Yesterday (January 06, 2010) the EPA proposed tightening the NAAQS for ozone from .075 parts per million (ppm) to between .060 and .070 ppm, still measured over 8 hour intervals. The EPA also extended the deadline for designating non-attainment areas on the previous 2008 standard until March 12, 2011. The EPA expects to complete its review over this proposed tightening of the standard by August of 2010. If the EPA moves forward with a tightened standard, it would begin a new process to designate areas for the 2010 ozone NAAQS on an accelerated schedule.
Tightening the standard to .060 ppm would also likely cause existing non-attainment areas to become more affected and perhaps several new counties to fall into non-attainment. The affected states will have to address this in the coming years through both their ERC trading programs and permit revisions. A tightened standard could also support a tighter cap under whatever fix the EPA comes up with for the CAIR program or successor legislation should something develop on that front.