Is smoking allowed in the apartments? Is it allowed in public areas?
If it is not allowed in public areas (like hallways, laundry room, etc) and they are smoking out there, then I agree with complaining. But if it is allowed in their actual apartment (that's how it was in our old apartment building), I don't know if there's much you can do.
I'd be happy to help draft an e-mail if they are smoking against the policy. But if it is within their right (there's no language in the lease against it), I unfortunately don't know if you have a leg to stand on.