Transportation energy data book: edition 23 - Oak Ridge National ...

12–6
Heavy diesel-powered vehicles were responsible for nearly one-half of highway vehicle nitrogen oxide
emissions in 2001, while light gasoline vehicles were responsible for the rest.
Table 12.5
Emissions of Nitrogen Oxides from Highway Vehicles, 1980–2001 a
(million short tons)
Source category 1980 1985 1990 1995 2000 2001
Percent of
total, 2001
Gasoline powered
Light vehicles & motorcycles 6.63 5.68 4.26 3.05 2.31 2.39 28.9%
Light trucksb 1.58 1.60 1.50 1.46 1.44 1.50 18.2%
Heavy vehicles 0.62 0.58 0.57 0.52 0.45 0.46 5.5%
Total 8.83 7.85 6.33 5.03 4.20 4.35 52.7%
Diesel powered
Light vehicles c 0.04 0.04 0.02 0.01 0.01 0.1%
Light trucksb c c 0.02 0.01 0.01 0.01 0.1%
Heavy vehicles 2.59 3.00 3.19 3.82 4.18 3.89 47.2%
Total 2.66 3.08
Total
3.26 3.85 4.19 3.90 47.3%
Highway vehicle total 11.49 10.93 9.59 8.88 8.69 8.25 100.0%
Percent diesel 23.1% 28.2% 34.0% 43.4% 48.2% 47.3%
Source:
U. S. Environmental Protection Agency, National Emission Inventory Air Pollutant Emission Trends
website www.epa.gov/ttn/chief/trends (Additional resources: www.epa.gov/oar/oaqps)
a The sums of subcategories may not equal total due to rounding.
b Less than 8,500 pounds.
c Data are not available.
TRANSPORTATION ENERGY DATA BOOK: EDITION 23—2003