Not just lungs affected by pollution.

• Position: Inflammation

Chronic inhalation of polluted air appears to activate a protein that triggers the release of white blood cells, setting off events that lead to widespread inflammation, states a study published in Circulation Research. This finding narrows the gap in researchers' understanding of how prolonged exposure to pollution can increase the risk for cardiovascular problems and other diseases.

The study describes how chronic exposure to very fine particulate matter triggers events that allow white blood cells to escape from bone marrow and work their way into the bloodstream. Their presence in and around blood vessels alters the integrity of vessel walls. They also collect in fat tissue, where they release chemicals that cause inflammation.

The cellular activity resembles an immune response that has spiraled out of control. A normal immune response to a pathogen or other foreign body requires some inflammation but, when inflammation is excessive and has no protective or healing role, the condition can lead to an increased risk for cardiovascular disease, diabetes, and obesity, as well as other disorders.

Though many questions about the beginning of this process remain unanswered...