TABLE 74b Nitrogen Oxide Emissions by Mode: 1991-2001
TABLE 74b Nitrogen Oxide Emissions by Mode: 1991-2001
(Thousands of short tons)
| 1991 | 1992 | 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Highway gasoline | 6,072 | 5,811 | 5,548 | 5,287 | 5,026 | 4,765 | 4,705 | 4,509 | 4,312 | 4,201 | 4,345 |
| Highway diesel | 3,377 | 3,495 | 3,614 | 3,732 | 3,850 | 3,968 | 4,087 | 4,111 | 4,035 | 4,192 | 3,904 |
| Aircraft | 70 | 71 | 72 | 73 | 73 | 74 | 83 | 91 | 100 | 88 | 81 |
| Marine vessels | 1,012 | 1,021 | 1,030 | 1,039 | 1,049 | 1,058 | 1,008 | 958 | 908 | 1,008 | 1,011 |
| Railroad | 962 | 979 | 996 | 1,014 | 1,031 | 1,048 | 1,061 | 1,073 | 1,085 | 1,001 | 999 |
| Other nonroad | 70 | 68 | 72 | 72 | 72 | 77 | 83 | 78 | 96 | 83 | 83 |
NOTES: Highway gasoline vehicles include: light-duty gas vehicles and motorcycles, light-duty gas trucks, and heavy duty gas vehicles. Highway diesel includes heavy-duty diesel vehicles, light-duty diesel trucks and vehicles. Marine vessels include: coal, diesel, residual oil, gasoline and other. Other includes: diesel and gasoline recreational vehicles, airport service, railway maintenance, and recreational marine service. This table does not include farm, construction, industrial, logging, light commercial, and lawn and garden equipment.
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 2002.