Tobacco Smoke

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Tobacco smoke1 is 'a mixture of particles that are emitted from the burning end of a cigarette, pipe, or cigar, and smoke exhaled by the smoker'2. These particles can be any of over 4,000 chemical compounds, 200 of which are known poisons and 43 are known to cause cancer in humans or animals3. Many of these 4,000 chemicals are strong irritants. Tobacco smoke is primarily composed of a dozen gases. There are large amounts of carbon monoxide, but nicotine4, benzene, formaldehyde and tar are also present. A list of deleterious components of tobacco smoke can be found in Toxic Tobacco Smoke, but a few of the more dangerous ones can be seen in the list below5:

  • Acetone

  • Ammonia

  • Arsenic

  • Benzene

  • Cadmium

  • Cyanide

  • Formaldehyde

  • Lead

  • Mercury

  • Nickel

  • Phenol

  • Styrene

  • Toluene

Tobacco smoke has been classified by the Environmental Protection Agency as a class "A" carcinogen. This rating is only placed on substances that are known to cause cancer in humans. This rating places cigarettes in the same category as a number of other chemicals including benzene and asbestos. Exposure to tobacco smoke is known as passive smoking. This is extremely dangerous, as none of the chemical compounds are able to be filtered out.

Isn’t There a Difference Between the Different Types of Tobacco?

There are a number of components that are present irrespective of the type of tobacco being smoked, though the quantity and presence of others does alter according to the tobacco. These have been outlined above. Most of the compounds present in tobacco smoke are formed during the burning of the tobacco, and are a mere by-product of the combustion process of various chemical compounds (precursors) present in the tobacco. As such, the chemical composition of the smoke depends on 2 factors – the chemicals in the tobacco and the conditions under which combustion occurs.

The chemical composition of tobacco is affected by the manufacturing processes of the tobacco company. The way in which the tobacco is grown, cultivated, disinfected, cured all affect the final tobacco. Companies also add a number of chemicals to add flavour to the tobacco and to dampen it. The combustion process is also as varied. It depends on the temperature of the combustion, the length of cigarette and stub, the presence of a filter and the type of filter, as well as the strength and degree of inhalation.

  • Cigars

  • Like cigarettes, cigar smoke contains over 4000 chemical compounds, with more than 50 of them being carcinogenic. Unfortunately, smoking a single cigar in an unventilated room produces the equivalent of 42 cigarettes. Cigar smoke, compared to cigarette smoke, contains 20 times the amount of ammonia, 10 times the amount of cadmium and 90 times the amount of nitrosamines6. The average cigar releases 3 times the amount of carcinogenic, cancerous material and 30 times the amount of carbon monoxide compared to a normal cigarette. The smoke from cigars are slightly alkaline, as opposed to cigarette smoke which is slightly acidic. This means that the smoke can be more effectively absorbed into the blood stream through the mucosal linings of the nose and mouth.

  • Pipes

  • It is difficult to find any information on the actual content of pipe smoke. It does have the advantage over other forms of tobacco smoking of having a lower combustion temperature, and the fact that not all the tobacco is burned. However, it must be stressed that despite this, there is still the presence of a number of dangerous chemical compounds. Pipe smokers are more likely to develop cancer of the mouth than cigarette smokers – mainly because they do not inhale the smoke to the same degree.

Light Cigarettes?

Although it would make sense for 'light' and 'ultra-light' cigarettes to have less of a health impact than 'full-strength' cigarettes, it does not appear to be the case. The ISO cigarette test measures the levels of tar, nicotine and carbon dioxide yields from cigarettes, and the results from this enable a cigarette to be labelled as 'light' or 'ultra-light'. However, it is not felt by the whole of the scientific community that these tests are meaningful. 'Light' cigarette filters contain small holes which are intended to maximise the amount of air mixed with the tobacco smoke, thereby reducing the measured readings of tar, nicotine and carbon monoxide. As these holes are covered by the smoker, the amount of air mixing is further reduced, increasing the concentration of chemicals further. Scientists feel that this 'skews' the results in favour of the cigarette7.

In the January 2000 edition of Journal of the National Cancer Institute, a study was published, which suggested that smokers contract twice the amount of tar and nicotine from 'low-tar' cigarettes than was previously believed. It was also suggested that 'low-tar' cigarettes carry a greater health risk than high tar cigarettes. The reasoning behind this is that the smoke from high tar cigarettes is too irritating to inhale very deeply. With the low-tar cigarette, the smoker can inhale deeper, resulting in more carcinogens and toxins entering the peripheral lung area. This has been attributed to the increase of the previously rare lung cancer - adenocarcinoma.

For these reasons, it is difficult to enable distinguishment between the different types of tobacco smoke. The amount of toxins you inhale depends on how much you smoke, and will increase if you:

  1. Inhale deeply.

  2. Take more puffs.

  3. Hold the smoke in your lungs longer.

  4. Smoke the cigarette right down to the filter.

  5. Cover the vent holes that are near the filter.

As such, this article will have to generalise to a certain degree. However, it is not in dispute that different tobacco contains the same dangerous chemicals, only the quantities present.

Short Term Effects of Tobacco Smoke?

When nicotine is inhaled, it reaches the brain faster than drugs that enter the body intravenously. Thus, smokers become physically and mentally addicted to nicotine, as they associate smoking with many social activities. It is a difficult habit to break, and giving up smoking is a difficult thing to do.

Short-term effects of nicotine in cigarette smoke include sweating and throat irritation. It also affects the mood of the smoker. Smoking can also cause vomiting to occur in new smokers.

Long Term Effects of Tobacco Smoke?

