On November 5, the Clean Air Act Scientific Advisory Committee ("CASAC") held a teleconference as a part of EPA's evaluation of potential revisions to the ozone NAAQS set in 2008. CASAC was established by Congress to oversee EPA's ozone NAAQS review, considering ozone's risks to health as well as the potential adverse economic impacts of a stricter standard. The committee is in the process of finalizing recommendations to revise the standard that was set in 2008 at 75 parts per billion ("ppb"). EPA's science advisors have said that the agency could be justified in considering an ozone standard between 50 ppb and 70 ppb. However, many experts say that setting the standard at the lower end of that spectrum would put much of the country in nonattainment. The background levels of ozone in many parts of the country are at or near 50 ppb. Stakeholders have urged the consideration of background levels in the process of establishing a new ozone NAAQS. 

EPA expects to issue a final rule revising ozone NAAQS in September 2014.