Read the statements carefully and choose the correct option: Assertion (A): PM2.5 has a more harmful effect on AQI than PM10. Reason (R): Smaller particles can penetrate deeper into the lungs and bloodstream.
Both A and R are true, and R is the correct explanation of A
Assertion (A): PM2.5 (particulate matter ≤ 2.5 µm) is widely recognised as more harmful to health and to the Air Quality Index (AQI) than the coarser PM10 (≤ 10 µm). Most national AQI calculations weight PM2.5 as a key driver of air-pollution health risk. ✓
Reason (R): PM10 particles are largely trapped in the nose and upper airways, but PM2.5 particles are small enough to bypass these defences, reach deep into the alveoli of the lungs, and even cross into the bloodstream, causing cardiovascular and respiratory damage. ✓
The reason directly explains why the assertion is true — smaller size leads to deeper penetration, which is precisely the mechanism that makes PM2.5 more harmful.
Hence both A and R are true, and R is the correct explanation of A.
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