Question

An air pollutant which can cause acid rain and which is injurious to respiratory tissue is

• A. Sulphur dioxide
• B. Carbon dioxide
• C. Nitric acid
• D. Lead nitrate

Answer 1

The correct option is A Sulphur dioxide

Sulfur dioxide is readily absorbed through the upper respiratory tract when inhaled. It reacts with the moisture of mucous membranes to form sulfurous acid (H${}_2$SO${}_3$), which is a severe irritant. This leads to breathing difficulties, respiratory illness and changes in pulmonary defenses. Thus the correct answer is option A.