainment area has to attain the standard.
Ozone classifications set nonattainment new source review tons per year (tpy) major source emissions thresholds and offset ratios.
Marginal
•100 tpy
•1.1:1
Moderate
•1.15:1
Serious
•50 tpy
•1.2:1
Severe
•25 tpy
•1.3:1
tpy = tons per year
To understand why redesignation substitutes are important to the HGB and DFW areas, it is important to understand the Federal Clean Air Act’s (FCAA) classification scheme for ozone.
Classifications are important because they drive the State Implementation Plan (SIP) requirements for a nonattainment area, including nonattainment New Source Review (NSR) thresholds and offset ratios.
Classifications also determine how much time a nonattainment area has to attain the standard.
Note: I’m not including the extreme classification because it only applies to areas in California.

4. HGB Ozone NAAQS Classifications
One-Hour
1997
2008
HGB
Ozone NAAQS Classifications
Severe
One-Hour:
Severe
1997:
2008:
Marginal*
* The HGB area’s marginal classification for the 2008 ozone NAAQS is expected to be bumped up to a moderate classification by the end of 2016.
Severe
NAAQS = National Ambient Air Quality Standards
Currently, New Source Review (NSR) offsets and thresholds are based on the area’s severe classification for the 1997 eight-hour ozone standard.
Note the asterisk: we anticipate the EPA will reclassify the HGB area to moderate by the end of 2016.
Marginal*

5. DFW Ozone NAAQS Classifications
One-Hour
1997
2008
DFW
Ozone NAAQS Classifications
Serious
One-Hour:
Serious
1997:
2008:
Moderate
Serious
For DFW, the serious nonattainment area requirements apply.
Moderate

6. What is a redesignation substitute?
The redesignation substitute is the EPA’s latest and most substantial attempt to address Federal Clean Air Act (FCAA) requirements in place for a revoked ozone National Ambient Air Quality Standard (NAAQS).
The redesignation substitute was established in the EPA’s Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements; Final Rule
Redesignation substitutes are required to meet the substance of the FCAA Section 107, which describes the requirements for a nonattainment area to be redesignated to attainment.
The EPA does not redesignate areas for a revoked NAAQS, so redesignation substitutes are important because they are currently the only way for states to remove nonattainment area requirements for those standards.
Redesignation substitutes are also important because they are a formal recognition of the progress that has been made in air quality improvement.
What is a redesignation substitute?
Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements; Final Rule

7. Section 107 Redesignation Versus Redesignation Substitute
Attainment of NAAQS
Permanent & Enforceable Emissions Reductions
Maintain NAAQS for 10 Years
Maintain NAAQS for 20 Years & Contingency Plan
SIP Revision
Section 107 Redesignation Versus Redesignation Substitute
§107 Redesignation Required Elements:
Attainment of NAAQS
Permanent & Enforceable Emissions Reductions
Maintain NAAQS for 20 Years & Contingency Plan
SIP Revision
Redesignation Substitute Required Elements:
Maintain NAAQS for 10 Years
A redesignation substitute is very similar to a true redesignation request and includes most of the same elements:
Attainment of the applicable NAAQS
A showing that attainment was due to permanent and enforceable emissions reductions
A demonstration that the area will continue to attain the NAAQS for 10 years after EPA approval
The redesignation substitute differs from a true redesignation in two important ways:
It is not a SIP revision, but what EPA terms a “showing”
Does not require a second 10-year demonstration of maintenance or contingency measures

8. Texas Redesignation Substitutes
Attained Standard:
2013
Submitted to EPA:
July 22, 2014
Approval:
October 20, 2015
HGB One-Hour Ozone
No §185 fee program SIP submittal required
Allows removal of nonattainment NSR permitting requirements for one-hour NAAQS
Effect
HGB One-Hour Ozone:
The area attained the standard in 2013.
The redesignation substitute was submitted to the EPA on July 22, 2014.
The EPA published final approval of the redesignation substitute on October 20, 2015.
Effect:
No §185 fee program SIP submittal is required for the one-hour standard.
Allows removal of nonattainment NSR permitting requirement for one-hour standard.

9. Texas Redesignation Substitutes
Attained Standard:
2014
Submitted to EPA:
August 18, 2015
Proposed Approval:
May 25, 2016
HGB 1997
Eight-Hour Ozone
HGB 1997 Eight-Hour Ozone:
The area attained the standard in 2014.
The redesignation substitute was submitted to the EPA on August 18, 2015.
The EPA published proposed approval of the redesignation substitute on May 25, 2016.
Effect:
No §185 fee program SIP submittal is required for the 1997 standard.
Approval would allow removal of nonattainment NSR permitting requirement for 1997 eight-hour standard.
No §185 fee program SIP submittal required
Would allow removal of nonattainment NSR permitting requirement for eight-hour NAAQS
Effect

10. Texas Redesignation Substitutes
Attained Standards:
2006 & 2013
Submitted to EPA:
August 18, 2015
Proposed Approval:
May 25, 2016
DFW One-Hour &
1997 Eight-Hour Ozone
DFW One-Hour & 1997 Eight-Hour Ozone:
The area attained the one-hour standard in 2006 and the 1997 eight-hour standard in 2013.
The redesignation substitute was submitted to the EPA on August 18, 2015.
The EPA published proposed approval of the redesignation substitute on May 25, 2016.
Effect:
Approval would allow removal of nonattainment NSR permitting requirements for both the one-hour and 1997 eight-hour standards.
Would allow removal of nonattainment NSR permitting requirements for one-hour and eight-hour NAAQS
Effect

11. Effects of Final EPA Approval
Final EPA approval would not relieve sources from obligations under previously established permit conditions.
Current SIP control measures would remain in effect.
HGB – 100 tpy and 1.15:1
After HGB reclassification is finalized, the major source thresholds and offset ratios would be:
DFW – 100 tpy and 1.15:1
HGB – 100 tpy and 1.1:1
If the redesignation substitutes were approved today, the major source thresholds and offset ratios would be:
Nonattainment NSR thresholds and offsets would be based on classification for 2008 ozone NAAQS.
Effects of Final EPA Approval
Nonattainment NSR thresholds and offsets based on classification for ozone NAAQS
Current SIP control measures remain in effect
Because the redesignation substitutes are not SIP revisions, the EPA is not held to a schedule to complete review.
If the redesignation substitutes were approved today, the major source thresholds and offset ratios would be:
HGB – 100 tpy and 1.1:1
DFW – 100 tpy and 1.15:1
After HGB reclassification is finalized, the major source thresholds and offset ratios would be:
HGB – 100 tpy and 1.15:1
Does not relieve sources from obligations under previously established permit conditions

12. Contact Information
Walker Williamson
SIP Team Leader
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Walker Williamson:
SIP Team Leader
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