Question

Explain how the use of CNG in automobiles has reduced pollution in our cities.

Answer 1

Hint: Compressed natural gas (CNG) (methane stored at high pressure) is a fuel that can be used in place of gasoline, diesel fuel and liquefied petroleum gas (LPG). CNG combustion produces fewer undesirable gases than the aforementioned fuels.

Complete step by step answer:
Combustion of fuels like petroleum causes the addition of many harmful pollutants like unburnt carbon, particulate matter and many fume gases enter the air and cause respiratory diseases.
Compressed Natural Gas (CNG) produces these harmful products in very less quantity. It is a comparatively cleaner fuel. Therefore, the use of CNG has reduced pollution in our cities.
In comparison to other fuels, natural gas poses less of a threat in the event of a spill, because it is lighter than air and disperses quickly when released. Biomethane — refined biogas from anaerobic digestion or landfills — can be used.
CNG is made by compressing natural gas, which is mainly composed of methane ($C{{H}_{4}}$ ), to less than 1% of the volume it occupies at standard atmospheric pressure. It is stored and distributed in hard containers at a pressure of 20–25 MPa (2,900–3,600 psi), usually in cylindrical or spherical shapes.

Note: CNG fuel systems are sealed, preventing fuel losses from spills or evaporation. CNG is less likely to ignite on hot surfaces, since it has a high auto-ignition temperature, and a narrow range (5–15 percent) of flammability.