Who are more susceptible to carbon monoxide poisoning?

• A. Non-smokers
• B. Smokers
• C. Children
• D. Elderly

Answer: (B)

Carbon monoxide poisons by binding to hemoglobin far more readily than oxygen, forming carboxyhemoglobin and reducing the blood’s oxygen-carrying capacity. The higher the baseline level of carboxyhemoglobin in a person, the less additional CO exposure is needed to cause tissue hypoxia. Smokers routinely inhale CO from cigarette smoke, so their carboxyhemoglobin levels are elevated even without an accidental exposure. Because they start from a higher COHb level, they experience the effects of additional CO—such as dizziness, headache, confusion, or loss of consciousness—at lower ambient CO levels than non-smokers. That makes smokers more susceptible to carbon monoxide poisoning. While children and the elderly can be more vulnerable due to physiology and reserve, the persistent CO exposure in smokers makes them the most at risk in typical scenarios.