| 天津城区2019年2~3月气溶胶粒径分布特征观测分析 |
| 摘要点击 5076 全文点击 709 投稿时间：2021-12-09 修订日期：2022-01-05 |
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| 中文关键词 天津城区 气溶胶 数浓度 粒径分布 日变化 |
| 英文关键词 Tianjin urban area atmospheric aerosol number concentration spectrum distribution diurnal variation |
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| 中文摘要 |
| 气溶胶粒径分布是反映气溶胶粒子来源、形成过程和污染特征的重要物理参数，为研究天津城市地区气溶胶数浓度和谱分布特征及其影响因素，利用扫描电迁移率颗粒谱仪（SMPS）对2019年2~3月天津河西区10~600 nm气溶胶数浓度粒径分布进行了采样分析.结果表明，冬末春初天津市10~600 nm气溶胶数浓度、表面积浓度和体积分数分别为22188.22 cm-3、1581.08 μm2·cm-3和70.76μm3·cm-3，气溶胶数浓度、表面积浓度和体积分数谱均为单峰分布，峰值粒径分别位于109.40、269.00和429.40 nm.核模态（10~20 nm）、爱根核模态（20~100 nm）和积聚模态（100~600 nm）粒子数浓度分别占气溶胶总数浓度的1.40%、52.44%和46.16%.气溶胶数浓度日变化具有明显的周末效应，工作日为三峰分布，峰值出现在道路交通早晚高峰和午后，周末呈双峰分布，峰值出现在道路交通早晚高峰且出现时间比工作日推迟1~2 h，汽车尾气排放对城区气溶胶浓度增加起重要作用.气象条件对天津城区气溶胶粒径分布有明显影响，气溶胶在偏东风和西南风条件下数浓度较高，非降水日相对湿度（RH）增加导致气溶胶谱分布向大粒径方向移动，随着RH由小于20%升高到50%~60%，气溶胶数浓度谱峰值粒径由50nm增大到131 nm，降水对100~200 nm气溶胶粒子有明显的清除作用，降水过程导致气溶胶谱峰值粒径减小到98 nm. |
| 英文摘要 |
| The aerosol size distribution is an important physical parameter reflecting the source, formation process, and pollution characteristics of aerosol particles. In order to study the properties of aerosol number concentration and size distributions in the Tianjin urban area,the aerosol number concentration and size distributions ranging from 10-600 nm were detected using a scanning mobility particle sizer (SMPS) during February and March, 2019. The results showed that in the Tianjin urban area, the aerosol number concentration,surface area concentration. and volume concentration in the size range of 10-600 nm were 22188.22 cm-3, 1581.08 μm2·cm-3, and 70.76 μm3·cm-3,respectively, in late winter and early spring. The aerosol number concentration,surface area concentration, and volume concentration spectrum were all unimodally distributed,and the peak value sizes were 109.40, 269.00, and 429.40 nm. The number concentrations of the nucleation mode (10-20 nm),Aitken mode (20-100 nm), and accumulation mode (100-600 nm) aerosols accounted for 1.40%, 52.44%, and 46.16% of the total number concentration. The diurnal variation in aerosol number concentration showed three peaks (06:00-08:00, 12:00-14:00, and 18:00-20:00) on work days and two peaks (07:00-08:00 and 19:00-21:00) on weekends. The peaks appeared 1-2 hours later on weekends,and the increment of aerosol number concentration was attributed to vehicle exhaust emissions. Meteorological factors had a significant influence on the aerosol size distribution in Tianjin; aerosol number concentration values were high in east and southwest wind. On non-precipitation days,the aerosol number size distribution moved to larger size ranges with the increment of relative humidity (RH); as the RH increased from <20% to 50%-60%,the size peak increased from 50 nm to 131 nm. The precipitation removed 100-200 nm aerosol particles discernibly,which resulted in the size peak decreasing to 98 nm. |
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