Seasonal and spatial variation of solvent extractable organic compounds in fine suspended particulate matter in Hong Kong

Abstract The results of a 12-month study of more than 100 solvent extractable organic compounds (SEOC) in particulate matter (PM) less than or equal to 2.5 μm (PM2.5) collected at three air monitoring stations located at roadside, urban, and rural sites in Hong Kong are reported. The total yield of SEOC that accounts for ∼8–18% of organic carbon (OC) determined by a thermal optical transmittance method was 125-2060 ng/m3, which included 14.6–128 ng/m3 resolved aliphatic hydrocarbons, 39.4–1380 ng/m3 unresolved complex mixtures, 0.6–17.2 ng/m3 polycyclic aromatic hydrocarbons, 41.6–520 ng/m3 fatty acids, and <0.1–12.1 ng/m3 alkanols. Distinct seasonal variations (summer/winter differences) were observed with higher concentrations of the total and each class of SEOC in the winter and lower concentrations in the summer. Spatial variations are also obvious, with the roadside samples having the highest concentrations of SEOC and the rural samples having the lowest concentrations in all seasons. Characteristic ...