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| Titel |
Airborne measurements of trace gases and aerosols over the London metropolitan region |
| VerfasserIn |
G. R. McMeeking, M. Bart, P. Chazette, J. M. Haywood, J. R. Hopkins, J. B. McQuaid, W. T. Morgan, J.-C. Raut, C. L. Ryder, N. Savage, K. Turnbull, H. Coe |
| 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 ; 12, no. 11 ; Nr. 12, no. 11 (2012-06-13), S.5163-5187 |
| Datensatznummer |
250011234
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| Publikation (Nr.) |
 copernicus.org/acp-12-5163-2012.pdf |
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| Zusammenfassung |
| The Emissions around the M25 motorway (EM25) campaign took place over the
megacity of London in the United Kingdom in June 2009 with the aim of
characterising trace gas and aerosol composition and properties entering and
emitted from the urban region. It featured two mobile platforms, the UK
BAe-146 Facility for Airborne Atmospheric Measurements (FAAM) research
aircraft and a ground-based mobile lidar van, both travelling in circuits
around London, roughly following the path of the M25 motorway circling the
city. We present an overview of findings from the project, which took place
during typical UK summertime pollution conditions. Emission ratios of
volatile organic compounds (VOCs) to acetylene and carbon monoxide emitted
from the London region were consistent with measurements in and downwind of
other large urban areas and indicated traffic and associated fuel
evaporation were major sources. Sub-micron aerosol composition was dominated
by secondary species including sulphate (24% of sub-micron mass in the
London plume and 29% in the non-plume regional aerosol), nitrate (24%
plume; 20% regional) and organic aerosol (29% plume; 31% regional).
The primary sub-micron aerosol emissions from London were minor compared to
the larger regional background, with only limited increases in aerosol mass
in the urban plume compared to the background (~12% mass increase
on average). Black carbon mass was the major exception and more than doubled
in the urban plume, leading to a decrease in the single scattering albedo
from 0.91 in the regional aerosol to 0.86 in the London plume, on average.
Our observations indicated that regional aerosol plays a major role on
aerosol concentrations around London, at least during typical summertime
conditions, meaning future efforts to reduce PM levels in London must
account for regional as well as local aerosol sources. |
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