Abstract
The air in several industrial plants was sampled with instruments that are sensitive to particle number and mass concentration. Number-size distributions were obtained with an automatic light-scattering particle counter and a membrane filter-light microscope technique. Comparative results show the number counts to agree within a factor of approximately two over the size range of particles larger than 0.3 micron diameter. The polystyrene-calibrated optical counter underestimates the size of absorbing particles by a factor of 3. Number concentration data from impinger samples do not agree well with those from the other techniques. Aerosol mass concentrations were measured with a two-stage sampler, total filter and Lundgren Impactor. Over the range of concentrations of 1–80 mg/m3, the results agree within a factor of approximately three. Mass-size distributions were obtained with the Lundgren Impactor.