Public Notice of the Implementation of Contingency Rules for Collin, Dallas, Denton, and Tarrant Counties
The DFW area has failed to attain the 1997 eight-hour ozone National Ambient Air Quality Standard by the June 15, 2010, attainment deadline based on monitoring data. The ambient ozone monitoring data from 2007, 2008, and 2009, which have been validated by the TCEQ staff, indicate that the DFW area has an ozone design value of 86 parts per billion (ppb), thereby exceeding the 1997 eight-hour ozone standard of 0.08 parts per million (which is met when the design value is 84 ppb or lower).
Owners and operators of certain storage tanks and transport vessels for Volatile Organic Compounds (VOCs), in Denton, Tarrant, Dallas, and Collin Counties will be required to comply with stricter emissions requirements. Compliance is requested as soon as possible, but no later than May 20th, 2011.
Ozone at ground level is harmful to humans in a variety of ways, including aggravation of asthma. This ground level ozone is created by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight.
Nearly as much of the VOC emissions in North Texas come from oil and gas activities: 112 tons per day (TPD), as from vehicle traffic: 120 TPD.
The 1997 8-hour Ozone standard is no more than 0.08 ppm. The 2008 standard is 0.075 ppm. One part per million (PPM) is roughly equivalent to inhaling two teaspoons per day of that substance.