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Lung Cancer Risks for People Who Don't Smoke

traffic jam on city streets with exhaust fumes coming from cars

Not all people who get lung cancer smoke. As many as 20% of people who die from lung cancer in the United States every year have never smoked or used any other form of tobacco. But, lung cancer in people who have never smoked is one of the most fatal cancers in the United States.

While it’s true that staying away from tobacco is the most important thing any of us can do to help lower our risk of getting lung cancer, there are also other risk factors. Some of the risk factors for lung cancer can cause changes or mutations in the lung cells. These changes can lead to abnormal cell growth and sometimes cancer. Some people who get lung cancer have no known risk factors.

Researchers continue to make progress in understanding what can cause lung cancer in people who have never used tobacco:

  • Radon gas. Radon is a naturally occurring radioactive gas that results from the breakdown of uranium in soil and rocks. Outdoors, there is so little radon that it is not likely to be dangerous. But if there is radon indoors, it can be more concentrated. Breathing it in may increase a person's risk of lung cancer. According to the US Environmental Protection Agency (EPA), radon is the second leading cause of lung cancer in this country, and is the leading cause among people who don't smoke. 
  • Secondhand smoke. Each year, about 7,000 adults die of lung cancer as a result of breathing secondhand smoke. Laws that ban smoking in public places have helped to reduce this danger. The American Cancer Society Cancer Action NetworkSM (ACS CAN) - the nonprofit, nonpartisan advocacy affiliate of the American Cancer Society - is working to expand and strengthen these laws to further protect both people who smoke and those who don't from the dangers of secondhand smoke.
  • Cancer-causing agents at work. Some people are exposed to carcinogens (cancer-causing agents) such as arsenic, uranium, asbestos and diesel exhaust at their workplace. Work-related exposure to such cancer-causing materials has decreased as the government and industry have taken steps to help protect workers. Still, if you work around these agents, be careful to limit your exposure whenever possible.
  • Air pollution. In cities, air pollution (especially near heavily trafficked roads) appears to raise the risk of lung cancer slightly.
  • Gene mutations (changes). Certain changes in lung cells can lead to abnormal cell growth, and sometimes, cancer.

Lifestyle changes to lower risk

People who don't smoke avoid the greatest risk factor for lung cancer. But they can make some other lifestyle changes to help reduce their risk even more.

In addition to testing your home for radon, avoiding secondhand smoke, and limiting exposures to carcinogens at work , following a healthy eating pattern with a variety of fruits and vegetables may also help reduce your risk of lung cancer. Some evidence suggests that a diet high in fruits and vegetables may help protect against lung cancer in both people who smoke and those who don't. 

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.