Areas that fail to meet the national ambient air quality standards (NAAQS) for a criteria pollutant are required to develop a state implementation plan (SIP). SIPs include emission inventories, air quality projections, and control measures designed to reduce emissions. They demonstrate how an area will attain a standard by a future date.
State Implementation Plans – The District is in nonattainment of the ozone NAAQS. The District is in attainment of the PM2.5 and carbon monoxide (CO) NAAQS but was previously in nonattainment of both standards. The following SIPs for ozone, PM2.5, and CO were approved by the U.S. Environmental Protection Agency because they adequately demonstrate how the District plans to attain or maintain each NAAQS:
- Regional Haze SIP Second Planning Period
- 2015 8-Hour Ozone Infrastructure SIP
- 2008 8-Hour Ozone Maintenance Plan
- Regional Haze 5-Year Lookback First Planning Period
- 2008 8-Hour Ozone Infrastructure SIP
- Regional Haze SIP First Planning Period
- 1997 8-Hour Ozone Infrastructure SIP
- 1997 Fine Particulate Matter (PM2.5) Maintenance Plan
- 1994 Carbon Monoxide (CO) Maintenance Plan – effective through March 2016
Additional SIPs are available upon request.
Emission Control Programs – The following emission control program plans are included in the District’s SIP to meet Clean Air Act requirements:
Emission inventories are compilations of estimated emissions from various sources. Estimates are typically calculated using data on source activity and historical emission rates per pollutant.
- The District will receive $8.125 million dollars as a result of the penalty for Volkswagen’s use of defeat devices in light duty diesel vehicles. The settlement funds are primarily intended to reduce NOx emissions from diesel vehicles.
- The District has signed on to the MOU for the phase out of fossil fuel-burning medium- to heavy-duty truck and bus sales by 2050. In March of 2022, a multi-jurisdictional work group of which the District is a member released an action plan to lay the ground work for how this goal could be met.
The District’s air quality regulations also contain limits that sources in the District must meet.
When a SIP is approved by the EPA, control measures in the SIP become federally enforceable. A record of the history of changes to the District’s federally-approved SIP can be found in Title 40, Part 52, Subpart J of the Code of Federal Regulations.