Which gas is harmful and can cause difficulty breathing upon exposure?

• A. Sulphur Dioxide
• B. Oxygen
• C. Hydrogen
• D. Carbon Dioxide

Answer: (A)

Sulfur dioxide is a pollutant that irritates the airways when breathed in, causing coughing, throat irritation and shortness of breath. It dissolves in the moisture in the lungs to form sulfurous acid, which inflames and narrows the air passages, making breathing more difficult. This effect is especially noticeable for people with asthma or other lung conditions. In contrast, oxygen is what our bodies need to respire, so normal exposure isn’t harmful; hydrogen isn’t known to irritate the airways in typical exposures (its danger comes mainly from displacing air in enclosed spaces); carbon dioxide can cause breathing issues only at very high concentrations when it reduces the available oxygen. The immediate breathing difficulty linked to exposure points to sulfur dioxide.