For example, the BLF's review of previous research highlights that just three marijuana joints a day causes the same damage to the lung's airways as 20 cigarettes, mainly because of the way joints are smoked.

If you get to the point youre smoking 3 joints a day, Id say youre in trouble. Do some math.

That statement says essentially carcinogenically (not statistically, because they have yet to link it with statistics as I have iterated already), 3 joints = 20 cigarettes.

The average user smokes once or twice a week. Lets be safe and say 2 a week for the purpose of calculations.

2joints/week*week/7days*20cigarrettes/3joints= 2 cigarrettes/day

Honestly, I think you have to worry more about people who are smoking a pack a day.