AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Characterization of Rural Aerosol Hygroscopicity and Chemical Composition Influenced by Fog and Anthropogenic Emissions in Central Taiwan
CHIA-LI CHEN, Ting-Yu Chen, Hui-Ming Hung, Ping-Wen Tsai, Charles C.K. Chou, Wei-Nai Chen, National Taiwan University
Abstract Number: 438 Working Group: Aerosols, Clouds and Climate
Abstract Ambient submicron particles were investigated using a mini compact time-of-flight aerosol mass spectrometer (mini-c-ToF-AMS), a cloud condensation nuclei counter (CCNc), and a scanning mobility particle sizer (SMPS) from Dec. 1st to Dec. 24th 2018 in the Xitou forest area, Taiwan (23.40°N, 120.47°E, 1,178 m asl). Ambient wet aerosol particles were collected by a 13-stage nano-MOUDI II impactor (micro-orifice uniform deposit impactors) and post-analyzed by a Fourier-transform infrared spectroscopy (FTIR). This study investigates the influence of meteorological and geographical conditions (e.g., sea/land breeze circulation, upslope fog formation, and mountain-valley breezes) on chemical composition of non-refractory submicron particles and single hygroscopicity parameter (κ) of particles at Xitou. Organics (62%), sulfate (22%), and nitrate (6%) concentrations correlate moderately with chloride, suggesting the aerosol particles are likely northwesterly transported from coastal areas (a distance of 60~70 km) by sea breeze. The late afternoon (16:00-17:00) peak of aerosol particles is likely due to slow transport of 60-km industrialized pollutants from a coastal power plant and chemical plants by daytime sea breeze or valley breeze and combination of secondary organic aerosol formation. The κ ranges of sulfate particles derived from AMS particle time-of-flight (ptof) and FTIR measurement comparisons are 0.2< κ <0.5 and 0.6 < κ <0.8 during daytime on foggy days and non-foggy days, respectively. The high relative humidity range of 95% to 99% could likely promote the process of cloud droplets activation during nighttime, thus the derived κ value ranges of sulfate particles are lower than 0.4. This study will investigate the κ profile as a function of aerosol size derived from AMS-SMPS/AMS-FTIR and CCNc measurement and the impact of the upper stream anthropogenic emissions on the aerosol physical-chemical properties over the rural areas.