Carbonaceous aerosols at an industrial site in Southeastern Spain

The aim of the present study is to evaluate the possible influence of cement works on carbonaceous aerosol concentrations in the western Mediterranean. A PM2.5 and PM10 sampling campaign was performed between September 2005 and August 2006 in a suburban area close to two cement plants in southeastern Spain. All the samples were analyzed for elemental carbon (EC) and organic carbon (OC) using a thermal-optical method. The percentage contribution of total carbon to annual PM mass concentrations was 20 % for PM2.5 and 10 % for PM10. These values were lower than those reported for other European urban and industrial locations because of a higher proportion of crustal matter and secondary inorganic aerosols in the study area. The seasonal cycle of OC concentrations, with higher values in winter than in summer, was influenced by the transport of cement plants' emissions to the sampling site, as corroborated by the results obtained from the CPF analysis. In contrast, no clear effect of cement plants' emissions on EC concentrations could be established. The concentrations of secondary organic carbon (SOC) in the PM2.5 fraction were estimated using the EC tracer method. The contribution of SOC to the annual OC concentration was 50 %, varying between 30 % in July and 70 % in February. Contrary to expectations, SOC levels also exhibited a summer minimum, suggesting that photochemistry cannot be considered to be the leading factor in the formation of secondary organic aerosols in the research area.