Smoking
Overview
Smoking is the leading cause of lung cancer, which causes more deaths than any other form of cancer. Smoking affects both smokers and people nearby, through second-hand smoke.
Why is smoking hazardous?
There are three major reasons smoking is dangerous:
- “The nicotine effect”:
Nicotine is one of the major chemical components in the tobacco leaves used to make cigarettes. Nicotine reaches the brain just a few seconds after smoking begins. The rich blood supply in the lungs picks up any chemical in the air very rapidly.
Nicotine causes the nervous system to stimulate the release of adrenaline into the blood. When adrenaline increases in the blood, it causes the heart to beat faster, the blood vessels to constrict (to become more narrow), and the breathing rate to increase. Nicotine constricts blood vessels directly too. Constricted vessels create a large resistance for the heart to pump against. Nicotine also constricts the blood vessels in the heart and can promote heart attacks.
Initially nicotine gives the brain a boost, but when the effect wears off, fatigue and depression set in.
Nicotine is one of the most addictive drugs known. Just a few puffs can create cravings for nicotine in some people. And young people are more likely to get addicted quickly than older people!
- Lung irritation
In addition to nicotine, the burning of tobacco produces other hazardous materials. Some of them are:
Acetone – a solvent, used in nail polish remover, for example.
Carbon Monoxide – an odorless, colorless poisonous gas that is lethal in large doses. In smaller doses, carbon monoxide causes increased heart rate and shortness of breath. Carbon monoxide attaches itself to the red blood cells and blocks their ability to carry oxygen.
Formaldehyde – a preservative for dead bodies. In cigarette smoke, this chemical is a known carcinogen and causes respiratory problems.
Hydrogen Cyanide – short-term exposure can lead to headaches, dizziness, nausea and vomiting.
Lead – a highly toxic metal, capable of causing serious damage to the brain, kidneys, nervous system and red blood cells.
Cigarette smoke contains many organic tars that irritate delicate lung tissue. As the irritation increases, the lung linings begin to break down, reducing the efficiency of the lungs. One common disease resulting from the break down of the lung linings is emphysema.
In emphysema, the alveoli over inflate because they are trying to let more oxygen into the blood. This over inflation reduces the elasticity of the alveoli and makes them less efficient.
As emphysema progresses the lungs become less elastic and can no longer clear the air out of the lungs.
When the air remains in the lungs for a longer period of time than normal, the oxygen is depleted and carbon dioxide builds up.
When carbon dioxide builds up in the lungs, the alveoli swell and may even burst open. This causes tissue damage and can lead to scar tissue.
The lungs do not exchange old air for new air efficiently.
- Lung cancer- Smoking is the leading cause of lung cancer in the United States. Lung cancer causes more deaths in the United States than any other type of cancer. For more info click here. We will discuss this in depth on the next page.
Similar problems occur with snuff and chewing tobacco. The nicotine effect is the same. The irritation and cancer effects can be the same, except it is the mouth that is affected instead of the lungs.
Lung Cancer
Overview
Although lung cancer is the leading cause of cancer deaths in the United States, it is also one of the most preventable kinds of cancer. At least four out of five cases are associated with cigarette smoking. More than 170,000 people in the U.S. are diagnosed with lung cancer each year, most between the ages of 40 and 70. Click here for more statistics.
What causes lung cancer?
Cigarette smoke has 4000 chemicals and of these, over 40 are known to cause cancer. Normal human cells become cancer cells when exposed to carcinogens.
The risk of developing lung cancer in humans is proportional to the number of cigarettes smoked. Smokers are 8-20 times more likely to develop lung cancer compared to people who have never smoked.
For nonsmokers, here is a normal, inflated lung to compare to the smoker’s lung below. This is what your lungs should look like.
The picture on the left is a smoker’s lung. Cigarette smoke has tars and chemical agents in it that irritate the lungs and cause lung cancer to form. The cancer cells in this picture are shown by the whitish area in an otherwise blackened lung.
Source: American Lung Association
Why is lung cancer a serious problem?
Over 300,000 people die from lung cancer in the United States alone. The economic loss is calculated to be over two billion dollars a year.
Since the majority of lung cancer is diagnosed at a relatively late stage, only 10% of all lung cancer patients are ultimately cured. If the patient cannot be cured by surgery at the time the cancer is found, there is a 50% chance that death will occur in less than one year.
What are the symptoms of lung cancer?
In its early stages, lung cancer normally has no symptoms. Most lung cancers begin to grow silently, without any symptoms. Patients with lung cancer often do not develop symptoms until the cancer is in an advanced stage. The actual time from when one cell becomes cancerous until it is large enough to be diagnosed or produce symptoms may take as long as 10 to 40 years. When symptoms start to appear, they are usually caused by blocked breathing passages or by the spread of cancer to other parts of the body.
Conclusion
Smoking causes cancer. The occurrence of lung cancer can be reduced by not smoking.
