2017 Chico, CA/Butte County PM2.5 Redesignation Request and Maintenance Plan Categories Topics Air Quality Plans Programs California State Implementation Plans Type Information The California Air Resources Board (CARB) approved the Chico, CA/Butte County PM2.5 Redesignation Request and Maintenance Plan at a public hearing on November 16, 2017. This Plan was submitted to U.S. EPA as part of the State Implementation Plan. CARB DocumentsNotice of Public Hearing (10/13/2017)Staff Report (10/13/2017)District DocumentsDistrict Plan (9/26/2017)U.S. EPA Documents and ActionsFinal Rule: Chico Redesignation Request and Maintenance Plan for the 2006 24-hour PM2.5 Standard (83 FR 32064, eff. 8/10/2018)Proposed Rule: Chico Redesignation Request and Maintenance Plan for the 2006 24-hour PM2.5 Standard (5/9/2018)Final Rule: Determination of Attainment by the Attainment Date (82 FR 21711, eff. 6/9/2017) Related Resources 2024 Transport State Implementation Plan Amendment 2023 Carbon Monoxide SIP Revision 2024 San Joaquin Valley PM2.5 Plan