Source apportionment and elemental composition of PM2.5 and PM10 in Jeddah City, Saudi Arabia

This paper presents the first comprehensive investigation of particulate matter with an aerodynamic diameter less than or equal to 2.5 and 10 microns (PM2.5 and PM10) composition and sources in Saudi Arabia. We conducted a multi-week multiple sites sampling campaign in Jeddah between June and September, 2011, and analyzed samples by X–ray fluorescence (XRF). The overall mean mass concentration was 28.4 ± 25.4 μg m−3 for PM2.5 and 87.3 ± 47.3 μg m−3 for PM10, with significant temporal and spatial variability. The average ratio of PM2.5/PM10 was 0.33. Chemical composition data were modeled using factor analysis with Varimax orthogonal rotation to determine five and four particle source categories contributing significant amount of for PM2.5 and PM10 mass, respectively. In both PM2.5 and PM10 sources were (1) heavy oil combustion characterized by high Ni and V; (2) re-suspended soil characterized by high concentrations of Ca, Fe, Al, and Si; and (3) a mixed industrial source. The two other sources in PM2.5 were (4) traffic source identified by presence of Pb, Br, and Se; (5) other industrial source mixture; while in PM10 it was marine aerosol. To estimate the mass contributions of each individual source category, the PM mass concentration was regressed against the factor scores. Cumulatively, re-suspended soil and oil combustion contributed 77 and 82% mass of PM2.5 and PM10, respectively.