[Characteristics of organic carbon and elemental carbon in PM2.5 in Shuozhou City]

PM2.5 samples were collected at four sampling sites in Shuozhou during the heating and non-heating periods. Organic carbon (OC) and elemental carbon (EC) in PM2.5 were analyzed by Elementar Analysensysteme GmbH vario EL cube and the concentration, spatial and temporal distribution characteristics and main sources of OC and EC were studied. The results were as following: average concentrations of OC and EC in PM2.5 during non-heating period were (14.3 ± 2.7) μg x m(-3) and (10.3 ± 3.1) μg x m(-3) while (23.3 ± 5.9) μg xm(-3) and (20.0 ± 5.7) μg x m(-3) during heating period. The concentrations of OC and EC at four sites during the heating period were higher than those during the non-heating period. The concentrations of OC and EC at SW site during heating were the highest which were 28.5 μg x m(-3) and 28.1 μg x m(-3) while the concentrations at PS sites during non-heating period were the highest, which were 17.7 μg x m(-3) and 14.1 μg x m(-3). The ratios between OC and EC during the heating and non-heating period were all below 2 and the correlation between OC and EC was not good with R2 of 0. 66 during heating period and 0.52 during non-heating period which indicated that sources of carbon aerosols were complex. Carbonaceous aerosol pollution should be reduced by controlling the primary emissions such as coal combustion, vehicle exhaust and biomass burning, and by paying attention to secondary pollution at the same time to improve the air quality in Shuozhou City. The concentrations of SOC during heating and non-heating period were (6.44 ± 2.77) μg x m(-3) and (4.11 ± 1.92) μg x m(-3).