Passive Smoking (Secondhand Smoke)
The smoke emitted from the end of a burning cigarette has double the concentration of nicotine and tar when compared to the smoke actually inhaled by the smoker (through a filter). It also contains higher amounts of cancer-causing chemicals. This is because smokers inhale smoke that is filtered through both the unburned tobacco and the filter at the end of the cigarette. This means that non-smokers subjected to secondhand smoke breathe in a more potent smoke than smokers do. Therefore, non-smokers subjected to secondhand smoke may actually suffer worse consequences than the smokers themselves.
Here are some of the effects of second-hand smoking:
Lung Cancer – Long-term exposure to secondhand cigarette smoke has been shown to increase the risk of lung cancer by 20 – 30%. In fact, each year, hundreds of non-smokers die of lung cancer as a direct result of passive smoking.
Heart Disease – A study published in 1997 by the American Heart Association found that the risk of heart attack and subsequent death is 91% higher (i.e. almost double) for women who were regularly exposed to secondhand smoke when compared to woman who were not exposed. The risk was 58% higher for those who were only occasionally exposed.
Children – Children who are exposed to secondhand smoke have twice the risk of being hospitalized for chest illnesses such as pneumonia and bronchitis, than children not exposed to the smoke. They are also much more likely to get ear infections, tonsillitis, wheezing and childhood asthma. In fact, passive smoking in known to be one of the main contributory factors to the development of childhood asthma and has been shown to increase both the frequency and severity of the asthma attacks.
Now try answering a few questions about smoking and other nicotine products, in Activity 3.
Air Pollution
Overview
Everyday hundreds of toxic chemicals are released into the environment. Many of these chemicals are hazardous to our health and cause adverse reactions. Our body has some defense against these pollutants, but it is important to remember that we should do our best to avoid them. Let’s find out why.
What is air pollution?
Air pollution is a general term for a substance that contaminates the environment. For example, the exhaust emitted from cars contaminates the environment because it releases excessive amounts of ozone, carbon monoxide, nitrogen oxides, and lead.
Pollution can come from gases, particles, or liquids. Many times, these pollutants are man-made, but sometimes they can come from the environment. For example, pollen which is released by trees and plants, can become very abundant in the air we breathe and irritate those people who are allergic.
Why is air pollution so bad for your lungs?
Humans are a collection of organ systems all working together to keep the body in good working order. The body must maintain a balanced environment for the organ systems to function properly. When the body is exposed to pollutants, this balance can be disturbed. For example, when carbon monoxide, a deadly gas found in cigarette smoke and automobile exhaust, is inhaled into the lungs, it interferes with the bloods ability to take up oxygen. Click here to see how.
Some natural pollutants like pollen, ragweed, and molds trigger allergies in the body. Hay fever is a condition characterized by allergic reactions to these natural pollutants.
As the body is exposed to allergens, or allergy-causing substances, it begins to build up a defense. Once the body builds up a defense against a substance, it will release defensive substances like histamine to help protect the natural balance the body needs.
The release of histamine and other defensive substances can trigger itching, sneezing, tissue swelling, and sinus problems. While these may not be deadly, they are often inconvenient and can aggravate other conditions that may be present, like asthma.
Asthma is a condition where allergens like pollen, dust, or other kinds of pollution can cause the airways to become more narrow, and reduce airflow to the blood vessels in the lungs where gas exchange is taking place.
How can air pollution be prevented?
Air pollution cannot be prevented, but it can be reduced. Air pollution comes from many sources, some natural and others are man-made.
Automobile pollution is the largest contributor to air pollution in the United States. This can be reduced by increasing the use of public transportation systems, car pools, and reducing the amount of pollution vehicles cause.
Recycling is also a great way of helping reduce pollution. Recycling means that the factories which make goods for us, do not have to make as many products for us, and do not create as much waste which can pollute our environment.
Where is air pollution found the most?
Pollution is generally highest in large cities and industrial centers.
Pollution from natural sources like pollen from trees is a problem in the eastern and Midwestern United States.
Ragweed, which is the most common cause of hay fever, is found in most parts of the United States.
Pollution can also be an indoor problem. Some allergens like dust or cat and dog hair can build up inside homes and work places and cause extreme discomfort for individuals that are allergic to them. Another source of indoor pollution occurs from chemicals in new or remodeled buildings.
“Sick building syndrome” is a result of the build up of chemicals that are continuously released from new furniture, fabrics, detergents, paints, building materials.
“Sick building syndrome” is increasing in prevalence because buildings are becoming more efficient at heating and cooling the air in a building, by not circulating clean air from the outside into the building.
As chemicals build up in a building they can reach toxic levels and cause illness.
“Sick building syndrome” can be avoided by maintaining a clean environment with adequate circulation of air from the outside. It is also important to store hazardous chemicals properly. Buildings should also be inspected to make sure that the building materials used are safe to live or work in. Air vents and filters must be cleaned regularly to help reduce the number of airborne pollutants.