Carbon monoxide (CO)

Carbon monoxide (CO) is a colorless, odorless gas that is a product of the incomplete combustion of carbon-based fuels — including gasoline, diesel fuel, crude oil, and wood — and other natural and synthetic products. Main contributors of carbon monoxide emissions include vehicle exhaust from cars, trucks, and buses; gas-powered furnaces; and portable generators.

Health impacts of carbon monoxide

Carbon monoxide can affect the amount of oxygen carried by the bloodstream to critical organs, including the heart and the brain. Individuals with certain types of heart disease are at elevated risk of health impacts, especially for heart diseases in which the circulation of oxygen to heart tissues is already compromised. People with pre-existing heart issues can become subject to increased symptoms when under higher stress or during exercise, and can experience chest pains, known as angina.

Carbon monoxide also poses a significant acute health risk indoors. Sources of carbon monoxide in homes include gas stoves, leaking furnaces, car exhaust from attached garages, and space heaters. Effects of exposure range from fatigue at low concentrations of carbon monoxide to impaired vision and nausea at higher concentrations.

For additional information about the health impacts of air pollution in Minnesota, you can check out our most recent air quality report, or visit the Air quality and health webpage. You can also sign up for air quality alerts and forecasts, and check out current air quality.

Air quality standards that help protect us from adverse effects of carbon monoxide

Under the Clean Air Act, the U.S. EPA sets National Ambient Air Quality Standards (NAAQS) for carbon monoxide. In 2011, the EPA reviewed the science related to the health and environmental impacts of carbon monoxide and revised the national standards to reflect the most up-to-date information. The level of the current primary carbon monoxide standard is 9ppm over eight hours, and 35ppm over one hour. If these levels are exceeded more than once a year, the standard is considered to be violated.

The state of Minnesota is currently in compliance with the national standards for carbon monoxide. To see the MPCA’s monitoring data for carbon monoxide and other criteria pollutants, explore our Criteria Pollutant Data Explorer.

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