Are the GHGs in the National Emissions Inventory Complete?
No, the 2017 National Emissions Inventory (NEI) includes a subset of total national emissions of greenhouse gases (GHGs) for fires, mobile sources, and certain point sources. EPA provides a comprehensive assessment of all anthropogenic emissions and sinks of greenhouse gases in the annual Inventory of U.S. Greenhouse Gas Emissions and Sinks.
In the 2017 NEI, EPA included point source facility total values for four GHGs (CO2, CH4, N2O, and SF6) from the Greenhouse Gas Reporting Program (GHGRP) data when GHGRP facilities matched to NEI facilities. 2014 NEI and earlier did not include the GHGRP emissions. State, local, and tribal agencies voluntarily provide GHG emissions for a small number of smaller point sources in addition to those GHGRP sources, but many small point sources do not have GHG emissions in the NEI. GHG completeness in the NEI for fires is limited to emissions (and not sequestration or other carbon stock changes) of CO2 and CH4, and for mobile sources, we include estimates for CO2, CH4, and N2O. The NEI program does not include GHG emissions for nonpoint sources.
For more information, the EPA provides an overview of the relationship between the annual Inventory of U.S. Greenhouse Gas Emissions and Sinks and the GHGRP.