Ground based in situ observations of nephelometer at Egbert (CA0011R). These measurements are gathered as a part of the following projects GAW-WDCA, NOAA-ESRL and they are stored in the EBAS database (http://ebas.nilu.no/). Parameters measured are: aerosol_light_backscattering_coefficient in pm1, aerosol_light_backscattering_coefficient in pm1, aerosol_light_backscattering_coefficient in pm1, aerosol_light_scattering_coefficient in pm1, aerosol_light_scattering_coefficient in pm1, aerosol_light_scattering_coefficient in pm1