More than 200,000 people in the U.S. are diagnosed with lung cancer every year. And smoking is not always to blame.

Gomez: “Approximately 10-20% of patients who have lung cancer are never-smokers.”

Jorge Gomez is an oncologist at the Icahn School of Medicine at Mount Sinai in New York City.

He says that several environmental risk factors contribute to lung cancer in nonsmokers.

Some of the biggest are secondhand smoke and radon. But air pollution — caused in part by burning fossil fuels — has also been linked to the disease.

Gomez: “There are many studies that have looked at areas that clearly have a higher level of particulate matter and ozone, and there is a clear increase in the incidence of lung cancer.”

Scientists are still trying to understand exactly how air pollution particles increase the risk of lung cancer.

One recent study by researchers in the United Kingdom suggests that when tiny particles of pollution are inhaled, they can cause inflammation that can activate cells carrying cancer-forming mutations.

More research is needed to understand the biological mechanisms at work.

But Gomez says it’s clear that breathing air pollution puts people at higher risk of this deadly disease.

Reporting Credit: Sarah Kennedy / ChavoBart Digital Media