Acid deposition refers to the process by which acidic substances fall to the Earth's surface from the atmosphere. This can occur in the form of rain, snow, fog, or dust. The primary causes of acid deposition are emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx), which are produced by burning fossil fuels, industrial processes, and vehicle exhaust. When these gases react with water vapor in the atmosphere, they form sulfuric and nitric acids. When acid deposition occurs, it can harm ecosystems, soil, and water bodies. It can lead to the acidification of lakes and streams, negatively affecting aquatic life. Additionally, acid deposition can damage forests and crops, reducing agricultural productivity. Efforts to reduce emissions of SO2 and NOx are essential to mitigate the impacts of acid deposition on the environment.