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-K9hler理论获取了较宽粒径范围内(60 nm~9.8μm)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~9.8μm)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NO_(3)^(-)和SO_(4)^(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,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0.18~3.1μm粒径段均较高,对能见度恶化有重要的贡献.
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 gκ(RH)across a wide size range(60 nm to 9.8μm)was estimated using theκ-K9 hler 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 to9.8μm),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 NO_(3)^(-)and SO_(4)^(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[gκ(RH)=1.3-1.4]and aerosols in the 0.18-3.1μm 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.
作者
丁净
张裕芬
郑乃源
张会涛
余卓君
李立伟
元洁
唐淼
冯银厂
DING Jing;ZHANG Yu-fen;ZHENG Nai-yuan;ZHANG Hui-tao;YU Zhuo-jun;LI Li-wei;YUAN Jie;TANG Miao;FENG Yin-chang(China Meteorological Administration-Nankai University Cooperative Laboratory for Atmospheric Environment-Health Research,State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control,College of Environmental Science and Engineering,Nankai University,Tianjin 300350,China;Tianjin Environmental Meteorological Center,Tianjin 300074,China;Tianjin Eco-Environmental Monitering Center,Tianjin 300071,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2021年第2期574-583,共10页
Environmental Science
基金
天津市科技计划项目(18ZXSZSF00160)
国家自然科学基金项目(41771242)
天津市自然科学基金项目(18JCYBJC23100)。
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
Tianjin
winter
haze episode
aerosol
hygroscopic growth factor
size distribution
作者简介
丁净(1990-),女,博士,主要研究方向为气溶胶物理与化学,E-mail:dingjing0824@126.com;通信作者:张裕芬,E-mail:zhafox@126.com;通信作者:郑乃源,E-mail:zerozny2002@163.com。
