Bureau of Transportation Statistics (BTS)

Table 4-39. Estimated National Average Vehicle Emissions Rates by Vehicle Type Using Reformulated Gasoline (Grams per mile)

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  1995 1996 1997 1998 1999 2000E
Light-duty vehicles            
Exhaust HC 1.43 1.38 1.34 1.30 1.28 1.16
Nonexhaust HC 0.69 0.68 0.66 0.64 0.60 0.37
Total HC 2.12 2.06 2.00 1.94 1.88 1.53
Exhaust CO 16.46 16.14 15.90 15.62 15.48 15.41
Exhaust NOx 1.59 1.54 1.49 1.43 1.39 1.29
Light-duty trucks            
Exhaust HC 2.11 2.02 1.93 1.84 1.78 1.63
Nonexhaust HC 0.85 0.80 0.78 0.75 0.73 0.47
Total HC 2.96 2.82 2.71 2.59 2.51 2.10
Exhaust CO 22.15 21.62 21.20 20.59 20.22 19.95
Exhaust NOx 1.96 1.93 1.91 1.85 1.82 1.71
Heavy-duty vehicles            
Exhaust HC 4.40 4.02 3.62 3.22 2.96 2.65
Nonexhaust HC 2.53 2.38 2.24 2.10 1.99 1.30
Total HC 6.93 6.40 5.86 5.32 4.95 3.95
Exhaust CO 72.26 65.30 58.59 51.68 46.18 41.04
Exhaust NOx 5.47 5.35 5.24 5.04 4.88 4.67
Motorcycles            
Exhaust HC 1.92 1.89 1.88 1.86 1.86 1.82
Nonexhaust HC 1.91 1.91 1.91 1.91 1.90 1.43
Total HC 3.83 3.80 3.79 3.77 3.76 3.25
Exhaust CO 17.46 17.46 17.46 17.36 17.36 17.36
Exhaust NOx 0.84 0.84 0.84 0.83 0.83 0.83
Average of all RFG and diesel vehicles            
Exhaust HC 1.77 1.70 1.64 1.58 1.54 1.41
Nonexhaust HC R0.75 0.73 0.71 R0.68 0.64 0.41
Total HC 2.52 2.43 2.35 2.25 2.18 1.82
Exhaust CO 19.38 18.83 18.37 17.81 17.45 17.17
Exhaust NOx 2.61 2.54 2.48 2.39 2.32 2.19

KEY: CO = carbon monoxide; E = Estimate; HC = hydrocarbon; NOx = nitrogen oxide; R = revised;RFG = reformulated gasoline.

NOTES: As of July 1 of each year. Vehicle types are defined as follows: light-duty vehicles (passenger cars up to 6,000 lb gross vehicle weight rating GVWR) ; light-duty trucks (pickups and minivans up to 8,500 lb GVWR); heavy-duty vehicles (8,501 lb or more GVWR); motorcycle (on-highway only). The data in this table are based on MOBILE5b, and reflect the introduction of RFG starting in 1995. Emissions factors are national averages based on the following assumptions: ambient temperature 75 ºF, daily temperature range 60 -84 ºF, 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).
Emissions estimates in this table assume 100% RFG.

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

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