If you are a host and prefer a non-smoking guest you can clarify this in the description of your listing. Theres also an option on the house rules to opt in or out on a couple things such as smoking/ drinking or parties.
This also goes for hosts who do not mind smokers. If you are a guest looking for a smoke-friendly home, you can directly ask the host if they have not indicated so in their listing. If you are a smoker, you definitely want to express this to the host. This is because a host may prefer someone who is smoke-free only to stay in their home and vice-versa.