The role of stability in fine pesticide droplet dispersion in the atmosphere: A review of physical concepts

The investigation of the role of atmospheric stability in the atmospheric d ispersion of pesticide sprays and powders has largely been approached from an empirical standpoint. This article discusses the physical basis underlyi ng the observed results relying on work done by boundary layer meteorologis ts and air pollution engineers. An examination of the turbulence equation, atmospheric turbulence spectra, and simple applied modeling techniques base d on accumulated data all lead to the conclusion that atmospheric stability will influence droplet dispersion through reduced mixing as the atmosphere becomes more stable. The magnitude and interaction of stability with spray application parameters requires further study.