An hour of sniffing diesel fumes in a busy city street may not just give you headache - it can alter the way your brain functions, says a new research which shows that inhaling exhaust induces a stress response in the brain's activity.
The research, led by Paul Borm from Zuyd University in The Netherlands, has for the first time demonstrtated that inhalation actually alters brain activity.
In the study, 10 volunteers were made to spend one hour in a room filled with either clean air or exhaust from a diesel engine. They were wired up to an electroencephalograph (EEG), a machine that records the electrical signals of the brain, and their brain waves were monitored during the exposure period and for one hour after they left the room.
The analyses after 30 minutes found that the diesel exhaust began to affect brain activity. The EEG data suggested that the brain displayed a stress response, indicative of changed information processing in the brain cortex, which continued to increase even after the subjects had left the exposure chamber.
The concentration of diesel exhaust that the subjects breathed was set to the highest level that people might encounter in the environment or at work, for example on a busy road or in a garage.
"We believe our findings are due to an effect nanoparticles or 'soot' particles that are major component of diesel exhaust. These may penetrate to the brain and affect brain function. 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," Borm said.
One link to understanding the mechanism of this effect is that oxidative stress is one consequence of particles depositing in tissue and oxidative stress has also been implicated in degenerative brain diseases such as Parkinson's and Alzheimer's disease.
"It is conceivable that the long-term effects of exposure to traffic nanoparticles may interfere with normal brain function and information processing," Borm said.
"Further studies are necessary to explore this effect, and to assess the relationship between the amount of exposure to particles and the brain's response and, and investigate the clinical implications of these novel findings," he added.
The study is published in the journal Particle and Fibre Toxicology.