Effects of vehicle weight and model year on vehicle contribution to atmospheric pollutant inventories.

摘要

The objective of this study was to determine the effects of vehicle weight and model year on vehicle contribution to atmospheric pollutant inventories. The weight class of the vehicle was found to have the greatest impact on vehicle emissions with NOx increasing 285% while PM increased 269% when going from a 12,000 lbs GVWR vehicle to a 52,000 GVWR vehicle with engines certified to the same emissions standards. The vehicle age had a significant impact on emissions production with NOx and PM both increasing 148% and 183% respectively going from a 1985 model year vehicle to a year 2000 model year vehicle. "Off-cycle" emissions were not originally a focus of this study, however, as testing began, it was clear that some of the vehicles were showing "off-cycle" behavior. Vehicle mileage was shown to have an impact on emissions production. Two vehicles, one with an odometer reading of 501,586 and another with 769,413, were shown to have NOx and PM production increase 141% and 49% respectively, when going form the lower mileage vehicle to the higher mileage vehicle. These vehicles were of the same model year, same GVWR and roughly the same engine power.