This study was conducted by the Dept. of Preventive Medicine, Kyung-Hee University, School of Medicine as a preliminay test for the effects of Fluorine Compounds to the Plants from April through August, 1971. Fluorine was measured with Zirconium-Alizarine method and the following findings could be obtained : 1. Most high densities (25.7pptm) was found around the industrial areas and lowest (19.3pptm) around residential sections in Seoul. 2. Average density of Fluorine in the atmosphere of Seoul City was 22.3 pptm which can damage such plants as Pine, Strawberry, Peach and Grapes. 3. Fluorine contests (22.3pptm) in Seoul area atmosphere of shows about 4 times more than that of Cincinnati, Ohio, U.S.A.