Sulphate Aerosols

The Union Ministry of Power has said that it would wait for the Central Pollution Control Board (CPCB) to decide on whether flue gas desulphurisation (FGD) units should be mandatory for all coal-fired thermal power plants.

Scientific Viewpoint:

• Studies by CSIR and IIT Delhi suggest that sulphate aerosols from TPPs contribute less than 5% to levels that impact human health.
• A certain amount of sulphate aerosols in the atmosphere is considered necessary, as too little may increase global warming.

What is FGD?
FGD units are retrofit technologies installed in TPPs to reduce sulphur dioxide (SO₂) emissions from coal combustion.

SO₂ and Sulphate Aerosols:

• SO₂ in the air forms sulphate aerosols, which:
  • Cool the atmosphere by reflecting sunlight (global dimming)
  • Worsen air quality, leading to particulate pollution and respiratory illnesses

Economic Impact:

• The installation cost of FGD units is around ₹1 crore per megawatt of installed capacity.

Environmental Complexity:

• Sulphate aerosols originate from both human and natural sources (e.g., volcanoes, organic decay).
• Their dual impact:
  • Help offset global warming (via sunlight reflection)
  • Contribute to air pollution and health issues
• Example: Volcanic eruptions like Tambora and Krakatoa led to global cooling due to sulphate aerosol release into the stratosphere.