Placement of growing room

Most of the time when I smoke, or toke at my house it is in my garage, which happens to be right below my growing area. The thing is though, is that there are no vents, or air passage that connects the two, and the only thing separating them is the floor/ceiling. I have heard that you can not have tobacco smoke around your growing area, but my question is (actually I have two) is that A) is marijuana smoke as bad for your plants as the tobacco smoke is (it seems like smoke is smoke, but just out of curiosity) and my second question is, is can I continue to smoke in my garage, or is there a high potential, that it will fuck up my garden. (I have 2 plants that have already sprouted, and look fine so far)

thanks

When you go into your grow room.. after you smoke in your garage.. are there any signs of the smoke entering that (grow) room?

cheers