Earlier this year, a Federal Appeals Court ruled that the Federal 9 ug/m3 PM2.5 ambient air quality standard will stand. As a result, EPA is now warning many states that they could have areas that are in “nonattainment” with EPA’s tightened federal limit for fine particulate matter (PM2.5) that will require tough emissions controls. This notice comes at the same time as the agency appeals a lower court order that required final designations by Feb. 6 and challenges the standard itself. On Oct. 2 EPA announced that it had sent letters to all 50 states informing them of initial monitoring and other data that indicate whether areas within their jurisdictions could be in nonattainment with the national ambient air quality standards (NAAQS) for PM2.5. States have 120 days to respond. According to a one report only 14 states including, Connecticut, Mississippi, Nebraska, Nevada, New York, North Carolina, North Dakota, Rhode Island, South Dakota, Tennessee, Vermont, Washington and the District of Columbia were found to have no data showing exceedances and were slated to be found in attainment with the standard. The agency’s actions are required by the U.S. District Court for the Northern District of California, which set Feb. 6 as the deadline for EPA to complete the area designations rulemaking. We understand that EPA is appealing the ruling and recently pressed the U.S. Court of Appeals for the 9th Circuit to accelerate briefing in the agency’s challenge. Meanwhile, several states and industry groups are asking the Supreme Court to reverse the appellate court ruling that upheld the original standard. This is a very restrictive standard that is nearing background levels, which is why so many states are going to have nonattainment areas.