EPA has issued a final rule repealing the “grandfather” provision for fine particulate matter—particles 2.5 microns in diameter or smaller (PM 2.5)— which provision allowed certain facilities with federal prevention of significant deterioration (PSD) permits on file before July 15, 2008, to use coarse particles as a surrogate for fine particles. 76 Fed. Reg. 28,646 (5/18/11). EPA took no action on a proposal that would have terminated early the use of the surrogate policy under state PSD programs that are part of an approved state implementation plan (SIP). Accordingly, use of the policy, which allowed facilities to use coarse particles as a surrogate during the three years they were given to revise their SIP to comply with fine particle standards, ended on May 16, 2011.

Coarse particles (PM-10) are those that are 10 microns in diameter or smaller, but larger than 2.5 microns in diameter. The grandfather provision was based on an interim policy for coarse particulate matter as a surrogate EPA adopted in 1997 and codified in 2008. 73 Fed. Reg. 28,321. EPA believes the policy is no longer needed because technical tools and test methods now exist to monitor and calculate fine particle emissions. According to EPA, the final rule will affect fewer than 30 proposed new major sources or modifications under the federal PSD program.