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Titolo:
Sources and chemical composition of atmospheric fine and coarse particles in the Helsinki area
Autore:
Pakkanen, TA; Loukkola, K; Korhonen, CH; Aurela, M; Makela, T; Hillamo, RE; Aarnio, P; Koskentalo, T; Kousa, A; Maenhaut, W;
Indirizzi:
Finnish Meteorol Inst, FIN-00810 Helsinki, Finland Finnish Meteorol Inst Helsinki Finland FIN-00810 00810 Helsinki, Finland Helsinki Metropolitan Area Council, FIN-00521 Helsinki, Finland Helsinki Metropolitan Area Council Helsinki Finland FIN-00521 i, Finland State Univ Ghent, Inst Nucl Sci, B-9000 Ghent, Belgium State Univ Ghent Ghent Belgium B-9000 st Nucl Sci, B-9000 Ghent, Belgium
Titolo Testata:
ATMOSPHERIC ENVIRONMENT
fascicolo: 32, volume: 35, anno: 2001,
pagine: 5381 - 5391
SICI:
1352-2310(200111)35:32<5381:SACCOA>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
NEUTRON-ACTIVATION ANALYSIS; PARTICULATE AIR-POLLUTION; LOW-PRESSURE IMPACTOR; AEROSOL-PARTICLES; TRACE-ELEMENTS; UK ATMOSPHERE; URBAN; SPECTROMETRY; DISSOLUTION; DEPOSITION;
Keywords:
atmosphere; urban; rural; fine particles; coarse particles; elements; ions; chemical composition; sources;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Physical, Chemical & Earth Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Pakkanen, TA Finnish Meteorol Inst, Sahaajankatu 20 E, FIN-00810 Helsinki,Finland Finnish Meteorol Inst Sahaajankatu 20 E Helsinki Finland FIN-00810
Citazione:
T.A. Pakkanen et al., "Sources and chemical composition of atmospheric fine and coarse particles in the Helsinki area", ATMOS ENVIR, 35(32), 2001, pp. 5381-5391

Abstract

During April 1996-June 1997 size-segregated atmospheric aerosol particles were collected at an urban and a rural site in the Helsinki area by utilising virtual impactors (VI) and Berner low-pressure impactors (BLPI). In addition, VI samples were collected at a semi-urban site during October 1996 May 1997. The average PM2.3 (fine particle) concentrations at the urban and rural sites were 11.8 and 8.4 mug/m(3), and the PM2.3-15 (coarse particle) concentrations were 12.8 and about 5 mug/m(3), respectively. The difference in fine particle mass concentrations suggests that on average, more than one third of the line mass at the urban site is of local origin. Evaporation of fine particle nitrate from the VI Teflon filters during sampling varied similarly at the three sites, the average evaporation being about 50-60%. The average fine particle concentrations of the chemical components (25 elements and 13 ions) appeared to be fairly similar at the three sites for most components. which suggests that despite the long-range transport, the local emissions of these components were relatively evenly distributed in theHelsinki area. Exceptions were the average fine particles Ba, Fe, Sb and Vconcentrations that were clearly highest at the urban site pointing to traffic (Ba, Fe, Sb) and to combustion of heavy fuel oil (V) as the likely local sources. The average coarse particle concentrations for most components were highest at the urban site and lowest at the rural site. Average chemical composition of fine particles was fairly similar at the urban and rural sites: non-analysed fraction (mainly carbonaceous material and water) 43% and 37%, sulphate 21% and 25%, crustal matter 12% and 13%, nitrate 12% and 11%, ammonium 9% and 10% and sea-salt 2.5% and 3.2%, respectively. At the semi-urban site also, the average fine particle composition was similar. At the urban site. the year round average composition of coarse particles was dominated by crustal matter (59%) and the non-analysed components (28%, mainly carbonaceous material and water). while the other contributions were much lower: sea-salt 7%, nitrate 4% and sulphate 2%. At the rural site, the coarse samples were collected in spring and summer and the percentage was clearly lower for crustal matter (37%) and sea-salt (3%) but higher for the not-analysed fraction (51%). At the semi-urban site, the average composition of coarse particles was nearly identical to that at the urban site. Correlations between the chemical components were calculated separately for fine and coarse particles. In urban fine particles sulphate, ammonium, Tl. oxalate and PM2.3 mass correlated with each other and originated mainly from long-range transport. The sea-salt ions Na+, Cl- and Mg2+ formed another group and still another group was formed by the organic anions oxalate, malonate, succinate, glutarate and methane sulphonate. Ni and V correlated strongly pointing to combustion of heavy fuel oil as the likely source. In addition, some groups with lower correlations were detected. At the rural and semi-urban sites, the correlating components were rather similar to thoseat the urban site, although differences were also observed. (C) 2001 Elsevier Science Ltd. All rights reserved.

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Documento generato il 22/01/20 alle ore 18:38:18