What is the primary source of sulfur dioxide (SO2) in the atmosphere?

The primary source of sulfur dioxide (SO2) in the atmosphere comes from the burning of fossil fuels, particularly coal. When coal is combusted, it releases various pollutants, including sulfur oxides, since coal often contains sulfur compounds within it. This process is prevalent in power generation and industrial activities that rely on coal as an energy source.

While natural volcanic activity does release sulfur dioxide, it is not the primary contributor compared to human activities, particularly those associated with fossil fuel combustion. Vehicle emissions contribute to air pollution but are more closely associated with nitrogen oxides and carbon monoxide than sulfur dioxide. Industrial waste disposal can indirectly cause pollution, but it is not considered a direct primary source of SO2. Hence, the significant emissions of sulfur dioxide linked to coal burning underscore its role as the main contributor to atmospheric SO2 levels.