Abstract
Hyogo Prefecture has been conducting various surveys and investigations regarding the challenge of acid rain. The fruits of the activities were reviewed and summarized from the viewpoint of wet deposition, dry deposition, the impact on the forest ecosystem, and transboundary transport. Wet deposition was studied for precipitation and fog (cloud) water. The precipitation samples collected at five sites with different site classifications were studied to clarify the features of precipitation, such as the degree of acidification and its mechanism. Fog (cloud) water was compared with precipitation. The survey was carried out for 7 years at Mt. Rokko, located near an urbanized area. In addition, the generation of the fog (cloud) water, the trend of the concentration of the chemical components in the fog (cloud) water, and the relationship of the generation and disappearance of the fog (cloud) water with the behaviors of atmospheric gases and aerosols were studied. The dry deposition of sulfur dioxide and nitric acid was estimated based on a survey done by the four-stage filterpack method. The impact and input-output balance of material were studied for the watershed located at sites with different site classifications: Mt. Rokko, an urbanized area, and Mt. Awaga, a rural area. The wet-only precipitation, the bulk precipitation collected by the filtering-type bulk sampler, the fog (cloud) water, the throughfall, the stemflow, and atmospheric gases and aerosols were comprehensively surveyed and studied. The input-output balance of sulfur was studied in the catchment area set up on Mt. Awaga. The concentrations of aerosol and gases in ambient air in winter at the site facing the Sea of Japan were surveyed by 6-h interval sampling using the four-stage filter-pack method, and the transboundary transport of air pollutants from the Eurasian Continent and/or the Korean Peninsula to Japan was quantified. The surveys and the research will progress continuously, more comprehensively, and more progressively. More inclusive approaches to limiting air pollution and protecting the atmospheric environment from acid rain will be promoted.
