Influence of petrochemical installations upon PAH concentrations at sites in Western Saudi Arabia

Özet

Measurements of 16 polycyclic aromatic hydrocarbon (PAH) congeners (particles and vapour) have beenmade at three sites over a distance of 230 km on the Red Sea coast of Saudi Arabia. The data have beenpooled with an earlier dataset from three sites in the city of Jeddah, with one urban site common to bothstudies. The concentrations and congener profiles are broadly similar for the two measurement campaignsat the common site. Coefficients of Divergence have been calculated and show more substantialdifferences between the sites within the city of Jeddah than are found between the sites to the north ofthe city which emphasises the strong concentration gradients within Jeddah in comparison to thosefound in the atmosphere of the coastal sites to the north of the city. A sub-set of data corresponding todays on which the air mass travelled from the northwest parallel with the Red Sea coast, hence linkingthe three sites, showed a progressive reduction in concentrations as the air mass travelled towards thesoutheast, which is attributed to emissions from a large source area to the northwest of the samplingsites and either atmospheric dilution or chemical reaction accounting for a progressive reduction inconcentrations with advection of the air mass. The congener profile is very similar to that identified inearlier work relating to oil refinery emissions and is consistent with the major petrochemical installationat Yanbu contributing substantial emissions to the atmosphere which are advected to downwind sites.