Transportation Conformity Guidance on the Revocation of the 1997 Primary Annual PM2.5 NAAQS, EPA-420-B-16-072
Abstract
This guidance describes how the revocation of the 1997 primary annual PM2.5 National Ambient Air Quality Standard (NAAQS) will be implemented and when transportation conformity stops applying for this NAAQS. It fulfills a commitment EPA made in November 2015 to provide additional information once it finalized the PM2.5 state implementation plan requirements rule. This guidance provides the additional information related to the revocation of the 1997 primary annual PM2.5 NAAQS.