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Frequently Asked Questions and Answers
Isn't it true that the modeling that has been conducted does NOT predict attainment of the 8 hour standard at all DFW monitors?
Yes, however modeling is not perfect. Based on conservative modeling assumptions, seven of the nine monitors in the DFW area are predicted to show attainment with the 8 hour standard by the end of the 2009 ozone season. The other two monitors are close to the standard. EPA recognizes inherent uncertainties do exist with modeling, and the model only reflects the reductions mandated by State and federal law. EPA's guidance indicates that additional analyses should be part of all modeled attainment demonstrations where modeled projections are close to attainment. This is called Weight of Evidence (WOE). Among the items that EPA's guidance indicates that WOE should include are analyses of recent emission and monitoring trends, other emission changes not previously quantified such as local initiatives any additional modeling, and new information that was not included in the modeling analyses. The SIP proposed today has included such an analysis and we believe that the total assessment shows that in fact, all the DFW monitors will show attainment by the end of 2009. We understand that a WOE approach will be followed this year by many cities in the nation, such as Philadelphia, Charlotte, and Baltimore.
1. Why is EPA proposing a conditional approval of the DFW SIP?
2. What are accumulated pollution credits?
3. What measures are included in the DFW SIP?
4. Will the measures in the DFW SIP bring the area into attainment? How soon?
5. When will EPA consider final approval for the DFW SIP?
6. How does the new 8-hour ozone standard (0.075 ppm) impact this plan?
7. Will the state have to draft a new SIP once the new 8-hour standard goes into effect?
8. Why didn’t the DFW area just request a ‘bump up’ like Houston?
9. How long did it take the TCEQ to develop the DFW SIP?
10. How long did it take EPA to review the DFW SIP?
11. What is the significance of Texas being first in the nation to have its SIP approved?
12. Why is EPA taking public comments on the proposed approval?
13. When are the public comments due?
14. What will EPA do with the public comments?
15. What are the major controls in the DFW 8-hour SIP passed by TCEQ on May 23, 2007?
16. Isn't it true that the modeling that has been conducted does NOT predict attainment of the 8 hour standard at all DFW monitors?
17. What has been done to improve the Dallas Fort Worth 8-hour Ozone SIP since it was submitted to EPA Region 6?
18. What are the major measures and factors that make up the Weight of Evidence argument?
19. What would be the consequences if EPA did not approve the DFW 8-hour SIP?
20. What are our options if we approve the SIP and the area does not reach attainment by the June 15, 2010 attainment date?