How do cigarette filters work?

Cigarette filters are the brown or white fibrous part that goes to the mouth. Some cigarettes do not have one. A great many assumptions circulate about cigarette filters. Here is what they are for and how they work.

What exactly is a cigarette filter?

The cigarette filter is a small piece of cellulose acetate at the end of the cigarette. It is the part that goes into the mouth. Obtained through a chemical modification of cellulose, cellulose acetate comes in the form of fibres treated with titanium dioxide, a substance known for its toxicity. The fibres are then compacted with an irritant plasticiser called triacetin. That is how the cigarette filter is made.

What types of tobacco filter exist?

As you might expect, there is more than one type of tobacco filter. Manufacturers say they are working to make this small plug less harmful.

The foam cigarette filter

These are the most common ones, made of cellulose acetate. Some also contain charcoal, said to increase the effect. Foam filters are white and end up yellowed by the time the cigarette is finished. They are the ones fitted to ready-made cigarettes. They also come in several sizes for smokers who roll their own.

The biodegradable cigarette filter

Because they are highly polluting, cigarette filters are being reinvented in a biodegradable, more environmentally friendly version. These are made from hemp or unbleached paper, or from untreated cotton.

The card cigarette filter

Working on the same principle as the biodegradable filter, card filters make cigarettes easier to roll. They are rolled into an M, W, O or even S shape. They too come in several sizes.

The plastic cigarette filter

Also known as cigarette holders, they are credited with three roles: blocking the toxic material in cigarettes, keeping fingers from yellowing and limiting how much smoke drifts near the face. They come in several sizes.

The reusable cigarette filter

Presented by its makers as limiting the effects of smoke and tobacco on the teeth, the reusable cigarette filter has its followers.

What is a cigarette filter for, and does it work?

The stated role of cigarette filters is to create a barrier between the tars and other toxic material in tobacco and the smoker’s mouth. They were also devised to soften the acrid taste of tobacco smoke. In principle, at each puff some of the toxic material remains trapped in the fibres and so does not reach the body.

The effectiveness of filters is disputed, however. The Comité National Contre le Tabagisme (CNCT), the French national committee against smoking, states that filters make the harmful substances in tobacco more dangerous, because smokers who feel protected tend to inhale for longer. The organisation draws a link between filters and the rise in bronchial adenocarcinomas, a more aggressive form of lung cancer. It adds that by softening the acrid edge of the smoke, filters leave smokers less aware of how dangerous cigarettes are.