Engaging in certain behaviors and exposure to harmful elements in the environment increases your risk for lung cancer. Other risk factors are uncontrolled, making some people naturally more susceptible to the disease. Smoking compounds every risk factor, dramatically increasing your chance of developing lung cancer.   

Personal History and Lifestyle Choices


Smoking tobacco (cigarettes, cigars, and pipes) is the number-one risk factor for lung cancer. It is responsible for nearly 90% of all lung cancer cases. Tobacco and tobacco smoke contain 4,000 chemicals (such as nitrogen oxide and carbon monoxide), many of which are carcinogenic (cancer-causing). Inhaling the chemicals in a cigarette immediately triggers a change in lung tissue. Your body is initially able to repair the damage, but its ability to do so decreases as exposure continues. The more frequent and the longer you smoke, the greater your chance for lung cancer.

Second-hand smoke

If you don’t smoke, but are exposed to cigarette smoke regularly in your daily environment (at home or work, or in restaurants and bars), you increase your risk for lung cancer by 20-30%.


Current research suggests that if a member of your immediate family (mother, father, sibling, aunt, uncle, or grandparent) has or had lung cancer, you may have a slightly higher risk of developing the disease, even if you don’t smoke. At this point, it is unclear whether genetics causes lung cancer, or merely increases your susceptibility to it. 


Lung cancer usually occurs in people aged 50 or older, and most people diagnosed with lung cancer are over the age of 65. The older you get, the longer you are exposed to harmful chemicals, therefore increasing your likelihood for cancer.


A balanced diet provides your body with the vitamins and minerals it needs to maintain good health. (However, some studies suggest that beta carotene supplements may increase the risk of lung cancer in smokers.) If you don’t eat a diverse mix of healthy foods, such as fruits and vegetables, you may have an increased risk for lung cancer, especially if you are a smoker.  

Past Lung Disease

Past lung illnesses, such as tuberculosis, recurring bronchitis, emphysema, and chronic obstructive pulmonary disease (COPD), can cause inflammation and scarring in the lungs. If you have a history of chronic illnesses that affect the lungs, you may be at a greater risk of developing lung cancer.

Radiation Therapy to the Chest

Radiation therapy used to treat other cancers, such as Non-Hodgkin’s lymphoma and breast cancer, may increase your risk of lung cancer, especially if you smoke.

Environmental Factors


Radon is an odorless, colorless, and tasteless gas that occurs naturally with the breakdown of uranium in rocks and soil. Unsafe levels of radon can exist in work environments and homes, where it can go undetected. Furthermore, people who smoke have an increased risk from the affects of radon that those who don’t smoke. Radon is the second-leading cause of lung cancer in the United States.


Asbestos is an industrial material used in construction for insulation and as a fire retardant. When the material is disturbed, small fibers become airborne and can be inhaled. If you are exposed to asbestos regularly, you are at a greater risk for developing lung cancer.

Other Chemicals and Minerals

Exposure to other chemicals, such as arsenic, beryllium, cadmium, vinyl chloride, nickel compounds, chromium compounds, coal products, mustard gas, chloromethyl ethers, and diesel exhaust, greatly increases your risk for lung cancer.

Air Pollution

Recent studies show that air pollution, especially if you live or work in a city where air quality is low, may slightly increase your risk for lung cancer. The risk is still much lower than smoking. Only 5% of lung cancer deaths around the world are cause by outdoor air pollution.