Approval and Promulgation of Air Quality Implementation Plans; Colorado; Revisions to Regulation Number 3

The Environmental Protection Agency (EPA) is proposing approval of a portion of the State Implementation Plan (SIP) revisions submitted by the State of Colorado on February 25, 2015. The revisions are to Colorado Air Quality Control Commission (Commission) Regulation Number 3, Parts A, B and D. The amendments the EPA is proposing to act on include: Revisions to provisions for permitting emissions for particulate matter less than 2.5 micrograms (PM2.5) in Part D, modifications to the provisions for filing revised Air Pollution Emission Notices (APEN) in Part A and updates to public notice publication requirements in Part B. This action is being taken under section 110 of the Clean Air Act (CAA).