I’m not sure how true that is, but I recently found out that one of the worst things about cigarettes, is the fertilizer they use to grow tobacco for the US breaks down to radioactive polonium and lead. This is the reason for tumors and cancer. Think of that next time someone lights up around you.
Your breathing carbon monoxide and it goes into your lungs just as if you’re smoking yourself. My stepmother died of lung cancer never having smoked a cigarette in her life, just my Dad’s second hand smoke.