CANNABIS SMOKE MORE TOXIC THAN PUFFING TOBACCO

Cannabis smokers are exposed to more toxic chemicals in each puff
than those who smoke only tobacco, scientists have found. Earlier
research shows cannabis smokers are more prone to lung damage than
cigarette smokers.

In tests, directly inhaled cannabis smoke contained 20 times more
ammonia than cigarette smoke, five times more hydrogen cyanide and
five times the concentration of nitrogen oxides, which affect
circulation and the immune system.

Researchers led by David Moir at Health Canada investigated after
noting there are 4,000 chemicals and toxins listed for tobacco smoke
but no such list for cannabis.

They set up machines that "smoke" the plants and collect the
fumes.

The scientists first analysed smoke that would be inhaled directly,
but later examined "sidestream smoke", which accounts for 85% of the
fumes you inhale if you sit next to a smoker. This smoke contained
higher levels of almost every toxin measured, except for compounds
known as polycyclic aromatic hydrocarbons, which were more
concentrated in directly inhaled cigarette smoke.

The chemicals combine to cause harmful health effects. Polycyclic
aromatic hydrocarbons have been linked to reproductive disorders and
cancer, while, at high levels, ammonia can cause asthma.

"Cannabis contains similar carcinogens to tobacco, in particular
volatile organic compounds," Stephen Spiro of the British Lung
Foundation told New Scientist magazine.

"That these exist in similar or even higher proportions to tobacco
smoke is a great worry."

In July scientists in New Zealand reported that smoking a single
cannabis joint could cause as much lung damage as five chain-smoked
cigarettes. Much of the damage is believed to be caused by smokers
inhaling cannabis more deeply than tobacco and holding it in up to
four times as long.