NOTES: Revisions to
previous estimates are all related to the development of the 1999
National Emissions Inventory (NEI). The 1999 estimates in the
table are taken from Version 2 of the 1999 NEI and reflect many new
data submissions from state and local air management agencies. The
1999 emissions estimates from mobile sources are in most cases
based on the new MOBILE6 and the draft NONROAD2002 emissions
models. This is the first time that estimates using these models
have appeared in this format. Some but relatively few mobile source estimates were provided by state
air agencies. The largest set of state-submitted data in 1999
was from California. Estimates for mobile sources for years prior
to 1999 were made consistent with the estimates for 1999 and later,
allowing for a generally consistent time trend except that
state-submitted data were incorporated for 1999 only. See the
tables in appendix B for definitions of "highway" and
"other" vehicles.
SOURCE: U.S.
Environmental Protection Agency (EPA), Office of Air Quality
Planning and Standards, National
Emissions Inventory, Air Pollutant Emission Trends, available at http://www.epa.gov/ttn/chief/trends/index.html/, as of August 2003.
