How bad is second hand smoke exposure following a breast augmentation?

Both my boyfriend and his grandfather (who we are taking care of) smoke cigarettes. They only smoke outside the house but if I travel in a car with them, they typically smoke in the car. I try to avoid breathing it in as much as possible. I plan to be extra viligent about avoiding it around my BA. What timeframe is the most critical for this (i.e. How many weeks beforehand and after)? Also, do I need to have my boyfriend change his clothes after smoking? What can happen if I am exposed to it?