The single biggest thing you can do is not smoke, or quit if you do

Smoking causes about 80 to 90 percent of lung cancers in people who develop the disease. If you have never smoked, your risk stays low throughout your life. If you smoke now, quitting at any age reduces your risk — even people who quit in their 60s or 70s see their risk drop compared to those who keep smoking.

The risk does not disappear immediately. Someone who quits at 40 takes about 10 years to reach the lung cancer risk of someone who never smoked. Someone who quits at 60 still sees their risk fall, though it stays higher than a lifelong non-smoker. But the longer you do not smoke, the lower your risk becomes.

Secondhand smoke also raises lung cancer risk, though the increase is smaller than for active smokers. If you live or work around smokers, reducing that exposure matters — asking someone to smoke outside, opening windows, or spending less time in that space all help.

Key Takeaways

  • Not smoking is the most powerful way to prevent lung cancer, and quitting at any age lowers your risk compared to continuing to smoke.
  • Radon, a colorless radioactive gas that seeps into some homes from the ground, causes lung cancer in people who breathe it over years; testing your home costs $15 to $30 and takes a few days.
  • Secondhand smoke and air pollution raise lung cancer risk, though the effect is smaller than smoking itself.
  • A screening test called low-dose CT can catch early lung cancers in current or former heavy smokers, but it is not a prevention method — it finds cancer earlier, not prevents it from forming.

Testing your home for radon

Radon is a radioactive gas that comes from uranium in soil and rock. It seeps into homes through cracks in foundations, gaps around pipes, and other openings. You cannot see it, smell it, or taste it. Over decades of breathing radon-contaminated air, your lung cancer risk rises — the EPA estimates radon causes 15,000 to 22,000 lung cancer deaths per year in the United States, making it the second leading cause after smoking.

You find out whether your home has radon by testing. A short-term test takes 2 to 7 days and costs $15 to $30; you place a detector in the lowest lived-in level of your home (usually the basement) and send it to a lab. A long-term test runs for 90 days or more and gives a better picture of your year-round exposure. If the test shows radon above 4 picocuries per liter (pCi/L) — the EPA's action level — you can reduce it by sealing cracks, improving ventilation, or installing a radon mitigation system, which typically costs $1,200 to $2,500.

Radon risk varies by geography. Some regions have naturally higher radon levels in soil. The EPA provides a radon zone map on its website showing which counties have elevated radon potential. Even if your county is in a low-risk zone, testing is still worthwhile because radon levels vary house to house.

Reducing exposure to air pollution

Long-term exposure to outdoor air pollution — particularly fine particles called PM2.5 and nitrogen dioxide from vehicle exhaust and industrial sources — raises lung cancer risk. The effect is smaller than smoking, but it is real and affects people who have never smoked.

You cannot eliminate air pollution exposure entirely, but you can reduce it. On days when air quality is poor (check your local air quality index), limit outdoor activity, especially strenuous exercise. If you live near a highway or industrial area, keeping windows closed on high-pollution days helps. HEPA filters in home air purifiers can reduce indoor PM2.5, though they work best in a single room with the door closed.

Indoor air quality also matters. Cooking on gas stoves releases nitrogen dioxide; using a range hood or opening a window while cooking reduces buildup. Secondhand smoke indoors is a form of air pollution that you can control more directly by asking smokers to smoke outside.

Screening if you are a current or former heavy smoker

Screening does not prevent lung cancer, but it can catch it earlier when treatment is more likely to work. A test called low-dose CT (computed tomography) takes detailed X-ray images of your lungs and can find small tumors that a regular chest X-ray would miss.

Screening is recommended for people aged 50 to 80 who have smoked a pack a day for 20 years or more, or who quit within the last 15 years. The test takes about 10 minutes and involves no injection or contrast dye. You lie still while the scanner moves around your chest. The radiation dose is much lower than a standard CT scan.

Screening has a tradeoff: it sometimes finds nodules (small spots) that turn out to be benign, leading to follow-up scans or biopsies that cause anxiety and cost. Talk with your doctor about whether screening makes sense for you based on your smoking history and overall health. If you do get screened, it is usually done once a year.

Alcohol and diet

Heavy alcohol use is linked to higher lung cancer risk, though the connection is less direct than with smoking — alcohol may damage lung tissue or weaken immune function. Moderate drinking (up to one drink a day for women, two for men) does not appear to raise lung cancer risk.

Diet has a smaller effect than smoking or radon, but some evidence suggests that diets high in vegetables and fruits may offer modest protection. This is not a substitute for quitting smoking or testing for radon, but eating more vegetables is good for overall health regardless.

Occupational and environmental exposures

Certain jobs expose workers to lung cancer risk. Asbestos, silica dust, diesel exhaust, and some metals (like chromium and nickel) can cause lung cancer after years of exposure. If your work involves these materials, your employer is required to provide safety equipment and monitoring. Use protective equipment as instructed, and report unsafe conditions.

Some people have a family history of lung cancer even among non-smokers, which suggests a genetic component. If multiple relatives developed lung cancer, talk with your doctor about whether screening or genetic testing might be relevant for you.

Frequently Asked Questions

If I quit smoking 20 years ago, do I still need to worry about lung cancer?

Your risk is much lower than if you still smoked, but it remains higher than someone who never smoked. The longer you have been quit, the better. If you have a significant smoking history (many pack-years), talk with your doctor about whether screening might be useful, since former smokers can still develop lung cancer.

Does vaping prevent lung cancer the way quitting smoking does?

Vaping is not a proven way to prevent lung cancer. While it exposes you to fewer of the chemicals in cigarette smoke, it still delivers nicotine and other substances to your lungs. If you are trying to quit smoking, talk with your doctor about medications and support that have stronger evidence.

How often should I test my home for radon?

Test once to know your baseline level. If the result is below 4 pCi/L, you do not need to retest unless you make major changes to your home (like sealing the foundation). If you install a mitigation system, test again after a few months to confirm it worked, then periodically to ensure it is still effective.

Can supplements or vitamins prevent lung cancer?

No supplement has been shown to prevent lung cancer. Some studies suggested beta-carotene supplements might help, but later research found they actually increased risk in smokers. Focus on the things with evidence: not smoking, testing for radon, and reducing air pollution exposure.

What if I have symptoms like a persistent cough — does that mean I have lung cancer?

A persistent cough can have many causes, including infection, allergies, or acid reflux. See your doctor if a cough lasts more than a few weeks. They can examine you and order imaging if needed. Catching any lung disease early, whether cancer or something else, is important.