An Observational Study on Physical Properties of Atmospheric Aerosol in and Optical Autumn in Nanjing

摘要

Based on observing data of atmospheric aerosol in the north suburban area of Nanjing from September to November in 2007,the number concentration,mass concentration,size distribution and optical properties of atmospheric aerosol particles and the relation to meteorological factors were analyzed,and their concentration and optical properties during hazy and non-hazy days were compared. The results showed that aerosol pollution was serious in autumn in this region; the deterioration of visibility had close correlation to fine particles,that is,the average number concentration of aerosol was 17 044. 2 cm-3,in which ultra fine particles accounted for 64.3%; the daily average mass concentration of PM2. 5was 281μg/m3,and the ratio of PM2. 5to PM10was 0. 74; the accumulation mode particles dominated in number and surface concentration distributions,while the volume concentration distribution presented a main peak at size of 1. 0-2. 8 μm; fine particles increased during hazy days compared with non-hazy days; the scatter coefficient closely correlated to the particle size,concentration and atmospheric humidity. It was also indicated that meteorological conditions played a critical role in formation of hazy weather,that is,weak large-scale weather systems,low wind speed,high humidity and strong inversion were favorable conditions for hazy weather in autumn.