Abstract
Organic chemical pollutants in atmospheric particulate matter (PM) have a potential toxicity hazard resulting in human responses that vary from no discernible effect to premature death. The formation and sources of PM also affect air quality of metropolitan areas as well as climate change. The new developments and industrial activities in the Middle East, especially Saudi Arabia, are expected to contribute to the natural, regional, and anthropogenic input sources of organic matter (OM). Here we report the occurrence, concentrations and sources of organic tracers, including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), plasticizers, and petroleum biomarkers, in ambient atmospheric PM from the city of Dhahran, Saudi Arabia. The major compounds were unresolved complex mixtures (UCM) of branched and cyclic hydrocarbons (489±296ngm−3), plasticizers (131±119ngm−3 for phenyl phosphates, 87±42ngm−3 for phthalates), n-alkanes (73±53ngm−3), hopane biomarkers (11±8ngm−3), n-alkanones (6.7±6.3ngm−3), PAHs (2.0±2.1ngm−3), n-alkanols (1.2±1.2ngm−3), sterane biomarkers (0.4±0.3ngm−3), and sterols (0.5±0.4ngm−3). Obviously, UCM and plasticizers were the major components (56±9% and 26±10% of the total extracts, respectively) in the PM of Dhahran, which might have adverse public health effects. The major sources of this OM are emissions from industrial factories north of the city, plastics and biomass burning, and petroleum product combustion (traffic/refining).