Synergetic analysis of springtime air pollution episodes over Gwangju, Korea

Abstract

The characteristics of springtime aerosols, including their optical and microphysical properties, were analyzed for the months of March to May of 2009 in Gwangju (35.23 degrees N, 126.84 degrees E), Korea. A high Light Detection and Ranging (LIDAR)-derived aerosol depolarization ratio (6) of 0.25 +/- 0.04 was determined on dust particles during the observation period. The Angstrom exponent values of the 440-870 nm wavelength pair (angstrom(440-870)) and single-scattering albedo at 675 nm (0675) measured by a CIMEL sun/sky radiometer were 0.77 +/- 0.19 and 0.95 +/- 0.01, respectively. The elevated dust layers reached a maximum elevation of 4 km above sea level. Anthropogenic/smoke particles that originated from highly populated/industrialized regions could be distinguished by their relatively smaller particle size (angstrom(440-870) ranged between 1.33 and 1.36) and higher light -absorbing (Omega(675) of 0.92 +/- 0.01) characteristics. These aerosols are mostly distributed at altitudes <1.2 km. The root-mean-square deviation (RMSD) between the aerosol optical depth (AOD, tau) derived from LIDAR (TuDAR) and from the tau(CIMEL) sun/sky radiometer (tau(CIMEL)) varied with respect to the surface PM10 concentration. The RMSD between tau(LIDAR) and tau(CIMEL) was as low as 13% under lower PM10 concentration levels (<100 Rg/m(3)). In contrast, the RMSD between tau(LIDAR) and tau(CIMEL) increased three times (similar to 31%) under high surface IDMio concentration levels (>100 g/m(3)). These results suggest that the accuracy of tau(LIDAR) is influenced by specific atmospheric conditions, regardless of its uncertainty. (c) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.