TABLE 74a  Change in Nitrogen Oxide Emissions by Mode: 1991-2001,,,,,,,,,,,
Index: 1991 = 1.00,,,,,,,,,,,
,,,,,,,,,,,
,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001
Highway gasoline,1.00,0.96,0.91,0.87,0.83,0.78,0.77,0.74,0.71,0.69,0.72
Highway diesel,1.00,1.03,1.07,1.11,1.14,1.18,1.21,1.22,1.19,1.24,1.16
Aircraft,1.00,1.01,1.03,1.04,1.04,1.06,1.19,1.30,1.43,1.26,1.16
Marine vessels,1.00,1.01,1.02,1.03,1.04,1.05,1.00,0.95,0.90,1.00,1.00
Railroad,1.00,1.02,1.04,1.05,1.07,1.09,1.10,1.12,1.13,1.04,1.04
Other nonroad,1.00,0.97,1.03,1.03,1.03,1.10,1.19,1.11,1.37,1.19,1.19
"
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. These tables do 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.",,,,,,,,,,,