2. These materials pose an immediate threat to life even when emitted in relatively low amounts.

3. Such pollutants are not immediately life-threatening, but they may be harmful over a long period of tome or in very large amounts.

4. The warming of the surface of the earth is due to the presence of gases in the atmosphere that prevent heat from escaping into space.

5. Is the reaction of industrial pollution, like sulfur dioxide and nitric acids, with water vapor in the air results in a form of precipitation.

6. Can lead not only to higher incidences of skin cancer and genetic disorders.

7. Kind of pollution

8. A quantitative measure of population size

9. This compound when release to atmosphere can degrade the ozone layer in the atmosphere.

10. Aside from climatic changes it is also a consequence of higher global temperature.

12. CFC’s

13. Non – hazardous

14. Population Density

15. Non – Hazardous

16. Global warming

17. Ozone depletion

18. Melting glaciers

19. Hazardous

20. Acid rain