Studies on Size Distribution and Mixing State of Black Carbon Aerosols in China

近年来，东亚地区工业活动的迅速发展导致了该地区气溶胶的大量增加。大气气溶胶通过散射和吸收改变辐射收支。因为黑碳（BC）气溶胶（例如，在2006物理年，通过对北京市大气中BC的质量浓度、粒径分布和粒径分布的观测，与北京大学等国际研究组在中国北京地区和珠江三角洲地区进行了一系列研究。在2007物理年，利用三维化学传输模型，从排放源、化学生产、传输过程和去除过程等方面对这些数据进行了精细的分析和解释。观测结果表明，北京地区BC浓度有明显的日变化，夜间出现最大值。模式计算通过边界层高度等的日变化很好地再现了这一特征。虽然大的日常变化被发现二次气溶胶，如无机气溶胶，他们是小BC。模型计算结果表明，北京周边100 km范围内，前24 h的BC排放量控制了BC的浓度。在中心，排放量远达500公里，在前3天内被发现影响浓度的二次气溶胶，如硫酸盐通过积累在稳定的天气尺度的气象条件下。

Recent rapid growth of industrial activities in East Asia has been causing large increase in aerosols in this area. Atmospheric aerosols modify the radiation budget through scattering and absorption. Because black carbon (BC) aerosols (e.g., soot) efficiently absorb the solar radiation, they have been recognized one of the most important aerosol compounds the solar radiation, they have been recognized one of the mot important aerosol compounds for climate change.In the physical year of 2006, measurements of BC mass concentrations, size distribution, and mixing sate were in the Beijing region and Peal River Delta (PRD) region in China with Peking University Research Groups and some other international research groups. Aerosol chemical composition and some other parameters were also simultaneously measured.In the physical year of 2007, these data were precisely analyzed and interpreted from the viewpoint of emission sources, chemical production, transport processes, and removal processes using three-dimensional chemistry transport model. Observations show that BC concentrations in Beijing have a clear diurnal variation with a maximum during night. This feature was well reproduced by model calculations through diurnal variations, such as that in the boundary layer height. Although large day-to-day variations were found for secondary aerosols, such as inorganic aerosols, they were small for BC. Model calculations showed that BC concentrations were generally controlled by BC emissions within 100 km around Beijing within previous 24 hours. On the centrally, emissions as far as 500 km within previous 3 days were found to affect concentrations of secondary aerosols, such as sulfate through accumulations under stable synoptic-scale meteorological conditions.