Nicotine produces effects on the lungs, and tar exposes the user to the risk of emphysema, which is a common disease among cigarette smokers. It is 10 times more likely to occur in smokers than in non-smokers. Smoking causes most cases of emphysema, and 16,700 Americans died in 2000 from bronchitis8.

Tar exposes the user to the risk of bronchial disorders9. For example, chronic bronchitis is a common disease among cigarette smokers. It is 10 times more likely to occur in smokers than in non-smokers. Smoking causes most cases of chronic bronchitis, and 1,167 Americans died in 2000 from bronchitis.

Nicotine produces effects on the heart. The carbon monoxide in the smoke increases the chance of cardiovascular10 diseases, including coronary heart disease and strokes. The risk of congestive heart failure is also increased by the effects of nicotine. 170,000 Americans die each year from smoking-related heart diseases.

Nicotine produces effects on the stomach, neurotransmitters11, and sympathetic and parasympathetic nervous systems13.

43 of the poisons in a cigarette are known to cause cancer. Tar exposes the user to the risk of lung cancer, which is the most serious effect of smoking. Cancers of the mouth, lips, pharynx, larynx, oesophagus, pancreas, uterine cervix, kidney and bladder are also associated with cigarette, cigar and pipe smoking. Smoking is directly responsible for 87% of lung cancer cases (resulting in 3,000 annual non-smoker deaths). 30% of US cancer deaths (130,000 per year) are linked to smoking.

Smoking has also been linked to conditions and disorders, including slower healing of wounds, infertility, and peptic ulcer disease.

It is believed that a mother who smokes has an increased risk of giving birth prematurely. This may cause the baby to have underdeveloped lungs and air passages. If smoke is present in the air after birth, these airways may decrease in diameter. This will increase any breathing difficulties, possibly causing bronchitis or pneumonia. This will further reduce the baby’s health.

It is believed that a mother who smokes will produce a smaller baby. Smaller babies are more likely to need special care and stay longer in hospital. Some may die either at birth or within the first year.

Through research it has been shown that children born to smokers, are prone to asthma, increased frequency of colds, coughs and middle-ear infections. There are approximately 150,000 to 300,000 cases of lower respiratory tract infections, in children less than 18 months of age, in America. This results in 7,500 to 15,000 annual hospitalisations, which are believed to be caused by passive smoking.

Women who smoke generally have earlier menopause. If women smoke cigarettes and also take oral contraceptives they are more prone to cardiovascular and cerebrovascular14 diseases than other smokers. This is especially true for women over 30 years old.

Each year smoking kills more Americans than alcohol, cocaine, crack, heroin, murder, suicide, car accidents, fires and AIDS combined. In total, cigarette disease victims die more than twenty years before the life expectancy of non-smokers.

Thus, about 430,700 Americans die annually (including those affected indirectly, such as premature babies due to prenatal maternal smoking and some victims of passive smoking).

How Does Tobacco Smoke Affect Babies?

Pre-Natal Effects

When a pregnant mother smokes, the nicotine and carbon monoxide from the cigarette smoke penetrate through to the placenta. This prevents the foetus from getting the necessary nutrients and oxygen needed to grow. Smoking may decrease the immunity of the foetus, which can cause infection. Smoking may even lead to learning difficulties, in later life.

The lack of nutrients, coupled with the lack of oxygen increases the risk of having a spontaneous abortion (miscarriage), a stillborn or premature infant, or an infant with low birth weight. If the baby is premature, there is also the possibility that the lungs are not fully developed.

Smoking accounts for 20-30% of low birth weight babies, 14% of premature births and 10% of all infant deaths.

Postnatal Effects

Babies are more likely to die of cot death than any other cause15, and babies who are exposed to tobacco smoke are at an increased risk of cot death: 30% of the cases of cot death could be related to smoking. A baby who is exposed to the smoke of 20 or more cigarettes a day is eight times more likely to be a victim of cot death.

The British Medical Association have produced a Tobacco Fact File, which presents all sorts of key facts and data about tobacco. It is an invaluable source of excellent information.

What's in a Cigarette?Why Tobacco Raises Cot Death RiskCot DeathFactsheets from the Lung and Asthma Information Agency
1Tobacco smoke is sometimes referred to as second-hand smoke, or Environmental Tobacco Smoke (ETS).2Taken from the Environmental Health Center website.3Of course, it should be remembered that any chemical compound is toxic, so long as you take enough of it. There is often a fine line between the concentration of a compound that can be beneficial to you, and the concentration of the same compound that can kill you.4Nicotine is an addictive drug.5If you are interested in the actual levels of toxicity of these compounds, the Risk Assessment Information System website provides you with all the necessary information.6The large percentage of nitrosamines are mutagens (they alter the genetic content of cells), and a number of them are organ specific carcinogens.7But then you can always find a statistician to argue either point for any set of data.8For reference, at the end of the 90s, there were roughly 50 million smokers within the US.9Bronchial disorders are infections of the tubes to the lungs.10Science speak for the heart and blood vessels.11A neurotransmitter is a chemical that travels across the synapse12, enabling brain cells to communicate with each other. Some neurotransmitters excitatory and stimulate the target cell, whilst others are inhibitory and inhibit the target cell.12A synapse is the gap between neurons (nerve cells).13The Sympathetic and parasympathetic nervous systems are the two components of the autonomic nervous system (the involuntary part of the nervous system). They work together to control body functions such as the heart beating, digestion and the production of chemicals, such as hormones. 14The blood system to the brain.15The Foundation for the Study of Infant Deaths states: 'Cot death is the leading cause of death in babies over one month old - more deaths than from meningitis, leukaemia, other forms of cancer, household and road traffic accidents'.

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