The document discusses how smoking causes damage to the lungs and respiratory system. It begins by describing how tobacco smoke moves through the respiratory tract and deposits carcinogens and toxins in the lungs. A person who smokes a pack a day for 40 years will have inhaled smoke from over 290,000 cigarettes, placing them at high risk for diseases like COPD and lung cancer. Tobacco smoke irritates the lungs over time, scarring the tissue and reducing lung function. The document also reviews previous reports from the Surgeon General that established smoking as a leading cause of respiratory diseases.

1. Lungs/tobacco/smoking and Alveoli tissue
Introduction
The respiratory system extends from the nose and upper airway to the alveolar surface of the lungs,
where gas exchange occurs. Inhaled tobacco smoke moves from the mouth through the upper
airway, ultimately reaching the alveoli. As the smoke moves more deeply into the respiratory tract,
more soluble gases are adsorbed and particles are deposited in the airways and alveoli. The
substantial doses of carcinogens and toxins delivered to these sites place smokers at risk for
malignant and nonmalignant diseases involving all components of the respiratory tract including
the mouth.
Consider, for example, the lungs of a 60-year-old person with a 40-pack-year smoking history
starting at age 20 years. By age 60 years, this person will have inhaled the smoke from
approximately 290,000 cigarettes and will bear a substantial risk for chronic obstructive pulmonary
disease (COPD) and lung cancer. The dose of inhaled toxic particles and gases received from each
of these cigarettes varies depending on the nature of the tobacco, the volume and number of puffs
of smoke drawn from the cigarette, the amount of air drawn in through ventilation holes as the
smoke is inhaled, and local characteristics within the lung that determine the diffusion of toxic
gases and the deposition of particles. Because of this repetitive and sustained injurious stimulus,
the repair and remodel process that heals the damaged lung tissue takes place at the same time the
lung’s defenses continue to deal with this unrelenting inhalation injury.
This document addresses the mechanisms by which tobacco smoke causes diseases other than
cancer in the lower respiratory tract: the trachea, bronchi, and lungs. Beginning with the first
Surgeon General’s report in 1964[1], cigarette smoking has been causally linked to multiple
diseases and to other adverse effects on the respiratory system. In addition to causing lung cancer
and COPD, smoking increases the risk of death from pneumonia and causes chronic bronchitis [2].
Typically, the lungs of smokers show evidence of diffuse changes affecting the lining of the
airways, the epithelium, and the structure of the bronchioles, which are the smaller air-conducting
tubes.

2. Previous reports of the Surgeon General have also addressed the effects of smoking on the
respiratory tract. In discussing the plausibility of associations of cigarette smoke with chronic
bronchitis and emphysema, the 1964 report gave full consideration to the nature of tobacco smoke
and its effects on the respiratory tract [3]. That report concluded that cigarette smoking “… is the
most important of the causes of chronic bronchitis in the United States…” and that “a relationship
exists between pulmonary emphysema and cigarette smoking, but it has not been established that
the relationship is causal”. The 1984 report, which focused on COPD, covered mechanisms by
which smoking affects the lung’s structure and function and the deposition and toxicity of cigarette
smoke in the lung [4]. The report concluded that “cigarette smoking is the major cause of chronic
obstructive lung disease in the United States…”. The mechanisms of lung injury were considered
further in the 1990, 2004, and 2006 reports [5,6,7]
Impacts to alveoli
This seemingly perfect machine for breathing can break down or become less efficient because of:
 disease
 normal aging
 smoking and air pollution
Smoking
According to the U.S. Centers for Disease Control, tobacco smoke injures your lungs Trusted
Source and leads to lung diseases like chronic obstructive pulmonary disease (COPD),
emphysema, and chronic bronchitis.
Tobacco smoke irritates your bronchioles and alveoli and damages the lining of your lungs.
Tobacco damage is cumulative. Years of exposure to cigarette smoke can scar your lung tissue so
that your lungs can’t efficiently process oxygen and carbon dioxide. The damage from smoking
isn’t reversible.
Pollution
Indoor pollution from secondhand smoke, mold, dust, household chemicals, radon, or asbestos can
damage your lungs and worsen existing lung disease.

3. Outdoor pollution, such as car or industrial emissions, is also harmful to your lungs.
Disease
Chronic smoking is a known cause of lung disease. Other causes include genetics, infections, or
compromised immune systems. Chemotherapy and radiation treatments for cancer can also
contribute to lung disease. Sometimes the cause of lung disease is unknown.
Lung disease has many types, all of which affect your breathing. Here are some common lung
diseases:
 Chronic obstructive pulmonary disease (COPD). Airway obstruction from damaged
alveoli walls.
 Asthma. Inflammation narrows your airways and blocks them.
 COPD. Damage to the alveoli causes them to break down, reducing the surface area
available for gas exchange.
 Idiopathic pulmonary fibrosis. The walls surrounding the alveoli become scarred and
thickened.
 Lung cancer. Cancer can start in your alveoli.
 Pneumonia. The alveoli fill with fluid, limiting oxygen intake.
Aging
The normal aging process can slow down your respiratory system. You may notice that your lung
capacity is lessened, or that your chest muscles are weaker.
Older people also tend to be more at risk for pneumonia, both bacterial and viral.
Read more about growing older and your lung health.
Alveoli and lung health
Limit your exposure to pollutants
Use an air cleaner or purifier at work or at home to reduce indoor dust and fumes. You can also
wear a mask, if you’re exposing yourself to extra dust, mold, or allergens.
Be aware of days when outdoor air pollution is high. You can find forecasts online for

