The gas commonly responsible for acid rain is sulfur dioxide (SO2), which is emitted from burning fossil fuels, industrial processes, and volcanic eruptions. When sulfur dioxide combines with atmospheric moisture, it forms sulfuric acid, leading to acidic precipitation that can harm ecosystems, buildings, and water sources. Nitrogen oxides (NOx) can also contribute to acid rain. Monitoring these pollutants is vital for environmental protection, public health, and maintaining the balance of aquatic and terrestrial ecosystems.