daima, you sound a lot like Dr. Robert Melamede.

"That's not to say smoking marijuana is good," Melamede noted. It is a lung irritant and can cause respiratory problems, such as coughing. Also, it is full of carcinogens, so "even if it's not causing cancer, it's having negative effects," he said.
Wait, I just noticed that he didn't say that. The editors of cannabisnews.com must have stuck that there.