| 天津市冬季气溶胶吸湿因子的粒径分布特征 |
| 摘要点击 2353 全文点击 844 投稿时间：2020-07-28 修订日期：2020-08-11 |
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| 中文关键词 天津 冬季 重污染过程 气溶胶 吸湿增长因子 粒径分布 |
| 英文关键词 Tianjin winter haze episode aerosol hygroscopic growth factor size distribution |
| 作者 | 单位 | E-mail | | 丁净 | 南开大学环境科学与工程学院,中国气象局-南开大学大气环境与健康研究联合实验室,国家环境保护城市空气气溶胶污染防治重点实验室, 天津 300350
天津市环境气象中心, 天津 300074 | dingjing0824@126.com | | 张裕芬 | 南开大学环境科学与工程学院,中国气象局-南开大学大气环境与健康研究联合实验室,国家环境保护城市空气气溶胶污染防治重点实验室, 天津 300350 | zhafox@126.com | | 郑乃源 | 天津市生态环境监测中心, 天津 300071 | zerozny2002@163.com | | 张会涛 | 南开大学环境科学与工程学院,中国气象局-南开大学大气环境与健康研究联合实验室,国家环境保护城市空气气溶胶污染防治重点实验室, 天津 300350 | | | 余卓君 | 南开大学环境科学与工程学院,中国气象局-南开大学大气环境与健康研究联合实验室,国家环境保护城市空气气溶胶污染防治重点实验室, 天津 300350
天津市生态环境监测中心, 天津 300071 | | | 李立伟 | 天津市生态环境监测中心, 天津 300071 | | | 元洁 | 天津市生态环境监测中心, 天津 300071 | | | 唐淼 | 天津市生态环境监测中心, 天津 300071 | | | 冯银厂 | 南开大学环境科学与工程学院,中国气象局-南开大学大气环境与健康研究联合实验室,国家环境保护城市空气气溶胶污染防治重点实验室, 天津 300350 | |
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| 中文摘要 |
| 气溶胶粒径吸湿增长因子［g（RH）］是影响气溶胶消光和气溶胶辐射强迫的重要因素.利用吸湿性串联差分电迁移率分析仪（HTDMA）观测了天津市冬季不同污染状态下气溶胶粒子gm（RH）的粒径分布.同时基于水溶性离子的粒径分布，利用κ-Köhler理论获取了较宽粒径范围内（60 nm~9.8 μm）的gκ（RH），为环境状态下气溶胶光学参数和直接辐射强迫的模拟提供基础.结果表明，清洁状态下大气光化学反应较为活跃，超细粒子（<100 nm）的gm（RH）较高，gm（RH=80%）在1.30以上.重度污染天，气溶胶中水溶性离子的质量分数随粒子粒径增大而增加，导致gm（RH）随着粒子粒径增大而增大，300 nm粒子的gm（RH=80%）和gm（RH=85%）分别可达1.39和1.46.在较宽粒径范围（60 nm~9.8 μm）内，不同模态气溶胶的吸湿性强弱表现为积聚模态>爱根模态>粗模态.大气重污染过程中气溶胶粒径明显增大，积聚模态气溶胶中NO3-和SO42-含量较清洁天明显增加，受此影响，污染状态下积聚模态气溶胶的吸湿性较清洁天明显增强，gκ（RH）达到1.3~1.4，具有强吸湿性的气溶胶粒径范围也同时扩大，在0.18~3.1 μm粒径段均较高，对能见度恶化有重要的贡献. |
| 英文摘要 |
| Aerosol hygroscopic growth factors[g(RH)] are key for evaluating aerosol light extinction and direct radiative forcing. The hygroscopic tandem differential mobility analyzer (HTDMA) was utilized to measure the size-resolved gm(RH) under different polluted conditions in winter in Tianjin. Furthermore, based on the size distribution of aerosol water-soluble ions, the gκ(RH) across a wide size range (60 nm to 9.8 μm) was estimated using the κ-Köhler theory, which provides a basis for the estimation of aerosol optical parameters and direct radiative forcing under ambient conditions. Under clean conditions, ultrafine particles (<100 nm) were more hygroscopic and gm(RH=80%) was higher than 1.30 due to the active photolysis reaction. However, under severely polluted conditions, the proportion of water-soluble ions in aerosols increased with the increasing size; gm(RH) increased with particle size, where gm(RH=80%) and gm(RH=85%) for 300 nm particles was 1.39 and 1.46, respectively. For a wide size range (60 nm to 9.8 μm), the aerosols in the accumulation mode were more hygroscopic and aerosols in the Aitken mode were less hygroscopic, with coarse mode aerosols being the least hygroscopic. During the polluted period, the particulate size notably increased, and the mass fraction of NO3- and SO42- in the accumulation mode aerosols was significantly higher than during the clean period. Accordingly, the hygroscopicity of accumulation mode aerosols was strongly enhanced during the polluted period[gκ(RH)=1.3-1.4] and aerosols in the 0.18-3.1 μm size range all had a strong hygroscopicity. On polluted days, the synergistic effect of the increase in particle size, water-soluble ions, and aerosol hygroscopicity results in the considerable deterioration of visibility. |
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