One way to measure the toxicity (and there is certainly that) of tobacco smoke is to see your dentist regularly. You can not do that with inhaling or doing that nose thing; the doctor just cannot see enough and X-rays of either a horribly insensitive or pick up pathology too late. The dentist has a clear view. This may seem like a fatalistic view of the issue of inhaling as not a good thing and, as others have pointed out, as not inevitably desirable. Keep the smoke in your mouth and enjoy!