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| Titel |
Diesel-related hydrocarbons can dominate gas phase reactive carbon in megacities |
| VerfasserIn |
R. E. Dunmore, J. R. Hopkins, R. T. Lidster, J. D. Lee, M. J. Evans, A. R. Rickard, A. C. Lewis, J. F. Hamilton |
| 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 ; 15, no. 17 ; Nr. 15, no. 17 (2015-09-07), S.9983-9996 |
| Datensatznummer |
250120018
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| Publikation (Nr.) |
 copernicus.org/acp-15-9983-2015.pdf |
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| Zusammenfassung |
| Hydrocarbons are key precursors to two priority air pollutants, ozone
and particulate matter. Those with two to seven carbons have
historically been straightforward to observe and have been
successfully reduced in many developed cities through air quality
policy interventions. Longer chain hydrocarbons released from diesel
vehicles are not considered explicitly as part of air quality
strategies and there are few direct measurements of their gaseous
abundance in the atmosphere. This study describes the chemically
comprehensive and continuous measurements of organic compounds in
a developed megacity (London), which demonstrate that on a seasonal
median basis, diesel-related hydrocarbons represent only
20–30 % of the total hydrocarbon mixing ratio but comprise
more than 50 % of the atmospheric hydrocarbon mass and are
a dominant local source of secondary organic aerosols. This study
shows for the first time that 60 % of the winter primary
hydrocarbon hydroxyl radical reactivity is from diesel-related
hydrocarbons and using the maximum incremental reactivity scale, we
predict that they contribute up to 50 % of the ozone
production potential in London. Comparing real-world urban composition
with regulatory emissions inventories in the UK and US highlights
a previously unaccounted for, but very significant, under-reporting of
diesel-related hydrocarbons; an underestimation of a factor ~4
for C9 species rising to a factor of over 70 for C12
during winter. These observations show that hydrocarbons from diesel
vehicles can dominate gas phase reactive carbon in cities with high
diesel fleet fractions. Future control of urban particulate matter and
ozone in such locations requires a shift in policy focus onto gas
phase hydrocarbons released from diesels as this vehicle type
continues to displace gasoline world-wide. |
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