In this paper we discuss in detail some aspects of a technique for airborne studies of submicron aerosol using a nephelometric device. In particular, we analyze possible deviations of measured number density and size-spectrum from actual ones that can occur at aerosol sampling and transportation to scattering volume. We also present in this paper results of intercalibration measurements, which confirm the validity of estimations of the calibration uncertainties. These results also show that the value of the coefficient in the relation between the angular and integral characteristics of light scattering has been chosen correctly.