U.S. EPA Proposes Revisions to Address Error in New Source Review Regulations

On Friday March 16, 2012, the U.S. EPA proposed to revise the definition of regulated NSR pollutant under the Prevention of Significant Deterioration (PSD) regulations (40 CFR 51.166 and 52.21), and under the “Emission Offset Interpretative Ruling” (40 CFR Part 51 Appendix S).  The proposed revision will correct an error dating back to 2008 that was included in the final rule implementing the new source review (NSR) program for particulate matter with an aerodynamic diameter of less than or equal to 2.5 microns (PM_2.5).  Prior to the 2008 revisions, the NSR regulations did not require the inclusion of condensable particulate matter, consistent with applicable New Source Performance Standards (NSPS) for particulate matter (PM).  However, the existing definition of NSR regulated pollutant was changed in 2008 to require that PM emissions, PM₁₀ emissions, and PM_2.5 each include the condensable particulate matter fraction. The proposed revision, if finalized, will establish the pre-2008 interpretation that there is no requirement to include condensable particulate matter when measuring particulate matter emissions in the context of the PSD and NSR regulations (e.g., NSR applicability determinations for particulate matter emissions can exclude condensable particulate matter under the proposed revisions).  Particulate matter emissions will be regulated as a non-criteria pollutant (e.g., [a]ny pollutant that is subject to any standard promulgated under Section 111 of the Act) because there is no longer a National Ambient Air Quality Standard (NAAQS) for total suspended particulate (TSP).  While U.S. EPA’s acknowledgement of the error and their proposal to correct it is acknowledged, one has to wonder how many NSR applicability determinations that included particulate matter emissions would have exhibited a different outcome based on the proposed revisions.