Which of the following statements correctly describes PM2.5 and PM10 and the associated health concerns?

• A. PM2.5 are fine particles ≤2.5 microns; PM10 includes particles up to 10 microns; health concerns: cardiovascular and respiratory diseases.
• B. PM2.5 are coarse particles; PM10 are fine; health concerns: skin irritation only.
• C. PM2.5 are particles formed from water; PM10 from dust; health concerns: hair loss.
• D. PM2.5 and PM10 are the same; health concerns: none.

Answer: (D)

Understanding particle size matters for health effects. PM2.5 are fine particles with a diameter of 2.5 micrometers or smaller, while PM10 includes particles up to 10 micrometers; PM2.5 is actually a subset of PM10. The smaller the particle, the deeper it can travel into the lungs and even enter the bloodstream, which is why fine PM2.5 exposure is strongly linked to cardiovascular and respiratory diseases. Larger PM10 particles tend to deposit in the upper airways and can still cause irritation and respiratory symptoms, but they don’t reach as deeply. So, saying they are the same with no health concerns misses how size affects where particles go in the body and the associated risks. The correct view is that both PM2.5 and PM10 have health implications, especially for heart and lung health, with finer particles posing deeper and broader risks.