[Spatial distribution characteristics of carbonaceous aerosol during summer in Beibu Gulf Zone, China]

Daily (24-h average) PM2.5 samples were collected simultaneously at urban and suburban sites of nine cities (Nanning, Qinzhou, Fangchenggang, Beihai, Zhanjiang, Maoming, Haikou, Yangpu and Dongfang) in Beibu Gulf Zone during August 2009. All samples were analyzed for organic and elemental carbon (OC and EC) analyses by the thermal/optical reflectance following IMPROVE protocol. Characteristics of OC and EC concentration levels, spatial distribution, and the possible sources were discussed. The average concentrations of PM2.5, OC and EC in Beibu Gulf zone were (38.4 +/- 17.7), (9.2 +/- 2.6) and (1.9 +/- 1.1) microg x m(-3), respectively. The total carbonaceous aerosol (TCA) accounted for over 56.8% of PM2.5. OC mainly came from biomass burning and secondary organic carbon (SOC), while motor exhaust and industrial emissions were the primary source of EC during summer in Beibu Gulf Zone.