Ground based in situ observations of nephelometer at Lecce (University of Salento) (IT0017U). These measurements are gathered as a part of the following projects ACTRIS, GAW-WDCA and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: aerosol_light_backscattering_coefficient in pm25 (mass_concentration_of_backscattering_coefficient_in_pm2p5_in_air), aerosol_light_backscattering_coefficient in pm25 (mass_concentration_of_backscattering_coefficient_in_pm2p5_in_air), aerosol_light_backscattering_coefficient in pm25 (mass_concentration_of_backscattering_coefficient_in_pm2p5_in_air), aerosol_light_scattering_coefficient in pm25, aerosol_light_scattering_coefficient in pm25, aerosol_light_scattering_coefficient in pm25