Which human activities release sulfur dioxide and nitrogen oxides?

Human activities are the primary drivers of sulfur dioxide ($S{O}_2$) and nitrogen oxide ($N{O}_x$) emissions, which are the main precursors to acid rain. These pollutants are released into the atmosphere through the following activities:

• Burning Fossil Fuels: The combustion of coal, oil, and natural gas is the leading source of these emissions. This includes electric utilities and thermal power plants, which are major contributors to both $S{O}_2$ and $N{O}_x$ levels.1234
• Transportation: Vehicles powered by gasoline engines are significant sources of $N{O}_x$ emissions, accounting for a large percentage of the total output in many regions.132
• Industrial Processes: The smelting of metal ores and other industrial operations release significant quantities of sulfur dioxide.15

These pollutants are released when high combustion temperatures cause atmospheric nitrogen to react with oxygen, or when sulfur compounds present in fuels are oxidized during burning. Once emitted, these gases react with water and oxygen in the atmosphere to form sulfuric acid and nitric acid, which then fall to Earth as acid deposition.3512