THE GUARDIAN – Air pollution from traffic is linked to some of the more severe forms of dementia, and could be a significant cause of the condition among those who are not already genetically predisposed to it, research suggests.
Research carried out in Atlanta, Georgia, found that people with higher exposure to traffic-related fine particulate matter air pollution were more likely to have high amounts of the amyloid plaques in their brains that are associated with Alzheimer’s.
The findings, which will alarm anyone living in a town or city, but particularly those living near busy roads, add to the harms already known to be caused by road traffic pollution, ranging from climate change to respiratory diseases.
A team of researchers from Atlanta’s Emory University set out to specifically investigate the effects on people’s brains of exposure the type of fine particulate matter known as PM2.5.
This consists of particles of less than 2.5 microns in diameter – about a hundredth the thickness of a human hair – suspended in the air, and is known to penetrate deep into living tissue, including crossing the blood-brain barrier.
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Traffic-related PM2.5 concentrations are a major source of ambient pollution in the metro-Atlanta area, and also in urban centres across the planet.
The Emory researchers examined the brain tissue of 224 people from Atlanta, 90% of whom had a diagnosis of some form of dementia, who had agreed to donate their brains to medical science after their deaths.
They also investigated the traffic-related PM2.5 pollution exposure at subjects’ homes in the years leading up to their deaths.
The average level of exposure in the year before death was 1.32 micrograms per cubic metre (µg/m3) and 1.35 µg/m3 in the three years before death.
“We found that donors who lived in areas with high concentrations of traffic-related air pollution exposure, in particular PM2.5 exposure, had higher levels of Alzheimer’s disease neuropathology … ”
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