Measurement of the physical decay of aerosols by a light scatter method compared to a radioactive tracer method

The physical behaviour of aerosols atomized into stirred settling chambers, or into rotating drums, was examined by a radioactive tracer method and by a light scatter method. With suitable corrections, there was no difference between the two methods of measuring of physical decay. The tracer method is advantageous in that the data so obtained are on an absolute basis, whereas data from scattered light measurements are relative. The latter method, however, is less time consuming, provides an immediate notification of instrument performance and does not require that material be removed from the aerosol chamber for sampling purposes.