Reducing the quantities of substances in smoke
The World Health Organisation (WHO) recommends reducing the quantities of a number of substances found in tobacco smoke. This is intended to limit harmful health effects caused by tobacco smoke. Moreover, it should prevent new tobacco products with greater adverse health effects from coming onto the market.
The WHO has nominated nine substances. Click on the links below to get more information about each substance´s characteristics, how it is formed in tobacco smoke and in what quantities, adverse health effects, and, where this is known, its impact on smoking addiction.
- NNN (N-nitrosonornicotine)
- NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanon)
- carbon monoxide (CO)
Selection criteria for substances
The nine substances have been selected based on:
- Whether they cause adverse health effects
- The quantity of substance in the smoke in relation to its harmfulness (risk)
- The difference between different brands with respect to the amount of the substance in the smoke
- The possibilities of reducing the amount of the substance in the smoke by adapting the production process
- An expectation that when the amount of this substance is decreased, amounts of similar substances in the smoke will also decrease
The substances mentioned are just a few of the thousands of chemicals that comprise tobacco smoke. For this reason it is impossible to evaluate exactly how harmful a single substance is in this complex mixture. For instance, a given substance may react with other components in the smoke, which can affect how harmful the entire mixture is.
Exposure to substances in smoke
The quantity of each individual substance present in smoke is not the same for all cigarettes or all tobacco products. How much of a substance you are exposed to depends on the type of product (such as a cigarette or a cigar), the brand (because of the type of tobacco, the type of filter, and the additives used), as well as on a person’s smoking behaviour (how many puffs are taken and how deeply the smoke is inhaled).
The RIVMNational Institute for Public Health and the Environment develops methods for measuring the amounts of various substances in cigarettes or cigarette smoke. This information can be used to evaluate the substance’s harmful effects.