UPSC 2022: In the context of WHO Air Quality Guidelines, consider the following statements: 1. The 24-hour mean of PM2.5 should not exceed 15 μg/m³ and annual mean of PM2.5 should not exceed 5 μg/m³. 2. In a year, the highest levels of ozone pollution occur during the periods of inclement weather. 3. PM10 can penetrate the lung barrier and enter the bloodstream. 4. Excessive ozone in the air can trigger asthma. Which of the statements given above are correct?

The correct answer is option (b): 1 and 4 only. Watch the detailed video explanation in our Sherlocking Prelims course on UnlockIAS.

This question was asked in UPSC CSE Prelims 2022, GS Paper 1, as Question 44. It falls under Environment & Ecology > Pollution & Waste Management.

This question is rated "moderate". It requires sound conceptual understanding of the topic.

UPSC has asked 37 questions from Pollution & Waste Management (under Environment & Ecology) across multiple years. Visit the topic page to see the full list and year-wise trends.