Unfortunately, there may be some bylaws that say you cannot smoke in 'public' or 'common' property but it is completely legal for someone to smoke within their unit (whether it's owned by them or not, unless specified by the owner/landlord).
We had this issue in a condo I had owned a long time ago. I was a part of the strata and we had a 3rd party property management company as well. Where I live, there is a bylaw that restricts smoking in common areas. However, the owner of one particular unit (chain smoker) decided to stop smoking out on the patio and begin smoking in their unit. Although the smell would seep through the door and into the halls and to surrounding units, it was actually legal for them to do what they want in their own property. There was very little we or our property management company could do... for them to stop it would be a courteous thing not a legal thing. Which some people just don't care.