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| Titel |
Efficient determination of vehicle emission factors by fuel use category using on-road measurements: downward trends on Los Angeles freight corridor I-710 |
| VerfasserIn |
N. Hudda, S. Fruin, R. J. Delfino, C. Sioutas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 1 ; Nr. 13, no. 1 (2013-01-11), S.347-357 |
| Datensatznummer |
250017554
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| Publikation (Nr.) |
 copernicus.org/acp-13-347-2013.pdf |
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| Zusammenfassung |
| To evaluate the success of vehicle emissions regulations, trends in both
fleet-wide average emissions as well as high-emitter emissions are needed,
but it is challenging to capture the full spread of vehicle emission factors
(EFs) with chassis dynamometer or tunnel studies, and remote sensing studies
cannot evaluate particulate compounds. We developed an alternative method
that links real-time on-road pollutant measurements from a mobile platform
with real-time traffic data, and allows efficient calculation of both the
average and the spread of EFs for light-duty gasoline-powered vehicles (LDG)
and heavy-duty diesel-powered vehicles (HDD). This is the first study in
California to report EFs under a full range of real-world driving conditions
on multiple freeways. Fleet average LDG EFs were in agreement with most
recent studies and an order of magnitude lower than observed HDD EFs. HDD
EFs reflected the relatively rapid decreases in diesel emissions that have
recently occurred in Los Angeles/California, and on I-710, a primary route
used for goods movement and a focus of additional truck fleet turnover
incentives, HDD EFs were often lower than on other freeways. When freeway emission
rates (ER) were quantified as the product of EF and vehicle miles traveled (VMT) per time
per mile of freeway, despite a two- to three-fold difference in HDD
fractions between freeways, ERs were found to be generally similar in
magnitude. Higher LDG VMT on low HDD fraction freeways largely offset
the difference. Therefore, the conventional assumption that freeways with
the highest HDD fractions are significantly worse sources of total emissions
in Los Angeles may no longer be~true. |
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