Australia

CANNABIS smokers inhale far more toxic chemicals than those who puff on cigarettes new research shows.
When inhaled directly, marijuana smoke contains 20 times more lung-damaging ammonia and five times as much hydrogen cyanide and nitrogen oxides than cigarette smoke, a team led by David Moir at Health Canada reports.

In WA around 235,000 people use cannabis and it is the most widely used illicit drug nationwide, according to a survey by the Australian Governments Institute of Criminology.