📘 Q12. IAS Prelims 2022 — Science & Technology (Nanoparticles)
🧷 Authentic Classroom Explanation by IAS Monk
📌 The Question
Consider the following statements:
- Other than those made by humans, nanoparticles do not exist in nature.
- Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
- Nanoparticles of some commercial products which enter the environment are unsafe for humans.
Which of the statements given above is/are correct?
(a) 1 only
(b) 3 only
(c) 1 and 2
(d) 2 and 3
✅ Answer
(d)
🧑🏫 Classroom Explanation
- Statement 1 is not correct
Nanoparticles occur naturally in the environment. Examples include:- Volcanic ash and atmospheric dust
- Interplanetary dust particles
- Viruses (many are in the nanoparticle size range)
- Naturally occurring iron oxide, sulfide, gold, and silver nanoparticles
- Statement 2 is correct
Nanoparticles of titanium dioxide (TiO₂) and zinc oxide (ZnO) are widely used in cosmetics, especially sunscreens, for UV protection. Silver and gold nanoparticles are also added for antimicrobial and healing properties. - Statement 3 is correct
Certain engineered nanoparticles released into the environment through industrial processes, cosmetics, or consumer products can pose toxicological risks:- Occupational exposure during manufacture
- Consumer exposure during use
- Environmental persistence and bioaccumulation
Thus, statements 2 and 3 are correct.
🔍 Curiosity Raiser
Did you know?
Some nanoparticles can cross the blood–brain barrier, a protection that even many drugs cannot breach.
📚 Enrichment Notes
- Size range of nanoparticles: 1–100 nanometres
- Nanoparticles show new properties (optical, magnetic, chemical) different from bulk materials
- Nanotoxicology is a growing interdisciplinary field combining physics, biology, and environmental science
- Regulation of nanomaterials is a key emerging policy issue globally
🪔 IAS Monk Whisper
“Smallest particles often carry the biggest consequences.”