We are renting a house in which the basement is rented to someone else (the landlord and another tenant). This other tenant like to smoke from time to time. We, who live in the main floor, can smell the smoke through the heating vent. We have 6 y.o. son and worried if inhaling the smoke can harm our health. A friend of mine however, told us not to really worried because the smoke has to travel quite the distance and therefore, it may not be as harmful as if we sit next to a smoker. Is this true? And if so, what would be the explanation? Would the smoke lose its content, the nicotine, during the travel and we only smell an "empty" smoke without the nicotine in it and therefore it's not harmful anymore? Look forward to hearing any insight. TIA!