The 2011 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 2011 NEI was
built from emissions data in the Emissions Inventory
- Version 2 (released March 4, 2015)
- Version 1 (released September 30, 2013)
The data presented below are for the 2011 NEI version 2.
A description of each of the five data categories Point, Nonpoint, Onroad, Nonroad, and Event is provided below. Documentation for Version 2 will be available in June of 2015.
2011 National Emissions Inventory Data
The data posted at this site will include only the latest version of the 2011 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 2011 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.
2011 NEI Documentation
Documentation for the 2011 NEI is ongoing at this time. Updates will be posted as available. Requests for additional information can be made to the Info CHIEF Help Desk at email@example.com.
EPA is planning to develop a version 2 of the NEI in the summer of 2014. Version 2 will address issues found during the review of the Version 1.
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 2011 NEI v1 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
included in the point data category at individual airports. 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 is controlling a wildfire to use as a prescribed burn. This web page provides emissions for this data category as county totals. Day-specific and fire-specific emissions are available on the Emissions Modeling Clearinghouse with the 2011 emissions platform data.