Table 4-38. Estimated National Average Vehicle Emissions Rates by Vehicle Type and Fuel (Grams per mile)

Table 4-38. Estimated National Average Vehicle Emissions Rates by Vehicle Type and Fuel (Grams per mile)

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  1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000E
Gasoline (assuming zero RFG)                     
Light-duty vehicles                     
Exhaust and nonexhaust                      
hydrocarbons (HC) 3.09 2.91 2.77 2.65 2.57 2.49 R2.42 2.36 2.29 2.23 2.16
(Exhaust HC) (2.05) (1.92) (1.81) (1.72) (1.66) (1.60) (1.55) (1.51) (1.47) (1.44) (1.42)
(Nonexhaust HC) (1.04) (0.99) (0.96) (0.93) (0.91) (0.89) (0.87) (0.85) (0.82) (0.79) (0.74)
Exhaust carbon monoxide (CO) 24.68 23.42 22.40 21.65 21.10 20.52 20.14 19.86 19.52 19.36 19.28
Exhaust nitrogen oxide (NOx) 1.81 1.76 1.72 1.69 1.67 1.61 1.56 1.51 1.45 1.41 1.38
Light-duty trucks                     
Exhaust and nonexhaust HC 4.68 4.34 4.01 3.77 3.57 3.38 3.24 3.14 3.01 2.93 2.85
(Exhaust HC) (3.24) (3.03) (2.80) (2.61) (2.46) (2.31) (2.21) (2.13) (2.05) (1.99) (1.95)
(Nonexhaust HC) (1.44) (1.31) (1.21) (1.16) (1.11) (1.07) (1.03) (1.01) (0.96) (0.94) (0.90)
Exhaust CO 36.32 34.01 31.78 30.03 28.62 27.41 26.83 26.38 25.69 25.29 24.99
Exhaust NOx 2.36 2.25 2.16 2.10 2.04 1.97 1.95 1.92 1.87 1.84 1.80
Heavy-duty vehicles                     
Exhaust and nonexhaust HC 11.89 10.90 10.06 9.24 8.49 7.89 7.30 6.70 6.11 5.70 5.32
(Exhaust HC) (7.45) (6.79) (6.22) (5.53) (4.92) (4.51) (4.13) (3.73) (3.33) (3.07) (2.82)
(Nonexhaust HC) (4.44) (4.11) (3.84) (3.71) (3.57) (3.38) (3.17) (2.97) (2.78) (2.63) (2.50)
Exhaust CO 131.19 120.49 111.05 101.92 93.61 85.10 76.97 69.13 61.07 54.65 48.67
Exhaust NOx 6.49 6.28 6.05 5.85 5.69 5.48 5.36 5.25 5.05 4.89 4.72
Motorcycles                     
Exhaust and nonexhaust HC 4.68 4.56 4.48 4.41 4.38 4.33 4.29 4.29 4.27 4.26 4.26
(Exhaust HC) (2.31) (2.19) (2.11) (2.05) (2.02) (1.96) (1.93) (1.92) (1.90) (1.89) (1.89)
(Nonexhaust HC) (2.37) (2.37) (2.37) (2.36) (2.36) (2.37) (2.36) (2.37) (2.37) (2.37) (2.37)
Exhaust CO 20.89 20.61 20.60 20.59 20.59 20.47 20.47 20.47 20.35 20.35 20.35
Exhaust NOx 0.85 0.85 0.85 0.85 0.85 0.84 0.84 0.84 0.83 0.83 0.83
Diesel                     
Light-duty vehicles                      
Exhaust HC 0.73 0.74 0.75 0.75 0.76 0.77 0.76 0.74 0.71 0.67 0.63
Exhaust CO 1.68 1.71 1.72 1.73 1.74 1.74 1.74 1.71 1.67 1.62 1.57
Exhaust NOx 1.65 1.67 1.68 1.68 1.66 1.64 1.60 1.55 1.48 1.40 1.33
Light-duty trucks                     
Exhaust HC 1.08 1.14 1.15 1.14 1.13 1.11 1.09 1.05 0.98 0.91 0.84
Exhaust CO 2.03 2.10 2.09 2.07 2.04 2.02 1.99 1.95 1.88 1.80 1.73
Exhaust NOx 1.97 2.00 1.99 1.97 1.94 1.90 1.85 1.78 1.67 1.56 1.46
Heavy-duty vehicles                     
Exhaust HC 3.30 3.08 2.89 2.75 2.65 2.54 2.44 2.36 2.30 2.25 2.22
Exhaust CO 13.71 13.38 13.07 12.76 12.50 12.28 12.08 11.93 11.77 11.63 11.53
Exhaust NOx 21.05 19.59 18.14 16.89 15.81 14.79 13.96 13.33 12.66 11.93 11.24
Average of all vehicles, gasoline and diesel                      
Exhaust and nonexhaust HC 3.75 3.52 3.31 3.15 3.02 2.90 2.80 2.71 2.62 2.54 2.47
(Exhaust HC) (2.56) (2.40) (2.25) (2.13) (2.03) (1.93) (1.86) (1.80) R(1.74) (1.70) (1.67)
(Nonexhaust HC) R(1.18) (1.12) (1.06) (1.02) R(1.00) (0.97) (0.94) (0.91) (0.88) (0.84) (0.80)
Exhaust CO 29.97 28.29 26.81 25.62 24.68 23.75 23.11 22.58 21.94 21.53 21.20
Exhaust NOx 3.09 2.99 2.89 2.80 2.73 2.63 2.56 2.50 2.41 2.34 2.27

KEY: E = estimate; GVWR = gross vehicle weight rating; R = revised; RFG = reformulated gasoline.

NOTES: As of July 1 of each year. Vehicles types are defined as follows: light-duty vehicles (passenger cars up to 6,000 lb GVWR); light-duty trucks (pickups and minivans up to 8,500 lb GVWR); heavy-duty vehicles (8,501 lbs or more GVWR) ; motorcycle (highway only). This table revises the data shown in National Transportation Statistics because it is based on MOBILE5b, the U.S. Environmental Protection Agency's (EPA) latest highway vehicle emissions factor model. Interested readers can learn more about the Mobile5b model at thefollowing USEPA Internet site http://www.epa.gov/otaq. Emissions factors are national averages based on the following assumptions: ambient temperature 75 F, daily temperature range 60-84 F, average traffic speed 19.6 mph (representative of overall traffic in urban areas), standard operating mode (cold-start, hot-start, stabilized), vehicle-miles traveled fractions, no inspection/maintenance or antitampering programs, and gasoline volatility 9.0 per square inch RVP (Reid vapor pressure). See Table 4-39 for emissions from vehicles operating on reformulated gasoline. Data for nonexhaust HC is negligible for diesel light-duty vehicles, light-duty trucks, and heavy-duty vehicles.

SOURCE: U.S. Environmental Protection Agency, National Vehicle and Fuel Emissions Laboratory, unpublished data, Aug. 10, 2000.