Consider the following statements:
- 1.Other than those made by humans, nanoparticles do not exist in nature.
- 2.Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
- 3.Nanoparticles of some commercial products which enter the environment are unsafe for humans.
Which of the statements given above is/are correct?
Answer & explanation
Answer: (d) 2 and 3
Statements 2 and 3 are correct. Statement 1 is wrong because nanoparticles (particles of about 100 nanometres or less) also form naturally, for example in volcanic plumes and by erosion, apart from those made by humans.
- ✗ 1. Nanoparticles form naturally: gas-phase reactions that make them occur in the atmosphere and in volcanic plumes, and erosion of clay and plant debris makes them in liquids. Human activities such as cooking and welding add more.
- ✓ 2. Metal-oxide nanoparticles such as nano titanium dioxide are put into sunscreens and other cosmetic products.
- ✓ 3. Engineered nanoparticles from consumer products are now a source of exposure, and some materials become toxic when inhaled as nanoparticles, causing lung inflammation and heart problems.
Remember · Nanoparticles (about 100 nm or less) occur naturally too. Nano titanium dioxide goes into sunscreens and cosmetics; some engineered nanoparticles are hazardous when inhaled.
Sources
- European Commission (SCENIHR/GreenFacts) — Nanotechnologies, Level 2, Q4: How are nanoparticles formed? ↗ “Such reactions that generate nanoparticles occur naturally in the atmosphere , in volcanic plumes, and in human activities such as cooking, welding or smelting, and polymer manufacture.”
- US EPA ExpoBox — Exposure assessment tools by chemical classes: Nanomaterials ↗ “Examples include titanium dioxide [nano-TiO2], which might be incorporated in sunscreen; silver [nano-Ag], sometimes used as an antibacterial agent;”
- European Commission (SCENIHR/GreenFacts) — Nanotechnologies, Level 1 summary ↗ “Some materials could become toxic if they are inhaled in the form of nanoparticles. Inhaled nanoparticles may cause lung inflammation and heart problems.”
Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·