Sulfur Dioxide Trends
Under the Clean Air Act, the EPA sets national ambient air quality standards (NAAQS) for sulfur dioxide (SO2) 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 SO2 concentrations to ensure that the NAAQS are being met. The charts below based on this measurement data show that nationally, SO2 concentrations have decreased substantially over the years. For information on SO2 standards, sources, health effects, and programs to reduce SO2 pollution, please see our Sulfur Dioxide Pollution page.
