IGCSE Environment Key Words

1. A chemical process in which a substance reacts with oxygen to give off heat.
3. Contamination of the environment by harmful substances.
8. A chemical reaction involving the gain of electrons or a decrease in oxidation state.
9. The movement of water through the soil and porous rock.
10. The process by which water vapor becomes liquid.
11. The process of making an area more urban or increasing the population of cities.
13. The reduction of oxygen levels in a body of water.
16. The degradation of water quality by any process that changes ambient water temperature (two words).
17. The process of water movement through plants and its evaporation from leaves.
18. A type of air pollution formed by the reaction of sunlight with pollutants (two words).
20. Energy from a source that is not depleted when used, such as wind or solar power (two words).
22. The process by which organisms convert oxygen and glucose into energy.
24. The act of releasing something, especially gas or radiation, into the atmosphere.
26. A site for the disposal of waste materials by burial.
27. A substance that increases the rate of a chemical reaction without being consumed.
29. The study of the adverse effects of chemicals on living organisms.
31. The process of converting nitrogen gas into nitrogen compounds that plants can absorb (two words).
32. Liquid waste or sewage discharged into a river or the sea.

2. A layer in the Earth’s stratosphere that absorbs most of the Sun's UV radiation (two words).
4. The process of turning from liquid into vapor.
5. Process where water bodies become nutrient-rich, leading to excessive algae growth.
6. The lowest layer of the Earth’s atmosphere, where most weather occurs.
7. Metallic elements with high densities that are toxic at low concentrations (two words).
12. The process by which green plants use sunlight to synthesize foods with the help of chlorophyll.
14. Warming of the Earth's surface due to trapped heat (two words).
15. The accumulation of substances, such as pesticides, in an organism.
19. Water that flows over the ground surface rather than being absorbed.
21. A biological community of interacting organisms and their physical environment.
23. The removal of topsoil by natural forces such as wind and water (two words).
25. Natural fuels formed from the remains of ancient organisms (two words).
28. The layer of gases surrounding the Earth.
30. A chemical reaction involving the loss of electrons or an increase in oxidation state.