On Monday, EPA released its second external review draft of an updated Policy Assessment on the national ambient air quality standard for ozone.  It also released updated draft risk and exposure assessments.  To no one’s surprise, the new drafts confirm support for lowering the ozone NAAQS from 75 ppb to a range of 60 ppb to 70 ppb.

Why is this not a surprise?  Because, as I noted some time ago, the prior draft policy assessment also supported an NAAQS in the range of 60 ppb to 70 ppb.  Moreover, the Clean Air Science Advisory Committee weighed in on the prior draft, supporting a standard in the 60 ppb to 70 ppb range.  In fact, before getting cold feet, CASAC had indicated that the data would support a standard below 60 ppb.

Courts’ deference to CASAC determinations on these issues is pretty well established.  It seems clear that EPA has to lower the NAAQS to at most 70 ppb in order to survive judicial review.  It’s not even obvious that 70 ppb would stick, though that will be clearer after CASAC has reviewed this most recent draft Policy Assessment.

The other significant question is when EPA will actually issue the new standard.  After all, EPA was prepared to issue a new standard in 2011 or early 2012, when the White House put the proverbial kibosh on EPA’s plans.  Will EPA somehow manage to delay issuance of the new standard until after the November elections?  Now that the Super Bowl is over, I think that the Vegas bookies are putting their money on after.