EPA collects data from the states and regions on their air quality and state implementation plan (SIP) progress. This information is compiled in a database, and used to create reports, trend charts, and maps.

SIP status reports

Reports for nonattainment area SIP requirements

• Status of SIP requirements, listed by state: select a state from the map to view its SIP requirements progress report.
• National status of state SIP requirements: each criteria pollutant links to a full list of the requirements for that pollutant's SIP. Each requirement then links to a report on that requirement's progress, by state.

Reports for infrastructure SIP requirements

• Infrastructure SIP status reports listed by requirement
• Infrastructure SIP status reports listed by state

SIPs approved by EPA

• View approved SIPs by state, organized by states in each EPA region.

Air quality data

• SO₂ Design Values: view statistics that describe the air quality status of a given area relative to the level of EPA's National Ambient Air Quality Standards. These Excel reports are listed by pollutant.
• AirNow: see real-time air pollution data in the United States.
• Air Quality Trends for SO₂: View SO₂ level trends; measured nationally, regionally, and locally; up to 2014.

Designations

• SO₂ Designations: Find information on the process EPA, the states, and the tribes follow to designate areas as "attainment" (meeting) or "nonattainment" (not meeting) the sulfur dioxide standards.
• Green Book: listings of areas designated nonattainment for each NAAQS pollutant. It includes current designation and classification status, area maps, reports, and Federal Register notices.

• SO2 Data Requirements Rule Source List: Lists of facilities that emit SO2 submitted by state environmental agencies under the Data Requirement Rule to inform future designations, redesignations, or other decisions concerning attainment of standards.