In this paper, we present the results of axisymmetric, finite element-based numerical simulation studies of the turbulent airflow through a shrouded airborne aerosol sampling probe operating in a 100 m s(-1) airstream at a sampling altitude of 6069 m (20000 ft) above sea level. We calculate the aspiration efficiency of the sampler and the minimum transmission efficiency of the diffuser probe by simulating the trajectories of particles in the size range 0.1-15 mu m as they pass through the system. We compare these results with wind tunnel measurements and finite difference-based numerical simulation studies. We also estimate the minimum transmission efficiency of a shrouded probe recently rested in an aerosol wind tunnel.