Cigarette smoke contains thousands of different chemicals, or 'smoke constituents,' also referred to as 'smoke emissions.' The most commonly known smoke constituents are tar, nicotine and carbon monoxide (CO). In addition to these, more than 7,000 chemicals have been identified in tobacco smoke to date. Public health authorities have classified some 70 smoke constituents as likely causes of smoking-related diseases, such as lung cancer, heart disease and emphysema.
Smoke constituents are measured using laboratory machines. Today there are internationally standardized, validated test methods for only a few smoke constituents, including tar, nicotine and carbon monoxide.
Tar, Nicotine and Carbon Monoxide Yields
Most smokers are familiar with tar, nicotine and carbon monoxide, because many governments require manufacturers to measure them for every cigarette brand and display the results on cigarette packs.
Tar is not a specific smoke constituent, but a term that refers to particles in the smoke that are measured in machine test methods. These particles are made up of many smoke constituents, including some that public health authorities believe are likely causes of smoking-related diseases like lung cancer.
Nicotine is a naturally occurring chemical in the tobacco plant. When tobacco is burned, nicotine transfers into the smoke. Nicotine has been identified by public health authorities as the addictive substance in tobacco smoke.
Carbon monoxide is a gas that is formed in tobacco smoke. Carbon monoxide has been identified as a leading cause of cardiovascular disease (heart disease) in smokers.
Other Smoke Constituents
Thousands of other smoke constituents have been identified in tobacco smoke. In addition to nicotine and carbon monoxide, public health authorities have classified around 70 of them as likely causes of smoking-related diseases. Some of these constituents are arsenic, benzene, benzo[a]pyrene, heavy metals (e.g. lead, cadmium), hydrogen cyanide and tobacco-specific nitrosamines.