Abstract
We have observed the acid fog on Mt. Oyama in the Tanzawa Mountains since 1988 using active and passive fog samplers. The concentrations of the fog-water components significantly differ in each event due to their many dominating factors, which are air pollution, liquid water content, scavenging effect of canopies, wind, and rain. Frequently observed acid fog is caused by nitric acid, which is formed by the oxidation of nitrogen dioxide advected from the Kanto Plain. The fir and beech trees are declining in the forest where acid fog frequently occurs. We have investigated the exposure experiment involving the seedlings of fir and beech, and clarified the mechanism of the direct effect of acid fog on the seedlings. We have also investigated dew-water chemistry, gases of not only strong acids but also weak acids are absorbed in the dew-water, and severely contaminated dew-water is frequently observed in Yokohama.
