This fact sheet describes the data fields provided in support of EPA’s final 1-hour SO2 National Ambient Air Quality Standard (NAAQS) and answers frequently asked questions about those data  It provides the opportunity for States to demonstrate attainment through ambient air quality monitoring and/or emissions dispersion modeling. To assist states that choose to use emissions dispersion modelling, EPA is providing emissions data that is collected under the Part 75 continuous emission monitoring regulation. These data include stack characteristics and hourly emissions data provided by coal-fired sources that participate in the Acid Rain Program, Cross-State Air Pollution Rule, or former NOX Budget Trading Program. The data are primarily from electric generating units (EGUs) with some industrial boilers included. All of the sources collect emissions data using continuous emission monitoring systems (CEMS) and electronically report this information to the EPA on a quarterly basis. These data cover calendar years 2012 through 2014.

• Fact Sheet for EPA-Provided, State-Level Hourly Sulfur Dioxide (SO2) Data (PDF)(5 pp, 172 K)