The first study to explore the physical effect of road pollution on brain cells showed significant brain damage to test mice after only short-term exposure to the recreated conditions.
Researchers from the University of Southern California found the mice – which were exposed to traffic pollution for five hours a day, three times a week, for 10 weeks – were affected by a combination of tiny particles produced by burning fossil fuels and eroding car parts and road surfaces.
They found the test subjects’ brains showed signs of inflammation similar to premature ageing and Alzheimer’s disease. The neurons involved in learning and memory loss also showed significant damage, and the brain neurons of developing mice did not grow as well as those not subjected to the particles.
The study’s senior author, Dr Caleb Finch, said the traffic particles – around 1000
the width of a human hair – were too small to be captured by vehicle filtration systems.
“You can't see them, but they are inhaled and have an effect on brain neurons that raises the possibility of long-term brain health consequences of freeway air,” Dr Finch said.“Of course this leads to the question, 'How can we protect urban dwellers from this type of toxicity?' And that's a huge unknown.”
Dr Finch said if the research was supported by further studies, a solution would be difficult to find, and would not be as simple as switching to electric cars.
“It would certainly sharply decrease the local concentration of nanoparticles, but then at present electrical generation still depends upon other combustion processes – coal – that in a larger environment contribute nanoparticles anyway,” he said."It's a long-term global project to reduce the amount of nanoparticles around the world. Whether we clean up our cars, we still have to clean up our power generation.”