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Frequently Asked Questions and Answers
What has been done to improve the Dallas Fort Worth 8-hour Ozone SIP since it was submitted to EPA Region 6?
Since the submittal of the DFW 8-hour SIP to EPA on May 30, 2007, a number of actions have occurred to strengthen and clarify the SIP. These include continued and enhanced implementation of the TERP program, better understanding of emissions from airports, limitations on the use of pollution credits by power plants, and new survey of gas compressors. Each of these is discussed in more detail below.
There has been great collaboration between the TCEQ, EPA Region 6, and the North Central Texas Council of Governments since the SIP was received on May 30, 2007 in order to determine ways to strengthen the SIP and increase the certainty of achieving attainment of the 8-hour ozone standard. The following are six efforts.
1. TERP – This is one of the most important additions to the SIP based on the 80th Legislature providing additional funding for the program. The Governor of Texas signed House Bill 1, which allowed the Legislature to appropriate $297,144,243 in funding statewide for TERP. To assist in the implementation of TERP, EPA held a meeting on December 10, 2007 with TCEQ, Mayors, County Judges and Superintendents of Schools in the North Texas area asking them to join forces and collaborate with other cities, individuals and businesses to promote the aggressive participation in the TERP program. EPA, TCEQ, NCTCOG, City of Dallas, City of Ft. Worth, Greater Dallas Chamber of Commerce, Ft. Worth Chamber of Commerce, and the Texas Business for Clean Air partnered to maximize DFW's participation in this program.
As of June 17, 2008, applications for 644 TERP projects were submitted for the DFW area totaling $84,175,000. This was 57% higher than the Houston area which had applications for $53,644,000. The expected emission reduction benefit of the TERP funding is an added emission reduction of 14.2 tpd.
2. AirCheck Texas was funded in the DFW area at $21,348,583 each for fiscal years 2008 and 2009. As of June 12, 2008, 12,441 vouchers had been issued by the North Central Texas Council of Governments. Of these, 957 were repair vouchers redeemed for a total of $452,162 and 6,412 replacement vouchers had been redeemed for $19,256,000. This reflects a very high interest and work effort in administering the program by NCTCOG. The resulting emission reductions are difficult to quantify due to the varying makes, models, and years of cars in the program; therefore, the program is accounted for qualitatively in the SIP.
3. Also as part of the collaborative effort, the airport emissions inventory was a sector identified as meriting more intensive review. DFW International Airport, Love Field, the City of Fort Worth and the City of Dallas all agreed that there was value in a current assessment of the airport’s emissions. After adoption of the SIP, the NCTCOG worked to get more accurate and updated landing and take off (LTO) data from the City of Dallas and DFW International Airport. Based on the updated 2005 operational data for both airports, the emissions estimates for the 2009 attainment years for aircraft and GSE verified that emissions should be reduced by 9.4 tpd. Documentation of the effort is thoroughly provided in a letter and its attachments from TCEQ dated April 23, 2008.
4. Discrete Emission Reduction Credits (DERCs) Emission Inventory Adjustment - TCEQ included in the photochemical modeling for the SIP a conservative assumption that all 20.4 tpd of DERCs available in the bank would be used by March 1, 2009. However, since the DERC program began in 1993, no actual use of DERCs has occurred in the DFW nonattainment area. The State has committed to limit DERC use in 2009 to 3.2 tpd as a more realistic assumption, and will be addressing this in a SIP revision.
5. Back-up Generators - TCEQ adopted an enforceable regulation in Chapter 117 restricting the starting or operating of stationary diesel engines and stationary dual-fuel engines between 6:00am and noon. This restriction affects engines that are primarily used as back-up engines and will delay emission of NOx from testing until after noon to limit ozone formation. The measure is similar to control measures implemented for the Houston one-hour ozone attainment demonstration and approved by EPA. This measure in DFW is estimated to reduce NOx by 0.9 tpd. In the May 30, 2007 DFW SIP, this measure was not accounted for in the modeling. However, since the reduction is enforceable and quantifiable, and EPA supports this enforceable measure being modeled.
6. Gas Compressors – TCEQ researched the issue of emissions from oil and gas sources and provided their evaluation in a letter to EPA dated April 23, 2008. The overall net result of the survey shows that the number of compressor engines was underestimated. The reevaluation of the emissions from the new survey shows an overall estimate of 3 tpd more NOx than was projected in the May 23, 2007 SIP. This increase has been taken into consideration in the reanalysis of attainment.
Based on the effort to improve the emissions inventory for the airports, revisions to the projections of DERC usage, and the addition of back-up generators into the modeling, additional analysis was performed by TCEQ and EPA to determine the impact on future ozone levels and to provide support for the attainment demonstration.
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?
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