Diesel fueled cars are already associated with the negative image of heavy trucks clogging the air with their dark and sooty exhaust plumes, and a new study only goes further to damage it's reputation. Dutch scientists have found that breathing diesel exhaust fumes can trigger a response in the brain that can have damaging long-term effects on basic brain functions.

Studies in the past have already shown that small particles of soot in diesel exhaust can travel from the nose and lodge in the brain, but this is the first time researchers have found actual adverse effects on brain activity.

"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," said Zuyd University researcher Paul Borm in an interview with Reuters. "It is conceivable that the long-term effects of exposure to traffic nanoparticles may interfere with normal brain function and information processing."

Scientists put ten volunteers in a room filled with exhaust from a diesel engine (comparable with levels of an urban environment) for an hour and found that after just 30 minutes brain wave patterns displayed a ‘stress’ response. To make matters worse, researchers also said the small particles in the exhaust are also linked with respiratory and cardiovascular disease.

This is worrying considering that carmakers around the world are trying to increase the number of diesel models in their fleets, and it will be interesting to see if new emissions regulations will have a genuine effect on air quality in the near future.