No, there isn't really anything else that is close to MJ.

MJ smoke is not that harsh on your lungs either. There has never been a reported case of cancer from a cannabis smoker only, not does it contain as much tar as a cigg (despite what "doctors" say). It does do slight damage, but nothing that is life threatening in the long, or short run.

If you like the effects of cannabis, have you considered vaporizing? That would be a good alternative in your case if you're worried about damage on your lungs.

I've been smoking cannabis for about 5yrs now, not everyday, but at least twice a week, and my lungs are fine. Maybe not as healthy as most, but I certainly don't have coughing fits or cough up lung butter.

Peace :rasta: