Air Pollution Hinders Brain Processing

Researchers at Zuyd University in the Netherlands have reported that nanoparticles from inhaled air pollution reach the brain and alter the way it processes information.The study is the first to demonstrate this effect.

During the research, the Zuyd University team had 10 participants spend an hour in a closed room with either clean air or diesel engine exhaust, similar to an environment experienced by those who work in a garage or by the roadside.

The volunteers were monitored with an electroencephalograph (EEG) that measured electrical signals of the brain for a period of one hour after they left their room.

After 30 minutes, the researchers found that the brains of those in the rooms with diesel exhaust displayed an EEG stress response indicative of a change in processing functions in the cortex of the brain. This effect continued even though the participants were no longer exposed to the exhaust.

"We can only speculate what these effects may mean for the chronic exposure to air pollution encountered in busy cities where the levels of such soot particles can be very high," lead researcher Paul Borm told BBC News.

"It is conceivable that the long-term effects of exposure to traffic nanoparticles may interfere with normal brain function and information processing. Further studies are necessary to explore this effect."

Ken Donaldson, a professor of respiratory toxicology at the University of Edinburgh, told BBC News that a brain response to a new smell is not surprising.

"And it may not necessarily be negative, but such physiological changes do warrant investigation because there could indeed be a long-term effect. It's a very interesting, and potentially important, study."

Controlled studies examining air pollution’s effect on the brain presents ethical dilemmas, and longer-term studies of those living in areas of high pollution can be challenging since brain diseases are not always identified as the cause of death on death certificates. For instance, Alzheimer's patients often die of infection.

However, a study of dogs in Mexico showed those living in Mexico City, an area of high pollution, had brain lesions similar to those observed in Alzheimer's patients. The dogs in less-polluted rural areas had a much lower rate of brain damage.

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The study was published in the journal Particle and Fibre Toxicology. The full report can be viewed at http://www.particleandfibretoxicology.com/content/pdf/1743-8977-5-4.pdf