Tar, nicotine and carbon monoxide are all present in tobacco smoke
In many countries, tar and nicotine measurements are printed on cigarette packs and in several parts of the world, tar, nicotine and carbon monoxide have regulated limits.
But what are tar, nicotine and carbon monoxide? Here we offer simple descriptions.
What is 'tar'?
Cigarette smoke contains tiny particles, which can be collected on a filter pad in a laboratory when a cigarette is smoked by a machine. Tar is usually defined as the weight of particulate matter collected in this way, after water and nicotine are subtracted. Tar is a complex mixture of substances, which includes substances which in sufficient quantities are thought capable of initiating and promoting cancer.
What is nicotine?
Nicotine occurs naturally in the tobacco plant and is a constituent of tobacco smoke. It can also be found in some other plants, but at much lower levels than in tobacco. Nicotine has unusual pharmacological properties; it has both a mild stimulant effect, though less than that of caffeine, and a mild relaxing effect. At high levels, far higher than in the smoke from a cigarette, nicotine is toxic. Many public health authorities believe nicotine is responsible for causing an addiction to smoking through its pharmacological effects.
What is carbon monoxide?
Carbon monoxide is a gas formed when plant materials burn. It can combine with haemoglobin in blood, reducing the blood’s capacity to carry oxygen. Carbon monoxide in tobacco smoke is thought to be associated with the increased risk of heart disease from smoking.
For information about the measurement of tar, nicotine and carbon dioxide, see Measuring cigarette deliveries.