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Table 4-38: Estimated National Average Vehicle Emissions Rates per Vehicle by Vehicle Type using Gasoline and Diesel

(Grams per mile)

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  1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
GASOLINE (assuming zero RFG)                                    
Light-duty vehicles                                    
Exhaust HC 2.79 2.50 2.23 1.98 1.77 1.57 1.39 1.25 1.14 1.05 0.97 0.89 0.81 0.74 0.61 0.52 0.46 0.42
Nonexhaust HC 1.21 1.17 1.12 1.09 1.07 1.05 1.03 1.01 0.98 0.95 0.91 0.88 0.84 0.81 0.77 0.72 0.68 0.62
Total HC 4.00 3.67 3.35 3.07 2.84 2.62 2.41 2.26 2.12 2.00 1.88 1.77 1.65 1.54 1.37 1.25 1.13 1.04
Exhaust CO 42.89 39.15 35.54 32.23 29.32 26.60 24.18 22.38 20.86 19.54 18.53 17.80 16.98 16.14 13.79 12.57 10.87 10.28
Exhaust NOx 2.70 2.47 2.27 2.09 1.94 1.78 1.64 1.55 1.46 1.35 1.29 1.25 1.20 1.14 1.00 0.92 0.79 0.73
Light-duty trucks                                    
Exhaust HC 3.68 3.33 3.00 2.71 2.45 2.21 1.96 1.80 1.65 1.54 1.45 1.35 1.24 1.13 0.96 0.78 0.69 0.64
Nonexhaust HC 1.37 1.30 1.21 1.17 1.13 1.11 1.08 1.05 1.02 1.00 0.98 0.95 0.90 0.84 0.80 0.76 0.71 0.66
Total HC 5.05 4.63 4.21 3.88 3.59 3.32 3.04 2.85 2.68 2.54 2.43 2.30 2.14 1.98 1.76 1.54 1.40 1.31
Exhaust CO 56.23 51.99 47.93 44.34 40.77 37.51 34.47 32.20 30.23 28.28 26.81 25.43 23.85 21.51 18.76 16.23 14.33 13.52
Exhaust NOx 2.62 2.42 2.26 2.11 1.98 1.84 1.73 1.65 1.59 1.55 1.54 1.53 1.50 1.45 1.32 1.21 1.09 1.02
Heavy-duty vehicles                                    
Exhaust HC 3.66 3.34 3.03 2.76 2.39 2.16 1.94 1.73 1.51 1.35 1.22 1.09 0.98 0.82 0.73 0.64 0.53 0.48
Nonexhaust HC 2.74 2.60 2.34 2.25 2.16 2.07 1.97 1.87 1.79 1.69 1.62 1.54 1.48 1.41 1.35 1.24 1.14 1.07
Total HC 6.40 5.94 5.37 5.00 4.55 4.24 3.91 3.60 3.29 3.04 2.84 2.63 2.46 2.24 2.08 1.88 1.67 1.54
Exhaust CO 85.61 78.64 72.12 65.92 60.01 54.16 48.52 43.26 38.82 34.54 31.08 27.59 24.73 20.60 18.46 16.73 14.51 13.55
Exhaust NOx 7.19 6.96 6.72 6.52 6.35 6.11 5.89 5.73 5.56 5.40 5.26 5.13 5.01 4.91 4.62 4.28 3.73 3.33
Motorcycles                                    
Exhaust HC 2.01 1.88 1.82 1.75 1.72 1.69 1.63 1.63 1.62 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61
Nonexhaust HC 0.74 0.73 0.72 0.72 0.71 0.71 0.70 0.69 0.70 0.70 0.70 0.70 0.70 0.70 0.69 0.69 0.69 0.68
Total HC 2.74 2.60 2.54 2.46 2.43 2.40 2.34 2.32 2.32 2.31 2.31 2.31 2.31 2.31 2.31 2.30 2.30 2.29
Exhaust CO 15.15 14.78 14.77 14.76 14.76 14.67 14.59 14.59 14.59 14.59 14.59 14.59 14.59 14.59 14.59 14.58 14.59 14.59
Exhaust NOx 1.26 1.28 1.28 1.28 1.28 1.26 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25
