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| Titel |
Comparison of emissions from on-road sources using a mobile laboratory under various driving and operational sampling modes |
| VerfasserIn |
M. Zavala, S. C. Herndon, E. C. Wood, J. T. Jayne, D. D. Nelson, A. M. Trimborn, E. Dunlea, W. B. Knighton, A. Mendoza, D. T. Allen, C. E. Kolb, M. J. Molina, L. T. Molina |
| 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 ; 9, no. 1 ; Nr. 9, no. 1 (2009-01-06), S.1-14 |
| Datensatznummer |
250006625
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| Publikation (Nr.) |
 copernicus.org/acp-9-1-2009.pdf |
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| Zusammenfassung |
| Mobile sources produce a significant fraction of the total anthropogenic
emissions burden in large cities and have harmful effects on air quality at
multiple spatial scales. Mobile emissions are intrinsically difficult to
estimate due to the large number of parameters affecting the emissions
variability within and across vehicles types. The MCMA-2003 Campaign in
Mexico City has showed the utility of using a mobile laboratory to sample
and characterize specific classes of motor vehicles to better quantify their
emissions characteristics as a function of their driving cycles. The
technique clearly identifies "high emitter" vehicles via individual
exhaust plumes, and also provides fleet average emission rates. We have
applied this technique to Mexicali during the Border Ozone Reduction and Air
Quality Improvement Program (BORAQIP) for the Mexicali-Imperial Valley in
2005. We analyze the variability of measured emission ratios for emitted
NOx, CO, specific VOCs, NH3, and some primary fine particle
components and properties by deploying a mobile laboratory in roadside
stationary sampling, chase and fleet average operational sampling modes. The
measurements reflect various driving modes characteristic of the urban
fleets. The observed variability for all measured gases and particle
emission ratios is greater for the chase and roadside stationary sampling
than for fleet average measurements. The fleet average sampling mode
captured the effects of traffic conditions on the measured on-road emission
ratios, allowing the use of fuel-based emission ratios to assess the
validity of traditional "bottom-up" emissions inventories. Using the
measured on-road emission ratios, we estimate CO and NOx mobile
emissions of 175±62 and 10.4±1.3 metric tons/day, respectively,
for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road
emissions data from Mexico City indicated that fleet average NO emission
ratios were around 20% higher in Mexicali than in Mexico City whereas
HCHO and NH3 emission ratios were higher by a factor of 2 in Mexico
City than in Mexicali. Acetaldehyde emission ratios did not differ
significantly whereas selected aromatics VOCs emissions were similar or
smaller in Mexicali. Nitrogen oxides emissions for on-road heavy-duty diesel
truck (HDDT) were measured near Austin, Texas, as well as in both Mexican
cities, with NOy emission ratios in Austin < Mexico City <
Mexicali. |
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