[Characteristics of Organic and Elemental Carbon in PM and PM in Yulin City, Guangxi].

Two hundred eighteen PM and 202 PM samples were collected at three sampling sites to study the pollution characteristics of carbonaceous aerosols in Yulin from July 2015 to March 2016. Organic carbon (OC) and elemental carbon (EC) in the PM and PM samples were analyzed by a Multiwavelength Thermal/Optical Carbon Analyzer, and the characteristics, including pollution levels, temporal and spatial distributions, and possible sources of OC and EC, were investigated. The results showed that the OC and EC mass concentrations in PM in Yulin were 10.99 and 5.11 μg·m, respectively, while the OC and EC mass concentrations in PM were 7.51 and 4.70 μg·m, respectively. Strong correlations between OC and EC were found in PM(=0.58) and PM(=0.60). The winter average concentrations of secondary organic carbon (SOC) in PM and PM were 14.50 μg·m and 6.74 μg·m, respectively. The SOC/OC ratios in both the PM and PM were higher than 0.5. The contribution of SOC to OC was 80.6% in PM and 77.7% in PM, which were the highest in the summer, in accordance with the high temperature and strong solar radiation in the summer.