A preliminary analysis of the inhalable particulate lead in the ambient atmosphere of the city of Riyadh,Saudi Arabia

The inhalable particles in the ambient atmosphere in the city of Riyadh have been sampled during the working day (7 a.m.–4 p.m.) over the test period. Samples were taken every 3 h using an Automatic Dichotomous Sampler placed in the College of Engineering, King Saud University at a height of 25 m above the ground. A weather station 3 m above the sampler was used to record (simultaneously) the meteorological data. These data were used to determine the wind rose and the hourly standard deviation of the horizontal wind direction, which, in turn, gives the hourly atmospheric stability class.The particulates in each size range: coarse (2.5–15 μm) and fine (〈 2.5 μm) were analyzed using an Atomic Absorption Unit to determine the lead content in each sample.The results were then used to determine the directional fluxes of fine and coarse lead particulates. It has been shown that the average concentration of lead during the working day is about twice the international standards. The concentration decreases during the weekends (Thursday and Friday) due to the reduction in traffic loads, and decreases to a minimum on Fridays when most of industrial activities are stopped. More than 70% of the lead fluxes passed by the sampler are associated with wind from E to S which is the direction of the city center and the industrial site of Riyadh.