Dataset

Environmental Protection Agency National Emission Inventory (NEI)

Environmental Protection Agency National Emission Inventory (NEI)
Data Category
Facility compliance and enforcement
Spatial Extent
United States
Chemicals
CAPs • HAPs
Provider
Environmental Protection Agency
Temporal Resolution
Annual Average
Update Frequency
Every 3 Years
Description

Compilation of air emissions estimates from various sources, including point sources like petrochemical facilities, transportation and fires. Data is compiled from other EPA emissions programs and from data provided by state, local and tribal agencies.

Potential Uses
• Find air emissions totals or trends for an area
Limitations
Point source emissions are self-reported by facilities to state and local agencies, which then report to EPA. Some states and local agencies don't require HAPS reporting, so EPA fills in HAPs data gaps using TRI leading to variable data quality among states. Reporting of start-up, shut-down, maintenance, and malfunction emissions is not currently required. Many emissions are modeled rather than measured, adding additional uncertainty.