My mom smokes, I hate smoke, It smells so bad. She smokes a lot in her room. Its so bad for me that I put weather striping around her door and a foam smoke blocker. That blocks like 98% and there is still like 2% of that smell and the ac vent it right in front of the door. omg. I was waking up with headaches from her smoke going into my room through the ac vent. I put this 3m In and I feel better now. I plan to keep this kind of product in.