Atmospheric PM2.5 pollution and the risk of elements have become the important topics in the atmospheric research. The target area is located in the southern margin of the Taklamakan Desert, with extremely arid climate and the annual precipitation is rare, and dust weather affects the atmospheric environment in the region every year. Based on the PM2.5 samples were collected from the urban area of Hotan city in January, April, July and October in 2014. Seventeen metal elements in PM2.5 were analyzed using ICP-MS. EF and PMF method were used to analyzed the sources and assessed the health risk during the dust and non-dust periods. The results showed that, (1) the seasonal variation of PM2.5 were: spring (973.59 μg·m-3)>summer (728.08 μg·m-3)>autumn (366.51μg·m-3)>winter (259.84 μg·m-3), and have a positive correlation with the wind speed and temperature. (2) The concentration of elements in dust period (108.12~268.25 μg·m-3) were significantly higher than non-dust period (43.19~126.41 μg·m-3). Elements Ni, Cd and Pd were enriched in autumn, the EF values were 10.26, 42.06 and 27.39, respectively. Ni, Zn, As, Cd and Pd was enriched in winter, which values were 22.46, 11.03, 18.49, 84.53 and 206.03, respectively. (3) Four major sources were identified by PMF model in dust and non-dust period, such as traffic emissions, biomass burning, fossil-fuels combustion and soil dust, with the contributions of 17.66%, 10.58%, 9.97% and 61.78%, respectively in dust period, and 23.63%, 20.34%, 18.39% and 37.63%, respectively in non-dust period. (4) The non-cancer hazard indexes and carcinogen risk were both lower than the threshold values, suggesting that they will not harm the health.%大气PM2.5污染和金属元素健康风险已成为大气环境研究热点.研究目标区域位于塔克拉玛干沙漠南缘,气候极其干旱,全年降水稀少,风沙较多,沙尘天气一定程度上影响着该区域的大气环境.于2014年1月、4月、7月和10—11月在和田市城区采集PM2.5样品,采用电感耦合等离子体质谱仪(ICP-MS)测定了样品中的17种金属元素,分析了金属元素在不同季节沙尘和非沙尘气象状况下的暴露特征及与气象参数的关系,采用富集因子(EF)和正交矩阵因子(PMF)法对金属元素来源进行了分析并对健康风险进行了评价.结果表明,(1)PM2.5质量浓度季节性特征表现为春季(973.59μg·m-3)>夏季(728.08μg·m-3)>秋季(366.51μg·m-3)>冬季(259.84μg·m-3),并且PM2.5质量浓度与风速和温度呈正相关.(2)PM2.5中金属元素质量浓度在沙尘天气(108.12~268.25μg·m-3)明显高于非沙尘天气(43.19~126.41μg·m-3),秋季金属元素Ni、Cd和Pb出现富集,EF值分别为10.26、42.06、27.39;冬季Ni、Zn、As、Cd和Pb出现富集,EF值分别为22.46、11.03、18.49、84.35、206.03.(3)金属元素在沙尘期间的来源主要为汽车排放(17.66%)、生物质燃烧(10.58%)、化石燃料9.97%和扬沙(61.78%),非沙尘期间4种排放源的贡献分别为23.63%、20.34%、18.39%、37.63%.(4)健康风险评价结果表明,金属元素风险指数小于阈值1,可以忽略;致癌金属Cr的致癌风险值小于10-6,没有致癌风险,但Co、Ni、As和Cd的致癌风险值在10-6~10-4之间,有一定的致癌风险.
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