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目的探讨兰州市冬季室内外颗粒物污染特征及其理化特性。方法于2012年11月至2013年1月在不同采样点(混合区、工业区、郊区、公共场所)连续采集大气颗粒物(PM2.5和PM10)样品,分别采用离子色谱法和原子吸收分光光度法测定PM2.5和PM10中水溶性离子(F-、Cl-、NO3-、SO42-、Na+、NH4+、K+、Mg2+、Ca2+)和重金属(Fe、Pb、Cd和Cu)。结果调查期间PM2.5和PM10浓度均超过GB 3095—2012《环境空气质量标准》二级标准限值。除公共场所PM2.5外,其余采样点PM2.5和PM10污染均呈现为室外高于室内;室内颗粒物中水溶性离子主要为SO42-、NO3-、Cl-和NH4+,室外主要为SO42-、NO3-和Cl-;水溶性离子对PM2.5的贡献室外高于室内,对PM10的贡献则相反;室内外颗粒物中重金属污染均表现为室外高于室内,城区高于郊区,且Fe污染水平整体较高,Pb、Cd分别在混合区和工业区污染较重。结论本次调查的兰州市冬季室内外颗粒物污染较为严重,应进一步关注颗粒物中水溶性离子、铅、镉的污染水平。
Objective To investigate winter indoor and outdoor particulate matter pollution characteristics and their physico-chemical characteristics in Lanzhou City. Methods Samples of atmospheric particulate matter (PM2.5 and PM10) were continuously collected at different sampling points (mixed area, industrial area, suburban area and public places) from November 2012 to January 2013 and analyzed by ion chromatography and atomic absorption spectrophotometry Method to determine the content of water soluble ions (F-, Cl-, NO3-, SO42-, Na +, NH4 +, K +, Mg2 +, Ca2 +) and heavy metals (Fe, Pb, Cd and Cu) in PM2.5 and PM10. Results During the investigation, PM2.5 and PM10 concentrations exceeded the second-level standard limit of Ambient Air Quality Standard GB 3095-2012. In addition to the PM2.5 in public places, the PM2.5 and PM10 pollution in other sampling sites were both outdoor and indoor. The main water-soluble ions in indoor particulate matter were SO42-, NO3-, Cl- and NH4 +, the outdoor mainly SO42-, NO3- and Cl-. The contribution of water-soluble ions to PM2.5 was higher in the outdoor than in the interior, and the contribution to the PM10 was the opposite. The heavy metal pollution in indoor and outdoor particulate matter was higher in the outdoor than in the suburbs, As a whole, Pb and Cd were more polluted in the mixed area and industrial area respectively. Conclusion The indoor and outdoor particulate matter pollution in Lanzhou City in this survey is more serious. We should pay more attention to the pollution levels of water-soluble ions, lead and cadmium in the particulate matter.