AIIMS 2019 Botany Air Pollution Assertion Reason Question

Option B is correct because the assertion accurately states that particulate matter (PM₂.₅) poses health risks due to its ability to penetrate deep into the respiratory system, while the reason correctly identifies that larger particles are filtered by the nasal cavity and throat. However, the reason does not explain why PM₂.₅ is harmful, as it pertains to smaller particles that bypass these filters.

Option A is incorrect because, although both statements are true, the reason does not explain the assertion. Option C is incorrect since both statements are true, and option D is incorrect because both statements are valid. Understanding the health implications of PM₂.₅ and the body's filtration mechanisms is crucial for recognizing air quality's impact on health.