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State Implementation Plans (SIPs)
State Implementation Plans (SIPs) SIPs are federally enforceable plans that have been adopted by a state to meet Clean Air Act requirements under a specific National Ambient Air Quality Standards (NAAQS). SIPs include programmatic requirements, emission inventories, air quality projections, and control measures designed to reduce emissions.
The District is classified as in nonattainment of the ozone NAAQS, but as of April 2025 has clean data and is awaiting a formal redesignation to attainment after we submit a redesignation request and maintenance plan. The District is in attainment of the PM2.5 and carbon monoxide (CO) NAAQS, but was previously in nonattainment of both standards. The District is in attainment for all other standards.
Types of SIPs
- Attainment Demonstration — Demonstrates how an area that has failed to meet a NAAQS for a criteria pollutant will attain a standard by a future date.
- Maintenance Plan — Applies specifically to areas that have recently attained compliance with the NAAQS after previously being in nonattainment. The maintenance plan focuses on how the area will continue to maintain compliance with the established air quality standards over a set period, typically 10 years.
- Regional Haze SIP — Outlines how a state will reduce air pollution from various sources to improve visibility in national parks and wilderness areas, ensuring compliance with the Clean Air Act.
- Infrastructure SIP — Comprehensive strategies required by all states and districts upon the promulgation of a new NAAQS. Demonstrates that a jurisdiction has the necessary legal and programmatic requirements in place to successfully implement state requirements under the Clean Air Act regardless of its attainment status.