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| Air Quality Research |
| Title: | Dallas-Fort Worth Transport Project |
| Project Period: | 01/12/2004 - 04/15/2004 |
| Total Budget: | $67,760 |
| Sub-Contractors: | ENVIRON - Till Stoeckenius, Greg Yarwood ($67,760)
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Ozone concentrations in the Dallas – Ft. Worth (DFW) area have exceeded the National Ambient Air Quality Standard (NAAQS) for many years. Tarrant, Dallas, Denton, and Collin counties (the four “core” counties) were originally classified as "moderate" nonattainment with respect to the 1-hour ozone NAAQS in 1991. This four county region is currently designated as a serious 1-hour ozone nonattainment area with an attainment date of 2005.
In 1997, EPA promulgated a new, 8-hour average ozone standard which is generally more stringent than the previous 1-hour standard. Texas is currently developing a Transitional SIP which will address attainment of both the 1-hour and 8-hour standards. This SIP is due to be submitted in 2004. Texas and EPA are currently in discussions concerning the boundaries of the new 8-hour DFW nonattainment area. EPA proposed including all twelve counties that constitute the DFW Consolidated Metropolitan Statistical Area (CMSA) in the new nonattainment area whereas Texas recommended excluding five of the outlying CMSA counties from the new nonattainment area.
High ozone events in the DFW area are influenced by NOx and VOC emissions from sources within the four core county region, by emissions from counties just outside of this region, and by transport of ozone and ozone precursors from other parts of Texas and neighboring states.
Modeling of the August, 1999 high ozone episode conducted in support of the current SIP revision demonstrated the importance of NOx sources and regional transport. Transport from sources located in counties surrounding the central DFW area may or may not be subject to nonattainment area controls such as emission offset requirements depending on where the nonattainment area boundary is ultimately drawn. In addition, transport from upwind locations will change in future years in response to economic growth and implementation of emission control measures affecting those locations. Due to their potential significance, additional information is needed on the relative impacts of transport from these sources on violations of the ozone NAAQS in DFW.
Related Documents
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| Page Updated/Reviewed: 05/24/2006 11:48 AM |
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