The main aim of this study was to evaluate the prevalence of respiratory symptoms among men and women separately in areas with relatively low traffic density. Data on respiratory symptoms were collected from questionnaires in the Hordaland Health Study. A total of 16,412 individuals, 40 to 45 years, were asked to participate (response rate: 55% for men and 66% for women). Women residing in areas with the highest traffic density had increased prevalence of daily cough (18% vs 8.2%, p