宜昌城区霾与非霾天气下PM_(2.5)中12种元素污染特征比较

Comparison of characteristics of twelve elements in PM_(2.5) during haze and non-haze episodes in urban areas of Yichang City

目的了解宜昌城区霾与非霾天气下PM_(2.5)中元素污染特征,为本地区雾霾天气对人体健康效应的研究以及环保调控措施的制定提供科学依据。方法 2016年12月-2017年11月利用中流量采样器采集大气中PM_(2.5),电感耦合等离子体质谱检测铍、铝、铬、锰、镍、砷、硒、镉、锑、汞、铊和铅含量后,对12种元素霾与非霾天气下的差异进行比较。结果宜昌市大气中PM_(2.5)质量浓度的年均值为56. 4μg/m3,呈冬季(94. 0μg/m3)>春季(50. 6μg/m3)>秋季(36. 6μg/m3)>夏季(28. 1μg/m3)趋势; 12种元素中污染水平最高的是铝(141. 2 ng/m3),其次依次是铅(37. 8 ng/m3)、锰(25. 3 ng/m3)、砷(5. 29 ng/m3)等。检测的12种元素占PM_(2.5)质量浓度的0. 393%,非霾日(0. 555%)高于霾日(0. 232%)。结论宜昌市大气中PM_(2.5)污染情况较以往有所改善,但砷、铬、铅等金属污染应当予以重视。

Objective To investigate the pollution characteristics of elements in atmospheric fine particles(PM2.5) in haze and non-haze episodes in urban areas of Yichang City,and to provide a scientific basis for estimating the PM2.5health effects in local areas and developing environmental protection measures. Methods PM2.5samples were collected by a sampler of medium-flow capacity from December 2016 to November 2017. The contents of elements,including beryllium,aluminum,chromium,manganese,nickel,arsenic,selenium,cadmium,stibium,mercury,thallium and lead were detected by inductively coupled plasma-mass spectrometry(ICP-MS),and then the differences in mass concentration of the twelve elements between haze and non-haze episodes were compared. Results The annual mean concentration of PM2.5in urban areas of Yichang City was 56. 4 μg/m^3,showing a tendency of winter(94.0 μg/m^3) > spring(50.6 μg/m^3) > autumn(36.6 μg/m^3) > summer(28.1 μg/m^3). The pollution level of aluminum(141.2 ng/m^3) was the most serious,followed by lead(37.8 ng/m^3),manganese(25.3 ng/m^3) and arsenic(5.29 ng/m^3). The detected twelve elements accounted for 0.393% of PM2.5mass concentration,and their proportion in PM2.5mass concentration in non-haze days was significantly higher than that in haze days(0.555% vs. 0.232%). Conclusions The condition of PM2.5pollution in the atmosphere in Yichang City has been improved,but heavy metal pollution such as arsenic,chromium and lead should be taken seriously.