Asthma and the motorways--one District's experience

Proposals to widen the section of the M25 motorway that passes through East Surrey caused considerable concern and claims that the traffic on the road was responsible for an increasing prevalence of asthma. This study was designed to ascertain the prevalence of asthma-related symptoms among schoolchildren in the District and determine whether there was an association with proximity to a motorway.

A total of 2387 children aged between 13 and 14 from 17 schools in East Surrey were invited to participate in a survey of the prevalence of asthma-related respiratory symptoms. The survey instrument used was the core asthma questionnaire of the International Survey on Asthma and Allergies in Childhood (ISAAC). The children were grouped according to electoral ward of residence and comparisons were made between urban and rural wards, and the presence or absence of a section of motorway.

The prevalence of reported symptoms varied from 2.2 per cent reporting sleep disturbance on more than one night each week to 40 per cent reporting a wheezing episode at some time in their lives; 16 per cent reported a diagnosis of asthma. The overall prevalence of symptoms did not differ greatly from that reported in other similar studies. There was a decrease in the prevalence of asthma-related symptoms in areas close to motorways, which was statistically significant for two questions. This is unlikely to be due to the rural location of the motorways.

This study suggests that the motorways in East Surrey, in their present configuration, are not responsible for an increased prevalence of respiratory symptoms associated with asthma.