1. Atmosphere consist of 78% nitrogen, 21% oxygen, 1% argon and 0.03%......

2. The addition of certain contaminants or pollutants to the environment is called

3. Pollution began to be recognized as a serious threat during the industrial revolution of the

4. CNCS means

5. Sulphur dioxide is produced as a result of various

6. The key source of sulphur dioxide include

7. Smoke release from thermal power plants contains

8. Oxidation of SO2 forms

9. Lungs cancer is caused by

10. Cardiovascular diseases are caused by

11. Destroys chloroplast in plants

12. ..... can be observed as a brown haze above the cities

13. Coal and oil are burnt at high temperature in industries and engines of vehicles.

14. can caused heart failure.

15. is a colorless, odourless, non-irritating but very poisonous gas.

16. is produced by the incomplete combustion of coal and other fossil fuels.

17. Smoke released from motor vehicles and industries is the main source of

18. Damage to the central nervous system

19. Reducting in the oxygen-carrying capacity of hemoglobin.

20. are the main cause of Skin cancer.

21. Compound of chlorine, fluorine, and carbon atoms.

22. Major cause breaks down of ozone layer.

23. are used in aerosol spray, as a cooling agent in refrigerators, AC, and foam packing.

24. Chemical reactions involving air pollutants can  create acidic rain compounds

25. can cause damage to vegetation and buildings.

26. can destroy leaves of plants.

27. the result of excessive oxides of carbon, sulphur, nitrogen, and smoke in the atmosphere.

28. Stone buildings are corroded called stone cancer by

29. Kill aquatic life, destroy leaves and bark, corrodes the metals and stones of buildings, damage the Crops by

30. Ozone is a Greek word which means

31. Ozone made of ... oxygen atoms O3

32. The upper part of the atmosphere has a high concentration of ozone molecules, known as the ozone layer or

33. One .... molecule from CFCs can destroy up to 100,000 ozone molecules.

34. At least 25% of the total area of a country must be covered by forest but in Pakistan, only ..... of the total area is covered

35. Oxygen, freshwater, solar energy, timber, and biomass  are

36. Fossil fuels, metal ores, and groundwater are

37. Rain can Carry oxides of nitrogen to rivers and soil, which can lead to abnormal growth of algae, this is called

38. Greenhouse gases are Carbon (Co2), methane, oxides of nitrogen, water vapors, ozone and oxygen

39. Global warming and climate change is due to

40. which of the following is not a greenhouse gas: