Arrange the following fuels in the decreasing order of air pollution caused by burning a kilogram of each of them :
[amp_mcq option1=”CNG, Petrol, Diesel” option2=”Diesel, Petrol, CNG” option3=”Petrol, Diesel, CNG” option4=”Diesel, CNG, Petrol” correct=”option2″]
This question was previously asked in
UPSC CAPF – 2014
– Diesel: Diesel fuel is heavier than petrol and its combustion typically produces more particulate matter and higher levels of NOx, especially from older engines or those without modern emission controls. It can also contain more sulfur, leading to SOx emissions.
– Petrol (Gasoline): Petrol combustion produces significant amounts of CO, NOx, and unburnt hydrocarbons. While generally producing less PM than diesel, its emissions of other pollutants can be substantial.
– CNG (Compressed Natural Gas): CNG is primarily methane (CH4). Burning CNG is considered much cleaner than burning petrol or diesel. It produces significantly lower levels of PM, CO, NOx, and hydrocarbons. It contains virtually no sulfur, so no SOx emissions.
Ranking from most polluting to least polluting per kilogram burned (considering typical emissions profiles): Diesel > Petrol > CNG.
Therefore, the decreasing order of air pollution caused is Diesel, Petrol, CNG.