Environmental and Health Issues of Sulphur Dioxide

Sulphur dioxide, SO₂ is one of the by-products of the Contact Process. It is one of the sources of environmental pollution.

Acid Rain

1. Sulphur dioxide (SO₂) is the pollutant primarily associated with acid rain.
2. Acid rain occurs when pH of the rain is between 2.4 and 5.0. This is due to the reaction of sulphur dioxide, SO₂ with rainwater.
   SO₂ + H₂O→ H₂SO₃
3. The negative effect of acid rains includes
1. corrosion of concrete building and metal structure.
2. corrosion of monuments and statues made from marble
3. causes erosion of top soil.
4. killing aquatic life.

Health Effects

1. SO₂ is an irritant when it is inhaled and at high concentrations may cause severe problems in asthmatics such as narrowing of the airways, known as bronchoconstriction.
2. Asthmatics are considerably more sensitive to the effects of SO₂ than other individuals.

Sources of SO₂

1. The principal source of SO₂ is from the combustion of fossil fuels in domestic premises and, more importantly, non-nuclear power stations.
2. Other industrial processes such as manufacturing of sulphuric acid also contribute to the presence of SO₂ in the air.