Air pollution comes from factories, power stations and cars.Chemicals in the smoke from power stations cause a lot of damage.They can travel hundreds of miles in the wind before falling to the ground in the rain.But this "chemical rain" gradually destroys trees in the forests and kills fish in the lakes.In Germany, over 50% of the country's trees had been damaged by the year 1986.

　　空气污染来自工厂、电站和汽车。电站发出的烟雾中所含的化学物质造成很大的破坏。这些化学物质可以随风飘走几百英里，然后才随雨水降落地面。但是这种“化学雨”逐渐摧毁森林里的树木，杀死湖泊中的鱼。在德国，到1986年止，全国已经有过半数的树木被摧残。