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Tianjinwinterhaze episodeaerosolhygroscopic growth factorsize 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

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g_m（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g_κ（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g_m（RH）较高，g_m（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g_m（RH）随着粒子粒径增大而增大，300 nm粒子的g_m（RH=80%）和g_m（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SO₄^2-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，g_κ（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 g_m(RH) under different polluted conditions in winter in Tianjin. Furthermore, based on the size distribution of aerosol water-soluble ions, the g_κ(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 g_m(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; g_m(RH) increased with particle size, where g_m(RH=80%) and g_m(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 SO₄^2- 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[g_κ(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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