EPA Rule on Carbon Monoxide Adds New Monitoring Requirement for Metropolitan Roadways, but Standards Will Stay the Same

The Environmental Protection Agency (EPA) announced its final rule this week affirming the current national air quality limits for carbon monoxide (CO), which describe how much of the pollutant is acceptable in outside air. EPA’s statement said the agency, after a careful review of the science, determined that the current standards for the pollutant protect the public health, including those who are most susceptible to the gas.

While finding existing limits for carbon monoxide are strong enough, EPA did alter its monitor siting requirements for large urban areas, increasing its focus on transportation routes. The agency will now require carbon monoxide monitors placed near roads in 52 urban areas around the country. Urban areas having populations of 1 million or more persons must have one near-road monitor operational by January 1, 2017. Near-road monitors required for urban areas having 2.5 million or more persons must be operational by January 1, 2015.

The President of the American Lung Association, Charles D. Connor, while supporting EPA’s efforts to better capture roadside concentrations of carbon monoxide, called the final rule a “disappointing step,” noting EPA had missed the opportunity to strengthen the standards.

Carbon monoxide, a colorless, odorless gas, reduces oxygen delivery to the body’s organs, such as the heart and brain. Connor expressed concern in his statement that “[p]eople who live near or work on or near busy highways should not risk their lives and their health.” EPA’s announcement noted it would be gaining important data about carbon monoxide levels affecting neighborhoods located near busy roadways, which would inform future reviews of the standard.

EPA’s current standard for carbon monoxide is 9 parts per million (ppm) measured over 8 hours, and 35 ppm measured over 1 hour. The entire country is currently in attainment of these limits. Since 1980, carbon monoxide levels have actually dropped by 80 percent, mostly due to emission controls for motor vehicles.

The Clean Air Act requires EPA to set national ambient air quality standards for carbon monoxide and five other major pollutants. EPA first set air quality standards for carbon monoxide in 1971. The last review of these standards was completed in 1994, at which time EPA declined to revise the limits. EPA’s current review was completed according to a court-ordered deadline. Environmental groups previously brought a citizens suit against the agency in U.S. District Court, alleging that EPA had failed to review the carbon monoxide standard every five years as required by federal law. See Communities for a Better Environment, et. al v. EPA, 2008 WL 1994898 (N.D.Cal. May 5, 2008).