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20 <br />2. Air Quality Planning <br />USEPA originally declared Durham County, Wake County and Dutchville Township in Granville <br />County non-attainment for ozone (03) under the 1-hour ozone standard and Durham County and <br />Wake County non-attainment for Carbon Monoxide (CO) on November 15, 1990. Ozone, the <br />primary component of smog, is a compound formed when volatile organic compounds (VOC) and <br />oxides of nitrogen (NOR) mix together in the atmosphere with sunlight. NOR and VOC are referred <br />to as ozone "precursors." Durham County, Wake County and Dutchville Township were <br />redesignated by USEPA to attainment with a maintenance plan for ozone under the 1-hour standard <br />on June 17, 1994 and Durham County and Wake County were redesignated by USEPA to attainment <br />with a maintenance plan for CO on September 18, 1995. <br />In 1997 the NAAQS for ozone was reviewed and revised to reflect improved scientific <br />understanding of the health impacts of this pollutant. When the standard was revised in 1997, an <br />eight-hour ozone standazd was established that was designed to replace the one-hour standard. The <br />USEPA designated the entire Triangle azea as a "basic" non-attainment azea for ozone under the <br />eight-hour standazd with an effective date of June 15, 2004; the designation covered the following <br />geographic areas: <br />• Durham County <br />• Wake County <br />• Orange County <br />• Johnston County <br />• Franklin County <br />• Granville County <br />• Person County ' . <br />• Baldwin, Center, New Hope and Williams Townships in Chatham County <br />On December 26, 2007, the Triangle Area was redesignated as attainment with a maintenance <br />plan for ozone under the eight-hour standazd. The USEPA direct final rule from the Federal <br />Register for CO is found in Appendix A. The USEPA direct final rule for ozone is provided in <br />Appendix B. <br />2.1 Emissions Budgets <br />DENR prepared emissions budgets as part of their CO and 8-hour ozone maintenance plans for <br />those areas subject to budgets. Each of the eight counties or portions of counties in the bulleted <br />list above is part of the Triangle ozone maintenance azea under the 8-hour ozone standard and has <br />emissions budgets for NOR. Emissions budgets were established for 2008 and 2017. The 2008 <br />budgets apply for years up to and including 2016, while the 2017 budgets apply for 2017 and all <br />subsequent yeazs. The December 26, 2007 Federal Register notice establishing the NOR budgets <br />deemed VOCs insignificant, hence no VOC budgets apply to the region. <br />Durham and Wake Counties have CO maintenance requirements under the most recent SIP <br />Maintenance Plan update, which supplemented the pre-existing 2005 CO budgets with new <br />2015 budgets for each county. Under the update, the existing 2005 budgets from the prior SIP <br />apply between 2005 and 2014 and the newer 2015 budgets apply from 2015 onwazds. <br />12 <br />