Measurement of ultrafine aerosol particle size distributions at low concentrations by parallel arrays of a diffusion battery and a condensation nucleus counter in series

Abstract This paper describes an instrument configuration capable of measuring size distributions over the 0.014–0.2 μm size range at particle concentrations typical of state-of-the-art clean rooms (10 −3 particles/cc or less). The configuration consists of a parallel array of diffusion batteries each with its own condensation nucleus counter and each drawing an independent air sample for analysis at one size cut. The combined outputs of all CNC/DB pairs yield the desired size distribution as illustrated for several clean room operating conditions.