Studies can cover a wide spectrum for many reasons. I've seen enough solid quality studies implicating second hand smoke, the jury is in, for me.
I have no need to bother my friend as you suggest. He's shown me plenty before. I'd rather he spent his time doing what he does best for the air of Hawaii.
Give me their names, authors, etc.
Don't hedge, don't tell me to find them for myself, just give me their names so I can go look at them.
My mind is open enough to be changed.
I haven't seen even a large minority of studies that support your stance.