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Q44·GS Paper 1 · Prelims 2025

Plastic in Everyday Items

EnvironmentPollution & WasteHow-many countingEasyStatic

Question

In the context of WHO Air Quality Guidelines, consider the following statements: Which of the statements given above are correct?

  1. 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. 2.

    In a year, the highest levels of ozone pollution occur during the periods of inclement weather.

  3. 3.

    PM10 can penetrate the lung barrier and enter the bloodstream.

  4. 4.

    Excessive ozone in the air can trigger asthma.

Options

a

1, 3 and 4

b

1 and 4 only

Answer
c

2, 3 and 4

d

1 and 2 only

Explanation

Statements 1 and 4 are correct. Statements 2 and 3 are incorrect.

Ozone pollution actually peaks during sunny, warm weather due to photochemical reactions, not during inclement (stormy/cloudy) weather. Furthermore, it is the ultra-fine PM2.5 particles that cross the lung barrier into the bloodstream; PM10 is generally too large and lodges in the upper respiratory tract.

Ground-level ozone requires sunlight to form; PM2.5 is the specific particulate size that penetrates the bloodstream.

Answer: (b).

Question details

Year

2025

Paper

GS Paper 1

Question

Q44

Subject

Environment

Sub-topic

Pollution & Waste

Type

How-many counting

Difficulty

Easy

Nature

Static

Source hint

WHO Global Air Quality Guidelines Revision

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