Question

Read the below statements marked as Assertion (A) and Reason (R). Mark the correct options:

Assertion (A): PM2.5 is more harmful than PM10 in AQI.

Reason (R): PM2.5 particles are smaller and can reach deep into the lungs and bloodstream

• A. Both A and R are true, and R is the correct explanation of A.
• B. Both A and R are true, but R is not the correct explanation of A.
• C. A is true, but R is false.
• D. A is false, but R is true

Answer 1

Answer:

A. Both A and R are true, and R is the correct explanation of A.

Particulate Matter (PM2.5 vs. PM10)

• Particulate Matter (PM) refers to a mixture of solid particles and liquid droplets found in the air.
• PM2.5 consists of fine inhalable particles with a diameter of 2.5 micrometers (µm) or smaller, whereas PM10 includes particles with a diameter of 10 micrometers or smaller.

Why PM2.5 is More Harmful

• Deeper Penetration: Due to their extremely small size, PM2.5 particles bypass the body's natural defense mechanisms (like nasal hair and mucus) and penetrate deep into the alveoli of the lungs.
• Entry into Bloodstream: PM2.5 particles are small enough to cross the blood-air barrier in the lungs and directly enter the bloodstream.
• Health Effects: Once in the blood, PM2.5 causes systemic inflammation, severe cardiovascular diseases, strokes, and chronic respiratory disorders, making it far more lethal than PM10.
• PM10 Behavior: PM10 particles (like coarse dust and pollen) are larger and mostly get trapped in the upper respiratory tract (nose, throat, and trachea) and are easier to clear out through coughing or sneezing.

Air Quality Index (AQI) in India

• The National Air Quality Index (AQI) in India was launched in October 2014 by the Ministry of Environment, Forest and Climate Change (MoEFCC).
• India's AQI measures 8 major pollutants:
  • PM2.5
  • PM10
  • Nitrogen Dioxide (NO₂)
  • Sulphur Dioxide (SO₂)
  • Carbon Monoxide (CO)
  • Ozone (O₃)
  • Ammonia (NH₃)
  • Lead (Pb)