Characteristics of Atmospherical Particles PM_(2.5) and PM_(10) over Xi'an in Spring
Characteristics of Atmospherical Particles PM_(2.5) and PM_(10) over Xi'an in Spring
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发表时间：
2013
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通讯作者：
Wang Pin
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作者：
Wang Pin
为研究西安市春季大气气溶胶的化学特征和来源，采用小型采样器在2周内对西安市4个城区的大气细颗粒物PM2.5和可吸入颗粒物PM10进行了24 h的同步采样。采用重量法、离子色谱法、热光碳分析仪和ED-XRF光谱法分别测定PM2.5和PM10的质量浓度、碳分析（有机碳和元素碳）、水中无机离子（NH 4+、Na+、K+、Ca 2+、Mg 2+、F-、Cl-、SO 42-、NO3-）和微量元素（Ca和Fe）。结果表明，PM10的平均质量浓度是PM2.5的3倍。与非沙尘期相比，沙尘期土壤有机碳含量急剧增加。沙尘暴过程中SO 42--NO3--NH 4+浓度明显高于正常日，主要是由于干沙尘暴增强颗粒物的稀释作用。根据沙尘暴期间大气中Ca、Fe元素的浓度比和气团轨迹，分析了沙尘暴期间PM2.5和PM10的输送路径和来源。用离子平衡法估算CO 32-浓度。沙尘暴期间的CO 32-浓度与Ca 2+浓度有很强的相关性，说明沙尘暴期间的主要成分是CaCO 3。
To evaluate the chemical profiles and sources of spring aerosol over Xi'an,24 h a day fine particulate matter PM2.5 and inhalable particulate matter PM10 samples were collected at 4 urban sites simultaneously in 2 weeks using minival samplers. PM2.5 and PM10 mass concentrations,carbon analyses(organic and elemental carbon),water inorganic ion(NH4 +,Na+,K+,Ca2+,Mg2+,F-,Cl-,SO4 2-,NO3-) and trace elements(Ca and Fe) were determined by gravimetry, ion chromatography, thermal-optical carbon analyzer and ED-XRF spectrometry,respectively. The results show that the average mass concentration of PM10 is 3 times larger than that of PM2.5. Comparing with that in the non-dust period a sharp increase in organic carbon level is observed during the dust period. SO4 2--NO3--NH4 +concentration is much higher in dust storm events than in normal days, mainly due to dilution of enhanced particulates in dry dust storm. The transport pathways and sources of PM2.5 and PM10 in dust storm period are identified on the basis of the air mass trajectories and the ratio of Ca and Fe elements. CO3 2-concentration is estimated using the method of ion balance. A strong relationship is observed between evaluated CO3 2-and measured Ca2+, which indicates that CaCO3 is a main composition during dust storm period.