what is acid rain

Acid rain is a type of precipitation that has elevated levels of hydrogen ions, making it unusually acidic. Normal rain has a pH of 5.6, while acid rain generally has a pH between 4.2 and 4.4. Acid rain can take many forms, including rain, snow, fog, hail, or even dust that is acidic. It is caused by emissions of sulfur dioxide and nitrogen oxide from human sources, such as electricity generation, animal agriculture, factories, and motor vehicles. These compounds react with water, oxygen, and other chemicals in the atmosphere to form sulfuric and nitric acids, which then mix with water and other materials before falling to the ground. Acid rain has been shown to have adverse impacts on forests, freshwaters, soils, microbes, insects, and aquatic life-forms. In ecosystems, persistent acid rain reduces tree bark durability, leaving flora more susceptible to environmental stressors such as drought, heat/cold, and pest infestation. Acid rain is also capable of detrimenting soil composition by stripping it of nutrients such as calcium and magnesium which play a role in plant growth and maintaining healthy soil. Acid rain can also damage physical structures such as limestone buildings and cars, and when it takes the form of inhalable fog, it can cause health problems including eye irritation and respiratory issues.