UPSC Prelims 2022 Question:

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 manufacture of some cosmetics
3. Nanoparticles of some commercial products which enter environment are unsafe for humans.
   
   

Which of the statements given above is/are correct?

Explanation: 

• • Nanoparticles are incredibly tiny particles of a given substance. Nanoparticles are less than 100 nanometers thick. To give some perspective, a nanometer is 1000 times smaller than the thickness of one strand of hair.
    
    

• Nanoparticles can be naturally created, for example, minuscule droplets of sea spray. However, most nanoparticles are created in the lab. For sunscreen, the nanoparticles in question are zinc oxide and titanium dioxide. These ingredients are broken down into ultra-fine particles before being added to your sunscreen. So, statement 1 is not correct and statement 2 is correct. 
  
  

• Inhaled particulate matter can be deposited throughout the human respiratory tract, and an important fraction of inhaled nanoparticles deposit in the lungs. Nanoparticles can potentially move from the lungs to other organs such as the brain, the liver, the spleen and possibly the foetus in pregnant women. So, statement 3 is correct. 
  
  

Therefore, option (4) is the correct answer.

Subject: Science & Technology|Nanotechnology