On June 30, 2013, the US Environmental Protection Agency released a revision to the Air Emissions Reporting Rule (AERR). The rule states the goal of the revisions is to "reduce reporting burden for state, local and tribal agencies, improve consistency and clarity with other rules, and better reflect current inventory technologies and practices."
The AERR was first published in 2008 as a replacement to the previous Consolidated Emissions Reporting Rule (CERR), which was published in 2002. Both regulations were created to improve the ability of the EPA to gather emissions data on a national level. The data is used to create a national inventory of air pollutant emissions. You can see this data in use and search for the conditions in your area at the EPA's MY Environment.