Acid rain is a form of precipitation that contains high levels of nitric and sulfuric acids. It can occur in the form of rain, snow, fog, and even dust that falls from the sky. Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Sulfur dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. As a result, the two compounds can travel long distances where they become part of the rain, sleet, snow, and fog that we experience on certain days.

Human activities are the main cause of acid rain. Over the past few decades, humans have released so many different chemicals into the air that they have changed the mix of gases in the atmosphere. Power plants release the majority of sulfur dioxide and much of the nitrogen oxides when they burn fossil fuels, such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain.

Acid rain can have serious consequences for the environment. It can increase the acidity of lake water, which can cause changes in the assemblages of plants and animals that occur naturally in the lake. Acid rain can also leach copper, aluminum, and other heavy metals out of the soil and into runoff and drinking water. Acid rain can damage forests, especially those at higher elevations. The acid deposits rob the soil of essential nutrients such as calcium and cause aluminum to be released in the soil, which makes it hard for trees to take up water. Trees leaves and needles are also harmed by acids. Acid rain can also damage physical structures such as limestone buildings and cars. When it takes the form of inhalable fog, acid precipitation can cause health problems including eye irritation and respiratory distress.

In summary, acid rain is caused by the release of sulfur dioxide and nitrogen oxides into the atmosphere, where they react with water, oxygen, and other chemicals to become sulfuric and nitric acid respectively. Human activities, such as burning fossil fuels, are the main cause of acid rain. Acid rain can have serious consequences for the environment, including increased acidity of lake water, damage to forests, and harm to physical structures and human health.