I use a YM-2 (Ambex) roaster - three to five pounds per batch. Honestly, it smokes a lot as you reach 1st crack, but not much more than gas grill loaded with juicy burgers. So if you are talking about a small roaster I wouldn't worry too much. Unless you have it going for very long periods at a time.
Frankly, if your neighbors are normal, they will follow the wafts of toasty aromal to your home in hopes of partaking in what is sure to be the freshest coffee in the neighborhood. In other words, share the wealth and they won't mind so much.