The dangers tobacco poses to the heart and lungs have been well established by medical science, and anti-smoking campaigns are now decades-old. To protect nonsmokers from secondhand smoke, dozens of cities and states have banned smoking in public spaces.
“This leads to chronic inflammation and cellular damage— and, by the way, secondhand smoke is generally worse” than what actually enters the smoker’s mouth, Gordon says. That’s because the smoker is typically breathing it in through a filter that removes some of the byproducts of the burning tobacco. Secondhand smoke is completely unfiltered.