Partitioning of major and trace components in PM10–PM2.5–PM1 at an urban site in Southern Europe

Partitioning of major and trace components in PM10–PM2.5–PM1 at an urban site in Barcelona (Spain) in the Western Mediterranean was studied in the period 2005–2006. Particular attention was paid to the partitioning of mineral matter and to the evidence of possible interactions of mineral matter with other pollutants (gaseous pollutants and secondary PM). The results showed a high contribution of mineral matter (mainly anthropogenic, but sporadically associated with African dust outbreaks) in levels of both PM10 and PM2.5. A high proportion of nitrate was also present in the coarse fractions as a result of the interaction of mineral matter with gaseous pollutants. As at most urban sites in Europe, sulphate and carbonaceous aerosols are mainly present in the finer PM fractions. The PM1–2.5 fraction resembled that of PM10 in composition. The chemically unaccounted fraction (mostly bounded water) had also a fine grain size, probably because of the fine size of the hygroscopic aerosol components. The data series follow an increasing trend for PM1 levels (and less clearly for PM2.5) from 1999 to 2006, whereas no trend is observed for PM10.The contributions of African dust and regional soil resuspension to the annual PM10 levels has been estimated in around 1–2 and 2–3 μg m−3 in this part of Spain. The African dust outbreaks accounted for around 15–20 exceedances of the European daily PM10 limit value.Finally, the data obtained were compared with data from selected European sites to highlight major differences in levels and speciation of PM.