Abstract
It is very important to know the nature of aerosol particles in the atmosphere which have sizes ranging from 10-7 to 10-5cm in radius. Particulary, it is interesting to measure the “charged fraction” of particles, i.e. the ratio of the charged particle concentration to the total concentration from the viewpoint of atmospheric electricity.
In order to produce a charge equilibrium state of aerosols of a large ion range, sample air containing aerosol particles was irradiated by α-ray (210Po 200μCi) for a few seconds. By this method, the equilibrium state was quickly attained.
For the purpose of determining whether the aerosols are in a charge equilibrium state or not, we measured the fraction of the charged particle oncentration to the total concentration, and compared that obtained with the natural aerosols sampled simultaneously with that brought to an equilibrium state by the above-mentioned method. It was found that the equilibrium state is established for a short time immediately before sunrise when the mospheric conditions are stable.
