Blood markers reveal how air pollution may lead to lung cancerResearchers have identified chemical changes in the blood that may help explain how air pollution leads to lung cancer, according to a new study. Air pollution is already known to be a major cause of lung cancer, but scientists have struggled to understand exactly how dirty air triggers the disease inside the body. The participants, drawn from two long-running US cancer studies, gave blood samples while still healthy. Some participants went on to develop lung cancer years later. Still, they say identifying these biological warning signs could eventually help doctors flag people at higher risk from air pollution before cancer develops, and could point toward new targets for prevention.