Composition of rainwater and influences over different regions of the world

Abstract Rainwater composition is important for human beings and ecological systems. Polluted rainfall affects aquatic environments such as streams, lakes, and marshes where it can be harmful to fish and other wildlife. As it flows through the soil, polluted rainfall water can leach out toxic materials that can then be accumulated in the food chain. The formation of rainfall begins with the evaporation of water, mostly from the oceans, and the presence and composition of atmospheric aerosols. The association between aerosol composition and cloud droplets influences the composition of rainwater. Wet deposition from rainwater cleans up all the coarse particles from the ambient air. The number of soluble materials influences the composition of rainwater that arrives on the earth’s surface. Different regions and land use over the world have different effects on the characteristics of rainwater composition. Among the characteristics, the formation of acid rain was found to be the most influential process impacting the environment as well as ecological systems in different parts of the world. In this chapter, we present information on aerosols that influence the formation of clouds and rainfall. The compositions of aerosols from different sources determine the composition of anions and cations in rainwater that determine the pH of rainwater all over the world.