云冈石窟大气细颗粒物水溶性离子污染特征

Pollution Characterization of Water-soluble Ions in Atmospheric PM_(2.5) Collected in Yungang Grottoes

为了解大同云冈石窟景区大气PM_(2.5)浓度及PM_(2.5)中水溶性离子污染特征,分别于2012年12月16-22日、2013年7月3-6日、10月28-31日、2014年4月13-18日使用中流量大气PM_(2.5)采样器在景区内两采样点共采集PM_(2.5)样品42个,运用称重法计算大气PM_(2.5)质量浓度,使用离子色谱仪测定了PM_(2.5)中Na^+、K^+、Mg^(2+)、Ca^(2+)、NH_4^+、F^-、Cl^-、NO_3^-和SO_4^(2-) 9种水溶性无机离子含 量。结果表明:采样点大气PM_(2.5)质量浓度介于28.1～q257.8μg/m^3。20#石窟采样点大气PM_(2.5)浓度均值普遍高于研究院采样点,与石窟前人类活动较多有关。所测离子中二次离子SO_4^(2-)、NO_3^-、NH_4^+所占比重较大,三者结合方式主要为(NH_4)_2SO_4、NH_4HSO_4、NH_4NO_3。除10月外,其它采样期内[NO_3^-]/[SO_4^(2-)]比值均小于1,景区周围固定源对大气二次颗粒物的影响大于移动源。

In order to investigate the mass concentration of PM^2.5 and pollution characterization of water-soluble ions of Yungang Grottoes scenic region,overall 42 PM^2.5samples were collected at two sites inside the scenic region on December16-22,2012,July 3-6 and October 28-31,2013,and April 13-18,2014,respectively,using a medium-volume PM^2.5impactor（100 L/min）. The mass concentrations of atmospheric PM^2.5 were obtained through the gravimetric method and the contents of water-soluble ions such as Na~＋,NH4^＋,K^＋,Mg^2＋,Ca^2＋,F^-,Cl^-,NO3^- and SO4^2- were determined using an ion chromatography. Results showed that the PM^2.5 mass concentration was between 28.1 μg/m^3 and 257.8 μg/m^3. Atmospheric PM^2.5 average mass concentration of 20# Grottoe was higher than Yungang Grottoes Research Institute,related to more human activities before the grottoe. Three secondary ion SO42-,NO3-,NH4＋accounted for a larger proportion in measured ion,their combination ways were mainly （NH4）2SO4,NH4HSO4,NH4NO3. The mass concentration ratio of [NO3^-] and [SO4^2-] was less than 1 except October,the influence of stationary sources was greater than that of mobile sources on atmospheric secondary particle around the scenic region.