The USEPA requires States to inventory and submit emissions from air pollution sources. These sources include Point Sources (industrial stationary sources), Nonpoint Sources (small facilities, lawn mowers, wood stoves, etc.), and Mobile Sources (cars, trucks, boats, etc.). Only the Point Source emissions are required to be reported to the USEPA every year. Nonpoint and Mobile sources are reported every three years. The most recent comprehensive three-year inventory was for the 2017 calendar year.
Inventory data is used to verify whether air programs previously enacted are being effective and to aid in designing air programs needed to ensure air quality is improved or maintained. Additionally, for new rule development, the USEPA uses these emissions estimates to model the risk to nearby communities; especially for toxic air pollutants.