Question: smoking one joint is equal to 20 cigarettes?
Answer: Counting up 'joint-years' A pack-year is equivalent to smoking 20 cigarettes a day for a year, which comes out to 7,300 cigarettes. Marijuana exposure was measured in "joint-years." A joint-year is equivalent to one joint — or filled pipe bowl — a day for a year, or, simply enough, 365 joints.