On 11/25/14, EPA proposed to tighten the ground-level ozone standards to within a range of 65 to 70 ppb or possibly as low as 60 ppb, as compared to the current NAAQS of 75 ppb. Public comments will be accepted for 90 days after publication in the Federal Register. And, EPA plans to issue the final revised ozone NAAQS by 10/01/15.
Proposed Rule: http://www.epa.gov/glo/pdfs/20141125proposal.pdf
More information: http://www.epa.gov/glo/actions.html#nov2014