Publication Date

2018

Document Type

Article

Organizational Units

Chemistry and Biochemistry

Keywords

Atmospheric chemistry, Emissions, Pollutants

Abstract

The University of Denver has collected on-road fuel specific vehicle emissions measurements in the Chicago area since 1989. This nearly 30 year record illustrates the large reductions in light-duty vehicle tailpipe emissions and the remarkable improvements in emissions control durability to maintain low emissions over increasing periods of time. Since 1989 fuel specific carbon monoxide (CO) emissions have been reduced by an order of magnitude and hydrocarbon (HC) emissions by more than a factor of 20. Nitric oxide (NO) emissions have only been collected since 1997 but have seen reductions of 79%. This has increased the skewness of the emissions distribution where the 2016 fleet’s 99th percentile contributes ~3 times more of the 1990 total for CO and HC emissions. There are signs that these reductions may be leveling out as the emissions durability of Tier 2 vehicles in use today has almost eliminated the emissions reduction benefit of fleet turnover. Since 1997, the average age of the Chicago on-road fleet has increased 2 model years and the percentage of passenger vehicles has dropped from 71 to 52% of the fleet. Emissions are now so well controlled that the influence of driving mode has been completely eliminated as a factor for fuel specific CO and NO emissions.

Copyright Statement / License for Reuse

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

Rights Holder

Gary A. Bishop, Molly J. Haugen

Provenance

Received from author

File Format

application/pdf

Language

English (eng)

Extent

20 pgs

File Size

6.3 MB

Publication Statement

This article is redistributed with permission of the publisher under the following license: https://pubs.acs.org/page/policy/authorchoice_termsofuse.html

The article was originally published as Bishop, G. A.; Haugen, M. J., (2018) The story of ever diminishing vehicle tailpipe emissions as observed in the Chicago, Illinois area. Environ. Sci. Technol. 52(13), 7587-7593, DOI: 10.1021/acs.est.8b00926. User is responsible for license compliance.

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