August 15, 2011

EPA Affirms National Air Quality Standards for Carbon Monoxide Are Protective of Public Health

Air monitoring updates will put more focus on urban communities located near roadways

Contact Information: Cathy Milbourn [email protected] 202-564-7849 202-564-4355 Enesta Jones [email protected] 202-564-7873 202-564-4355


WASHINGTON – After a careful review of the science, the U.S. Environmental Protection Agency (EPA) is affirming the current national air quality standards for carbon monoxide (CO). The science shows that the current standards protect public health, including those who are most susceptible, and the environment. Since 1980, levels of CO in the air have fallen by 80 percent, mostly as a result of motor vehicle emissions controls.

CO is a colorless, odorless gas emitted from combustion processes. Nationally, and particularly in urban areas, the majority of CO emissions come from motor vehicles. CO can cause harmful health effects by reducing oxygen delivery to the body’s organs (like the heart and brain) and tissues.

To ensure people are protected from unhealthy concentrations of CO and to develop better information about CO and its health impacts, EPA is revising the air monitoring requirements.
The changes will require a more focused monitoring network with CO monitors placed near roads in 52 urban areas with populations of 1 million or more.

Monitors in areas with populations of 2.5 million or more are required to be operational by January 1, 2015 and monitors required in areas with populations of 1 million or more are required to be operational by January 1, 2017
. These new monitoring sites will give EPA important data about CO levels that may be affecting public health in neighborhoods located near busy roadways. The data will also be used to determine compliance with the current standards and to help inform future reviews of the standard.

The current health standards are 9 parts per million (ppm) measured over 8 hours, and 35 ppm measured over 1 hour. CO levels at monitors across the country are quite low and are well within the standards, showing that federal, state and local efforts to reduce CO pollution have been successful and are providing important public health protections to all Americans.

The rule is consistent with the advice and recommendations from the agency’s independent science advisors, the Clean Air Act Scientific Advisory Committee.
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