Chemical Composition of Water-soluble Ions and Carbonate Estimation in Spring Aerosol at a Semi-arid Site of Tongyu, China
Chemical Composition of Water-soluble Ions and Carbonate Estimation in Spring Aerosol at a Semi-arid Site of Tongyu, China
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DOI：
10.4209/aaqr.2011.02.0010
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发表时间：
2011-08
影响因子：
4
通讯作者：
Zhenxing Shen;Xin Wang;Renjian Zhang;K. Ho;Junji Cao;Meigen Zhang
中科院分区：
文献类型：
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作者：
Zhenxing Shen;Xin Wang;Renjian Zhang;K. Ho;Junji Cao;Meigen Zhang
2006年4月至6月亚洲沙尘事件频繁发生期间，在中国东北半干旱地区通榆每天采集细小气溶胶样本（PM2.5）。测定了过滤器样品中九种水溶性离子的浓度。结果表明，通榆站PM2.5平均质量浓度为260.9 µg/m 3 ，9种水溶性离子总质量浓度约占PM2.5质量的17%。采样期间观测到9次沙尘暴（DS）事件，PM2.5平均浓度为528.0 μg/m 3 ，总离子平均浓度为39.5 μg/m 3 ；在非沙尘暴 (NDS) 期间，这些值分别为 111.7 和 19.6 µg/m 3 。 DS 样品中大多数水溶性离子的质量浓度远高于 NDS 样品中的质量浓度。 DS 样品中离子与 Fe 的比例稳定，而 NDS 样品中离子与 Fe 的比例较为分散，表明通榆采集的 NDS 样品中人为影响显着。此外，DS事件期间观测到的K + /Fe、Ca 2+ /Fe、Na + /Fe、NO3 /Fe和SO4 2/Fe比值的稳定值应与东北地区土壤灰尘的离子组成特征相关。 NDS 样品的离子平衡计算表明这些气溶胶颗粒呈碱性，而 DS 样品呈强碱性。 DS 过程中测量到的阴离子不足意味着存在碳酸盐，这可用于评估碳酸盐浓度。观察到计算的碳酸盐浓度和检测到的碳酸盐浓度之间存在良好的关系，这表明离子平衡提供了另一种估计 DS 过程中碳酸盐含量的方法。
Fine aerosol samples (PM2.5) were collected daily at Tongyu, a semi-arid site in northeast China from April to June 2006, when Asian dust events occurred frequently. The concentrations of nine water-soluble ions were determined in the filter samples. The results showed that the mean mass level of PM2.5 at Tongyu station was 260.9 µg/m 3 , and the total mass concentration of the nine kinds of water-soluble ions occupied ~17% of the PM2.5 mass. Nine dust storm (DS) events were observed during the sampling period with mean concentrations of 528.0 μg/m 3 for PM2.5 and 39.5 μg/m 3 for total ions; during non-dust storm (NDS) periods, these values were 111.7 and 19.6 µg/m 3 , respectively. The mass concentrations of most of the water-soluble ions in the DS samples were much higher than those in the NDS samples. The ratios of ions to Fe were stable in DS samples, while they were more scattered in NDS samples, suggesting that the anthropogenic influence was significant in NDS samples collected at Tongyu. Moreover, the observed stable values of the K + /Fe, Ca 2+ /Fe, Na + /Fe, NO3 /Fe, and SO4 2/Fe ratios during the DS events should be associated with the ionic composition characteristics of soil dust in northeastern regions. Ion balance calculations for the NDS samples suggest that those aerosol particles were alkaline while DS samples were strongly alkaline. A deficit of measured anions during DS implies the presence of carbonate, which can be used to evaluate the carbonate concentration. A good relationship between the calculated and detected carbonate concentration was observed, which demonstrates that the ion balance supplies another method for estimating the carbonate content during DS.