Diesel - it goes to your head!

By Jayne Warren - 18/03/2008

Breathing in diesel fumes, it seems can go straight to your head - and it's not good news.

A study published in the Particle and Fibre Toxicology Journal reveals that an hour of exposure to diesel exhaust can actually alter brain activity. Previous studies have already suggested that very small particles, called nanoparticles, breathed in from polluted air can end up in the brain - but this is the first time that scientists have demonstrated that inhalation actually alters brain activity.

Ten volunteers - who must have been a bit deranged or paid a lot - spent one hour in a room filled with either clean air or exhaust from a diesel engine. They were then 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.

After about 30 minutes the diesel exhaust began to affect brain activity. The EEG data showed 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 fumes 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.

Lead researcher Paul Borm from Zuyd University in The Netherlands said: “We believe that nanoparticles, or ‘soot’ particles - which are the major component of diesel exhaust - may penetrate to the brain and affect its 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.”

Oxidative stress - a consequence of particles depositing in tissue - has also been implicated in degenerative brain diseases such as Parkinson’s and Alzheimer’s disease.

Borm continued: “It is conceivable that the long-term effects of exposure to traffic nanoparticles may interfere with normal brain function and information processing. We need to investigate the clinical implications of these novel findings.”

As a final note, studies that expose volunteers to potential toxins are limited for ethical reasons - which makes further research rather tricky. Borm is currently conducting experiments where volunteers inhale artificially generated nanoparticles that are free from the other chemicals that are generated, along with the nanoparticles in diesel exhaust.

In any event, it's not good news for those living in heavily polluted cities, nor for car mechanics or truck drivers ...