Size-segregated aerosol chemical composition at a boreal site in southern Finland, during the QUEST project
Item
Title (Dublin Core)
Size-segregated aerosol chemical composition at a boreal site in southern Finland, during the QUEST project
Description (Dublin Core)
Size-segregated aerosol samples were collected during the QUEST field campaign at Hyytiälä, a boreal forest site in Southern Finland, during spring 2003. Aerosol samples were selectively collected during both particle formation events and periods in which no particle formation occurred. <P style="line-height: 20px;"> A comprehensive characterisation of the aerosol chemical properties (water-soluble inorganic and organic fraction) and an analysis of the relevant meteorological parameters revealed how aerosol chemistry and meteorology combine to determine a favorable "environment" for new particle formation. The results indicated that all <I>events</I>, typically favored during northerly air mass advection, were background aerosols (total mass concentrations range between 1.97 and 4.31 µg m<sup>-3</sup>), with an increasingly pronounced marine character as the northerly air flow arrived progressively from the west and, in contrast, with a moderate SO<sub>2</sub>-pollution influence as the air arrived from more easterly directions. Conversely, the <I>non-event </I> aerosol, transported from the south, exhibited the chemical features of European continental sites, with a marked increase in the concentrations of all major anthropogenic aerosol constituents. The higher <I>non-event</I> mass concentration (total mass concentrations range between 6.88 and 16.30 µg m<sup>-3</sup>) and, thus, a larger surface area, tended to suppress new particle formation, more efficiently depleting potential gaseous precursors for nucleation. The analysis of water-soluble organic compounds showed that clean nucleation episodes were dominated by aliphatic biogenic species, while <I>non-events</I> were characterised by a large abundance of anthropogenic oxygenated species. Interestingly, a significant content of α-pinene photo-oxidation products was observed in the <I>events</I> aerosol, accounting for, on average, 72% of their WSOC; while only moderate amounts of these species were found in the <I>non-event</I> aerosol. If the organic vapors condensing onto accumulation mode particles are responsible also for the growth of newly formed thermodynamically stable clusters, our finding allows one to postulate that, at the site, α-pinene photo-oxidation products (and probably also photo-oxidation products from other terpenes) are the most likely species to contribute to the growth of nanometer-sized particles.
Creator (Dublin Core)
Cavalli, F.
Facchini, M. C.
Decesari, S.
Emblico, L.
Mircea, M.
Jensen, N. R.
Fuzzi, S.
Date (Dublin Core)
2018-06-28
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-6-993-2006
https://acp.copernicus.org/articles/6/993/2006/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
