Characterization of organic functional groups, water-soluble ionic species and carbonaceous compounds in PM10 from various emission sources in Songkhla Province, Thailand

PM10 samples were collected at nine sampling stations using a high volume (hivol) air sampler during the period of June–November 2007. Using the ATRFTIR technique, the chemical compositions of organic and water-soluble ionic species (WSIS) PM10 aerosols from each emission source were identified. WSIS such as SO4 2-, NO3 -, CO3 2- , NH4 + were mainly found in PM10 aerosols. The highest concentrations of NO3 -, NH4 + and CO3 2- were detected in aerosols collected from sampling sites adjacent to traffic roads. This can be explained by the heterogeneous reaction of SO2/NO2 mixtures with carbon soot that lead to the highest contribution of WSIS in combustion particles from vehicle exhausts. In addition, the ratios of organic carbon/elemental carbon (OC/EC) collected at heavy traffic road, bus terminal and traffic demonstrated the lowest values of