The U.S. Environmental Protection Agency (EPA) proposed to reclassify the Dallas-Fort Worth area (DFW) as being in severe nonattainment of the original 8-hour ozone standard of 84 parts per billion. The proposal will be published for public comment in the Federal Register in seven to 10 days. Upon publication, a 30-day public comment period will begin.
EPA has been coordinating closely with Texas Commission on Environmental Quality (TCEQ), North Central Texas Council of Governments, elected officials and statewide environmental organizations in preparation for the proposed action. While DFW’s air quality has steadily improved as its population grows, the area missed a June 2013 deadline to attain the 1997 ozone standard. Because the area did not meet the deadline of June 15, 2013, to attain the 1997 standard, the Clean Air Act requires EPA to reclassify DFW as a severe nonattainment area.
EPA revised the 8-hour health-based standard for ozone in 2008. In 2013, EPA proposed for public comment guidelines for the revised standard, including plans to revoke the 1997 ozone standard for all purposes and to no longer reclassify areas under the old standard. However, this proposal still is not final.
TCEQ has developed a clean air plan for the revised 2008 ozone standard and is expected to submit that plan to EPA for review by July 2015. A copy of the proposed plan is publicly available at http://www.tceq.texas.gov/airquality/sip/dfw/dfw-latest-ozone .
DFW air quality has significantly improved over the last decade. Ten years ago, the 8-hour average was 98 parts per billion (ppb); the preliminary value for 2010-2014 is 81 ppb. During that time, DFW has also been among the fastest-growing regions in the country. The area’s achievement came through a combination of federal measures to clean up fuels and reduce emissions from engines, state measures to reduce emissions from stationary sources, and efforts of the public during ozone season—including using public transport, refueling in the evenings, and properly maintaining their vehicles.