摘要
利用吸湿性串联微分电迁移粒径分析仪(H-TDMA)开展颗粒物吸湿性测量,通过对观测结果进行整理,并结合其他研究成果对我国不同环境下亚微米颗粒物吸湿性进行表征.梳理了包括城市、乡村、高山和郊区近海岸点不同大气环境下11个观测点的测量数据,发现不同环境、不同季节的大气颗粒物来源不同,颗粒物吸湿性、粒径分布及模态分布特征差异大.城市点的吸湿参数?观测值约为0.1~0.3;乡村点比城市点略高,约0.15~0.4;高山点(118.11°E,30.07°N)的?约为0.2~0.3;郊区近海岸点(114.17°E,22.28°N)的?约为0.2~0.4.除北京郊区点(怀柔冬季观测)外,其余乡村点和城市点均观测到亚微米颗粒物吸湿性随粒径增加而增强;高山点和郊区近海岸点的颗粒物吸湿性随粒径的变化不显著.除高山点(黄山)观测到较高频率的单模态分布(只有吸湿模态)外,其他观测点均呈现2~3个模态分布,说明颗粒物呈外混态.北京和杭州的H-TDMA观测结果显示颗粒物吸湿性随着相对湿度(RH)的增加而增加,没有表现出与纯硫酸铵类似的潮解行为.颗粒物吸湿性与化学组分的闭合研究发现,与离线膜采样获取的化学组分相比,高时间分辨率的在线化学粒径谱分布信息可以有效提高闭合度,同时有机物的密度与吸湿性,黑碳颗粒物质量浓度谱分布的精确估算将进一步提高闭合度.
In the past several years,the measurements of particle hygroscopicity were deployed using H-TDMA(Hygroscopicity-Tandem Differential Mobility Analyzer).This study compiled the outcomes in our group and published results to summarize the hygroscopicity of the sub-micrometer particles in various environments in China.Theκvalues in the urban areas were around0.1~0.3.In rural areas,theκvalues ranged from0.15to0.4,which were slightly higher than the urban one.Theκvalues at a mountain site(118.11°E,30.07°N)and a near-coastal site(114.17°E,22.28°N)were0.2~0.3and0.2~0.4respectively.Except for the observation in a rural site of Beijing during wintertime,the particle hygroscopicity increased with increasing particle size in other rural and urban sites.No significant dependency between the hygroscopicity and particle size in the mountain and coastal areas.Typically,particle hygroscopicity showed2~3modes distribution,indicating an external mixing state of atmospheric particles.However,high frequency of a single mode(hydrophilic mode)was observed in the mountain site.The growth factor(GF)smoothly enhanced with increasing relative humidity(RH)in the atmosphere of Beijing and Hangzhou,without showing a delinquent behavior.The closurestudies between particle hygroscopicity and chemical composition showed that the hygroscopicity can be well predicted using size-resolved particle chemical composition.The precise detections of particle density and hygroscopicity of organics,and the mass size distribution of black carbon are still needed for the improvement of closure study.
作者
王渝
吴志军
胡敏
WANG Yu;WU Zhi-jun;HU Min(State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China)
出处
《中国环境科学》
EI
CAS
CSSCI
CSCD
北大核心
2017年第5期1601-1609,共9页
China Environmental Science
基金
国家自然科学基金(41475127,41571130021)
国家重点研发计划(2016YFC0202801)
环保部公益项目(201409010)
关键词
颗粒物吸湿性
粒径分布
模态分布
有效吸湿参数
化学组分
particle hygroscopicity
size distribution
hygroscopic mode distribution
effective hygroscopic parameters
chemical composition
