Question 80 from UPSC CSE 2021 - Environment

Question

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.

IASCODEX · Accepted Answer

Correct Option: D. 1, 2, 3, 4, and 5

Strategy: Identify all plausible sources of ultrafine magnetite particles, focusing on those generated by friction, combustion, or electrical processes. The following sources are considered valid and will be included:
- Vehicle brakes and engines
- Microwave stoves
- Power plants, especially coal-based
- Telephone lines

Key Info: Magnetite (Fe3O4) is a strongly magnetic iron oxide frequently found as a nanoparticle air pollutant. Significant exposure routes include ambient air, indoor environments, and various industrial settings.

**Sources of Magnetite Nanoparticles**
- **Vehicle brakes and engines:** Frictional wear in brake pads and disc rotors, as well as engine combustion, generate magnetite-rich particulate matter (PM), a major urban air pollutant. Numerous studies confirm these sources, especially in metropolitan traffic environments.
- **Power plants:** Especially coal-fired units emit fly ash containing magnetite and other iron oxides during the combustion of fossil fuels. This constitutes a significant environmental source of particle pollution.
- **Microwave stoves:** Overheated metal elements, arcing, or deterioration of internal components in microwave ovens can release nanoparticles, including magnetite, into indoor air. Studies on indoor air quality identify such appliances as non-negligible sources.
- **Telephone lines:** Degradation or arcing at electrical connections, especially in outdated or poorly maintained infrastructure, can create metallic and iron oxide particles, such as magnetite, which are then released into the environment.

**Health Impact**
Inhaled ultrafine magnetite particles can bypass the blood-brain barrier by entering the olfactory bulb directly via nerves. They have been linked in some studies to increased risks of neurodegenerative diseases, including Alzheimer's disease, owing to their redox activity and surface properties.

Overall, both outdoor and indoor environments, from natural and anthropogenic sources, contribute to the pervasive presence of magnetite nanoparticles within human-inhabited spaces.

IASCODEX · Answer

Option A: 1, 2, 3, and 5 only

IASCODEX · Answer

Option B: 1, 2, and 4 only

IASCODEX · Answer

Option C: 3, 4, and 5 only