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| Titel |
Spatiotemporal distribution of light-absorbing carbon and its relationship to other atmospheric pollutants in Stockholm |
| VerfasserIn |
P. Krecl, A. C. Targino, C. Johansson |
| 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 ; 11, no. 22 ; Nr. 11, no. 22 (2011-11-21), S.11553-11567 |
| Datensatznummer |
250010205
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| Publikation (Nr.) |
 copernicus.org/acp-11-11553-2011.pdf |
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| Zusammenfassung |
Carbon-containing particles have deleterious effects on both
Earth's climate and human health. In Europe, the main sources of
light-absorbing carbon (LAC) emissions are the transport (67%) and
residential (25%) sectors. Information on the spatiotemporal variability
of LAC particles in urban areas is relevant for air quality management and
to better diagnose the population exposure to these particles. This study
reports on results of an intensive field campaign conducted at four sites
(two kerbside stations, one urban background site and a rural station) in
Stockholm, Sweden, during the spring 2006. Light-absorbing carbon mass
(MLAC) concentrations were measured with custom-built Particle Soot
Absorption Photometers (PSAP). The spatiotemporal variability of MLAC
concentrations was explored by examining correlation coefficients (R),
coefficients of divergence (COD), and diurnal patterns at all sites.
Simultaneous measurements of NOx, PM10, PM2.5, and meteorological
variables were also carried out at the same locations to help
characterize the LAC emission sources.
Hourly mean (± standard deviation) MLAC concentrations ranged from
0.36±0.50 at the rural site to 5.39±3.60 μg m−3 at
the street canyon site. Concentrations of LAC between urban sites were
poorly correlated even for daily averages (R<0.70), combined with highly
heterogeneously distributed concentrations (COD>0.30) even at spatial
scales of few kilometers. This high variability is connected to the
distribution of emission sources and processes contributing to the LAC
fraction at these sites. At urban sites, MLAC tracked NOx levels and
traffic density well and mean MLAC/PM2.5 ratios were larger
(26–38%) than at the background sites (4–10%). The results suggest
that vehicle exhaust emissions are the main responsible for the high
MLAC concentrations found at the urban locations whereas long-range
transport (LRT) episodes of combustion-derived particles can generate a
strong increase of levels at background sites.
To decrease pollution levels at kerbside and urban background locations in
Stockholm, we recommend abatement strategies that target reductions of
vehicle exhaust emissions, which are the main contributors to MLAC and
NOx concentrations. |
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