An Observational Study of the Hygroscopic Properties of Aerosols over the Pearl River Delta Region

• 作 者: Haobo Tan Yan Yin Xuesong Gu Fei Li P.W. Chan Hanbing Xu Xuejiao Deng
• 机 构: Institute of Tropical and Marine Meteorology, China Meteorological Administration, Guangzhou,Guangdo
• 出 处: 第十一届全国气溶胶会议暨第十届海峡两岸气溶胶技术研讨会
• 发表日期: 2013年5期
• 关键词: H-TDMA aerosol hygroscopicity urban aerosol haze Pearl River Delta

　　Hygroscopic growth can significantly affect size distribution and activation of aerosol particles,as well as their effects on human health,atmospheric visibility,and climate.In this study,a H-TDMA (Hygroscopic Tandem Differential Mobility Analyzer) was utilized to measure hygroscopic growth factor and mixing state of aerosol particles at the CAWNET station in Panyu,Guangzhou,China.A statistical analysis of the results show that,at relative humidity (RH) of 90%,for less-hygroscopic particles of 40-200 nm in diameter,the growth factor (gLH) was around 1.13,while the number fraction (NFLH) varied between 0.41±0.136 and 0.26±0.078; for more-hygroscopic particles,the growth factor (gMH) varied between 1.46 and 1.55 with the average equivalent ammonium sulfate ratio ( AS 错误!未找到引用源.) ranging from 0.63 to 0.68.The differences in AS among particle of different sizes reveal that more-hygroscopic inorganic salts,such as ammonium sulfate and ammonium nitrate,are of more effective condensation growth for Aitken mode particles.A combined analysis of the probability density function of growth factor (Gf-PDF) and simultaneous meteorological data shows that during clean periods with air masses moving from the north,the particles are more likely to have homogeneous chemical composition,while during polluted or pollution accumulation periods,variations in mean number weighted growth factor (gmean) and NFMH become more pronounced,indicating that locally-emitted aerosol particles tend to be in an externally mixed state and contain a certain proportion of less-hygroscopic particles.This study can help improve our understanding of aerosol hygroscopicity and its impact on the atmospheric visibility and environment.