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Short note: SO2 emission and impact

Short answer

SO₂ is a pungent gas from burning sulphur-containing fuels like coal and diesel. It irritates eyes and lungs, causes acid rain that damages ecosystems and buildings, forms PM2.5, and harms vegetation. Control includes low-sulphur fuel, flue gas desulphurisation, and switching to clean energy.

Write a short note on SO2 emission and its impact.

Sulphur dioxide (SO₂) is a colourless gas with a pungent smell, produced when fuels that contain sulphur (coal, heavy fuel oil, diesel) are burned: S + O₂ → SO₂.

Sources

  • Coal-fired power plants (largest source), industries, brick kilns using coal, and metal smelting.
  • Diesel and heavy-oil vehicles and ships; volcanic eruptions (natural).

Impact

  • Human health: irritation of eyes, throat and lungs, cough, asthma attacks, bronchitis, and reduced lung function; harms children and elderly most.
  • Acid rain: SO₂ oxidises to SO₃ and with water forms sulphuric acid (SO₂ + ½O₂ → SO₃; SO₃ + H₂O → H₂SO₄). This acidifies lakes and soil, kills fish and forests, and damages buildings, monuments (marble) and metals.
  • Particulate formation: sulphate aerosols form fine particles (PM2.5) and haze.
  • Vegetation: damages leaves and reduces crop yield.
  • Climate: sulphate aerosols have a slight cooling effect.

Control

Use low-sulphur fuel, flue gas desulphurisation (limestone scrubber: SO₂ + CaCO₃ → CaSO₃ + CO₂), fluidised bed combustion, and switch to clean energy such as hydropower and solar.

✓ Answer checked by Claude Opus 5.5 (high effort)

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