Tag Archives: NAAQS

US EPA Finalizes Revisions to Ozone National Ambient Air Quality Standard

On October 1, US EPA issued much-anticipated final rule revisions intended to tighten the ground-level ozone (O3) national ambient air quality standard (NAAQS). US EPA will set the primary ozone NAAQS at 70 parts per billion (ppb). This new standard significantly lowers the existing 75 ppb standard set in 2008. This will push portions of the … Continue Reading

US EPA Releases Proposed 8-hr Ozone Standards

On November 25, 2014, US EPA released its long-awaited proposal to tighten the 8-hr ground-level ozone standard. The impacts of this rule are difficult to overstate. Unless changed, it will push much of the country into non-attainment, forcing state regulators to pursue emissions reductions while making permitting more difficult and restricting growth. A Smoggy Past: … Continue Reading

US EPA Issues Final PM2.5 Implementation Rule Following Remand

On June 2, US EPA published a final rule that outlines the regulatory framework states must follow to implement the 1997 and 2006 standards for fine particulate matter, or PM2.5.  The Rule was issued in response to a remand from the D.C. Circuit Court of Appeals in January 2013, which returned for correction a pair of rules … Continue Reading

D.C. Circuit Upholds US EPA’s Revised PM2.5 Standard Despite Serious Concerns Raised

On May 9, the Court of Appeals for the D.C. Circuit upheld US EPA’s rule revising the annual National Ambient Air Quality Standard (NAAQS) for fine particulate matter (PM2.5) despite serious concerns regarding how states and regulated entities are to proceed under new rules.  The January 2013 final rule lowers the annual allowable limit for PM2.5, eliminates the option of “spatial … Continue Reading