Comparison between dry method and wet method

Differences of amounts of deposited impurities obtained by the British Standard deposit gage and dust jar.II

Abstract

In the first report of their study, the authors have pointed out that there were marked differences in the amounts of deposit obtained by the British Standard deposit gage (BG) and the dust jar recommended by the Pharmaceutical Society of Japan (DJ), and that these differences should be caused by the difference of the dry method and the wet method.
This study was done to confirm this assumption, during July 1960 to June 1961. In this study, 3 kinds of dust collector-BG, DJ, and a wet modification of BG devised by I. Saito (wet BG)-were used at the 3 stations in Tokyo city at first, increasing to 11 stations by November 1960.
Values at every stations showed similar tendencies, and the results obtained in the first report were reproduced in this study. There were good agreements between DJ values and wet BG values. Therfore, as far as this study concerned, the dust collecting efficiency of the collector was quite indifferent to its form or size, and was decided chiefly whether the sampling method taken was dry or wet. The wet method showed much higher efficiency than the dry method, because in the dry method the pollutants once fallen into the dust collector were apt to be blown out by the wind.