Synergetic analysis of springtime air pollution episodes over Gwangju, Korea

A high Light Detection and Ranging (LIDAR)-derived aerosol depolarization ratio (δ) of 0.25 ± 0.04 was determined on dust particles during the observation period. The Ångström exponent values of the 440–870 nm wavelength pair (Å440–870) and single-scattering albedo at 675 nm (Ω675) 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 (Å440–870ranged between 1.33 and 1.36) and higher light-absorbing (Ω675of 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, τ) derived from LIDAR (τLIDAR) and from the CIMEL sun/sky radiometer (τCIMEL) varied with respect to the surface PM10concentration. The RMSD between τLIDARand τCIMELwas as low as 13% under lower PM10concentration levels (< 100 μg/m3). In contrast, the RMSD between τLIDARand τCIMELincreased three times (~ 31%) under high surface PM10concentration levels (> 100 μg/m3). These results suggest that the accuracy of τLIDARis influenced by specific atmospheric conditions, regardless of its uncertainty.