A case study of aerosol characteristics during a haze episode over Beijing

This work presents the variation of aerosol characteristics obtained before, during and after the haze episode in October, 2010 in Beijing, a highly industrialized city which located in the northwest of North China Plain with more than 21 million inhabitants. Surface solar irradiance was measured by pyranometer which showed great differences between hazy and non-hazy days. Aerosol scattering coefficients were obtained by integrated nephelometer and the influence of relative humidity on aerosol scattering coefficient was investigated by means of the Weather Research and Forecasting Model Wave Watch III (WRF-WW3) imagery. Spectral aerosol optical thickness was measured by Sun photometer and Angstrom exponent were calculated to investigate the variation of aerosol loading and modes under different weather conditions. Haze weather process favoured the formation of the secondary aerosol, which contributed to the increase of fine mode particles. (C) 2013 The Authors. Published by Elsevier B.V.