Influence of particle size on efficiency deposition of aerosol on larvae gypsy moth
~ Pergamon
PII: 50021-8502(96)00316-3
J. Atn>JOl Sci.• Vol. 21. Suppl. I. pp. 5487-5488. 1996 CopyriahlO 1996 EIKvier Science Ud Printed in 0 .....1...
J. Atn>JOl Sci.• Vol. 21. Suppl. I. pp. 5487-5488. 1996 CopyriahlO 1996 EIKvier Science Ud Printed in 0 .....1 Brilain. All rishls reserved
0021-8502/96515.00 + 0.00
INFLUENCE OF PARTICLE SIZE ON EFFICIENCY DEPOSITION OF AEROSOL ON LARVAE GYPSY MOTH KP. KOUTSENOGII, O.V. CHANKINA, E.\. KIROV, V.1. MAKAROV, V.M. SAKHAROV, G.N. ZAGULYAEV Institute of Chemical Kinetics and Combustion S8 RAS 630090 Novosibirsk, Russia KEYWORDS
The aim of the studies is to determine the rate of insecticide deposition on insects depending on particle size and concentration and on the rate of aerosol flow. Experiments were carried out in vertical wind tunnel. The generator with a rotating disc [1] produced a flow of monodisperse aerosols. The concentration of aerosol particles was varied by changing the consumption of working liquid pressed out by condensed air at the center of the rotating disc through a needle capillary. The particle size was determined by disc rotation rate controlled by air pressure. Aerosol flow was generated by centrifugal blower. The insects were Gypsy Moth larvae of 1 instar. The insecticide was 't: isomer of HCH. Chemical analysis was performed by gas-liquid chromatography. 11 The method sensitivity was 10. g in the introduced sample (10 ~L). Experimental data obtained by studying monodisperse particles with diameter 8, 28, 57 microns and polydisperse aerosols with a mass-median size of about 12 J.1m show that when the contact with contaminated surface is insignificant, the amount of insecticides settling on larvae linearly increases with residence time in aerosol flow. The above regularity was observed in the range mass concentration of insecticide aerosol from 0,01 to 3 IlgL·1 for monodisperse particles and from 0,01 to 40 ~gL·1 for the particles of micron size. The velocity of aerosol flow varied from 0,5 ·1 to 3 ms . The treatment of experimental data shows that the accumulation rate on larvae for the given values of particle size and of the rate of aerosol flow is proportional to aerosol particle concentration and increases with residence particle size and the rate of aerosol flow. The rate of preparation accumulation on larvae at unit concentration defines the efficiency of aerosol particle capture by insects. For the particles with a massmedian size of 1-2 um no difference has been observed the efficiency of particle precipitation on the larvae with varying flow rate from 0.5 to 3 ms" . At the same time, for the particle of 8 urn the efficiency of particle precipitation on the larvae increases almost two hundred times with varying rate from 0,5 to 3 ms" . As the particle size increases, the influence of air flow rate is insignificant. The same data testify to very strong dependence of accumulation rate on particle size. S487
S488
Abstracts of the 1996 European Aerosol Conference
It has been found that 50% of insect mortality have been observed upon sedimentation of one and the same dose of y - HCH (14 ± 6 Ilg per 1 g) independently of aerosol particle size concentration and on the rate of aerosol flow. The data obtained is shown that a lethal dose is obtained when the aerosol particles precipitation on larvae directly from the suspended state.
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