Abstract
This paper is described the method of measurement of organic substance contained within air-borne dusts, using the oxydative reaction by silber bichromate. In the determination of organic substance, sampling technique is used Katz's method, and residual bichromate is determined by photoelectric method. The result as follows : The contents of organic substance of the particles due to smog and tobacco smoke are the highest, and the deposited particles in residences, department stores and others are higher than that of the surface earth particles, and the contents of accumulated earth particles are the lowest.
