Background Proposals to widen the section of the M25 motorway that pas
ses through East Surrey caused considerable concern and claims that th
e 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 wh
ether there was an association with proximity to a motorway. Methods 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 a
sthma-related respiratory symptoms, The survey instrument used was the
core asthma questionnaire of the International Survey on Asthma and A
llergies in Childhood (ISAAC). The children were grouped according to
electoral ward of residence and comparisons were made between urban an
d rural wards, and the presence or absence of a section of motorway. R
esults The prevalence of reported symptoms varied from 2.2 per cent re
porting sleep disturbance on more than one night each week to 40 per c
ent reporting a wheezing episode at some time in their lives; 16 per c
ent reported a diagnosis of asthma. The overall prevalence of symptoms
did not differ greatly from that reported in other similar studies. T
here was a decrease in the prevalence of asthma-related symptoms in ar
eas close to motorways, which was statistically significant for two qu
estions. This is unlikely to be due to the rural location of the motor
ways. Conclusion 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.