Hence, rain water falling from a polluted atmosphere is more acidic, typically between pH 4.1 and 5.6. Because of the ever increasing quantity of sulfur and nitrogen oxides, rain falling from polluted atmospheres is becoming more and more acidic. In the United States, most industry can be found in the eastern part of the Midwest and in the Northeast. Therefore, one might expect acid rain problems in those areas. Not so simple.
Climatic patterns modify the distribution of the pollutants, and thus the distribution of acid rain.
For example, areas downwind from some industries might be in greater danger of acid rain than the areas immediately surrounding the industry that produced the air pollutants. When the acid rain falls, it is incorporated in our rivers, lakes, and soil. The acids in the rain cause numerous complex chemical reactions to occur, thus further modifying the river, lake, or soil chemistry. Many organisms can not live in acidified waters. For example, game fish such as trout, bass, and perch do not thrive in water below pH 5.