Road risk

living close to main roads could put your child at risk. A study conducted by German researchers in the Munich metropolitan area showed that traffic- related pollution could be responsible for increasing the risk of allergy and respiratory diseases by more than 50 per cent in children. Parents were asked to fill questionnaires about their children's respiratory symptoms and diagnoses, which included information on asthma, obstructive bronchitis, hay fever, eczema etc.

Ambient air was tested for particulate matter (pm2.5) and NO₂ at each of the forty locations near high traffic areas once in each season between March 1999 and July 2000. pm2.5 absorbance was also measured as a marker for diesel exhaust particles. Researchers used the distance of the children's home to the nearest main road as a surrogate for their exposure to traffic related air pollutants.

After controlling for factors such as pets at home, number of siblings, environmental tobacco smoke etc, researchers found strong positive associations between the distance to the nearest main road and asthmatic bronchitis, hay fever, eczema and sensitization in children. While pm2.5 absorbance was associated with asthmatic bronchitis, hay fever and allergic sensitization to pollen, NO₂ exposure was associated with eczema.

"We found negative effects on children living closer than 50 m from a busy road with declining effects for children living farther away and speculate that this reflects exposure to a traffic related aerosol," said the researchers in the study published in the American Journal of Respiratory and Critical Care Medicine (Vol 177).

The findings provide strong evidence for the adverse effects of traffic related air pollutants on respiratory diseases as well as on allergic sensitization. The results contribute substantially to the current knowledge of traffic exposure and allergic sensitization.