Read the passage and answer the following questions :

Air pollutants also deleteriously affect the respiratory system of humans and of animals. Harmful effects depend on the concentration of pollutants, duration of exposure and the organism. Smokestacks of thermal power plants, smelters and other industries release particulate and gaseous air pollutants together with harmless gases, such as nitrogen, oxygen, etc. These pollutants must be separated/ filtered out before releasing the harmless gases into the atmosphere.There are several ways of removing particulate matter; the most widely used of which is the electrostatic precipitator , which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant . Automobiles are a major cause for atmospheric pollution atleast in the metro cities. As the number of vehicles increase on the streets, this problem is now shifting to the other cities too. Proper maintenance of automobiles along with use of lead-free petrol or diesel can reduce the pollutants they emit. Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases. As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water, and carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively. Motor vehicles equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst. You may ask the question as to why CNG is better than diesel. The answer is that CNG burns most efficiently, unlike petrol or diesel, in the automobiles and very little of it is left unburnt. Moreover, CNG is cheaper than petrol or diesel, cannot be siphoned off by thieves and adulterated like petrol or diesel.

Which of the following can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant ?

Electrostatic precipitator.

The correct answer is Option (3) – Electrostatic precipitator

The technology that can effectively remove over 99% of particulate matter present in the exhaust from a thermal power plant is the electrostatic precipitator (ESP).

While scrubbers and catalytic converters are effective in reducing certain pollutants from exhaust gases, such as sulfur dioxide and nitrogen oxides ,they are not primarily designed for particulate matter removal to the extent of over 99%. Electrostatic precipitators, on the other hand, are specifically designed for capturing particulate matter by using electrostatic forces to trap and remove particles from the exhaust stream.