State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan.
Environ Pollut. 2014 Feb;185:149-57. doi: 10.1016/j.envpol.2013.10.037. Epub 2013 Nov 24.
The chemical composition of Beijing aerosol was measured during summer and winter. Two distinct episodes were identified. Water-soluble potassium (K(+)) increased significantly during the firework episode in winter with an episode to non-episode ratio of 4.97, whereas the biomass burning (BB) episode in summer was characterized by high episode to non-episode ratios of levoglucosan (6.38) and K(+) (6.90). The BB and firework episodes had only a minor influence on the water-soluble OC (organic carbon) to OC ratio. Based on separate investigations of episode and non-episode periods, it was found that: (i) sulfate correlated strongly with both relative humidity and nitrate during the typical winter period presumably indicating the importance of the aqueous-phase oxidation of sulfur dioxide by nitrogen dioxide, (ii) oxalate and WSOC during both winter and summer in Beijing were mainly due to secondary formation, and (iii) high humidity can significantly enhance the formation potential of WSOC in winter.
在北京，对夏季和冬季的气溶胶化学成分进行了测量。结果识别出两个明显的阶段。在冬季的烟花燃放阶段，水溶性钾（K(+)）显著增加，其阶段到非阶段的比值为 4.97，而夏季的生物质燃烧（BB）阶段则以左旋葡聚糖（6.38）和 K(+)（6.90）的高阶段到非阶段比值为特征。BB 和烟花阶段对水溶性 OC（有机碳）与 OC 的比值只有很小的影响。根据对阶段和非阶段的单独调查，发现：（i）在典型的冬季，硫酸盐与相对湿度和硝酸盐密切相关，可能表明二氧化氮通过氮氧化物对二氧化硫进行水相氧化的重要性；（ii）冬季和夏季北京的草酸盐和 WSOC 主要是由于二次形成；（iii）高湿度可以显著提高冬季 WSOC 的形成潜力。
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