冰雪和降水中黑碳的分布特征与来源研究进展

Advances of Distribution Characteristics and Sources of Black Carbon in Snow and Precipitation

黑碳(black carbon,BC)影响着全球辐射平衡、大气环境和人体健康,而降水是大气中黑碳的主要去除方式.简述了降水中黑碳的分析方法,重点论述了国内外降水中黑碳的分布特征和对黑碳的去除效率,以及模型和碳同位素示踪技术在识别黑碳来源的应用.结果表明:①单颗粒黑碳光度计因其检测限低、分析速度较快等优点在分析液相介质黑碳中应用较多.②降水中黑碳含量在空间上呈现较大差异,中国降水中黑碳含量较两极地区高2~3个数量级,越靠近两极地区,降水中黑碳含量越低,且工业革命后冰芯中黑碳含量有所增加.由于不同地区工业类型和化石燃料燃烧效率的差异,中国降水中黑碳含量大于东亚其他地区及欧洲地区.长时间(>8 h)降水对黑碳的去除效果较好.③混合单粒子拉格朗日积分轨迹模型、正定矩阵因子分解模型和碳同位素示踪技术相结合能更好地分析降水中黑碳的来源.研究显示,我国降水中黑碳含量较高、污染较重,但对城市降水中黑碳污染的关注还不足,未来应加强对不同地区城市降水中黑碳的观测,充分利用分析模型和碳同位素示踪技术解析降水中黑碳的来源.

Black carbon(BC)affects the balance of global radiation,atmospheric environment and human health.Precipitation is the main way to remove black carbon from the atmosphere.We described the analysis methods of BC in the precipitation,and discussed the distribution characteristics of BC,the scavenging efficiency of precipitation on BC,and the application of model and carbon isotope tracing on identifying the sources of BC.The results show that:(1)The Single Particle Soot Photometer is usualy used to analyze BC in liquid medium because of its low detection limit and fast analysis speed.(2)The mass fractions of BC in precipitation show large spatial differences,with 2-3 orders of magnitude higher in China′s precipitation than in polar regions.The values decrease with the distance close to the polar regions,while the values obtained from ice core increased since the Industrial Revolution.Different types of industries and fossil fuel efficiencies resulted in higher BC concentration in precipitation in China than in other parts of East Asia and Europe.Long-term(>8 h)rainfall has a high removal efficiency of BC.(3)The combination of Hybrid Single Particle Lagrangian Integrated Trajectory Model,Positive Matrix Factorization and carbon isotope tracing can better identify the sources of BC.Due to the high mass fractions of BC in precipitation and insufficient data,it is recommended to conduct future research in China to enhance the urban observations of BC in precipitation in different regions,and to identify its sources using models and carbon isotopes.