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@ARTICLE{Visser:275787,
author = {Visser, S. and Slowik, J. G. and Furger, Markus and Zotter,
P. and Bukowiecki, N. and Canonaco, F. and Flechsig, U. and
Appel, K. and Green, D. C. and Tremper, A. H. and Young, D.
E. and Williams, P. I. and Allan, J. D. and Coe, H. and
Williams, L. R. and Mohr, C. and Xu, L. and Ng, N. L. and
Nemitz, E. and Barlow, J. F. and Halios, C. H. and Fleming,
Z. L. and Baltensperger, U. and Prévôt, A. S. H.},
title = {{A}dvanced source apportionment of size-resolved trace
elements at multiple sites in {L}ondon during winter},
journal = {Atmospheric chemistry and physics},
volume = {15},
number = {19},
issn = {1680-7324},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {PUBDB-2015-04235},
pages = {11291 - 11309},
year = {2015},
abstract = {Trace element measurements in PM$_{10–2.5}$,
PM$_{2.5–1.0}$ and PM$_{1.0–0.3}$ aerosol were performed
with 2 h time resolution at kerbside, urban background and
rural sites during the ClearfLo winter 2012 campaign in
London. The environment-dependent variability of emissions
was characterized using the Multilinear Engine
implementation of the positive matrix factorization model,
conducted on data sets comprising all three sites but
segregated by size. Combining the sites enabled separation
of sources with high temporal covariance but significant
spatial variability. Separation of sizes improved source
resolution by preventing sources occurring in only a single
size fraction from having too small a contribution for the
model to resolve. Anchor profiles were retrieved internally
by analysing data subsets, and these profiles were used in
the analyses of the complete data sets of all sites for
enhanced source apportionment.A total of nine different
factors were resolved (notable elements in brackets): in
PM$_{10–2.5}$, brake wear (Cu, Zr, Sb, Ba), other
traffic-related (Fe), resuspended dust (Si, Ca), sea/road
salt (Cl), aged sea salt (Na, Mg) and industrial (Cr, Ni);
in PM$_{2.5–1.0}$, brake wear, other traffic-related,
resuspended dust, sea/road salt, aged sea salt and S-rich
(S); and in PM$_{1.0–0.3}$, traffic-related (Fe, Cu, Zr,
Sb, Ba), resuspended dust, sea/road salt, aged sea salt,
reacted Cl (Cl), S-rich and solid fuel (K, Pb). Human
activities enhance the kerb-to-rural concentration gradients
of coarse aged sea salt, typically considered to have a
natural source, by 1.7–2.2. These site-dependent
concentration differences reflect the effect of local
resuspension processes in London. The anthropogenically
influenced factors traffic (brake wear and other
traffic-related processes), dust and sea/road salt provide
further kerb-to-rural concentration enhancements by direct
source emissions by a factor of 3.5–12.7. The traffic and
dust factors are mainly emitted in PM$_{10–2.5}$ and show
strong diurnal variations with concentrations up to 4 times
higher during rush hour than during night-time. Regionally
influenced S-rich and solid fuel factors, occurring
primarily in PM$_{1.0–0.3}$, have negligible resuspension
influences, and concentrations are similar throughout the
day and across the regions.},
cin = {DOOR ; HAS-User},
ddc = {550},
cid = {I:(DE-H253)HAS-User-20120731},
pnm = {899 - ohne Topic (POF3-899) / FS-Proposal: II-20100006 EC
(II-20100006-EC)},
pid = {G:(DE-HGF)POF3-899 / G:(DE-H253)II-20100006-EC},
experiment = {EXP:(DE-H253)D-L-20150101},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000362971000023},
doi = {10.5194/acp-15-11291-2015},
url = {https://bib-pubdb1.desy.de/record/275787},
}