This is possibly common knowledge but did you know how bad it actually is for you? Did you know that a study done by the World Health Organisation (WHO) showed 600,000 people worldwide die every year to secondhand smoke. Scaling it down, 1 in 100 people are affected and almost a third are children!!
This is terrible but there are ways you can avoid it. Make sure you don't have people smoking inside your home. Be sure to go to restaurants and bars that do not allow smoking. Also avoid places where people will even smoke outside. Try to avoid it as best as you can.
Reference - WHO World Health Organisation