Correlation between inorganic pollutants in the suspended particulate matter (SPM) and fine particulate matter (PM2.5) collected from industrial and residential areas in Greater Cairo, Egypt

Simultaneous sampling collection of suspended particulate matter (SPM) and fine aerosol particles with an aerodynamic diameter equal or less than 2.5 μm (PM2.5) from industrial and residential areas of Greater Cairo, Egypt, has been carried out during two different seasons namely autumn 2014 and winter 2014/2015. The average mass concentrations of both SPM and PM2.5 samples are higher than the annual mean levels, especially for the samples collected from the industrial area. In addition, the mass concentrations of SPM are much higher than the PM2.5 mass concentrations during the whole sampling period. The ratios of the mass concentration between the SPM and PM2.5 were determined to be equal to 20 ± 6 and 17 ± 4 for the residential and industrial areas, respectively, and these ratios seem to be constant during the two mentioned seasons. Based on our previous elemental analysis results using multiple secondary target energy dispersive X-ray fluorescence (EDXRF), 18 elements in both SPM and PM2.5 samples have been quantified. Remarkable variations in the elemental concentrations between the SPM and PM2.5 samples were obtained. Comparison and statistical analysis of the elemental composition of both SPM and PM2.5 have been investigated. The PMF model EPA 5.0 was utilized for source identification on both PM fractions. Seven sources were identified and their relative contributions in the two areas of the study were investigated.