Pollution & Waste Management
Types of pollution, causes, effects and management strategies
Pollution = introduction of harmful substances into the environment at levels damaging to living organisms.
Air pollution:
- Sources: vehicle exhaust (CO, NOₓ, PM2.5), industrial emissions (SO₂), burning crop stubble, brick kilns
- Effects: respiratory diseases (asthma, COPD), acid rain (SO₂ + H₂O → H₂SO₄), global warming (CO₂, methane)
- Solutions: catalytic converters, electric vehicles, renewable energy, regulations
Water pollution:
- Sources: industrial effluent (heavy metals), agricultural run-off (fertilisers, pesticides), untreated sewage
- Effects: eutrophication (fertilisers → algal bloom → O₂ depletion → fish die), waterborne diseases (typhoid, cholera)
- Solutions: sewage treatment plants, industrial regulations, buffer zones along rivers
Soil pollution:
- Sources: pesticides, industrial waste, plastic litter
- Effects: reduces crop yield, enters food chain
Solid waste management (hierarchy):
- Reduce (use less)
- Reuse (use again)
- Recycle (process into new materials)
- Recover (energy from waste)
- Dispose (landfill — last resort)
Noise pollution: Traffic, industry, loudspeakers — causes stress, hearing loss, sleep disruption.
Key Points to Remember
- 1Air: CO2, SO2, NOx from vehicles and industry
- 2Water: sewage and fertilisers cause eutrophication
- 3Waste hierarchy: Reduce → Reuse → Recycle → Recover → Dispose
- 4Acid rain: SO2 + H2O → sulphuric acid damages ecosystems
Pakistan Example
Karachi's Air Quality Crisis — Pakistan's Environmental Emergency
Karachi and Lahore regularly appear among the world's most polluted cities (IQAir rankings). Lahore's AQI exceeds 500 during winter crop stubble burning season. Karachi's industrial areas (SITE, Korangi) release heavy metals into Lyari and Malir rivers. The Punjab government's Green Stimulus and Lahore High Court orders on brick kilns show environmental law responding to pollution crises — core AKU-EB Environmental Studies content.
Quick Revision Infographic
Environmental Studies — Quick Revision
Pollution & Waste Management
Key Concepts
Formulas to Know
Waste hierarchy: Reduce → Reuse → Recycle → Recover → DisposeAcid rain: SO2 + H2O → sulphuric acid damages ecosystemsKarachi's Air Quality Crisis — Pakistan's Environmental Emergency
Karachi and Lahore regularly appear among the world's most polluted cities (IQAir rankings). Lahore's AQI exceeds 500 during winter crop stubble burning season. Karachi's industrial areas (SITE, Korangi) release heavy metals into Lyari and Malir rivers. The Punjab government's Green Stimulus and Lahore High Court orders on brick kilns show environmental law responding to pollution crises — core AKU-EB Environmental Studies content.