In 2008, EPA established a new national ambient air quality standards (NAAQS) standard.  This was an 8-hour standard of 0.075 ppm.  States were required to recommend a designation of areas that did not meet this standard.  TDEC recommended that only the portion of Blount County within the Great Smoky Mountains National Park be designated as Nonattainment, and the rest of the state be designated as Attainment.  As a fall-back alternative, TDEC recommended that Knox County and two adjacent partial counties (the northern portion of Blount County and a small portion of Anderson County) also be designated as nonattainment.  TDEC acknowledged nonattainment measurements for Blount County at high elevations within the GSMNP, and argued that they were predominantly influenced by long range transport.

Instead, on April 30, 2012, EPA designated all of Shelby, Knox and Blount Counties as nonattainment, as well as a small portion of Anderson County near the TVA Bull Run Steam Plant.  The consequence is more restrictive and difficult air pollution permitting in these counties for major new sources, and major modifications of existing sources, of nitrous oxides (NOx) and volatile organic compounds (VOCs).  The difficulties this will pose in recruiting industries in these areas was discussed in this Knoxville News Sentinel article.