[Characteristics of Organic and Elemental Carbon in PM10 and PM2.5 in Yulin City, Guangxi].

ABSTRACT

Two hundred eighteen PM10 and 202 PM2.5 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 PM10 and PM2.5 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 PM10 in Yulin were 10.99 and 5.11 µg·m-3, respectively, while the OC and EC mass concentrations in PM2.5 were 7.51 and 4.70 µg·m-3, respectively. Strong correlations between OC and EC were found in PM10(R2=0.58) and PM2.5(R2=0.60). The winter average concentrations of secondary organic carbon (SOC) in PM10 and PM2.5 were 14.50 µg·m-3 and 6.74 µg·m-3, respectively. The SOC/OC ratios in both the PM10 and PM2.5 were higher than 0.5. The contribution of SOC to OC was 80.6% in PM10 and 77.7% in PM2.5, which were the highest in the summer, in accordance with the high temperature and strong solar radiation in the summer.