Many sources: transport, farming, homes and waste, not just factories. Learn it step by step →
Pollution & Waste is a core part of GCSE Environmental Science. Revise the key concepts and common mistakes below, then lock them in with the free games.
Key concepts
PM2.5Fine particles under 2.5 micrometres harming lungs.
NOxNitrogen oxides from vehicles forming smog and acid.
SOxSulfur oxides from coal causing acid rain.
EutrophicationNutrient overload triggering algal blooms and dead zones.
Point SourcePollution from a single identifiable outlet, e.g. pipe.
Diffuse SourcePollution spread over a wide area, e.g. farm runoff.
ConcentrationMass of pollutant divided by volume of medium.
BODBiochemical oxygen demand; oxygen used by microbes.
DilutionReducing concentration by adding more solvent/water.
Biotic IndexScore based on indicator species in a habitat.
AQIAir Quality Index summarising pollutant levels.
Acid RainRain with pH below 5.6 from SOx and NOx.
Noise PollutionUnwanted sound disturbing wildlife and human health.
Light PollutionExcess artificial light obscuring stars and altering ecology.
Common mistakes to avoid
Questions where students often pick the tempting wrong answer — make sure you know the right one:
Where does pollution come from?✗ Only from factories.✓ Many sources: transport, farming, homes and waste, not just factories.
Practise Pollution & Waste — free games
Test yourself with these quick revision games for this topic: