Presumably, I'm sure there are others who have noticed this as well. If you look closely at the smoke rising from a cigarette, you will notice a slight-to-mild brownish discoloration of the smoke. Contrarily, if you look at the smoke rising from the bowl of your piece of choice, the smoke tends to be pure; a milky-white pure. It is quite obvious the difference in Cannabis smoke versus Tobacco smoke, therefore, should not be compared to one another - a strategy often used by Prohibitionists. See where I'm getting at?
Terrible idea to bring up to prohibitionists. Meth or Crack/cocaine in a lightbulb turns white. All you need to do is look at the umbers to see how non-toxic marijuana smoke is.