A new practical formula for calculating free-stream aerosol particle properties in airborne sampling applications

In this paper, we derive a new formula for determining the free stream aerosol particle size distribution from airborne measurements with a sharp-edged aspirating diffuser sampler backed by a filter. We point out that Computational Fluid Dynamics (CFD) and Computational Particle Dynamics (CPD) can be used to determine the conversion factor for translating the size distribution of particles collected on the filter to the free stream aerosol particle size distribution which is the quantity of interest in airborne aerosol particle sampling.