Measurements of nonvolatile size distribution and its link to traffic soot in urban Shanghai.
Measurements of nonvolatile size distribution and its link to traffic soot in urban Shanghai.
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DOI：
10.1016/j.scitotenv.2017.09.176
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发表时间：
2018-02
期刊：
影响因子：
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通讯作者：
Shuqin Jiang;X. Ye;Ruyu Wang;Ye Tao;Zhen Ma;Xin Yang;Jianmin Chen
中科院分区：
文献类型：
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作者：
Shuqin Jiang;X. Ye;Ruyu Wang;Ye Tao;Zhen Ma;Xin Yang;Jianmin Chen
2014年1月冬季，利用V-TDMA（Volatility Tandem Differential Mobility Analyzer）对上海市区大气颗粒物的粒径分布和粒径分辨的颗粒物挥发度进行了测量。VSF超过0.85的非挥发性模式粒子总是与更易挥发的模式粒子外部混合。对于100-400 nm的颗粒，平均VSF范围为0.58 - 0.65，随着颗粒尺寸的增加而增加。对于50-400 nm的颗粒，非挥发性模式平均贡献了15-20%的数量分数。由于它们的疏水性质，不挥发性颗粒不容易通过湿沉积除去。非挥发性模态颗粒物浓度与NOx浓度具有良好的相关性，表明非挥发性模态颗粒物主要来源于新鲜交通烟尘.集合VSF和非挥发模态粒子数分数的日变化在晴天有两个峰值，分别对应于早晚高峰。50 nm颗粒的VSF分布是相似的，而在积累模式范围内，更挥发性模式的数量分数和挥发性物质的量在更挥发性模式的颗粒在雾霾期间的过渡期间，比在清洁期间，表明不同的贡献从传输源。
Measurements of particle size distribution and size-resolved particle volatility were conducted using a volatility tandem differential mobility analyzers (V-TDMA) in the urban area of Shanghai during wintertime in January 2014. The nonvolatile mode particles with VSF exceeding 0.85 were always externally mixed with more-volatile mode particles. The average VSF ranged from 0.58 to 0.65 for 100–400 nm particles, increasing with the increase of particle size. On average, the nonvolatile mode contributed 15–20% of number fraction for 50–400 nm particles. Due to their hydrophobic nature, the nonvolatile particles were not easily removed by wet deposition. The concentrations of the nonvolatile mode particles and NOxwere well correlated, indicating that the nonvolatile mode particles were mostly attributed to be fresh traffic soot. The diurnal variations in ensemble VSF and number fraction of nonvolatile mode particles exhibited two peaks in clean days, corresponding to morning and evening rush hours. The VSF distributions of 50 nm particles were similar during a transition between haze to clean periods whereas in the accumulation mode range, the number fraction of more-volatile mode and the amount of volatile materials in the more-volatile mode particles during haze periods are considerably larger than those in clean periods, indicating different contribution from transported sources.