EPA's Efforts to Reduce CO

Carbon Monoxide

Reducing emissions of CO is an important part of EPA's strategy for cleaner air. The U.S. Environmental Protection Agency (EPA), states, and local governments work as partners to reduce emissions of CO. EPA's main approaches to reduce CO have been to establish national ambient air quality standards, to require national controls for motor vehicle emissions, and to require reductions from large industrial facilities.

National health-based air quality standards

EPA set two national health protection standards for CO: a one-hour standard of 35 parts per million and an eight-hour standard of 9 parts per million. Across the nation, air quality stations measure the levels of CO and other pollutants in the air. These measurements are compared to the standards. Areas that have CO levels that are too high must develop and carry out plans to reduce CO emissions. Click here for a list of U.S. areas not meeting the national air quality standards.

Control of motor vehicle emissions

Auto emissions controls have led to reductions in CO emissions.

Starting in the early 1970's, EPA has set national standards that have considerably reduced emissions of CO and other pollutants from motor vehicles, including tailpipe emissions, new vehicle technologies, and clean fuels programs. Since 1970, CO emissions from on-road vehicles (which includes cars, motorcycles, light- and heavy-duty trucks) have been reduced by over 40 percent. The greatest reductions have been in emissions from cars (nearly 60 percent).

**Milestones in Motor Vehicle**
**Emissions Controls**
1970	Clean Air Act sets first auto emissions standards.
1974	EPA sets fuel economy standards.
1975	First catalytic converters are used for CO and hydrocarbons. First use of unleaded gas in catalyst-equipped cars.
1983	Vehicle inspection and maintenance programs established in 64 cities.
1990	Clean Air Act Amendments set new tailpipe standards.
1992	Oxyfuel introduced in cities with high CO levels.
1994	Phase-in of new vehicle standards and technologies begins.

Permits for large industrial facilities

Large industrial or commercial facilities are required by EPA to obtain a permit prior to construction, to ensure that they are well-controlled and do not cause significant adverse health and environmental impacts. Generally, this would include industrial boilers and incinerators that might release significant CO emissions to the air.

For more information:

EPA's Efforts to Reduce CO

Carbon Monoxide

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