Question

According to Central Pollution Control Board, air pollutants responsible for great harm have a size (in µm) of
A. 1.0 or less
B. 1.5 or less
C. 2.5 or less
D. 2.5-5.2

Answer 1

Hint: Air pollution is the major cause for the depletion of atmosphere as well as causes various respiratory problems. The major air pollutants are released from the automobiles that cause release of harmful gases in the atmosphere at a large scale especially in the metro cities.

Complete Answer:
Air pollutants are the major cause for dilapidated health of all living organisms on this earth. They reduce the growth and yield of the crops and also premature death of the plants. Air pollutants majorly cause respiratory problems in humans and animals. The respiratory problems include asthma, bronchitis, emphysema, occupational disorders too.

 According to the Central Pollution Control Board, air pollutants responsible for great harm have a size 2.5 or less µm that are responsible for causing greatest harm to human health. These fine particles can be inhaled deep into the lungs and can easily cause respiratory or breathing problems. The respiratory symptoms include irritation, inflammation and damage to the lungs that sometimes leads to premature death.

The correct option is C i.e. 2.5 or less.

Additional information: Harmful effects on the human beings depend on the concentration of pollutants, duration of exposure and the organism to which it affected.
There are several ways to control pollution like:
- For controlling smoke released from smokestacks of thermal power plants, smelters and other industries, electrostatic precipitators are used which is responsible for the removal of over 99% particulate matter present in the exhaust.
- For controlling the harmful gases released from automobiles, proper maintenance should be done along with the use of lead free petrol and diesel.
- Catalytic converters like platinum-palladium and rhodium should be fitted into automobiles for reducing emission of poisonous gases. These converters are responsible for the conversion of unburnt hydrocarbons into carbon dioxide and water and carbon monoxide and nitric oxide converted into carbon dioxide and nitrogen gas respectively.

Note: In the automobiles fitted with catalytic converters, unleaded petrol or diesel should be used as lead is responsible for inactivating these catalytic converters. Besides this, minimizing the use of automobiles by sharing cabs or using CNG equipped vehicles are also helpful for minimizing the air pollution.