Traffic related air pollution and acute hospital admission for respiratory diseases in Drammen, Norway 1995-2000.

The aim of this study was to estimate the associations between seven ambient air pollutants [particulate matter (PM10), nitrous dioxide (NO2), sulfur dioxide (SO2), ozone (O3), benzene, formaldehyde and toluene] and acute hospital admissions for respiratory diseases in Drammen, Norway 1995-2000. Time-series analysis of counts was performed by means of generalized additive models with log link and Poisson distribution. The results showed that benzene was the pollutant having the strongest association with respiratory diseases for the total study period, the relative risk of an interquartile increase of benzene was 1.095 with 95% confidence interval: 1.031-1.163. The corresponding results were 1.049 (0.990-1.112) for formaldehyde, 1.044 (1.000-1.090) for toluene, 1.064 (1.019-1.111) for NO2, 1.043 (1.011-1.075) for SO2, 0.990 (0.936-1.049) for O3 and 1.022 (0.990-1.055) for PM10. Dividing the total study period into two 3-year periods, there was a substantial reduction in the exposure levels of the volatile organic compounds (benzene, formaldehyde and toluene) from the first to the second period. Separate analyses for the second time period showed weaker association between these pollutants and the health outcome. This study provides further evidence for short-term respiratory health effects of traffic related air pollution.