--- title: "Air pollution, pollutants, sources and remedies" subject: "Engineering Chemistry" chapter: 3 key: "semester_2/engineering_chemistry:air-pollution-sources-remedies" source: https://www.bctengineer.com/q/semester_2/engineering_chemistry/air-pollution-sources-remedies site: BCT Engineering --- # Air pollution, pollutants, sources and remedies Engineering Chemistry · Chapter 3: Environmental Chemistry - Asked in: 2073 Magh, 1+2+2 marks - Video: [Air Pollution](https://www.youtube.com/watch?v=_dTtvtlct9k) — Bozeman Science - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_2/engineering_chemistry/air-pollution-sources-remedies - Whole chapter: https://www.bctengineer.com/md/semester_2/engineering_chemistry/chapter-3 ## Question What is air pollution? What are the main pollutants of air and their sources? Give possible remedies of air pollution. ## Short answer Main pollutants: CO (incomplete combustion), SO₂ and NOx (fuel burning), particulates (industry, brick kilns), lead (petrol). Remedies: clean fuels (LPG, CNG), catalytic converters, industrial control devices (electrostatic precipitators), afforestation, and strict emission laws. ## Answer #### Air pollution **Air pollution** is the presence in the air of one or more substances (gases, liquids or solids) in such quantity and for such duration that they are harmful to human beings, animals, plants, materials or the environment. #### Main pollutants and their sources | Pollutant | Main sources | Effects | |---|---|---| | Carbon monoxide (CO) | Incomplete combustion in vehicles, wood and coal fires | Combines with haemoglobin (carboxyhaemoglobin), reducing O₂ transport; headache, death | | Sulphur dioxide (SO₂) | Burning coal and oil, smelters, brick kilns | Respiratory diseases; acid rain; damages plants | | Oxides of nitrogen (NOx) | Vehicles, power plants, high temperature combustion | Lung irritation; photochemical smog; acid rain | | Hydrocarbons / VOCs | Vehicle exhaust, solvents, evaporation of petrol | Photochemical smog; some are carcinogenic | | Particulate matter (dust, smoke, PM₁₀, PM₂.₅) | Brick kilns, construction, vehicles, burning of waste and forests | Asthma, bronchitis, lung cancer; reduced visibility | | Lead | Leaded petrol, batteries | Damages brain and nerves, especially in children | #### Possible remedies - Use clean fuels (LPG, CNG, electricity, biogas), low-sulphur fuel, and lead-free petrol. - Fit catalytic converters and enforce vehicle emission standards; ban old polluting vehicles. - Install control devices in industries: electrostatic precipitators, cyclone separators, bag filters, scrubbers. - Convert to zigzag kilns in brick industry; avoid open burning of waste. - Plant trees and green belts; better town planning and public transport. - Strict pollution-control laws and public awareness. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Why is CO poisonous? A. It reacts with lung tissue to form acid B. It makes blood too thick to flow C. It destroys ozone in the lungs D. It combines with haemoglobin to form carboxyhaemoglobin, reducing O2 transport Answer: D. CO binds haemoglobin, so less oxygen is carried. (Key point: CO effect) 2. CO in air comes mainly from A. Incomplete combustion in vehicles and wood/coal fires B. Complete combustion of LPG C. Photosynthesis D. Evaporation of water Answer: A. Incomplete combustion gives CO. (Key point: CO source) 3. Which pollutants cause photochemical smog? A. SO2 with smoke in cold weather only B. NOx with hydrocarbons/VOCs in sunlight C. CO with N2 D. Lead with CO2 Answer: B. NOx and hydrocarbons react in sunlight to form smog and ozone. (Key point: NOx smog) 4. Which are remedies for air pollution from vehicles? A. Leaded petrol and old vehicles B. Burning waste openly C. Clean fuels (LPG, CNG), lead-free petrol, catalytic converters D. Using high-sulphur coal Answer: C. Cleaner fuels and catalytic converters cut emissions. (Key point: Fuel and vehicles) 5. Which devices control particulate emission from industries? A. Catalytic converters only B. Trickling filters C. Activated sludge tanks D. Electrostatic precipitators, cyclone separators, bag filters, scrubbers Answer: D. These capture particulates and gases before release. 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