北京市冬季霾天气可吸入颗粒物的矿物学研究

应用原样X射线衍射(XRD)、Raman激光微探针(LRM)和X射线荧光光谱(XRF)分析技术, 对2008年北京市冬季霾天气、正常天气和降雪后天气中采集到的可吸入颗粒物(PM₁₀)样品进行物相和元素分析, 并讨论PM₁₀的矿物及元素含量变化特征。霾天气PM₁₀浓度为262.7 μg/m³,之后正常天气的浓度为174.8 μg/m³, 均超过国家二级限定浓度。XRD 物相分析显示霾天气时绿泥石含量高于正常天气, 而石英、伊利石、长石和方解石等矿物的含量均低于正常天气。霾天气时二次颗粒物总含量达到37.9%, 比其后的正常天气的30.6%略高, 二次颗粒物中的氯化铵存在于所有样品中, 其含量从霾天气时的9.6% 降至正常天气时的5.9%, 显示出霾天气对氯化铵等二次颗粒物的生成有促进作用。LRM 在霾天气样品中探测到了覆盖在石英、方解石和硅酸盐颗粒表面的硫酸盐和有机物, 显示出大气PM₁₀已成为重要的污染物载体。XRF定量分析结果与XRD分析结果一致, 显示Al和Si等元素含量在霾天气时明显下降, 而S和Cl则在霾天气颗粒物中大量富集。

Mineralogical Study on Inhalable Particles during the Haze Period in Winter Beijing

X-ray diffraction (XRD), laser Raman microprobe (LRM) and X-ray fluorescence(XRF) were used to study the mineral and elemental component of atmospheric inhalable particles (PM₁₀) collected during the periods of haze day, normal day and the day after precipitation respectively in 2008 winter in Beijing. The concentration of PM₁₀ collected during the haze periodis 262.7 μg/m³, and the pollution of PM₁₀ in the following day exceeds the national standard level Ⅱ. The results of XRD phase analysis indicates that the concentration of chloride of haze day is higher than that in the normal day, and the behavior of other crustal minerals are different from that of chloride. Thetotal concentration of secondary aerosols in the haze day is 37.9%, higher than 30.6% of normal day, which shows the enhancement effected by the haze weather condition. Especially ammoniumchloride, existing in all samples, its percentage decreased from9.6% (haze day) to 5.9% (normal day). Moreover, the LRM individual particle analysis shows that the organic matter and sulphate minerals cover other minerals in the PM₁₀ of haze day, which means the mineral particles in the atmosphere becomethe convenient carrier for the pollutant material. Besides, the results of XRF elemental quantitative analysis are consistent with the results of XRDphase analysis, and it shows the concentrations of Al and Si decrease in the haze day, and S and Cl enrich in the haze period.