Pot-smoking may carry higher risks

Smoking a joint is equivalent to 20 cigarettes in terms of lung cancer risk, New Zealand scientists have found, as they warned of an “epidemic” of lung cancers linked to cannabis.

In a report in the European Respiratory Journal, the scientists said that cannabis could be expected to harm the airways more than tobacco because its smoke contains twice the level of carcinogens, such as polyaromatic hydrocarbons.

The method of smoking also increases the risk, since joints are typically smoked without a filter and almost to the very tip, which increases the amount of smoke inhaled. The cannabis smoker inhales more deeply and for longer, facilitating the deposition of carcinogens in the airways.