People are mainly exposed to formaldehyde when it is released in exhaust fumes, in food preparation and in cigarette smoke.
Formaldehyde in tobacco smoke
Formaldehyde is not added to tobacco products. Rather, formaldehyde is produced when additives such as sugars, sorbitol, guar gum, cellulose fibres, and carob and gum in tobacco are burnt. Smokers inhale it when they take a puff of smoke (first-hand smoke). It is inhaled to a lesser extent by passive smokers (second-hand smoke).
Adverse health effects
Formaldehyde is a carcinogenic substance and has been classified by the International Agency for Research on Cancer (IARC) as ‘carcinogenic to humans’ (Group 1). Formaldehyde causes cancer in the nose and trachea and can even cause leukaemia. Inhaling formaldehyde from tobacco smoke can also cause irritation of the airways and damage to airway cells. Formaldehyde can also be irritating to the eyes.
Effect of smoking addiction
Formaldehyde can increase dependence on smoking, causing smokers to smoke more in both quantity and frequency. This leads to exposure to greater amounts of toxic substances in tobacco smoke. One reaction product of formaldehyde is norharman. This chemical causes certain substances in the brain—neurotransmitters—to decompose more slowly. This effect is similar to the positive effect antidepressants have on a person’s mood, and stimulates smoking behaviour.