The Clean Air Act Amendments of the 1990 and the federal transportation authorization legislation - Safe, Accountable, Flexible and Efficient Transportation Equity Act - A Legacy for Users (SAFETEA-LU) require that plans and programs in the Long Range Transportation Plan (LRTP) and the Transportation Improvement Program (TIP) not degrade air quality. An air quality conformity analysis and determination must be done to prove that implementation of the plans will not "cause or contribute to any new violation of any standard in any area, increase the frequency or severity of any existing violation of any standard in the area, or delay timely attainment of any standard or any required interim emission reductions or other milestones in any area."
Three pollutants are a concern for the Winston-Salem Urban Area Metropolitan Planning Organization - ozone, carbon monoxide and particle pollution less than 2.5 microns (PM2.5) in diameter. The Air Quality Conformity Analysis summary for carbon monoxide and ozone is in Chapter 8 of the 2035 Long Range Transportation Plan Update (LRTP) document and the detailed analysis is located in the Appendices of that document.
Nationally, PM2.5 is a recent addition to the pollutants requiring conformity analysis. In North Carolina, Catawba, Davidson and Guilford Counties were identified as nonattainment in 2005. On April 6, 2006, the Federal Highway Administration and the Environmental Protection Agency approved The PM2.5 Conformity Analysis and Determination Report for the Triad. The report and appendices are available for review in Adobe Acrobat PDF format.
The following link will open in a new window; the linked web site is not part of the City of Winston-Salem: