A plant indicator of air pollution and human health in Japanese rural communities.

An investigation of the effects of air pollution on vegetation and human health was conducted in a low-degree air-polluted Japanese rural area. The validity of the criteria, which were expressed as Bi-band ratios (R/B, R/G) in leaves of Japanese cedars based on infrared air photography, has been proved worthwhile for estimating the injury to the cedars. The degree of injury to the cedars by field survey showed a significant positive correlation with the concentration of sulfur oxide in the air for the last 3 years. The quantity of water-soluble sulfur in leaves of the cedar was less in the leaves of the less-injured cedars. In school children with positive skin reactions in the area, "subacute cough" (la and/or 3a by BMRC) and "phlegm" (6a and/or 8a by BMRC) had a significant positive correlation with the degree of injury to the cedars.