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| Titel |
Source contributions to 2012 summertime aerosols in the Euro-Mediterranean region |
| VerfasserIn |
G. Rea, S. Turquety, L. Menut, R. Briant, S. Mailler, G. Siour |
| 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. 14 ; Nr. 15, no. 14 (2015-07-21), S.8013-8036 |
| Datensatznummer |
250119915
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| Publikation (Nr.) |
 copernicus.org/acp-15-8013-2015.pdf |
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| Zusammenfassung |
In the Mediterranean area, aerosols may originate from anthropogenic or
natural emissions (biogenic, mineral dust, fire and sea salt) before
undergoing complex chemistry. In case of a huge pollution event, it is
important to know whether European pollution limits are exceeded and, if so,
whether the pollution is due to anthropogenic or natural sources. In this
study, the relative contribution of emissions to surface PM10, surface
PM2.5 and total aerosol optical depth (AOD) is quantified. For Europe
and the Mediterranean regions and during the summer of 2012, the WRF and
CHIMERE models are used to perform a sensitivity analysis on a 50 km
resolution domain (from −10° W to 40° E and from
30° N to 55° N): one simulation with all sources
(reference) and all others with one source removed. The reference simulation
is compared to data from the AirBase network and two ChArMEx stations, and
from the AERONET network and the MODIS satellite instrument, to quantify the
ability of the model to reproduce the observations. It is shown that the
correlation ranges from 0.19 to 0.57 for surface particulate matter and from
0.35 to 0.75 for AOD. For the summer of 2012, the model shows that the region
is mainly influenced by aerosols due to mineral dust and anthropogenic
emissions (62 and 19 %, respectively, of total surface PM10 and 17
and 52 % of total surface PM2.5). The western part of the
Mediterranean is strongly influenced by mineral dust emissions (86 % for
surface PM10 and 44 % for PM2.5), while anthropogenic emissions
dominate in the northern Mediterranean basin (up to 75 % for PM2.5).
Fire emissions are more sporadic but may represent 20 % of surface
PM2.5, on average, during the period near local sources. Sea salt mainly
contributes for coastal sites (up to 29 %) and biogenic emissions mainly
in central Europe (up to 20 %).
The same analysis was undertaken for the number of daily exceedances of the
European Union limit of 50 μg m−3 for PM10 (over the
stations), and for the number of daily exceedances of the WHO recommendation
for PM2.5 (25 μg m−3), over the western part of Europe
and the central north. This number is generally overestimated by the model,
particularly in the northern part of the domain, but exceedances are captured
at the right time. Optimized contributions are computed with the
observations, by subtracting the background bias at each station and the
specific peak biases from the considered sources. These optimized
contributions show that if natural sources such as mineral dust and fire
events are particularly difficult to estimate, they were responsible
exclusively for 35.9 and 0.7 %, respectively, of the exceedances for
PM10 during the summer of 2012. The PM25 recommendation of
25 μg m−3 is exceeded in 21.1 % of the cases because of
anthropogenic sources exclusively and in 0.02 % because of fires. The
other exceedances are induced by a mixed contribution between mainly mineral
dust (49.5–67 % for PM10 exceedance contributions, 4.4–13.8 %
for PM2.5), anthropogenic sources (14.9–24.2 % and
46.3–80.6 %), biogenic sources (4.1–15.7 % and 12.6–30 %) and
fires (2.2–7.2 % and 1.6–12.4 %). |
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