Major advances have been made in molecular marker analysis to distinguish between natural and anthropogenic organic matter
inputs to the atmosphere. Resuspension of soil and sand by wind is one of the major mechanisms that produces particle dusts
in the atmosphere. Soil and sand samples from the Riyadh area were collected in winter 2002, sieved to remove coarse particles
and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The total extracts were analyzed by gas chromatography–mass
spectrometry in order to characterize the contents and identify the potential sources of the organic components. The major
organic compounds of these extracts were derived from natural biogenic and anthropogenic sources. Organic compounds from natural
sources, mainly vegetation, were major in samples from outside the city of Riyadh and included
n-alkanes,
n-alkanoic acids,
n- alkanols, methyl alkanoates, and sterols. Anthropogenic inputs were significant in the fine particles of soil and sand samples
collected from populated areas of the city. They consisted mainly of
n-alkanes, hopanes, UCM (from vehicular emissions), and plasticizers (from discarded plastics,
e.g., shopping bags). Carbohydrates had high concentrations in all samples and indicate sources from decomposed cellulose fibers
and/or the presence of viable microbiota such as bacteria and fungi.