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The 2008 National Emissions Inventory

The National Emissions Inventory (NEI) is a comprehensive and detailed estimate of air emissions of both Criteria and Hazardous air pollutants from all air emissions sources. The NEI is prepared every three years by the USEPA based primarily upon emission estimates and emission model inputs provided by State, Local, and Tribal air agencies for sources in their jurisdictions, and supplemented by data developed by the USEPA. The 2008 NEI was built from emissions data in the Emissions Inventory System (EIS).

A description of each of the five data categories Point, NonPoint, OnRoad, NonRoad, and Event is shown below. See below also for Documentation.

2008 National Emissions Inventory Data

The data posted at this site will include only the latest version of the 2008 NEI. This webpage should not be used as a reference for past versions of the NEI, and users wanting a record of data used in their analysis should archive and document those inventories to meet their own archival needs. Users should not assume that the data posted on this site will stay the same as the data they use at a given point in time.

Sector Summaries - Criteria and Hazardous Air Pollutants by 60 EIS emission sectors

*A complete sector file is provided below under "Additional Summary Data". To use the multiple selection boxes hold CTRL and click on options you would like to include in your query. To select multiples in order, click your first option then hold SHIFT + click the last selection to highlight everything in between. To unselect options use the same method as with selecting. Please allow time for large queries to process (i.e. county aggregated for all pollutants, all sectors, all regions).

National / State / County or Tribe Geographic Aggregation
National State County or Tribe
Pollutant Sector

Tier 1 Summaries - Criteria Air Pollutants only by 14 major tiers

National / State / County or Tribe Geographic Aggregation
National State County or Tribe
Pollutant Tier 1 Category

SCC Data Files

The full detail data files for the Point, Onroad, Nonroad and Nonpoint data categories can be downloaded from the following drop-down menu. Please note these files are larger than previous inventories and can be linked in Access if importing fails.

Additional Summary Data

  • Tribal Lands Emissions Summaries
    • Sector (Includes both criteria and hazardous air pollutants) (XLS, 647 KB)
    • Tier 1 (Includes criteria pollutants only) (XLS, 87 KB)
  • Facility Emissions Summaries
  • All Sector: National - county aggregated - sector file (zipped MDB, 33.7 MB)
  • Biogenics: Various levels of aggregation down to monthly county emissions (zipped XLS, 14.3 MB)
  • Tier Summaries: National/State/County summaries for Tier 1, Tier 2 and Tier 3
  • 2008 version 3 Pb facility-process: Point source facility-process summary for lead (Pb) (zipped CSV, 3.11 MB)
  • 2008 version 3 Hg: Point source facility-process, nonpoint, onroad, nonroad and national summary for mercury (Hg)(zipped ACCB, XLSX and PDF, 34.7 MB)

    Maps and Fusion Tables

    Fusion Tables (by Google) allow mapping data, creating charts, and using tabular data, including viewing, filtering, summing, and downloading. You can use the links below to access the 2008 NEI data using Fusion Tables. Google’s feedback link is the best way to ask for improvements since Google is trialing Fusion Tables – this link is under the gear icon at the upper right of the Fusion Table pages.

  • Instructions on using Google Fusion Tables (PDF, 238 KB)

  • All pollutants listed below Table Map
    Carbon Monoxide (CO) Table Map Mercury Table Map
    Volatile Organic Compounds (VOC) Table Map Chromium VI Table Map
    Oxides of Nitrogen (NOx) Table Map Arsenic Table Map
    Sulfur Dioxide (SO2) Table Map Acetaldehyde Table Map
    Particulate Matter ≤ 2.5 microns (PM2.5) Table Map Formaldehyde Table Map
    Particulate Matter ≤ 10 microns (PM10) Table Map Ethyl Benzene Table Map
    Ammonia (NH3) Table Map Acrolein Table Map
    Lead Table Map 1,3-Butadiene Table Map
    1,4-Dichlorobenzene Table Map
    Tetrachloroethylene Table Map


    2008 NEI Version 3 Technical Support Documentation (Draft)

    The 2008 NEI Technical Support Document is a draft and using an improved format from past documents. Although in draft form, this version provides all of the documentation available in past 2008 NEI releases as well as additional analysis about the sources of data used in the NEI. Placeholder sections are included so that major section numbers will not change in future verisons. This draft document will be replaced with updaed versions as they become available. Requests for updated sections can be made to the Info CHIEF Help Desk at info.chief@epa.gov.

  • 2008 NEI Technical Support Document, Draft (PDF, 3.74 MB updated 9/2013)
  • Appendices, Draft (PDF, 0.97 MB, updated 9/2013)
  • Supporting Data and Summaries (updated 9/2013)
    See Section 8 of the Technical Support Document for a list of supporting files and their contents. The contents are accurate and not draft, though more supporting data may be added later.
  • References (updated 9/2013)
    Throughout the documentation, references are made to EPA documents developed as part of the 2008 NEI effort. These are available in this zipped file. See also Section 8 of the Technical Support Document.

    Related Documents

  • Evaluation of NEI for use in Residual Risk Assessments, (PDF, 770 KB,12/14/2012)
  • Description of NEI Data Categories

    The NEI Point data category contains emissions estimates for sources that are individually inventoried and usually located at a fixed, stationary location, although portable sources such as some asphalt or rock crushing operations are also included. Point sources include large industrial facilities and electric power plants, but also increasingly include many smaller industrial and commercial facilities, such as dry cleaners and gas stations, which had traditionally been included in Nonpoint sources. The choice of whether these smaller sources are estimated individually and included as point sources or inventoried as a NonPoint source County or Tribal area aggregate is determined by the separate State, Local, or Tribal air agency.

    The NEI NonPoint data category contains emissions estimates for sources which individually are too small in magnitude or too numerous to inventory as individual point sources, and which can often be estimated more accurately as a single aggregate source for a County or Tribal area. Examples are residential heating and consumer solvent use.

    The NEI OnRoad and NonRoad data categories contain mobile sources which are estimated for the 2008 NEI v3 via the MOVES2010b and NONROAD models, respectively. NONROAD was run within the National Mobile Inventory Model (NMIM). Note that emissions data for aircraft, locomotives, and commercial marine vessels are NOT included in the NonRoad data category starting with the 2008 NEI. Aircraft engine emissions occurring during Landing and Takeoff operations and the Ground Support Equipment and Auxiliary Power Units associated with the aircraft are now included in the point data category at individual airports in the 2008 NEI. Emissions from locomotives that occur at rail yards are also included in the point data category. In-flight aircraft emissions, locomotive emissions outside of the rail yards, and commercial marine vessel emissions (both underway and port emissions) are included in the NonPoint data category.

    The Events data category includes wildfires,wild land fire use and prescribed burns. Wild land fire use has been included in the "Fires - Wildfires" sector. Emissions for these are presented as county totals on this website.


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