Air Pollution Leads to Acid Rain
When substances like nitrogen oxide and sulfur dioxide get into the atmosphere, combining with water, they can change the pH level of rain. Once the rainwater reaches a pH lower than 5.0 to 5.6, it qualifies as acid rain.
Acid rain is harmful to the environment. It can damage rivers and lakes, hurt aquatic life, and harm plant life (including forests and crops). In some cases, it may even damage buildings.