1 Collocated measurements of UV-B irradiance and aerosol optical characteristics have been carried out over Pune, western India from April 2004 to March 2005 to estimate the role of aerosols in UV-B radiation at the surface. It is found that a unit increases in aerosol optical depth reduces by about 40-56% of the harmful UV-B radiation that reaches the site. Ultraviolet-impact on human health is usually characterized by the UV-index (UV-I), and is estimated with the aid of a radiative transfer model using aerosol and ozone measurements over the site. The index is found to be in the extreme range (10.1 to 13.5) during pre-monsoon, high to extreme (8.5 to 11) during post- monsoon and high (7 to 10) during the winter seasons, vulnerable to sensitive skin. The estimated UV-I values are found to be compared well with SCIAMACHY satellite observed UV-I values with mean ratio of 0.95 ± 0.0
