The 2008 National Emissions Inventory
The National Emissions Inventory (NEI) is a comprehensive and detailed
estimate of air emissions of both
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
- Version 3 (March 1, 2013): Key updates are the use of the publicly-released MOVES2010b model for onroad mobile sources, updates to commercial marine vessel and residential woood emissions, additional VOC from biogenic emissions, addition of missing boiler mercury, addition of Puerto Rico emissions, review and update of lead emissions, and corrections to many issues identified in Version 2.
- Version 2 (April 10, 2012): Key updates are the use a draft version of the MOVES model for onroad mobile sources, a review and update of hazardous air pollutant emissions and additions of wildfires, prescribed burning and biogenic emissions.
- Version 1.5 (released May 16, 2011): Key updates are to include the nonpoint data and major updates to point sources in Indiana, Maryland, Nebraska, and Lincoln/Lancaster air agencies.
- Version 1 (released April 4, 2011)
Version History: Data from previous versions of the 2008 inventory are no longer available.
The data presented below are for the 2008 NEI version 3. For a detailed list of caveats and changes from version 2, and older versions, please see the Version 3 issues file.
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.
Additional Summary Data
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.
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 firstname.lastname@example.org.
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.
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.
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
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.