Organic aerosols in urban and waste landfill of Algiers metropolitan area:Occurrence and sources

In both downtown Algiers and the waste landfill of Oued Smar, the concentra tions of particulate organic compounds comprising n-alkanes, n-alkanoic aci ds, n-alkan-2-ones, polycyclic aromatic hydrocarbons (PAHs), oxygenated (OP AHs), and nitrated polycyclic aromatic hydrocarbons (NPAHs) in ambient air were measured from May 1998 to February 1999. All the components except OPA Hs had a tendency to strongly increase in colder weather. Motor vehicles we re found to be the main source of airborne particles in downtown Algiers, w hile the combustion and pyrolysis processes and bacterial activity seemed t o concur to the air pollution at the Oued Smar waste;landfill. The biogenic emission, which was restricted to the lighter fraction of the n-alkanes an d n-alkanoic acids, appeared to contribute at a lesser extent. The in-situ generation of some OPAHs and NPAHs seemed to contribute to air pollution, e specially during the summertime. As expected, the ambient concentrations of NPAHs and OPAHs were lower than those of their parent PAHs. The seasonal v ariations in ambient NPAH and OPAH concentrations are due partly to fluctua tions of precursors including NOx O-3, and OH radicals. In general, the win tertime concentrations of the organic pollutants in Algiers were similar to those measured in Europe and especially over the Mediterranean Basin. Furt her investigations have been planned in order to obtain a thorough knowledg e of the air pollution as well as the organic content of materials burning at the Oued Smar waste landfill. In particular, our concern will be address ed to sources of toxic components, to formulate strategies suitable for red ucing health risk for the populations living in the region of Algiers.