Licentiatavhandling Lund : Lund University. Department of Laboratory Medicine. Division of Occupational and Environmental Medicine, 2010

Background:Traffic-related air pollution is known to increase symptoms, hospital admissions and mortality for chronic respiratory diseases. There is also increasing evidence that it causes an increased incidence of chronic respiratory disease and allergy. This project investigated long-term effects on chronic respiratory disease in an area with relatively low levels of air pollution. Methods: Cross-sectional surveys in 2000, 2004 and 2005, in adults from Scania, southern Sweden, provided information on disease, self-reported traffic exposures, and potential confounders. Geocoded residential- and occupational addresses were linked to GIS-based road data, and dispersion modelled concentrations of nitrogen oxides (N0x) (annual means, 250x250m resolution). Results: Asthma, COPD and allergic rhinitis were associated with traffic at residential address. Traffic intensity >6 cars/min (8640 cars/day) on the heaviest road within 100m showed effects on most outcomes. Effects from NO were seen in the highest exposure quintile (annual average >19 pg/m3) Traffic exposure was associated with allergic asthma and allergic rhinitis, but not with asthma or rhinitis triggered by non-allergic factors. We also found an association between traffic and eczema. Asthma prevalence was associated with high traffic at residential address, but not with traffic at work-address, daily time spent outdoor in traffic or a combined exposure estimate. Conclusion: The results suggest that traffic causes chronic respiratory disease and allergy in an adult population in an area where exposure levels generally are below current air quality guidelines for most of the population.