Why is secondhand smoke dangerous?
Second hand smoke is dangerous because firsthand smoke is more dangerous. Cigarette smoke has more toxins, and carcinogens, and particulate matter than any other exposure to someone's physiology. And when someone is exposed near someone who is smoking a cigarette, the same risks that a smoker has pass along to a lower degree depending on the toxic load. But the diseases of people with second hand chronic long term exposure is a mirror image of the diseases that a smoker has themselves.