🌫️ Exam Summary: Urban air pollution (8.3)
Key Idea: Know primary vs secondary pollutants, the key health and environmental impacts, and management using tech + policy + behaviour.
🧪 Sources & chemistry (high yield)
- Primary pollutants: PM, CO, NOₓ, SO₂, VOCs (emitted directly)
- Secondary pollutants: O₃, PAN, secondary PM (formed in air)
- Photochemical smog: NOₓ + VOCs + sunlight → O₃
- Temperature inversion traps pollution near the ground
🫁 Impacts (use cause → effect chains)
- PM2.5: deep lung penetration → bloodstream → inflammation → heart disease/stroke risk
- Respiratory: asthma attacks, COPD; long-term cancer risk
- Environmental: acid deposition (SO₂/NOₓ), ozone damage to plants, haze, building corrosion
🛠️ Management (compare approaches)
- Tech: catalytic converters, diesel particulate filters, scrubbers, fuel switching, EVs
- Policy: emission standards, low-emission zones, fuel standards
- Economic/behaviour: congestion charges, public transport, cycling/walking, awareness
In 7–9 markers: compare multiple strategies and evaluate using effectiveness, cost, equity, feasibility and trade-offs (link to EVSs where relevant).