How do volcanic eruptions contribute to acid deposition?

Volcanic eruptions contribute to acid deposition by releasing gases that react with atmospheric moisture to form acids. While human activities are the primary cause of acid rain, volcanic activity serves as a natural source of these pollutants.12

During an eruption, volcanoes emit various gases, including sulfur dioxide, hydrogen chloride, and other volatile compounds. Once in the atmosphere, these emissions can react with water and oxygen to produce sulfuric acid, nitric acid, and hydrochloric acid. These acids then mix with cloud moisture, lowering the pH of precipitation and resulting in acid deposition.132

Unlike the widespread pollution caused by industrial fossil fuel combustion, the environmental impact of volcanic acid deposition is typically localized to the area surrounding the volcano.12