Effect of meteorologic conditions on total suspended particulate (TSP) levels and elemental concentration of aerosols in a semi-arid zone (Beer-Sheva, Israel)

The total suspended particulate (TSP) levels in Beer-Sheva, situated in a semi-arid area with winds bringing in dust from the surrounding deserts, was measured 41 times between June 1977 and May 1978. The TSP levels are correlated with climatic conditions. High TSP levels (890 ± 250 μg m^-3 were found during Sharav conditions and sandstorms (hot, dry weather, typical to this region). Low TSP levels (59 ± 28 μg m^-3)re found in the winter following rain. Usual TSP levels were found to be 140 ± 20 μg m^-3 occurring during normal weather conditions. The elemental composition of the Beer-Sheva aerosols were determined using instrumental neutron activation analysis (INNA) and X-Ray Fluorescence (XRF). The concentrations of the following elements Fe, Na, Br, K, Sm, Au, Sb, Ga, La, Yb, Lu, Se, Hg, Cr, Sc, Rb, Co, Ta and Zn were determined by INNA and Ca, Si, S, Ti, CI, Pb, Fe, V, Ni and Mn by XRF. Their relative abundances were found to depend on the prevailing TSP level.

The different patterns of elemental distribution as a function of TSP indicate the manifold origins of the TSP. A very high correlation coefficient between elemental concentrations of the following elements Ca, Si, Fe, V, Ti, Mn, Na, Ni, Co, La, K, Sc, Sm and TSP levels (> 0.94) suggest that they originate from natural sources. The very low correlation coefficients < 0.1 between the elemental concentrations of Br, Sb and Hg suggest strongly that the elements come primarily from local industry. The sources of other elements with correlation coefficients of the order of 0.5 (CI, S) are not clear-cut.