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| Titel |
Kerb and urban increment of highly time-resolved trace elements in PM10, PM2.5 and PM1.0 winter aerosol in London during ClearfLo 2012 |
| VerfasserIn |
S. Visser, J. G. Slowik, M. Furger, P. Zotter, N. Bukowiecki, R. Dressler, U. Flechsig, K. Appel, D. C. Green, A. H. Tremper, D. E. Young, P. I. Williams, J. D. Allan, S. C. Herndon, L. R. Williams, C. Mohr, L. Xu, N. L. Ng, A. Detournay, J. F. Barlow, C. H. Halios, Z. L. Fleming, U. Baltensperger, A. S. H. Prévôt |
| 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. 5 ; Nr. 15, no. 5 (2015-03-04), S.2367-2386 |
| Datensatznummer |
250119488
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| Publikation (Nr.) |
 copernicus.org/acp-15-2367-2015.pdf |
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| Zusammenfassung |
| Ambient concentrations of trace elements with 2 h time resolution were
measured in PM10–2.5, PM2.5–1.0 and PM1.0–0.3 size ranges
at kerbside, urban background and rural sites in London during winter 2012.
Samples were collected using rotating drum impactors (RDIs) and subsequently
analysed with synchrotron radiation-induced X-ray fluorescence spectrometry (SR-XRF).
Quantification of kerb and urban increments (defined as
kerb-to-urban and urban-to-rural concentration ratios, respectively), and
assessment of diurnal and weekly variability provided insight into sources
governing urban air quality and the effects of urban micro-environments on
human exposure. Traffic-related elements yielded the highest kerb
increments, with values in the range of 10.4 to 16.6 for SW winds (3.3–6.9
for NE) observed for elements influenced by brake wear (e.g. Cu, Sb, Ba) and
5.7 to 8.2 for SW (2.6–3.0 for NE) for other traffic-related processes (e.g.
Cr, Fe, Zn). Kerb increments for these elements were highest in the
PM10–2.5 mass fraction, roughly twice that of the PM1.0–0.3 fraction. These elements also showed the highest urban increments
(~ 3.0), although no difference was observed between brake
wear and other traffic-related elements. All elements influenced by traffic
exhibited higher concentrations during morning and evening rush hours, and on
weekdays compared to weekends, with the strongest trends observed at the
kerbside site, and additionally enhanced by winds coming directly from the
road, consistent with street canyon effects. Elements related to mineral
dust (e.g. Al, Si, Ca, Sr) showed significant influences from
traffic-induced resuspension, as evidenced by moderate kerb (3.4–5.4 for SW,
1.7–2.3 for NE) and urban (~ 2) increments and increased
concentrations during peak traffic flow. Elements related to regional
transport showed no significant enhancement at kerb or urban sites, with the
exception of PM10–2.5 sea salt (factor of up to 2), which may be
influenced by traffic-induced resuspension of sea and/or road salt. Heavy-duty vehicles appeared to have a larger effect than passenger vehicles on
the concentrations of all elements influenced by resuspension (including sea
salt) and wearing processes. Trace element concentrations in London were
influenced by both local and regional sources, with coarse and intermediate
fractions dominated by traffic-induced resuspension and wearing processes
and fine particles influenced by regional transport. |
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