FACT SHEET

CONSTITUENTS OF TOBACCO SMOKE

Tobacco smoke contains more than 3,800 chemicals, many of which are poisonous.

The major poisonous chemicals in tobacco smoke are:

2-nitropropane                     Hydrogen cyanide                        
Acetaldehyde                       Insecticide residues (e.g. DDT)         
Acrolein                           Isoprenoids                             
Acrylonitrile                      Naphthalenes                            
Alkanes and Alkenes                Nickel                                  
Ammonia                            Nicotine                                
Aromatic amines                    Nitrogen oxides                         
Arsenic                            Nonvolatile nitrosamines                
Aza-arenes                         Other nitrosamines                      
Benzenes                           Phenols                                 
Carbon monoxide                    Polonium-210                            
Carboxylic acids                   Polynuclear aromatic hydrocarbons       
Dimethylnitrosamine                Pyridine                                
Formaldehyde                       Urethane                                
Hydrazine                          Vinyl chloride                      

Tobacco smoke contains many carcingogens - that is chemicals that cause cancer. Those identified so far include:

11 Polynuclear aromatic hydrocarbons

4 N-heterocyclic hydrocarbons

9 N-nitrosamines

3 Aromatic amines

3 Aldehydes

12 Organic and inorganic compounds (including arsenic, benzene, cadmium, chromium and vinyl chloride) and the radioactive element polonium-210

Tobacco smoke contains hydrogen cyanide, ammonia, nitrogen dioxide, acrolein and formaldehyde. These chemicals paralyse the cilia - tiny hair-like brushes in the respiratory system and lugs. Smokers' lungs are more sensitive to cancer-causing chemicals because their cilia do not clear dust and mucus effectively.

Tobacco smoke contains naphthylamine and nitrosamines, which cause lung cancer. Smokers also absorb these carcinogenic chemicals through their lungs, contributing to cancer in other parts of the body such as the bladder, kidney and pancreas.

Tobacco smoke contains carbon monoxide. Carbon monoxide is a colourless, odourless, poisonous gas. Carbon monoxide interferes with uptake of oxygen in the lungs and with its release from the blood to the tissues that need it.

When carbon monoxide is inhaled it combines with haemoglobin in the blood to form carboxyhaemoglobin, which reduces the amount of oxygen available to the body's vital organs.

The amount of oxygen carried by the blood may be severely deprived in heavy smokers due to the effects of carbon monoxide. Oxygen levels may be reduced by as much as 15%.

Carbon monoxide restricts the oxygen available to the foetus, contributing to the low weight of babies born to women who smoke. The baby in the womb cannot grow normally if deprived of oxygen.

Cigarettes and tobacco contain nicotine. Nicotine is an addictive drug. Smokers become addicted to nicotine in a similar way to how heroin addicts become addicted to heroin, and cocaine addicts become addicted to cocaine.

Smokers who smoke regularly expose themselves to the effects of nicotine for 24 hours each day, as nicotine builds up in the body during the day and remains overnight.

A number of people have been poisoned or have died from swallowing nicotine. Most of these poisonings resulted from swallowing pesticides containing nicotine. Symptoms of nicotine poisoning include nausea, vomiting, abdominal pain, diarrhoea, headaches, sweating and pallor. In more severe cases of poisoning, victims suffer dizziness, weakness and confusion, convulsions, low blood pressure and coma.

Carbon monoxide and nicotine are the constituents of tobacco smoke most likely to contribute to the development of heart disease.

Benzo (a) pyrene, which is found in tobacco smoke and causes cancer in laboratory animals, has been shown to bind chemically to DNA. Interference with the normal structure and function of DNA is believed to be the first step in the development of cancer,