Pollution characteristics of atmospheric particulate mercury near a coal-fired power plant on the southeast coast of China

Özet

PM2.5 and PM10 samples were collected in a rural area from December 2014 to August 2015 near a coalfiredpower plant on the southeast coast of China. The total mercury concentrations in PM2.5 ranged from116.2 to 1070.9 pg/m3 and in PM10 from 173.4 to 1456.8 pg/m3, with averages of 309.5 ± 94.9 and387.5 ± 133.5 pg/m3, respectively. These were much higher than those found in many foreign cities. Theconcentrations of mercury in PM2.5 and PM10 varied seasonally, with the highest average concentrationin winter. This was probably due to the seasonal variation of meteorological conditions and concentrationof particulates. The highest mass-based concentration of mercury in PM2.5 and PM10 was observed inspring. This result might be related to the prevailing sea winds in spring. The spatial variation of particulatemercury conformed to the concentration distribution characteristics of pollutant dischargedfrom coal-fired power plant elevated source at the downwind area. The seasonal variation in the concentrationsof the four mercury species (including exchangeable particulate mercury: EXPM, HCl-solubleparticulate mercury: HPM, elemental particulate mercury: EPM, and residual particulate mercury: RPM)were all identical to the seasonal variation of total particulate mercury (TPM) in PM2.5 and PM10(winter > spring > summer). Owing to the variation of meteorological conditions, the proportion ofdifferent mercury species in TPM followed different seasonal trends. In contrast to RPM, the percentageof both HPM and EPM in PM2.5 was higher than in PM10.