On the elemental composition of PM2.5 in central Cairo, Egypt

Aerosol particles are among the criteria pollutants identified by many countries because of their effects on human health and the environment. Information about the elemental composition of the aerosol particles is useful for source apportionment and determining the possible negative effects of the particulate air pollution. In this study, fine aerosol particles (PM2.5) were collected over 24h once a week at roof level at the National Research Center in the center of Cairo, Egypt, between September 2010 and May 2011 using a cyclonic sampler. The site is representative of urban residential areas in the center of this megacity. Elemental determination was performed using an energy dispersive X-ray fluorescence spectrometer with a Mo secondary target, and the measured concentrations were evaluated using the quantitative X-ray analysis system/AXIL software package. The concentrations of 16 elements were determined in the collected aerosol samples, although some were generally not present at levels above the method's limit of detection. The concentrations of many of the elements exceeded those in other urban environments. The concentration of Pb was 95 +/- 200 ng/m3, well below the Egyptian legal limit of 500 ng/m3. This represents a significant decrease since 1997, when concentrations above 3 mu g/m3 were measured. The decrease is due to the banning of Pb in vehicle fuel in 1997 and the movement of Pb smelters from the central part of Cairo in 2002. Analysis of the elemental concentrations revealed seasonal variation in their levels and possible sources of the emissions, and enabled us to estimate their effects on human health. Copyright (c) 2013 John Wiley & Sons, Ltd.