Size Distribution Of N-Alkanes And Polycyclic Aromatic Hydrocarbons And Molecular Marker In Polar Portion In Aerosol From Typical Area Of Guangzhou

n-Alkanes and PAHs, organic carbon(OC) and elemental carbon (EC), molecular markers in polar portion in aerosol from typical area of Guangzhou were studied. Samples have been collected by Andersen Hi-Vol pumping system equipped with a five stage cascade impactor and a backup filter (size range: 10⁷.2μm, 7.2-3.0μm, 3.0¹.5μm, 1.5⁰.95μm, 0.95⁰.49μm,≤0:49μm) and Tianhoung equipment for TSP. They were measured using gas chromatography/mass spectrometry and Sunset laboratory to determine the size distribution of n-alkanes and PAHs and OC/EC. In addition, the tracers of biomass burning such as levoglucosan, β- sitosterol and dehydroabietic acid were identified and quantified in all samples and seasons. Saccharides used as a major polar (water-soluble) carbonaceous fraction derived from soil resuspension (agricultural activities) were found in all aerosol samples of Guangzhou. The results reached the following conclusions:(1) CPI₂ (values for petrogenic hydrocarbons), CPI3 (values for biogenic n-alkanes) revealed that the natural preferentially accumulated in the larger aerosol and the anthropogenic in the smaller.(2) The seasonal effect was related to the hydrocarbon content in per unit particle fractions, showing a preferential association of n-alkanes and PAHs with larger particles in the cold season. This seasonal trend was likely originated by a higher extend of gas-to-particle adsorption and condensation at lower temperature, their time to partition to larger particles in cold periods was shorter than that in warm periods. Moreover, this phenomenon could also be explained as the longer retention time of particle in atmosphere in cold periods than that in warm periods.(3) OC and EC were associated with the fine particle. Compared with OC, EC was...