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CENTRAL CAROLINA VEHICLE PARTICULATE EMISSION STUDY (FINAL REPORT)
Citation:
Knapp, K T., S B. Tejada, S. H. Cadle, D. R. Lawson, AND R. F. Snow. CENTRAL CAROLINA VEHICLE PARTICULATE EMISSION STUDY (FINAL REPORT). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/090 (NTIS PB2001-100186), 1999.
Description:
A study to characterize the exhaust emissions from a light-duty fleet of in-use vehicles representative of central North Carolina was conducted in 1999 during both a winter phase (February) and a summer phase (June - July). Summer temperatures averaged 78 F, while the winter temperatures averaged 63 F due to unseasonable warming. In the winter phase, 135 gasoline and 3 diesel vehicles were tested and in the summer phase, 120 gasoline and 5 diesel vehicles were tested. Ninety four percent of the vehicles were tested in as-received condition on the EPA transportable dynamometer using the IM240 driving cycle. The other six percent of the vehicles were tested on EPA's cold cell research chassis dynamometer in as-received condition. Regulated emission rates, PM10, aldehyde and ketone emissions rates were determined from all vehicles. In addition, PM2.5 and speciated hydrocarbon were determined from a subset of the vehicles. PUF/XAD samples were collected from a subset of the vehicles for analysis at Desert Research Institute for organic and elemental carbon, PAH's, nitro-PAHs, oxy-PAHs and the hopanes and steranes. Average PM10 emission rates for the gasoline-fueled vehicles were 4.6, 5.3, 17.3 and 19.6 mg/mi for the 1993-97, 1990-92, 1985-89, and pre-85 summer vehicles. The corresponding average PM10 emission rates for the winter phase, from a different vehicle fleet, were 7.8, 24.3, 26.0 and 69.4 mg/mi. The average PM10 and PM2.5 emission rates for the summer phase were 10.6 mg/mi (120 vehicles) and 7.2 mg/mi (16 vehicles) respectively with the corresponding median of 3.7 and 3.5 mg/mi. For the winter phase, the PM10 and PM2.5 average were 27.6 mg/mi (117 vehicles) and 32.2 mg/mi (45 vehicles) respectively and the corresponding median were 6.4 and 8.4 mg/mi. Linear regression of PM10 vs PM2.5 gave a slope of 0.92, intercept of -0.21 and an R2 of 0.99. Average total hydrocarbon emission rate was 0.63 g/mi for the summer phase and 1.1 g/mi for the winter phase. Average CO and NOx emission rates were 15.3 and 1.5 g/mi respectively for the summer and 14.3 and 2.1 g/mi respectively for the winter phase. Formaldehyde and acetaldehyde emission rates from 135 winter vehicles average 18.4 and 2.5 mg/mi respectively fro the winter and 9.2 and 1.7 mg/mi respectively from the 120 summer vehicles. Alkanes, alkenes, aromatics and oxygenates (alcohols/ethers) were 50, 11.7, 21.7 and 15.7% of the organic hydrocarbon emission in the winter phase and 41.5, 22.0, 28.7, and 1.6 % respectively in the summer phase. MTBE was the most abundant component of the oxygenate emissions.