Vaping Produces Far Less Second Hand Nicotine Than Smoking Respiratory Therapy First, Second and Thirdhand Smoke: The Differences and Dangers Tobacco Stops With Me Secondhand vape exposure detectable in children's saliva, breath Contemporary Pediatrics Passive smoking (secondhand smoke) is extremely harmful to children, especially infants. Because infants breathe faster than adults, they inhale more smoke toxins per minute. This exposes them to dangerous chemicals like nicotine,