1985 年 5 巻 1 号 p. 79-90
The product of visibility and the smoke density as expressed by the extinction coefficient is almost constant. This product depends mainly on the brightness of the object, the illuminating light in the room, and the smoke properties. However, with irritant smoke this simple relation can apply only to low smoke densities.
Experiments were made to elucidate the effects of irritant smoke on visibility. Twelve subjects were evaluated on their visual acuity with Landolt's ring test chart in a highly irritant smoke filling room and eye blink rate was measured, as an objective indication of eye irritation.
It is concluded that the lower visibility through fire smoke is attributed to the running tears due to irritants, as well as to the extinction coefficient. Based on this new understanding, the degree of physiological and physical effect is discussed.