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| Titel |
Long-term real-time chemical characterization of submicron aerosols at Montsec (southern Pyrenees, 1570 m a.s.l.) |
| VerfasserIn |
A. Ripoll, M. C. Minguillón, J. Pey, J. L. Jimenez, D. A. Day, Y. Sosedova, F. Canonaco, A. S. H. Prévôt, X. Querol, A. Alastuey |
| 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. 6 ; Nr. 15, no. 6 (2015-03-16), S.2935-2951 |
| Datensatznummer |
250119551
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| Publikation (Nr.) |
 copernicus.org/acp-15-2935-2015.pdf |
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| Zusammenfassung |
Real-time measurements of inorganic (sulfate, nitrate,
ammonium, chloride and black carbon (BC)) and organic submicron aerosols
(particles with an aerodynamic diameter of less than 1 μm) from a
continental background site (Montsec, MSC, 1570 m a.s.l.) in the western
Mediterranean Basin (WMB) were conducted for 10 months (July 2011–April
2012). An aerosol chemical speciation monitor (ACSM) was co-located with
other online and offline PM1 measurements. Analyses of the hourly,
diurnal, and seasonal variations are presented here, for the first time, for
this region.
Seasonal trends in PM1 components are attributed to variations in
evolution of the planetary boundary layer (PBL) height, air mass origin, and
meteorological conditions. In summer, the higher temperature and solar
radiation increases convection, enhancing the growth of the PBL and the
transport of anthropogenic pollutants towards high altitude sites.
Furthermore, the regional recirculation of air masses over the WMB creates a
continuous increase in the background concentrations of PM1 components
and causes the formation of reservoir layers at relatively high altitudes.
The combination of all these atmospheric processes results in a high
variability of PM1 components, with poorly defined daily patterns,
except for the organic aerosols (OA). OA was mostly composed (up to 90%)
of oxygenated organic aerosol (OOA), split in two types: semivolatile
(SV-OOA) and low-volatility (LV-OOA), the rest being hydrocarbon-like OA
(HOA). The marked diurnal cycles of OA components regardless of the air mass
origin indicates that they are not only associated with anthropogenic and
long-range-transported secondary OA (SOA) but also with recently produced
biogenic SOA.
Very different conditions drive the aerosol phenomenology in winter at MSC.
The thermal inversions and the lower vertical development of the PBL leave
MSC in the free troposphere most of the day, being affected by PBL air
masses only after midday, when the mountain breezes transport emissions from
the adjacent valleys and plains to the top of the mountain. This results in
clear diurnal patterns of both organic and inorganic concentrations. OA was
also mainly composed (71%) of OOA, with contributions from HOA (5%)
and biomass burning OA (BBOA; 24%). Moreover, in winter sporadic
long-range transport from mainland Europe is observed.
The results obtained in the present study highlight the importance of SOA
formation processes at a remote site such as MSC, especially in summer.
Additional research is needed to characterize the sources and processes of
SOA formation at remote sites. |
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