On April 2, 2026, the Board adopted amendments to keep Illinois’ ambient air quality standards (35 Ill. Adm. Code 243) identical in substance to the National Ambient Air Quality Standards (NAAQS). The amendments reflect three actions taken by the United States Environmental Protection Agency (USEPA) during the 18-month period of July 1, 2024 through December 31, 2025.
Publications 
