Shifting Standards for Particulate Matter
Under the Clean Air Act, an area designated for nonattainment for an NAAQS must develop and submit a State Implementation Plan (SIP). This document serves as a comprehensive, enforceable roadmap demonstrating how the area will come into compliance. For the 2024 PM2.5 standard, nonattainment area SIPs will be due within 18 months of the effective designation date, which was expected in February 2026.
