Tag: air pollution and its effects

• Compressed natural gas (CNG) (methane stored at high pressure) is a fuel which can be used in place of gasoline, diesel fuel, and propane/LPG. CNG combustion produces fewer undesirable gases than gasoline.
• Hence In Delhi, CNG vehicles are used to control air pollution.
• So, the correct answer is 'CNG vehicles'.

Aerosols are the minute particles that are released with the pressure and remain suspended in the air. These can be sold particles or liquid droplets. The natural aerosols appear in the form of the fog, dust, forest exudates, geyser steams etc. The anthropogenic aerosols are more harmful and persist for the longer duration, like smoke, particulate matter etc. The emission from the jets comprises mainly of the fluorocarbons that are emitted with an immense pressure to provide propulsion to the engine.

Hydroelectric power is the cleanest form of electricity generation without contributing to the air pollution as it does not require the burning of fuel for working and water is provided by a natural force and moreover, it is renewable by rainfall causing refilling of reservoir. The dams are built which provide storage and it helps in reducing greenhouse gases emissions apart from the fact that once it becomes operative these have a low maintenance cost.

Electrostatic precipitators use the principle of electrically charging particles in an exhaust and then allowing them to settle on variably charged platforms. It is done primarily for control of SPM or suspended particulate matter such as dust, fumes, smoke etc.

H$ _2$S is a primary air pollutant emitted from putrifying substances, refineries, bituminous fuels etc. It causes burning sensation of throat and eyes along with feeling of vomiting or nausea. In plants it may cause defoliation and mottled chlorosis.

PM or particulate matter of diameter $2.5\,\,\mu$m or less is the most harmful as they are inhaled deep into the lungs causing serious lung damages, deposition in respiratory tracts and even death of the person.