What are Aerosols?

• Aerosols are tiny solid or liquid particles suspended in the air. 

Properties of Aerosols:

1. Reflective Aerosols (e.g., sulphates):

• They act like mirrors, reflecting sunlight back into space.
• Net cooling effect at ground level.

2. Absorbing Aerosols (e.g., black carbon/soot):

• Absorb sunlight in the atmosphere, warming the upper air layers but reducing radiation at the surface.

Sources of Aerosol in India

• Aerosols in India are primarily released through fossil fuel combustion from vehicles and power plants, biomass burning such as crop residue and wood, and emissions from various industrial activities.

Problems Associated with Aerosols

1. Health Hazards:

• Aerosol causes 1.5 to 2.1 million deaths annually in India.
• Linked to respiratory, cardiovascular, stroke, and pregnancy-related complications.
• Fine particles (PM2.5) penetrate lungs and bloodstream.

2. Environmental and Climate Issues:

• Aerosols help cool the Earth by reflecting sunlight. If aerosol levels drop due to pollution control, hidden warming from greenhouse gases may cause a sudden temperature rise.
• Aerosols alter cloud properties and rainfall patterns unpredictably by either increasing cloud cover or inhibiting precipitation, disrupting agricultural cycles.
• Lead to increased ozone formation during summer as cleaner skies let more sunlight in.
• Ground-level ozone forms when sunlight reacts with nitrogen oxides (NOₓ) and volatile organic compounds (VOCs), especially under high heat and reduced aerosol presence.