UPSC Prelims 2021 · Question 25 of 97

UPSC Prelims 2021 question on Magnetite Pollution

Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following?

1. Brakes of motor vehicles

2. Engines of motor vehicles

3. Microwave stoves within homes

4. Power plants

5. Telephone lines

Select the correct answer using the code given below.

  1. 1, 2, 3 and 5 only
  2. 1, 2 and 4 only
  3. 3, 4 and 5 only
  4. 1, 2, 3, 4 and 5
Show answer

Answer: B. 1, 2 and 4 only

Verdict

Correct statements: 1, 2 and 4 only → Option (b).

Analysis

Magnetite can have potentially large impacts on the brain due to its unique combination of redox activity, surface charge and strongly magnetic behaviour. Airborne magnetite pollution particles <~200 nm in size can access the brain directly via the olfactory and/or trigeminal nerves, bypassing the blood-brain barrier.

These tiny particles, each less than a thousandth the width of a human hair, are generated by a wide variety of processes, both natural and fabricated, including forest fires and wood-burning stoves, road traffic pollution, and many high-temperature industrial processes.

Statement by statement

Statement 1 – CORRECT: Brake wear from motor vehicles is a known source of magnetite particles.

Statement 2 – CORRECT: Engines of motor vehicles (vehicle tailpipe sources) generate magnetite pollution.

Statement 3 – INCORRECT: Microwave stoves are not a source; however, poorly-sealed (wood-burning) stoves used for cooking/heating are. Microwave ovens are not in this category.

Statement 4 – CORRECT: Power plants and other industrial PM sources generate magnetite particles.

Statement 5 – INCORRECT: Telephone lines are not a source of magnetite particles.

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