. The collected PM 2.5 -samples were analyzed by ICP-MS for determination of lead. The average atmospheric PM 2.5 concentration was 50.8 mg/m 3 . Atmospheric PM 2.5 -concentrations were higher than the 24-h U.S. National Ambient Air Quality Standards (NAAQS) in 14 sample events. The average lead concentration for all samples was 0.07326 mg/m 3 . Atmospheric lead concentration was dependent on the sampling location. Concentrations at the two southern locations were higher than at the two northern locations. Southern locations had higher lead concentrations due to very high traffic density, in addition to their proximity to industrial zone. In general, the results of this study show a considerable decrease in atmospheric lead concentration 7 years after phasing out leaded gasoline. The study recommends further studies to accurately determine the current sources of atmospheric lead.

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Planning regulated occupational safety and health (OSH) inspections is dependent on the prioritization scheme followed by inspection agencies. It is probable that the methods used by OSH inspectorates for decision making on inspection priorities is not efficient enough to cover all the hazardous firms which is evidenced by less than expected reduction in injury rates in many countries. The objective of the current research is to present a prioritization model based on four criteria comprising thirteen subcriteria using an integrated Delphi, AHP and Double-Hierarchical TOPSIS (DH-TOPSIS) approach. The decision main and subcriteria as well as their pairwise comparisons were decided by a group of experts through a Delphi methodology. In addition, the weights of the main and subcriteria were determined using AHP method. Unlike the commonly applied TOPSIS method which uses subcriteria global weights in a single calculation process, the DH-TOPSIS method uses the local weights of the subcriteria to calculate the priority index of the alternatives (firms) with respect to the main criteria in a first TOPSIS calculation cycle. The resulting priority index is used as the evaluation scores of the firms in a second TOPSIS calculation cycle to prioritize firms for subsequent inspections. The DH-TOPSIS performed better than the global weight, single TOPSIS (GWS-TOPSIS) method with respect to the probability that the best alternative has the shortest distance to the ideal solution. Furthermore, the proposed model has a stable prioritization performance without rank reversal. As such, it is dynamic in handling large number of alternatives making it appropriate for prioritization of firms for OSH inspections. This approach can be further integrated with an appropriate scheduling methodology to improve the effectiveness of OSH inspections. INDEX TERMS AHP-TOPSIS, Delphi, double hierarchical TOPSIS, multicriteria decision making, regulated OSH inspections, safety inspections prioritization.