2023 National Emissions Inventory (NEI)

The National Emissions Inventory (NEI) provides emissions data for criteria air pollutants and hazardous air pollutants from facilities and other sources across the country (see FAQ). These data are available at both the facility level and as countywide totals. Below are the main 2023 NEI data products and supporting resources available on this page.

Online Data Retrieval Tool

Coming Soon - This tool allows users to filter and download custom lists of facilities and county total emissions data. 

Detailed Data, Other Summaries, Data Queries, and Facility Mapping

For advanced users, includes the most detail (large) database files, zipped modeling input files, smaller premade sector summaries, Tier 1 queries, sector queries, and single state point source queries and maps.

Documentation & Resources

• 2023 Technical Support Document

• 2023 NEI Plan

  • Appendix 1: Business Rules (pdf) (368.31 KB)

• 2023 NEI Resources for State, Local, Tribal Agencies

​​​​​2023 Nonpoint Wagon Wheel Supporting Data

• 2023 Nonpoint Wagon Wheel
• EIS Augmentation Datasets (including HAP augmentation, PM augmentation, PM speciation, Chromium speciation, HAP Aug profile name xref)
• Wagon Wheel Emission Factor Compendium

2023 Fires Supporting Data

• 2023 Prescribed Fire Activity Data Source Summary

2023 Commercial Marine Vehicle Documents

• 2023 Category 1 and 2 CMV Emissions Inventory Documentation (pdf)
• 2023 Category 3 CMV Emissions Inventory Documentation (pdf)

2023 Airport-Related and Aircraft Documents

• 2023 Development of Aircraft Emission Inventories (pdf)

2023 Locomotive and Railyard Documents

• 2023 National Emissions Inventory Locomotive Methodology (pdf)