Question

Which of the following describes the difference between pure air and polluted air?

• A. Polluted air contains carbon dioxide whereas pure air does not.
• B. Amount of carbon monoxide is much more in polluted air than pure air.
• C. Pure air contains only oxygen gas.
• D. Amount of sulphur dioxide and nitrogen dioxide is much more in polluted air than pure air.

Answer 1

Answer: (B), (D)

Amount of sulphur dioxide and nitrogen dioxide is much more in polluted air than pure air.

Pure air is composed of 78% nitrogen gas, 21% oxygen gas, and 0.03% carbon dioxide. Some other gases like argon, ozone, and water vapours are also present in small quantities. When this composition of air is disturbed by the addition of harmful substances or toxic gases such as nitrogen dioxide, sulphur dioxide, carbon monoxide, and particulate matter, then the air is said to be polluted.