ALZHEIMER’S DISEASE LINKED TO CITY POLLUTION?. Cause and effect?. If a cause then what is the mechanism?. More and more recent studies show a strong connection between exposure to airborne particles from car exhausts and Alzheimer’s disease (and possibly Lewy Body disease). The tiny airborne particles (Particulate Matter or PM 2.5), 1/30th diameter of a human hair) probably enter the brain via the nose, olfactory (smell) nerve and olfactory bulb or via a weakened ‘blood-brain barrier’. They may act by…..