AEROSOLS (Syllabus: GS Paper 3 – Env and Eco)

News-CRUX-10     14th October 2023        
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Context: The Hindu Kush-Himalaya-Tibetan Plateau region has been witnessing an alarming increase in aerosol levels, a new analysis by the Indian Space Research Organisation’s (ISRO) Physical Research Laboratory has shown.

  • Impacts: It could be driving increased temperatures, altering rainfall patterns, accelerating glacier retreat and initiating changes in the hydrological cycle in the region


  • About: Aerosols are minuscule solid or liquid particles suspended in the air or as a gas.
  • Types of Aerosols: Aerosols can be either natural, like fog or volcanic gas emissions, or artificial, such as smoke from burning fossil fuels.
  • Primary and Secondary Aerosols: Aerosol particles can either be directly emitted into the atmosphere (primary aerosols) or formed in the atmosphere from precursor gases (secondary aerosols).
  • Composition: Aerosol particles, though tiny, are diverse and consist of various inorganic and organic substances.
  • Size Range: True aerosol particles vary in diameter, ranging from a few millimicrometers to about 1 micrometer (10-4 cm). Particles smaller than 0.1 micrometer are sometimes referred to as Aitken nuclei.
  • Visible Forms: Visible manifestations of atmospheric aerosols include smoke, smog, haze, and dust.

Aerosols and Climate

  • Precipitation Catalysts: Dust and aerosol particles serve as nuclei for condensation and freezing, affecting the precipitation process.
  • Radiation Interaction: Aerosols can reflect or absorb incoming solar radiation, altering the brightness and reflectivity of clouds.
  • Atmospheric Heating: While absorption and reflection may reduce ground-level sunlight, enhanced atmospheric heating counteracts this effect, warming the Earth's surface.

Hindu Kush-Himalaya-Tibetan Plateau region

  • Geographic Expanse: It covers over 4.3 million square kilometers, spanning multiple countries including Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan.
  • Third Pole: This region is often referred to as 'The Third Pole' due to its remarkable snow and ice storage, which surpasses any other non-polar region globally.
  • Global Significance: Home to the world's highest mountains, it boasts all 14 peaks towering over 8,000 meters, serves as the origin of 10 major rivers, and functions as a vital global ecological buffer.
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