Figure 2-2-17 Trends in the Number of Young Sweetfish Swimming Upstream in the Tama River (Estimated Numbers)

Source: Tokyo Islands General Center for Agriculture, Forestry, and Fisheries

Figure 2-2-19 Damage to Crops and Plants Caused by Photochemical Oxidants

Photographs provided by the Center for Environmental Science in Saitama Prefecture

traditional buildings in North America and Europe. It is known that through air cycle systems on a global scale acid rain damages on areas several thousand kilometers away from the source of the material that caused it, and it is an environmental problem that crosses national borders.

In Japan, efforts related to trans-border air pollution, which was initially targeted at acid rain, have in recent years broadened to target photochemical oxidants. Photochemical oxidants are the substances that cause photochemical smog, which damages human health, crops, and plants (Figure 2-2-19).

Highly concentrated photochemical oxidants continue to be observed. In May 2009 an increase of concentration was seen across a wide area in the Kyushu and Chugoku regions, and a photochemical oxidant warning was issued for the first time in Kagoshima Prefecture. When it is predicted that photochemical smog can easily develop across a wide area, the Japan Meteorological Agency announces information about general smog weather. The National Institute for Environmental Studies uses an "air pollution prediction system" to predict the air pollution concentration of photochemical oxidants and nitrogen dioxide in the East Asian region from a weather model and a chemical transport model, and announces the results every hour on a trial basis in the form of a distribution map of pollution concentration (Figure 2-2-20). This prediction system divides East Asia into meshes of $ 100 \, km^{2} $ and Japan into meshes of $ 25 \, km^{2} $ , and since April 2010 it has been possible to indicate prediction results for all of Japan. Figure 2-2-20 shows in color gradation from yellow to red the areas for which highly concentrated photochemical oxidants were predicted by the air pollution prediction system in May 2009. Meanwhile, Figure 2-2-21 shows the distribution of concentration actually measured by the Ministry of the Environment's "Sora Mame Kun (Atmospheric Environmental Regional Observation System)" and the

Figure 2-2-18 Trends in Rate of Prevalence of Sewage Systems and Water Quality in the Tama River Basin

Note 1: Rate of prevalence is the rate of prevalence in the Tama River basin.

Note 2: Water quality is the annual BOD value at the Tama River Hara Bridge (75% water quality value)

Source: Bureau of Water Management, Tokyo Metropolitan Government

Figure 2-2-20 Air Pollution Prediction System

Source: National Institute for Environmental Studies, air pollution prediction system

state of photochemical oxidant warnings issued. According to these figures, on May 9 in each of the areas of Japan where highly concentrated photochemical oxidants were predicted, air pollution was actually measured.

There is also an environmental problem of trash that drifts via circulation in the ocean: it affects scenery and leisure; it affects security of everyday life, which is especially caused by medical waste; it affects the fishing industry and marine transport due to interference with navigation; and it affects living organisms in the ocean by entangling their bodies.

In Japan, related ministries and agencies are tying up under the Council for Promoting Measures Against Marine Litters, which was newly established based on the Law Concerning the Promotion of Disposal of Marine Litters for Conservation of Good Scenery and Environment on the Coasts. And monitoring of marine litters, studies for source of them, and actions against marine litters are going forward. Moreover, in order to strengthen world-wide measures to this problem, cooperation such as mutual information exchanges and policy dialogues for investigating for resource of marine litters come from are being promoted through.

All of the organisms on the Earth, including humans, are able to receive various benefits from the Earth by keeping ecosystems in good condition. The healthy interactions between ecosystems and organisms are essential to the existence of all organisms.