How do sulfur oxides from coal burning form sulfuric acid in the atmosphere?

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When coal containing sulfur impurities is burned, it releases sulfur dioxide (SO₂) into the atmosphere. This process leads to the formation of sulfuric acid through the following atmospheric interactions:12

  • Oxidation: Sulfur dioxide can react with oxygen in the air to form sulfur trioxide (SO₃), a process represented by the chemical equation: 2SO2+O2→2SO3.1
  • Hydration: Both sulfur dioxide and sulfur trioxide are acidic oxides that react with atmospheric moisture (water vapor). While sulfur dioxide reacts with water to form sulfurous acid, the reaction of sulfur trioxide with water produces sulfuric acid.12

This resulting sulfuric acid forms a mist in the atmosphere and eventually reaches the ground as a primary component of acid rain. This phenomenon is environmentally destructive, as it can damage forests, harm aquatic life in lakes and streams, and corrode metals and building materials. Because of these significant ecological and structural impacts, it is an ethical imperative to prioritize the development and implementation of cleaner energy technologies to mitigate such pollution.123