This happens to me too - the guy that lives below us is practically a chain smoker and lights up on the front porch 2-3 times an hour. DH likes to keep the window over the porch open, but I close it when I smell the smoke. There's nothing we can do as he's the landlord.

In the winter he flicks his butts off the porch and leaves them, so that in the spring when the snow melts they're all there, on the front steps and the lawn, and all over the sidewalk. It's absolutely disgusting.