1. Ozone Regulation under the Clean Air Act Darcy J. Anderson AZ Dept. of Environmental Quality

2. 2 Presentation Outline 8-Hour Ozone Standard – Background / Timeline 8-Hour Ozone Standard – Designation Process Arizona Designation Process – Examples Potential Impacts of 8-Hour Ozone Designations on Tribes Next Steps in 8-Hour Ozone Process

3. 3 NAAQS for Ozone 1-hr standard 0.12 ppm (parts per million) 8-hr standard 0.08 ppm

4. 4 The 8-Hr Rolling Average Average of 8 consecutive hours EPA ozone standard requires that 4 th highest 8-hr average be ≤ 0.084ppm –Actual standard is 0.080ppm, but anything ≤ 0.084 is truncated to 0.080 Small-group activity on this today at 1:45

5. 5 July 1997: EPA issued revised 8-hour health- based standard for ozone. –Studies show that long-term, low exposure to ozone as harmful to human health as short-term, high exposure. –New standard more protective for longer exposure 8-Hour Ozone Standard – Background / Timeline

6. 6 2000: EPA issues guidance documents February 2001: –U.S. Supreme Court upheld 8-hour ozone standard –Directed EPA to develop implementation approach

7. 7 Comparison of Ozone Standards StandardLevelAveraging Time Form (attainment test) One-Hour0.12 ppm1 hour Three exceedances at a monitor allowed in a three year period; fourth exceedance is a violation Eight-Hour0.08 ppm8 hours Three-year average of the annual fourth highest 8-hour concentration, calculated for each monitor* *Because of rounding convention, 0.085 ppm considered level of violation

8. 8 8-Hour Ozone Standard - Designation Process November 2002: lawsuit settlement –EPA & environmental groups agree on schedule for EPA to promulgate 8-hour ozone designations

9. 9 8-Hour Ozone Standard - Designation Process (cont.) February 27, 2003: EPA memorandum on 8-hour ozone designations –Extended deadline for states to submit recommendations for designating areas –New deadline July 15, 2003

10. 10 8-Hour Ozone Standard - Designation Process (cont.) June 2003: EPA proposes rule for implementing 8-hour NAAQS Final rule for implementing 8-hour NAAQS expected early 2004

11. 11 8-Hour Ozone Standard - Designation Process (cont.) July 15, 2003: State recommendations for area designations submitted to EPA Tribes could also submit recommendations by this date Options –Attainment / unclassifiable –Nonattainment

12. 12 8-Hour Ozone Standard - Designation Process(cont.) July 2003: Governor’s recommendation for AZ submitted to EPA –Recommended all areas of state attainment / unclassifiable for 8-hour standard except Phoenix metro area –No state jurisdiction / recommendation for Indian reservations –Some Arizona tribes submitted their recommendations

13. 13 Arizona Designation Process: Examples Monitoring data – exceedances, violations Location of emission sources Meteorology, geography, and jurisdictional boundaries Population Traffic and commuting patterns

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21. 21 Potential Impacts of 8-Hour Ozone Designations on Tribes Boundary / background / transport Tribes can provide valuable ozone data for urban nonattainment areas Tribes can conduct additional ozone and NOx monitoring to assist with model verification Public information / outreach (API) Ozone mapping – AIRNOW

22. 22 Next Steps in 8-Hour Ozone Process February 6, 2004: Revised nonattainment area recommendations due to EPA EPA looking at 2003 ozone monitoring data to determine effect on recommended area designations Designations and classifications published in FR by April 30, 2004

23. 23 Next Steps: Ozone Implementation Plan June 2, 2003 – EPA proposed rule to implement 8-hour NAAQS –Option 1: All areas under Subpart 2 –Option 2: Separate areas based on whether they meet the 1-hour standard Regulate areas meeting the 1-hour standard under Subpart 1 Regulate areas exceeding the 1-hour standard under Subpart 2 Subpart 1 - more flexible, minimal mandated controls Subpart 2 - proscriptive (attainment dates based on classification [marginal, moderate, serious, etc]

24. 24 Next Steps: Ozone Implementation Plan (cont.) –Anticipate implementation of new standard for Phoenix area either under subpart 1 or marginal under subpart 2 Subpart 1 option - Attainment demonstration due 2007; attainment required 2009 Subpart 2 option – Attainment required 2007 New control measures may be necessary to meet proposed attainment date

25. 25 Next Steps in 8-Hour Ozone Process: NOx Waiver What is a NOx waiver? Draft rule proposes NOx waiver under CAA Section 182(f) apply to any area designated nonattainment for 8-hour standard Requires new analysis to obtain waiver under 8-hour guidance

26. 26 NOx Waiver (cont.) NSR & RACT requirements for major stationary VOC sources also apply to major NOx sources Unless NOx waiver provision implemented

27. 27 For More Detail Refer to full text outline in manual Outline follows PowerPoint slide pages