Which statement correctly describes passive and second-hand smoke?

• A. Passive smoke is harmless to bystanders.
• B. Second-hand smoke contains not only the chemicals in passive smoke but also carbon dioxide.
• C. Passive smoke contains fewer chemicals than second-hand smoke.
• D. Second-hand smoke is more harmful than passive smoke.

Answer: (B)

Second-hand smoke is the mixture of the smoke you inhale from a burning cigarette and the smoke exhaled by the smoker. It contains the same harmful chemicals found in the smoker’s breath, but it also includes additional gases produced by combustion, such as carbon dioxide. This broader combination makes second-hand smoke more dangerous to people nearby because they’re exposed to more toxic substances than just the chemicals from the smoker’s own inhalation. The idea that passive smoke is harmless is incorrect, since it also carries toxic chemicals; stating that second-hand smoke has more chemicals than passive smoke captures the idea that the smoke in the environment includes extra components beyond what a smoker actually breathes.