4.  air quality
 pollen counts
 wind speeds and direction when you look up weather forecasts in your area
On days when the air quality index (AQI) is at an unhealthy range, keep your exposure minimal
by keeping doors and windows closed and circulating air inside.
Decrease how often you smoke
Number one on the list for keeping your lungs healthy is to not smoke.
If you’re interested in ways to quit, there are new methods to try, such as nicotine replacement
therapy. You can also check out blogs for people trying to quit. Or join a support group, such as
Quit Now: Freedom from Smoking, sponsored by the American Lung Association.
Take care of your health
 Get regular health checkups to know how your physical health is doing in general.
 Maintain a strong immune system. This can include keeping up-to-date with vaccinations
and flu shots.
 Eat a healthy diet, with a variety of fruits, vegetables, grains, and protein sources.
 Get regular exercise. Exercise helps keep your lungs in good shape by making them work
harder.
Experimental
Build a Lung Model Step-by-Step
1. Have an adult help you cut the 2-liter bottle in half; you will only use the top part; discard the
bottom and the bottle cap.
2. Cut a square of plastic from the bag. Make it big enough to cover the large opening of the cut
bottle (about 8”). Don’t worry about getting the edges perfectly straight!

5. 3. Stand the bottle top on the table and place the sheet of plastic over the large opening, use a large
rubber band to secure it around the bottle. Gently pull the edges of the plastic, so it is tight across
the top.
4. Cut off the excess plastic next to the rubber band.
5. Put the straw into the balloon and seal the opening around the straw with several pieces of tape.
Blow gently on the end of the straw to make sure air goes into the balloon. If the balloon doesn’t
puff out a little, seal it around the straw better so air cannot escape.

6. 6. Put the balloon end into the bottle’s opening and use modeling clay to secure the straw to the
bottle so that air can only pass through the straw.
7. Fold a piece of tape in half with sticky sides together leaving the ends exposed (only stick the
tape together in the middle). Attach the sticky ends to the bottom of the plastic.
8. Use the tape tab as a handle and gently pull down slightly on the plastic and watch what happens
to the balloon. Now push up gently while watching the balloon.
Results and discussion
The contraption you built is a model of how your lungs work! The plastic at the bottom works like
your diaphragm—a strong muscle that expands and contracts to cause your lungs to fill with air
and then empty out again. The movement of the balloon matches your breathing – when you
breathe in, your lungs fill with air just like the balloon did. That’s because the diaphragm expanded
making room for air to get in through the straw (which represents your airway, or trachea). When
you breathe out, your diaphragm contracts (or squeezes in) pushing all the air out of your lungs.

7. The same thing happened in your soda bottle model – when you pulled down on the plastic, the
balloon inflated slightly and when you pushed up, the balloon deflated! Inside your body, you have
two lungs that work together, and the diaphragm is below them. Air goes in and out of both of
your lungs at the same time. This model just represents one lung.
Conclusion:
This fake lung demonstrates how our lungs work. Air is taken in through the mouth and nose,
passes down the windpipe and into our lungs. The diaphragm at the bottom of our chest moves
down to create more space. As we breathe out the diaphragm raises again. The knotted balloon
represents the diaphragm and the balloon inside the container the lung. That’s how lungs work!!
Reference
[1]US Department of Health, Education, and Welfare. Smoking and Health: Report of the
Advisory Committee to the Surgeon General of the Public Health Service. Washington:
U.S. Department of Health, Education, and Welfare, Public Health Service, Center for
Disease Control; 1964. PHS Publication No 1103.
[2]US Department of Health and Human Services. The Health Consequences of Smoking: A
Report of the Surgeon General. Atlanta: U.S. Department of Health and Human Services,
Centers for Disease Control and Prevention, National Center for Chronic Disease
Prevention and Health Promotion, Office on Smoking and Health; 2004.
[3]US Department of Health, Education, and Welfare. Smoking and Health: Report of the
Advisory Committee to the Surgeon General of the Public Health Service. Washington:
U.S. Department of Health, Education, and Welfare, Public Health Service, Center for
Disease Control; 1964. PHS Publication No 1103.
[4]US Department of Health and Human Services. The Health Consequences of Smoking: Chronic
Obstructive Lung Disease A Report of the Surgeon General. Rockville (MD): U.S.

8. Department of Health and Human Services, Public Health Service, Office on Smoking and
Health; 1984. DHHS Publication No. (PHS) 84-50205.
[5]US Department of Health and Human Services. The Health Benefits of Smoking Cessation A
Report of the Surgeon General. Atlanta: US Department of Health and Human Services,
Public Health Service, Centers for Disease Control, National Center for Chronic Disease
Prevention and Health Promotion, Office on Smoking and Health; 1990. DHHS
Publication No. (CDC) 90-8416. [PubMed]
[6]US Department of Health and Human Services. The Health Consequences of Smoking: A
Report of the Surgeon General. Atlanta: U.S. Department of Health and Human Services,
Centers for Disease Control and Prevention, National Center for Chronic Disease
Prevention and Health Promotion, Office on Smoking and Health; 2004.
[7]US Department of Health and Human Services. The Health Consequences of Involuntary
Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta: U.S. Department
of Health and Human Services, Centers for Disease Control and Prevention, Coordinating
Center for Health Promotion, National Center for Chronic Disease Prevention and Health
Promotion, Office on Smoking and Health; 2006.