The aim of this article is to characterize the mean behavior of a polydisperse aerosol discharging streamwise into a homogeneous and nearly isotropic grid turbulence. Air-blast coaxial atomization was used to obtain a polydisperse aerosol composed of water droplets with diameters ranging from 5 to 200 mu m, with a mean arithmetic size of about 40 mu m. Properties of the dispersed phase, such as velocity, size distribution, size-velocity correlation, and number density, were measured by phase Doppler anemometry at several locations behind the grid in the developed jet region, beginning at 100 nozzle diameters downstream of the jet origin, where dilute spray conditions were encountered. The instrument was also used to evaluate the concentration profiles and to compare the mass flux evaluated at six explored stations to the initial flow rate at the nozzle. Further mean velocity profiles of the carrier airflow were obtained by pressure measurements. The mean behavior of the droplets is quantified in terms of mean Stokes numbers, and a turbulent Schmidt number is calculated for the mass and momentum transfer of the two-phase jet entrained by the turbulent co-flow. In the present case, the ''dispersion'' process appears to be controlled by the dominating inertial effects, and the larger droplets tend to accumulate on the outer edges of the jet.