Question

According to the Central Pollution Control Board (CPCB), which particulate size in diameter (in micrometers) of the air pollutants is responsible for the greatest harm to human health?
A. $2.5$ or less
B. $1.5$ or less
C. $1.0$ or less
D. $5.2$ - $2.5$

Answer 1

The particulate matter is classified as pollutants that have very fine size. The particulate matter can be solid or liquid particles. They are considered as a primary type of air pollutants which are the main source of polluting the air.

Complete answer:
The particulate matter is added into the air by the industries, automobiles, and by various other operations such as crushing, drilling, blasting, mixing, grinding, etc. The particulate matter is differentiated into two categories that are settleable and suspended.
As per the Central Pollution Control Board or CPCB the size of the particulate matter that is less than $2.5$ micrometer or less, is the main cause and is responsible for causing the greatest harm to human health. These fine particulate matters are inhaled via air, deep into the lungs. They cause various breathing and respiratory symptoms. Apart from that they also cause inflammation, irritation, and damage to the lungs, and premature death of babies.
Thus, based on the above information we can conclude that according to the Central Pollution Control Board (CPCB), the particulate that are $2.5$ or less in diameter (in micrometers) of the air pollutants is responsible for the greatest harm to human health.

Hence, the correct answer is option (A).

Note:
Some common types of particulate matter are aerosols, smoke, dust and mist, and pollens, spores, cysts, bacteria, etc. The aerosols are the vapor chemicals that are in the form of fluorocarbons, chlorofluorocarbons, oxides of nitrogen and sulfur, etc. The smoke is the visible suspension of the carbon.