Abstract
Recent studies of particulate and gaseous materials in the atmosphere have raised important questions about diffusion at distances of 10–100 km. A photometric densitometer, initially developed for a quantitative study of oil-fog concentrations at ground level, has been adapted for use in an aircraft. Real-time measurements of ground-level and airborne particle concentrations are presented to distances of 120 km, and the implications of these data in terms of large-scale dispersion are discussed.