DIESEL                                    
Light-duty vehicles                                    
Exhaust HC 0.68 0.69 0.71 0.73 0.75 0.77 0.79 0.81 0.81 0.82 0.80 0.76 0.73 0.73 0.60 0.58 0.48 0.36
Exhaust CO 1.49 1.52 1.56 1.60 1.64 1.69 1.73 1.76 1.78 1.79 1.78 1.75 1.73 1.74 1.59 1.57 1.41 1.21
Exhaust NOx 1.83 1.85 1.86 1.87 1.89 1.89 1.89 1.88 1.86 1.85 1.81 1.72 1.62 1.54 1.43 1.32 1.11 0.85
Light-duty trucks                                    
Exhaust HC 1.59 1.60 1.64 1.64 1.68 1.67 1.69 1.63 1.51 1.42 1.02 0.88 0.96 0.97 0.98 0.80 0.79 0.63
Exhaust CO 2.67 2.70 2.76 2.77 2.85 2.85 2.89 2.79 2.60 2.44 1.77 1.54 1.66 1.68 1.68 1.37 1.34 1.06
Exhaust NOx 2.71 2.66 2.62 2.56 2.53 2.46 2.42 2.31 2.17 2.07 1.76 1.64 1.67 1.66 1.59 1.37 1.30 1.09
Heavy-duty vehicles                                    
Exhaust HC 2.21 1.97 1.74 1.55 1.38 1.23 1.10 1.00 0.92 0.85 0.79 0.74 0.69 0.61 0.58 0.54 0.51 0.48
Exhaust CO 10.06 9.22 8.43 7.71 7.00 6.32 5.73 5.23 4.80 4.43 4.10 3.82 3.58 3.37 3.19 3.05 2.90 2.66
Exhaust NOx 23.34 22.14 21.47 21.10 20.75 20.49 20.24 20.04 19.84 19.14 18.05 16.68 15.52 13.92 12.50 11.45 10.55 9.60
Average Emissions Per Vehicle, RFG and Diesel Fleet                                    
Exhaust HC 2.98 2.70 2.42 2.18 1.96 1.76 1.56 1.43 1.32 1.23 1.16 1.08 0.99 0.91 0.77 0.65 0.581 0.543
Nonexhaust HC 1.21 1.16 1.10 1.06 1.04 1.01 0.99 0.97 0.94 0.91 0.89 0.86 0.82 0.77 0.74 0.69 0.65 0.604
Total HC 4.20 3.86 3.52 3.24 3.00 2.77 2.55 2.40 2.26 2.14 2.04 1.93 1.81 1.68 1.51 1.35 1.23 1.147
Exhaust CO 45.07 41.43 37.93 34.76 31.84 29.12 26.65 24.90 23.40 22.00 20.94 20.02 18.94 17.49 15.24 13.56 11.95 11.318
Exhaust NOx 4.15 3.92 3.75 3.61 3.49 3.36 3.24 3.18 3.12 3.02 2.91 2.78 2.65 2.48 2.25 2.07 1.87 1.726

KEY: CO = carbon monoxide; HC = hydrocarbon; NOx = nitrogen oxide; 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 is based on MOBILE6, the U.S. Environmental Protection Agency's (EPA) latest highway vehicle emissions factor model. Interested readers can learn more about the MOBILE6 model at the following USEPA Internet site http://www.epa.gov/otaq/m6.htm.

Emissions factors are national averages based on the following assumptions: ambient temperature 75 ºF, daily temperature range 60-84 ºF, average traffic speed 27.6 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.

Average emissions per vehicle rates assume a fleet comprised exclusively of gasoline and diesel vehicles. For emissions estimates of a fleet using RFG and diesel, see table 4-39.

SOURCE

U.S. Environmental Protection Agency, National Vehicle and Fuel Emissions Laboratory, personal communication, Nov. 29, 2007.
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