National Emission Inventory (NEI)
The U. S. EPA collects information about sources that release criteria and hazardous air pollutants into the atmosphere from federal, state, local, and tribal sources every three years in order to compile the National Emissions Inventory. The database includes estimates of annual air pollutant emissions from point, nonpoint, and mobile sources in the 50 States, the District of Columbia , Puerto Rico, and the Virgin Islands.
Toxics Release Inventory (TRI)
The Toxics Release Inventory (TRI) is a publicly available U.S. EPA database that contains information on toxic chemical releases and other waste management activities reported annually by certain covered industry groups, as well, as federal facilities. This inventory was established under the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA) and expanded by the Pollution Prevention Act of 1990.
National Toxics Inventory (NTI)
Prior to 1999, the U.S. EPA developed a National Toxics Inventory (NTI) (PDF- 12 Kb) every three years (1993, 1996) to estimate air toxics emissions. It was a complete national inventory of stationary and mobile sources that emitted toxic air pollutants, also known as hazardous air pollutants (HAPs). The NTI was the first step in the National-Scale Air Toxics Assessment.