Publication Date
8-2001
Document Type
Technical Report
Organizational Units
College of Natural Science and Mathematics, Chemistry and Biochemistry
Keywords
Atmospheric chemistry, Emissions, Pollutants
Abstract
The University of Denver has completed the first four years of a multi-year remote sensing study in the Chicago area. The remote sensor used in this study is capable of measuring the ratios of CO, HC, and NO to CO2 in motor vehicle exhaust. From these ratios, we calculate the percent concentrations of CO, CO2, HC and NO in the exhaust that would be observed by a tailpipe probe, corrected for water and any excess oxygen not involved in combustion. Mass emissions per mass or volume of fuel can also be determined. The system used in this study was configured to determine the speed and acceleration of the vehicle, and was accompanied by a video system to record the license plate of the vehicle. The fourth year of this study involved four days of fieldwork conducted at the on-ramp from Algonquin Rd. to eastbound I-290 in northwest Chicago. A database was compiled containing 22,065 records for which the State of Illinois provided make and model year information. All of these records contained valid measurements for at least CO and CO2, and 21,972 records contained measurements of HC and NO as well. The database, as well as others compiled by the University of Denver, can be found at www.feat.biochem.du.edu. The mean CO, HC and NO emissions for the fleet measured in the fourth year of this study were 0.26%, 94 ppm (when offset is removed) and 316 ppm, respectively. These values are amongst the lowest we have observed for a statistically significant fleet, and are again considerably lower than those for fleets previously measured in the Chicago area. Vehicle emissions as a function of vehicle specific power revealed that NO emissions show a positive dependence on specific power, while HC emissions show a negative dependence on specific power – the expected trends. Carbon monoxide emissions show a slight negative dependence on specific power in the range from –5 to 25 kW/tonne. This negative dependence of CO in less pronounced than previous years. Using vehicle specific power, it was possible to adjust the emissions of the vehicle fleet measured in 2000, 1999 and 1998 to match the vehicle driving patterns of the fleet measured in 1997. After doing so, average emissions of all three pollutants of the current fleet were lower than the emissions of the 1997 fleet. A model year adjustment was applied to 1983 to 1997 model year vehicles to track deterioration. It was observed that the average emissions of the fleet had declined, apparently more than offsetting expected emissions deterioration. It is possible that the recently implemented reformulated gasoline program caused this effect. Finally, an analysis of high emitters shows that there is significant overlap of vehicles that are high emitting for CO and HC.
Copyright Statement / License for Reuse
Copyright Date
8-1-2001
Rights Holder
Sajal S. Pokharel, Gary A. Bishop, Donald H. Stedman
Provenance
Received from author
File Format
application/pdf
Language
English (eng)
Extent
30 pgs
File Size
312 KB
Publication Statement
Copyright is held by the authors. User is responsible for all copyright compliance.
This research was supported by the non-profit Coordinating Research Council, Inc. (CRC). The final results of the research conducted by, or under the auspices of, CRC are available to the public.
Recommended Citation
Pokharel, S. S., Bishop, G. A., & Stedman, D. H. (2001). On-road remote sensing of automobile emissions in the Chicago area: Year 4. Atlanta, GA: Coordinating Research Council.