An Analysis of Michigan and California CO Remote Sensing Measurements

Abstract

Remote sensing measurements of CO emissions from onroad vehicles were made in California in 1991 and in Michigan in 1992. It was determined that both fleets had a small linear increase in the high emitter frequency (vehicles emitting more than 4% CO) as a function of vehicle age for 1986 and newer model vehicles. Although high emitting vehicles were only a small minority of the fleet, they had a dominant impact on the mean CO and total CO emitted by the fleet. In Michigan, the highest emitting 5% of passenger cars generated 45% of the CO from cars. In California, the highest emitting 5% of passenger cars generated 38% of the CO from cars. There was a high correlation between the mean CO emitted by each model year of vehicle and the frequency of high emitting vehicles within the model year for both the Michigan and California fleets. The frequency of high emitters within any model year had no obvious relation to that model year's certification standards. The high emitter frequencies for vehicles less than nine years old were very similar for the California and Michigan fleets. An increase in the high emitter frequency in the ten-year-old and older Michigan passenger car fleet (relative to the California passenger car fleet), suggests, but does not conclusively demonstrate, that the rate of high emitters in Michigan and California is reduced by the inspection and maintenance (I/ M) programs. INTRODUCTIONRemote sensors have been in use to measure the CO and HC emissions from on-road vehicles for approximately five years. These devices have shown potential for measuring vehicle fleet average emissions 1,2 and for identifying high emitting vehicles.3,4 Studies using these devices have shown dramatic differences in average fleet emissions as a function of vehicle model year.Several large-scale remote sensing studies have been performed over the last few years, making it possible to begin to compare the emissions from model year classes of vehicles that have been measured at widely different times. Such comparisons might begin to show the effects of deterioration of emissions within specific model year classes of vehicles. These studies can also be used to look for measurable effects on tailpipe emissions in areas subject to inspection and maintenance (I/M) programs.We will present measurements of CO emissions from tens of thousands of on-road vehicles obtained during the Michigan Roadside Study (MRS) of 1992.5 Mean CO concentrations and high emitter frequencies measured during

Driving cycle developments and their impacts on energy consumption of transportation

“…HC and PM, [19], some studies visualized number of significant findings with respect to the methodology used such as consistency and accuracy in measuring the vehicle emissions [20 -21]. On-road remote sensing was successfully used in many regions to specify vehicle fleet emissions such as in Monterrey, Nuevo Leon, Mexico [22], in the Denver metropolitan area [23], and in California, 1991 and in Michigan, 1992 [24].…”