[Pollution characteristics of organic and elemental carbon in PM2.5 in Taiyuan].

PM2.5 samples were collected at four sampling sites to study pollution characteristics of carbonaceous aerosols in Taiyuan during winter and summer. Organic carbon (OC) and elemental carbon (EC) in PM2.5 were analyzed by carbon analyzer, and the characteristics including pollution levels, temporal and spatial distributions of OC and EC, secondary organic carbon (SOC) and relationships of OC and EC were discussed in detail. The average concentrations of OC and EC in winter were 22.3 µg x m(-3) and 18.3 µg x m(-3), respectively, while in summer were 13.1 µg x m(-3) and 9.8 µg x m(-3), respectively. The concentrations of total carbon aerosol (TCA) accounted for 56.6% of PM2.5 in winter, and 36.5% in summer; the concentrations of OC and EC at four sites in winter were higher than those in summer, OC and EC levels showed a good uniformity in winter while in summer, the spatial distributions of OC and EC were obviously different; SOC levels were lighter than other cities; the correlation between OC and EC was stronger in winter than that in summer.

[Characterization of organic and elemental carbon in PM10 in Xinzhou City].

PM10 samples were collected at four sampling sites to study pollution characteristics of carbonaceous aerosols in Xinzhou during heating period (March) and non-heating period (July), 2011. Organic carbon (OC) and elemental carbon (EC) in PM10 were analyzed by Elementar Analysensysteme GmbH vario EL cube, and the characteristics including pollution levels, temporal and spatial distributions of OC and EC as well as OC/EC ratios were investigated in detail. The results were as following: OC and EC mass concentrations of PM10 in Xinzhou were (18.5 +/- 4.5) microg x m(-3) and (16.1 +/- 4.3) microg x m(-3), respectively. The concentrations of total carbon aerosol (TCA) accounted for 70.7% of PM10 during the heating period, and 43.8% during the non-heating period. The concentrations of OC at four sites during the heating period were higher than those during the non-heating period, and this trend was consistent with that of EC concentrations except for SQ site, which indicated coal combustion was a dominant source of OC and EC during the heating period. OC concentration at XT site and EC concentration at DC site were the highest, which were 24.1 microg x m(-3) and 22.0 microg x m(-3) respectively, while the concentrations of OC and EC at SQ site were both the lowest, which were 17.2 microg x m(-3) and 14.5 microg x m(-3), respectively, which indicated that the spatial distributions of OC and EC were obviously different. The average values of OC/EC ratios were all below 2, which indicated that the primary pollution was predominant. The correlation between OC and EC during the non-heating period was good with R2 of 0.55, indicating the emission sources were consistent and the vehicle exhaust played an important role, while the correlation was weak during the heating period (R2 = 0.13), which revealed that the emission sources of OC and EC were complicated. Carbonaceous aerosol pollution should be reduced by controlling the primary emissions such as coal combustion, vehicle exhaust, biomass burning and other industrial sources to improve the air quality in Xinzhou City.

[Characteristic of elements in PM2.5 and health risk assessment of heavy metals during heating season in Taiyuan].

The fine particulate matter (PM2.5) sampled during heating season in Taiyuan city and nineteen samples were used to investigate elemental concentrations and its source potential ecological risks of heavy metals, and to assess human exposure and health risk. The result indicated that main elements were Si, Ca, Al, Na, Mg, K, Fe in PM2.5. The main sources of elements in PM2.5 were divided into five categories including soil dust (43.46%), coal burning (15.69%), vehicle emission (13.41%), industrial dust (9.89%) and the construction cement dust (9.03%). Moreover, the order of potential ecological risk index of heavy metals in PM2.5 was Cd > Ni > Hg > Pb > Cu > Zn > As > Co > Cr > Mn, and the ecological hazards were high. The main exposure of heavy metals in atmosphere was respiratory inhalation . The exposure quantity for children was significantly higher than that for adult. The hazard index values suggested a potential non-carcinogenic risk in PM2.5.