proplan
Besides "carcinogens" being harmful to your health, you really don't want to be putting any substance "natural or chemically" altered into your lungs. Lungs, based on their physiology, are filtering mechanisms transporting oxygen. Lung linings can be irritated by may substances. Smoke is a natural irritant. Breathing clean or purified air and staying away from any potential lung irritant is the best course of action.
Herb Man Dan.