The concentration of several gases contained in a YAG laser induced smog was measured, and an improved gas scavenging system was tested for cleaning the smog. The YAG laser was practiced at its power of 80w for a few minutes, and the gas analysis was followed by an analogous way described in out previous paper.Judging from the figures shown in our previous two papers, the concentrations of NO_X, CO and CO_2 were not assumed so high as to be taken in account for pollution, too, by YAG laser; analysis for these gases was omitted.The concentrations of HCHO and CH_3COOH were 6 and 5 ppm, respectively, at their maximum. Those of H_2S and CH_3SH were 3 and 2 ppm, respectively, and that of CH_3NH_2 exceeded 60 ppm. The figures of HCHO, CH_3SH and CH_3NH_2 are beyond the standards for working room air : moreover, all of those observed are quite enough to be sensible as offensive smell.The experimentally tested ges scavenging system wax composed of a inlet cone, a inlet tube and a suction pump with a device of catalytically gas cleaning function. A filter inserted in the cone caught a considerably much quantity of micro-particle and tar like material. The gases to be detected in the off air from the pump were not found except trace of CH_3NH_2.
