10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Fine Particle pH in Urban Guangzhou, a Megacity of South China
ZHISHENG ZHANG, Jun Tao, Leiming Zhang, Zejian Lin, South China Institute of Environmental Sciences
Abstract Number: 663 Working Group: Aerosol Chemistry
Abstract Particle acidity is a critical parameter affecting aerosol processes and properties, yet it is poorly constrained in China. In the present study, hourly measurement of particulate and gaseous compositions along with meteorological parameters were observed in an urban site of Guangzhou, a megacity of South China. A total of 4688 sets of data were obtained. These data were used as inputs into ISORROPIA-Ⅱ thermodynamic equilibrium model running in the forward mode to estimate the fine particle pH. Fine particle pH in Guangzhou ranged from 1.3 to 5.7, with a mean of 2.8. It showed a clear diurnal pattern with peak value in the early morning hours and lowest value occurred in the afternoon. Higher fine particle pH were found on polluted cases when the particulate compositions were dominated by nitrate and ammonium. Sensitivity tests were performed by altering inputs to analyze the potential impacts of these variables on particle pH. It showed that NH3, SO4, relative humidity (RH) and temperature were the key factors affecting pH in Guangzhou. Under high RH and low temperature conditions, high NH3 and low sulfate concentrations tended to generate high pH particles.