How they work
Not all cigarettes are the same. Smokers around the world prefer many different tastes and strengths and our companies aim for excellence in every step of manufacturing.
Our companies work to understand the preferences of adult consumers and to design cigarettes to meet them. It’s the preferences of adult consumers that guide our tobacco blends – the mix of tobaccos that we use – and we work to ensure that these grades are available long-term to keep the tastes of our products consistent.
Food-type ingredients and flavourings are added to some types of cigarettes – typically American style blends – to balance the natural tobacco taste, replace sugars lost in curing and give individual brands their characteristic flavour and aroma. Other ingredients control moisture, protect against microbial degradation and act as binders or fillers.
Nicotine is not added in making cigarettes. It occurs naturally in all varieties of tobacco plants.
The filter, paper and level of filter ventilation are all chosen to affect the sensory strength and smoke yield of the cigarette. At each stage, there is constant quality control and testing.
Cigarettes have four basic components:
The tobacco rod includes tobacco lamina (the flat part of the tobacco leaf) and tobacco stem (midribs of the leaf).
The cigarette paper includes paper and adhesive.
The filter is made mainly from cellulose acetate fibres, known as tow. Cellulose acetate is derived from wood pulp. The fibres are bonded together with a hardening agent, triacetin plasticiser, which helps the filter to keep its shape. The filter is wrapped in paper and sealed with a line of adhesive. Sometimes charcoal is added to filters.
The tipping paper includes paper and adhesive.
Design adjustments achieve different strengths and tastes, and can reduce smoke yields of various smoke components, as measured by a standardised machine method.
To understand cigarette design, it helps to know how a cigarette burns. It is the combustion process – the burning of the cigarette – that produces tar. If hay were burned instead of tobacco, it would also produce a type of tar. When an item burns, it produces tiny particles mixed with gases – this is smoke. A cigarette filter traps some of these particles.
When a smoker puffs on a cigarette, whole smoke, including both fine particles and gases, is sucked through the tobacco rod and the filter. Gases pass through the filter and some particles are trapped in it. It is this particulate matter, minus nicotine and water, that is called tar.
Smoke has over 4,000 constituents, many of them also found in the air we breathe and in our food. These constituents include the emissions listed on packs, such as tar, nicotine and carbon monoxide. Water vapour is also produced by the combustion, because the burning of any organic material breaks down the chemical components and produces water.
For more than 25 years we’ve researched the degradability of our cigarette filter tips to test for breakdown depending on the physical environment – for example, on concrete, in water and in soil. Our current research shows that some constituents of our filters, such as papers, can degrade over a month to three-year time period, in certain environments. However, for other constituents in our filters, such as polymers or glues, research is inconclusive and requires further ecotoxicity and degradation testing. Therefore, our current conclusion is we know of no practical way of making consumer-acceptable filters that would degrade over a duration that would not cause short-term littering problems.
Smoking poses real risks of serious diseases. That’s why we are working to develop products that may be recognised as less harmful.