Why do cigarette filters have holes?
In the 1960s consumers became more aware of the harmful effects of smoking. Manufacturers responded to this by marketing ‘light’ cigarettes as a ‘healthier alternative’. The filters in these ‘light’ cigarettes contain very small ventilation holes through which extra air is drawn in when the smoker takes a puff of the cigarette. These ventilation holes appear to have a favourable effect on the concentration of harmful substances as they thin the smoke. Smokers often therefore perceive these cigarettes as being lighter and/or having a milder taste. Nowadays almost all cigarette filters have ventilation holes. The amount of additional air drawn in varies from 10 to 80 percent and depends on the number, the size and the position of the holes.
Ventilation holes in the filter paper of various cigarettes, enlarged using a microscope. The actual length of the red line is 1 millimetre.
Effects of filter ventilation
Smokers adapt their smoking behaviour
Smokers adapt their smoking behaviour (consciously or unconsciously) in order to inhale the amount of nicotine to which they are accustomed. If they smoke a cigarette with (more) ventilation holes, the concentration of nicotine per puff will be lower. In order to achieve the desired amount of nicotine they will inhale more deeply, take more and/or longer puffs or even smoke more cigarettes in a day. Smokers will also cover some of the ventilation holes, consciously or unconsciously, with their fingers and mouth while they are smoking. As a result they will inhale at least as many harmful substances as with cigarettes without ventilation holes.
Composition of the smoke changes
The extra air taken in with cigarettes that have filter ventilation also affects the composition of the smoke. The tobacco combustion process changes and, as a result, certain harmful substances are released in larger quantities. If smokers adapt their behaviour in order to achieve the same amount of nicotine as they would get with an unventilated cigarette, they will thus take in more of the other harmful substances. So it is important to consider the quantity of harmful substances in cigarette smoke in relation to the amount of nicotine.
Smokers’ perception is affected
Consumers do not always have the full picture about the risks related to cigarettes with filter ventilation. Some people think that they are less harmful to one’s health as these cigarettes have a milder taste and were originally sold as ‘light’ products. But as a result of the holes in cigarette filters there are more harmful substances in the smoke and smokers inhale more deeply and possibly even smoke more. The terms ‘light’ and ‘mild’ cigarette are therefore disputed and can no longer be used in the EU. Cigarettes with (more) ventilation holes may still be sold. They are often recognisable by packaging with lighter colours that looks like the former ‘light’ packaging.
Harmful substances in cigarette smoke
Ventilation holes in cigarette filters mean that smokers inhale at least as many harmful substances as when there are no holes in the filter. These are substances that are also present in the smoke of cigarettes without filter ventilation, such as tar, nicotine, carbon monoxide, tobacco-specific nitrosamines (NNN and NNK), acetaldehyde, acrolein. These substances are known to be very harmful to one’s health as they are toxic, carcinogenic and/or addictive.
Higher risk of cancer
It has been known for quite some time that cigarette smoking results in an increased risk of various types of cancer. Recent research has also demonstrated a link between the use of cigarettes with filter ventilation and a specific type of lung cancer, namely the adenocarcinoma.
Quantities of harmful substances in smoke
The quantities of harmful substances in cigarette smoke can be measured using a smoking machine. The ISO method that is currently used to determine TNCO values underestimates the quantity of harmful substances to which smokers are exposed. The “Canadian Intense” method is closer to human smoking behaviour as the ventilation holes in the filter are taped and inhalation is deeper and more frequent. RIVM already uses the Canadian Intense method for scientific research.
Relevance for the consumer
Cigarettes with filter ventilation are no less harmful than cigarettes whose filters have no ventilation holes. As a result of the change in smoking behaviour (conscious or unconscious) in order to achieve the desired amount of nicotine smokers actually inhale more harmful substances. The TNCO values that are determined in the test therefore do not provide an insight into the harmfulness for smokers.
RIVM has created a database containing the TNCO contents provided by manufacturers for cigarettes that were on the Dutch market in 2015. These show which cigarettes have low TNCO contents when they are smoked in the test according to the ISO method. These cigarettes probably have a lot of filter ventilation holes through which smokers possibly inhale more harmful substances than stated.
(On-screen title: Filter ventilation in cigarettes. Voice-over:)
Filter ventilation in cigarettes
(Did you know nearly all cigarettes)
VOICE-OVER: Did you know nearly all cigarettes
have tiny holes in the filter paper?
(In some cigarettes, the holes are visible to the naked eye.)
WALTHER KLERX: In some cigarettes, the holes are visible to the naked eye.
In other cigarettes, you must use a microscope to see them.
These holes cause the smoker and the smoke machine
to inhale extra air.
(We use this smoke machine to compare)
REINSKJE TALHOUT: We use this smoke machine to compare
the tar, nicotine and carbon monoxide emissions of various products.
In Europe, we've agreed to use the so-called ISO method to do so.
The ISO method involves keeping the filter holes open during testing.
But a real smoker wants to consume a certain quantity of nicotine
because he is addicted to it.
So, he will adapt his behaviour.
The smoker will take more drags, inhale more deeply
and partially block the filter holes with his lips or fingers.
(So, this study also uses)
VOICE-OVER: So, this study also uses
the Canadian Intense protocol, in which filter holes are sealed.
(This gives a better idea of what a real smoker consumes.)
TALHOUT: This gives a better idea of what a real smoker consumes.
In the ISO method, every minute, a 35-millilitre drag is taken.
In the Canadian Intense protocol, every thirty seconds
a 55-millilitre drag is taken.
(Now, based on the filter, we can see)
KLERX: Now, based on the filter, we can see
what the effect of the different methods is.
(With the ISO method, the filter is lightest)
With the ISO method, the filter is lightest
(so fewer components were consumed)
so fewer components were consumed
(than with the Canadian Intense method. That means)
than with the Canadian Intense method. That means
(that if you take bigger drags more often and seal off the holes)
that if you take bigger drags more often and seal off the holes
(you consume more harmful components than when you don't do so.)
you consume more harmful components than when you don't do so.
(So, holes in the filter do not make a cigarette less harmful.)
So, holes in the filter do not make a cigarette less harmful.
(The Dutch coat of arms, next to: National Institute for Public Health and the Environment. Ministry of Health, Welfare and Sport. The screen turns light blue and white. On-screen text: Want to learn more about filter ventilation in cigarettes? Surf to: rivm.nl/filterventilatie. An RIVM production, copyright 2017. Tomorrow's care begins today.)
Want to know more about filter ventilation in cigarettes?
Surf to: rivm.nl/filterventilatie.