Aircraft Applications of Insecticides in East Africa. IX.—Further Experiments on the Deposition in open Country of a coarse Aerosol released from an Aircraft

Abstract

Further experiments have been carried out to investigate how a coarse aerosol, released from a low-flying aircraft, is deposited upon the ground in open country. The aerosol had a mass median diameter of approximately 80 microns, and was produced by a boom-and-nozzle apparatus. The aircraft height was 65 ft. It is shown that the rate of deposition is related to the degree of atmospheric turbulence, of which a simple and easily measured parameter is given. The rate of deposition is greatest when there is a large temperature inversion and a low wind speed. A comparison is made with previous work where the aircraft height was 30 ft. Within the limits investigated, an increase in aircraft height reduces the deposits near the line of emission, but does not greatly affect the total amount that deposits within 150–200 seconds of production of the aerosol.