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Lu Q.,Southwest University | Zhao L.,Southwest University | Li L.,Chongqing Environmental Monitor Center | Yang F.,CAS Chongqing Institute of Green and Intelligent Technology | And 8 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2013

In order to understand the main chemical constituents within precipitations and their spatiotemporal variations in the Three Gorges Reservoir Region, the atmospheric precipitation samples were collected from three stations along the reservoir during 2000 to 2009. pH, conductivity, and ions were analyzed. Average pH values were 5.76, 6.03, and 5.52, and average conductivity were 117.3, 72.3, and 63.1 μS·cm-1 in Banan, Fuling and Wanzhou, respectively. The rainwater in these districts exhibited a significant acidification trend over the past decade with more serious pollution levels than those in Beijing, Chengdu, Shenzhen, and Hunan. The concentration of SO4 2- accounted for 77% of total anions, while NH4 + and Ca2+ were the major cations. The relatively low mass ratio of NO3 - to SO4 2- in the three stations indicated that the type of rain acidity was still dominantly from sulfuric acid. The ionic constituents of precipitation presented clear spatial-temporal variations, due to seasonal variations in emissions and meteorology, including the rainfall intensity. The ion concentrations were higher in winter and spring and lower in summer and autumn. Precipitation pollution in the three stations exhibited a clearly decreasing trend with distance from downtown Chongqing.

Peng C.,Chinese Academy of Sciences | Peng C.,Chongqing Technology and Business University | Zhai C.,Chongqing Environmental Monitor Center | Wang H.,Chinese Academy of Sciences | And 6 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2015

PM2.5 samples were collected during summer and winter in Wangzhou, a mountainous city in Three Gorges Reservoir, China. Organic carbon (OC) and elemental carbon (EC) were analyzed by thermal optical reflection (TOR) and investigated for their pollution characteristics and sources. The average concentrations of OC and EC were (7.09±1.86) μg·m-3 and (3.49±0.64) μg·m-3 in summer, higher than that in winter of (16.82±6.87) μg·m-3 and (6.21±2.06) μg·m-3, respectively. This may be related to biomass burning by local residents. The concentrations of OC in PM2.5 were significantly correlated with EC in winter (r=0.89), suggesting that they might have similar primary sources. The correlations between TC and K+ in PM2.5 were stronger in winter (r=0.88) than summer (r=0.69), suggesting biomass burning contributed significantly to the carbon pollution. The concentrations of secondary organic carbon (SOC) were estimated by OC/EC ratio method. The average concentration of SOC was (2.17±1.46) μg·m-3 in summer and (4.46±3.69) μg·m-3 in winter, contributed 28.18%±13.85% and 23.13%±12.30% to total OC, respectively. By calculating and analyzing the abundances of eight kinds of carbon components in PM2.5, motor vehicle emissions and biomass burning were indicated to be the major sources of carbon components in Wanzhou. ©, 2015, Science Press. All right reserved.

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