Air Quality State Implementation Plans; Approvals and Promulgations: California; Opacity Testing of Heavy-Duty Diesel Vehicles

Publication Date: 
Tuesday, May 10, 2022 - 4:00am

The Environmental Protection Agency (EPA) is taking final action to approve a revision to the California State Implementation Plan (SIP) concerning particulate matter (PM) emissions from heavy-duty (HD) diesel vehicles. We are approving state rules that regulate PM emission sources under the Clean Air Act (CAA or the Act).

Environmental Protection Agency