Air Pollution and Lung Cancer: What's the Link?

Lung cancer is becoming more common in people who never smoked. Scientists think air pollution might be a big reason why. A recent study looked at the DNA of lung tumors in 871 non-smokers from around the world. They found that people exposed to more pollution had more DNA changes linked to cancer. The study didn't prove that pollution directly causes lung cancer. But it did show a strong connection between pollution and certain DNA changes. These changes are often seen in smokers but were also found in non-smokers exposed to polluted air. The researchers also found a new type of DNA change in non-smokers. This change, called SBS40a, wasn't seen in smokers. The cause of this change is still a mystery. The study also found that people in polluted areas were nearly four times more likely to have a specific DNA change called SBS4. Secondhand smoke, on the other hand, didn't show a strong link to DNA changes. This suggests that its effect might be too weak to detect with current tools. The study also compared lung cancer genomes from non-smokers and smokers. This helped identify similarities and differences in their DNA changes. The study has some limitations. It only looked at regional pollution levels, not individual exposure. Also, some participants might have smoked more than they reported. Despite these limits, the findings add to growing evidence that pollution may trigger cancer in ways similar to smoking. Scientists are now working to understand this problem better. They plan to study more cancer genomes from a diverse, global group. This research is important because lung cancer in non-smokers is a growing issue worldwide.