Publication Date
6-2005
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 conducted a five-day remote sensing study in the Omaha, Nebraska area in September of 2004. The remote sensor used in this study measures 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 are also 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. Five days of fieldwork, September 13-17, 2004, were conducted on the uphill interchange ramp from westbound I-680 to westbound Dodge Rd. A database was compiled containing 20,778 records for which the states of Nebraska and Iowa provided registration information. All of these records contained valid measurements for at least CO and CO2, and 20,695 records contained valid measurements for 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. Due to road reconstruction, Omaha proved to be a difficult city to find a repeatable measurement site. Two different locations were used in 2002. The first a curved uphill off-ramp from westbound I-680 to eastbound Dodge Rd. (this site is directly across from this year's site) was abandoned because of insufficient traffic. The second an uphill on ramp from 84th St. to eastbound I-80 was not repeated this year because its driving mode proved too difficult to compare with other E-23 sites. Because of these differences, direct comparisons between the three sites are not made in this report. The mean CO, HC and NO emissions for the fleet measured in this study were 0.20%, 176ppm and 267ppm, respectively. The emissions measurements in this study exhibit a gamma distribution, with the dirtiest 10% of the measurements responsible for 79.8%, 60.8%, and 56.8% of the CO, HC, and NO emissions, respectively. The HC readings have been analyzed after subtracting a 70ppm offset, which has been used to reduce all of the measured HC values for comparisons. An analysis of high-emitting vehicles showed that there is some overlap of CO and HC high emitters, for instance 1.6% of the measurements contribute 18% of the total CO and 12% of the total HC. The noise levels in the CO, HC and NO measurement channels were determined to be within acceptable limits, however higher than in some previous studies. The higher noise levels were minimal when compared to the standard error of the mean of the measurements.
Copyright Statement / License for Reuse
Copyright Date
6-1-2005
Rights Holder
Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman
Provenance
Received from author
File Format
application/pdf
Language
English (eng)
Extent
28 pgs
File Size
752 KB
Publication Statement
Copyright is held by the author. User is responsible for all copyright compliance.
This research was supported by the nonprofit 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
Bishop, G. A., Burgard, D. A., & Stedman, D. H. (2004). On-road remote sensing of automobile emissions in the Omaha area: Year 2, September 2004. Atlanta, GA: Coordinating Research Council.