Environmental Issues - Air Pollution

Air pollution means degradation of the air quality which harmfully affects the living organisms as well as certain objects.

or

Contamination of air by harmful substances like poisonous gases, smoke, particulate matter, microbes, etc., is called air pollution.

"Air pollution occurs when harmful substances like gases, particles, and biological molecules are released into the air, negatively impacting human health and the environment."

Air Pollution

All the above pictures show large-scale emission of smoke through different agencies. This smoke directly mixes with the atmosphere, disturbing the balance between the constituents of air. This is called air pollution. 

Harmful Substances Released in Air Through Combustion of Fuels:

• Nitrogen dioxide
• Carbon dioxide
• Carbon monoxide
• Sulfur dioxide
• Soot

• Air pollutants are of two types - particulate (smoke, smog, dust, heavy metals) and gaseous (CO₂, CO, SO₂, NO, NO₂). PM2.5 particles cause the greatest harm, penetrating deep into the lungs, causing irritation and breathing disorders.
• NO₂ + water vapour = nitric acid, causing irritation to eyes, lungs, liver and kidneys. CO is a poisonous gas produced by the incomplete combustion of fuel.
• Three control mechanisms - Electrostatic Precipitator (removes 99% soot/dust from industrial exhaust), Exhaust Gas Scrubber (removes SO₂ using lime/water spray), Catalytic Converter (removes poisonous gases from automobile exhaust; requires unleaded petrol).
• Delhi was 4th most polluted city in 1990. Following Supreme Court orders, all city buses were converted to CNG by 2002 — economic, efficient and adulteration-proof.
• India adopted BS-VI emission standards in 2018, skipping BS-V, reducing CO₂ and SO₂ levels in Delhi.