What is the primary risk associated with smoking for aircrew?

• A. Increased lung capacity
• B. Decreased oxygen carrying capacity and increased CO exposure
• C. No health impact
• D. Improved endurance

Answer: (B)

Smoking mainly increases the risk because it lowers the blood’s ability to deliver oxygen. The smoke brings carbon monoxide, which binds to hemoglobin far more readily than oxygen does. This forms carboxyhemoglobin, reducing the amount of oxygen that can be carried in the blood and made available to tissues. It also makes it harder for the blood to release oxygen where it’s needed. For aircrew, operating at altitude already drops the partial pressure of oxygen, so any further decrease in oxygen delivery can quickly lead to hypoxia, impaired judgment, and reduced physical and cognitive performance—dangerous in flight. In addition, smoking adds ongoing exposure to CO and irritants that can worsen lung function and gas exchange. The other options imply benefits or no effect, which aren’t accurate; smoking does not increase lung capacity or endurance, and it clearly carries health risks.