气溶胶对可见度、人体健康、气候变化有重要影响。基于2014年夏季南京江心洲地区外场观测实验数据，对气溶胶的数浓度、粒径谱分布，粒子密度、混合状态，以及黑碳含量进行了分析。结果表明，观测期间气溶胶粒径集中分布在50～120 nm 之间，平均粒径79 nm，总数浓度波动较大，范围为2000～50000 cm －3，平均值在9000 cm －3左右；在本次观测中，新粒子生成事件较少；气溶胶主要为内混状态，存在少量外混状态（约占1.5％）；气溶胶密度主要分布在1.2～1.7 g／cm3之间，气溶胶粒径越大，密度越大，表明大粒子中无机物含量多，有机物含量低；粒子密度日变化与化学成分日变化相关性较好；70％的气溶胶中含有黑碳，200 nm 气溶胶中黑碳质量分数最高为7.07％。气象因素对气溶胶微物理特性有明显影响。%Aerosols have major impacts on visibility,human health,and climate.During the field observation in Nanjing Meteorological Bureau last summer,SMPS and APMare used to measure microphysical characteristics of aerosols,including particle number concentration,size distribution,density,mixing state,black carbon.During the measurement period,the particle size ranges from 50nm to 120 nm,and the average particle size is 79 nm.The total concentration varies between 2000 cm -3 ~50 000 cm -3 ,and the average concentration is around 9000 cm -3 . The new particle formation has little occurrence during this period.Aerosols are often internally mixed,while the externally mixed aerosols only account for 1.5%.The particles’density mainly concentrates between 1.2 ~1.7 g/cm3 .The density increases with the particle size,indicating a large mass fraction of sulfate and a small concentra-tion of organics in larger particles.The density shows a distinctive diurnal cycle,which corresponds to the diurnal cycle of chemical compositions.70% of aerosols containing black carbon,BC mass fraction increase with particle size,reaching a peak at 200 nm,then decreases.The meteorological factors have a significant effect on aerosol properties.
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