The lungs of a person who smokes may be larger, discolored, and inflamed compared to those of a person who does not smoke.

The lungs are part of the respiratory system, which takes oxygen in from the air and removes carbon dioxide. Although several factors may compromise lung function, including genetic diseases, infections, and environmental exposures, smoking remains one of the most dangerous.

In this article, we discuss the functional and structural differences between a smoker’s lungs and healthy lungs. We also provide some tips on quitting smoking and improving lung function.

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Illustration by Diego Sabogal

Smoking can change the physical appearance of the lungs. Diagnostic tests, such as a CAT scan and chest X-ray, may identify some of the changes. The chart below summarizes some common physical changes.

Healthy lungsSmoker’s lungs
PinkGray or black
Normal sizeHyperinflated
No inflammationPatches of inflammation
Dome-shaped diaphragmDiaphragm muscle loss

Smoking not only causes physical changes but also alters the function of the lungs. The amount of time that it takes for the changes to develop varies among individuals.

The changes cause several symptoms that interfere with normal breathing. In general, the differences between a smoker’s lungs and healthy lungs include the following:

Increased mucus production

Smoking may cause the lungs to produce more mucus.

This increased mucus production can happen for a few reasons, but it primarily occurs because smoking cigarettes damages the epithelial cells that line the airway. Inflammatory cells develop due to the damage, and this promotes goblet cell production, leading to increased mucus.

Although it can vary in consistency and quantity, the lungs of many smokers produce moderate-to-large amounts of thick mucus.


It is common for smokers to cough frequently or even develop a chronic cough. Often, smokers’ lungs sustain damage to the cilia. Cilia are small hairs in the airway that help keep dirt and other irritants out of the lungs.

Usually, smoking damages the cilia by either paralyzing or destroying them, which allows irritants to get into the airways. This may lead to a long-term cough.

Low oxygen levels

Smoking may lead to thickening and scarring of the capillary walls in the lungs. The capillaries are small blood vessels, which allow oxygen to pass through and subsequently travel to the tissues in the body. Damage to the capillaries may interfere with proper gaseous exchange, resulting in low oxygen levels.


Typically, a smoker’s lungs have more inflammation than healthy lungs. The chemicals in cigarettes may damage the tissues in the lungs, which leads to inflammation. Lung inflammation narrows the airways, often causing chest tightness and wheezing.

Shortness of breath

The combination of the changes that smoking causes in the lungs may lead to shortness of breath.

Several of these changes, including damage to the cells that line the airways, destroyed cilia, and increased mucus, make breathing difficult. As a result, breathlessness may occur with even mild physical exertion.

Learn more about lung function here.

Cigarette smoke contains more than 7,000 chemicals, including:

  • nicotine
  • ammonia
  • carbon monoxide
  • acetaldehyde

Some of the chemicals above are carcinogens, which means that they may cause cancer in humans. In addition, the chemicals may damage the lungs in other ways, such as leading to scarring or inflammation and damaging cells and blood vessels.

Over time, smoking may change the lungs enough to cause respiratory conditions, such as emphysema and chronic bronchitis. In addition to smoking, extensive exposure to secondhand smoke can change the lungs and lead to certain respiratory conditions.

Learn more about how smoking affects the lungs here.

One of the best ways to minimize the risk of lung damage is to avoid ever smoking. People who already smoke can choose from different options to help them break the habit. Those looking to stop smoking may wish to consider the following tips:

Learn about different quitting methods

There are many different ways to quit smoking, and no one way is right for everyone. Certain methods of smoking cessation have more research behind them than others, but even less-proven techniques work for some people.

Smoking cessation options include:

  • nicotine replacement, which is available in the form of patches, gums, and sprays
  • medication, such as bupropion (Zyban) or Chantix
  • hypnosis
  • counseling
  • acupuncture

Consider more than one method

There is no rule that someone must choose only one technique to help them quit smoking. Sometimes, a combination of methods is most effective. For example, using nicotine replacement therapy along with counseling may increase the chances of success for some people.

Enlist support

Some people might find it helpful to tell family and friends about their intention to quit smoking, as these loved ones may be able to provide support.

Alternatively, online and in-person support is available through the American Lung Association and

Stick with it

It is not uncommon to experience setbacks when trying to quit smoking. Giving in to temptation and having a cigarette does not mean failure. Instead, a person can learn from the experience and try to find additional or alternative ways to increase their chances of staying smoke-free in the future.

Learn more about how to quit smoking here.

Refraining from smoking is one of the best ways to keep the lungs healthy. However, people can take other steps to protect their lungs and maintain good lung health. These include:

  • Exercising regularly: Exercise helps increase how efficiently the body uses oxygen. It can also decrease the risk of certain diseases that may affect lung health. The Centers for Disease Control and Prevention (CDC) advise that all adults aim for at least 150 minutes of exercise a week.
  • Protecting against infection: In some cases, infections can damage the lungs. People can reduce the risk of lung infection by washing the hands frequently, staying away from people when they are sick, and getting an annual flu vaccine, if a doctor recommends it.
  • Reducing indoor pollutants: Various indoor air pollutants can lead to lung irritation, contribute to lung disease, and make current respiratory conditions worse. Keeping the home free from chemical solvents, asbestos, and secondhand smoke can help protect lung health.

Learn more about how to keep the lungs healthy here.

Smokers’ lungs are different than healthy lungs in several ways. Smoking can not only change the appearance of the lungs but also cause functional changes, such as damage to the cells that line the airway, the cilia, and the capillaries in the lungs.

The structural damage may result in various symptoms, including chronic coughing, increased mucus, and shortness of breath. The best way to avoid this is to refrain from or quit smoking. There are several ways to quit smoking, including using medication, nicotine patches, and behavioral counseling.