An Improved Airborne Aitken Nucleus Counter

Abstract

An instrument has been designed for measuring with high accuracy and resolution the size and concentration of atmospheric particles ≥0.005 ?m. It is pressure compensated for aircraft use and can take five readings per second with a system response time approximately 1 s. Its wide application is illustrated by results obtained with the equipment installed in CSIRO's Fokker F-27 research aircraft. These include vertical profiles of particle concentrations, size distributions covering the radius range 0.005 to 0.2 ?m and the horizontal delineation of boundary conditions between air masses of different origins as found in cumulus cloud/clear air interfaces.