Publication Date
3-2001
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 conducted the second year of a five year remote sensing study in the Los Angeles, CA 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 motor vehicle exhaust which would be observed by a tailpipe probe, corrected for water and any excess oxygen not involved in combustion. The system used in this study was also 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. Eight days of fieldwork between May 30 and June 6, 2000 were conducted on the uphill exit ramp from 91N to 60W in Riverside, CA. A database was compiled containing 23,303 records for which the State of California provided make and model year information. All of these records contained valid measurements for at least CO and CO2, 23,230 contained measurements for HC and 23,285 for NO data. The database, along with earlier databases and reports, can be found at www.feat.biochem.du.edu. The mean percent CO, HC, and NO were determined to be 0.50%, 0.012%, and 0.042%, respectively with an average model year of 1993.3. The mean emissions in gm/kg of fuel consumed for CO, HC and NO were 61.7, 2.2 and 6.0. The fleet emissions measured in this study exhibit a gamma distribution, with the dirtiest 10% of the fleet responsible for 73%, 78%, and 51% of the CO, HC, and NO emissions, respectively. The majority of measurements (62%) at this location were of vehicles measured once. The remaining 38% of the measurements were of vehicles measured at least twice. By removing all of the repeat measurements from the database and allowing each vehicle to appear only once, we have shown that these repeat measurements are not skewing the results and that the full database is statistically representative of the actual fleet at the measurement site. Using vehicle specific power, it was possible to adjust the emissions of the vehicle fleet measured in 2000 to match the vehicle driving patterns of the fleet measured in 1999. After doing so, slight improvement in CO emissions was seen. The HC and NO data seemed to contain other factors that confounded the analysis. A model year adjustment was applied to a fleet of specific model year vehicles to track deterioration. Using a fleet of 1983 to 1999 model year vehicles, the deterioration of the fleet was demonstrated for CO and HC. Tracking of model year fleets through the two years of study showed that decreased CO emissions of newer model year vehicles are more an effect of technology than of age. In other words, emissions of newer cars appear to deteriorate very slowly with increasing age. An analysis of high emitting vehicles showed that there is considerable overlap of CO and HC high emitters.
Copyright Statement / License for Reuse
Copyright Date
3-2001
Rights Holder
Sajal S. Pokharel, Gary A. Bishop, Donald H. Stedman
Provenance
Received from author
File Format
application/pdf
Language
English (eng)
Extent
31 pgs
File Size
181 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 Los Angeles area: Year 2. Atlanta, GA: Coordinating Research Council.