Ground based in situ observations of filter_absorption_photometer at Ispra (IT0004R). These measurements are gathered as a part of the following projects ACTRIS, EMEP, GAW-WDCA and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: aerosol_absorption_coefficient in pm10, aerosol_absorption_coefficient in pm10, aerosol_absorption_coefficient in pm10