Carbon Monoxide Trends

Under the Clean Air Act, the EPA sets national ambient air quality standards (NAAQS) for carbon monoxide (CO) at levels that are safe for public health and the environment. Air quality monitors operated by federal, state, local and tribal agencies throughout the country collect ambient measurements of CO concentrations to ensure that the NAAQS are being met. The charts below based on this measurement data show that nationally, CO concentrations have decreased substantially over the years. For information on CO standards, sources, health effects, and programs to reduce CO pollution, please see our Carbon Monoxide Pollution page.