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| Titel |
Levels and Speciation of Platinum in Size-Fractionated Atmospheric Aerosol in Urban and Rural Sites across Europe |
| VerfasserIn |
Martin Shafer, Dagmara Antkiewicz, Joel Overdier, James Schauer |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250136943
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| Publikation (Nr.) |
 EGU/EGU2016-18099.pdf |
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| Zusammenfassung |
| In this study we characterized the levels and speciation of platinum in a unique set of size-resolved atmospheric aerosol (PM) samples obtained from urban environments across Europe. From April-July 2012 we collected PM from roadside canyon, roadside motorway, and background urban sites in each of six European cities (Amsterdam, Frankfurt, London, Milan, Stockholm, and Thessaloniki). A Hi-Vol sampler was used to collect PM in three size classes (>PM7, PM7-PM3, PM3) and characterized for total platinum, soluble platinum (in a suite of physiologically relevant fluids – lung fluid (ALF), Gambles saline, 0.07M HCl, and MQ) and speciated forms (colloidal and anionic) within the soluble fractions. In addition we measured 50 other elements by SF-ICPMS, soluble ions by IC, and soluble organic carbon in the PM. Order-of-magnitude differences in air concentrations of total platinum were observed between urban sites, ranging from 4 to over 45 pg/m3; with a median level of 6 pg/m3. When platinum concentrations are normalized to PM mass the cross Europe and site-to-site variability was substantially reduced - a 3-fold variation from 200 to 600 ng/g was observed. Roadside canyon sites in London, Stockholm and Thessaloniki exhibited the highest concentrations; however levels at urban background sites were remarkably similar across the cities. Relatively consistent and low concentrations (1 to 2 pg/m3) of total platinum were observed at rural background sites across Europe. The contribution of coarse particles (>7 micron and 7-3 micron) to air concentrations of total platinum was very significant (>35% at nearly all sites). Soluble platinum fractions ranged from 2 to 6% (MQ to HCl) in rural background sites to 5 to 20% (MQ to HCl) in roadway canyon sites in London and Thessaloniki; with the extractable platinum fractions a strong function of pH. With the exception of urban canyon sites in London and Thessaloniki, soluble platinum concentrations in the fine aerosol (PM3) were all below 1 pg/m3. Rural background concentrations were especially low (<0.03 pg/m3 in MQ and 0.1 pg/m3 in the other solvents). Urban background concentrations are consistent across sites, averaging 0.1 pg/m3 in MQ, 0.2 pg/m3 in Gambles Solution, and 0.4 pg/m3 in ALF and HCl. The colloidal fraction (i.e. between 10kD and 200nm) was significant (10-50%) in many PM3 and PM >7 sample extracts. The lowest anionic fractions (<0.5%) were measured in MQ extracts of Northern Europe rural and urban background sites. The highest anionic factions (10-12%) were measured in ALF extracts of London, Stockholm, and Thessaloniki roadside canyon sites. Anionic platinum concentrations averaged 0.02 pg/m3 at rural background sites and 0.06 pg/m3 in roadside and canyon sites in MQ extracts. Anionic concentrations of platinum in Gambles and ALF extracts ranged from 0.1 pg/m3 in rural background sites to 0.4 pg/m3 in roadside and canyon sites. Much greater levels were measured in London and Thessaloniki urban canyon sites (1 – 2.5 pg/m3). |
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