Aerosol characteristics at a continental urban station in southern India

Abstract

Spectral Aerosol Optical Depth (AOD), Black Carbon (BC) mass concentration and Suspended Particulate Matter (SPM) measurements were made at an urban continental location, Bangalore (13°N, 77.6°E), in southern India. These results show that AODs reach a maximum during April (~0.5) and minimum during December (~0.2) at 500 nm. BC and SPM showed variations of 0.6-4.2 μg m³ and 120-195 μg m³, respectively. The Angstrom wavelength exponent (α) was ~1.0 during the dry season (December April), which, in conjunction with the high optical depth, indicates significant anthropogenic influence. Boundary layer dynamics plays an important role in the redistribution of aerosols at the surface. The seasonal variations in AOD, BC and SPM have an association with monsoon rainfall. The similarity in the seasonal characteristics of AOD, BC and SPM shows that the location is mostly characterised by anthropogenic activities during the dry periods (December-April).