Smoking and Your Lungs

What Cigarettes Do

When you smoke cigarettes, many chemicals enter your body through your lungs. Burning tobacco produces more than 4,000 chemicals. Nicotine (NIK-uh-TEEN), carbon monoxide (muh-NOK-side), and tars are some of these substances.

Smoking greatly affects your lungs and airways. Smokers get a variety of problems related to breathing. Problems range from an annoying cough to grave illness like emphysema (EM-fuh-ZEE-muh) and cancer.

How Your Lungs and Airways Change

Smoking cigarettes causes many changes in your lungs and airways. Some changes are sudden, last a short time, and then go away. Colds and pneumonia are examples of this.

Other changes happen slowly and last a long time, often for the rest of your life. These are chronic changes. Emphysema is an example of a chronic change.

Here is a list of the changes that happen in your lungs and airways when you smoke:

  • The cells that produce mucus in your lungs and airways grow in size and number. As a result, the amount of mucus increases. The mucus is also thicker.
  • The cleaning system in your lungs does not work well. The lungs have broom-like hairs, called cilia (SILL-ee-uh). The cilia clean your lungs. A few seconds after you start smoking a cigarette, the cilia slow down. Smoking one cigarette can slow the action of your cilia for several hours. Smoking also reduces the number of cilia, so there are fewer cilia to clean your lungs.
  • Your lungs and airways have more mucus, and the mucus is not cleaned out well. So the mucus stays in your airways, clogs them, and makes you cough. This extra mucus can easily get infected.
  • Your lungs and airways get irritated and inflamed. They become narrow and reduce the air flow. Even one or two cigarettes cause irritation and coughing.
  • As you age, it’s normal for your lungs not to work as well. When you smoke, your lungs age faster.
  • Your lungs can be destroyed. When lung tissue is destroyed, the number of air spaces and blood vessels in the lungs decreases. Less oxygen is carried to your body.
  • You are less protected from infection. When you smoke, the natural defenses your lungs have against infection do not work well.
  • Cigarette smoke has chemicals that can make normal cells change into cancer cells.

Weigh the Benefits of Quitting Smoking

When you smoke, you have a much greater chance of getting health problems. In this section, you will learn about the kinds of problems you can get from smoking. You will also learn how you benefit when you quit smoking.

Breathing-related symptoms

When you smoke:
  • Chronic cough
  • More mucus
  • Shortness of breath
  • Wheezing

When you quit:

  • Fast decrease in breathing-related symptoms no matter how much or how long you smoked
  • Easier breathing within 72 hours
  • Marked decrease in cough, mucus, shortness of breath, and wheezing within 1 month
  • Less irritated and inflamed airways
  • Cilia growth in 1 to 9 months
  • Lungs more able to handle mucus, self-clean, and fight infection

Colds and lung infections

When you smoke:
  • More colds and lung infections
  • Worse colds and lung infections

When you quit:

  • Fewer colds and lung infections
  • Milder colds and lung infections

Flu and pneumonia

Smoking increases the number of deaths from flu and pneumonia (new-MONE-yuh). As fewer people smoke, the death rate from flu and pneumonia drops rapidly.

When you smoke:

  • More and worse bouts of the flu
  • More chance of pneumonia
  • Poor response to flu vaccine

When you quit:

  • 50 percent less risk of pneumonia within 5 years
  • Fewer and milder bouts of the flu
  • Better response to flu vaccine

Chronic Obstructive Pulmonary Disease (COPD)

Cigarette smoking is a major cause of COPD. COPD stands for chronic (KRON-ick) obstructive (ob-STRUCK-tiv) pulmonary (PULL-muh-nair-ee) disease. COPD blocks the flow of air into and out of your lungs. It is a leading cause of death in the United States. More than 80 percent of COPD deaths are related to smoking. When you smoke, your risk of death from COPD is 10 times greater than if you did not smoke.

COPD includes two diseases: chronic bronchitis (bronk-EYE-tis) and emphysema.

When you have chronic bronchitis:

  • You get a long-lasting cough every year
  • Your cough produces a lot of mucus that blocks air flow

When you quit smoking:

  • Symptoms of chronic bronchitis decrease
  • Symptoms of chronic bronchitis may disappear over time

When you have emphysema:

  • Your lung tissue is destroyed over time
  • Your lungs are less able to take in fresh air and let out stale air
  • Your lungs and airways produce a lot of mucus that blocks air flow

When you quit smoking:

  • You get a small improvement right away
  • The disease slows down
  • You have a better chance of living longer


Asthma (AZ-muh) is a chronic airway disease. People with asthma have periods of shortness of breath, wheezing, chest tightness, and cough.

When you smoke:

  • Symptoms of asthma are harder to control; many inhalers aren't as effective

When you quit:

  • Symptoms of asthma decrease


Lung cancer is the leading cause of cancer death in the United States. Smoking causes 85 percent of lung cancer. Smokers have a higher number of pre-cancer changes in their airways than non-smokers.

When you smoke:

  • Pre-cancer tissue can change to cancer
  • Your risk of lung cancer and death is 20 times greater than a non-smoker’s
  • Your risk increases the more you smoke and the longer you smoke

When you quit:

  • Pre-cancer tissue may return to normal
  • Your risk of lung cancer decreases within 5 years
  • Your risk of lung cancer keeps decreasing over time

How Second-hand Smoke Affects You

When people are smoking, the air around them is polluted with tobacco smoke. This is called second-hand smoke. Second-hand smoke comes from two sources. The burning end of the cigarette produces smoke, and the smoker exhales smoke.

When near a person smoking, non-smokers breathe second-hand smoke. Other names for breathing second-hand smoke are “passive smoking” and “involuntary smoking.” Passive smoking has bad effects on the lungs and airways in both adults and children.

Researchers have studied adult non-smokers who breathe cigarette smoke in the work place. Results show these adults have impaired lungs. Second-hand smoke is a carcinogen (car-SIN-oh-jin). A carcinogen is a substance known to cause cancer. When you breathe second-hand smoke, your risk of lung cancer increases. In the United States each year, an estimated 3,000 people die from lung cancer caused by second-hand smoke.

When you breathe second-hand smoke, you can get:

  • Wheezing
  • Chronic cough
  • Increased mucus
  • Shortness of breath
  • Trouble controlling asthma
  • More lung infections and pneumonia
  • Lung cancer

Stay away from second-hand smoke.

Get Help to Quit Smoking

UPMC offers programs to help people quit smoking. Another name for quitting smoking is smoking cessation (sess-AY-shun). For help to quit smoking, call the UPMC Referral Service at 1-800-533-UPMC (8762).

Reviewed 2011

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