In January 1987, an air pollution episode occurred in central and western Europe. Levels of SO2, NO2, black smoke, sulphates and other components were elevated, with 24 hour average concentrations of SO2 reaching a maximum of close to 300 micrograms/m3 in an area in the southeast of the Netherlands. Pulmonary function was measured in a group of children of 6-12 years old at the end of the episode, and also two and three and a half weeks after the episode. A baseline lung function value was obtained about three months before the episode. Pulmonary function growth between baseline and retest dates was estimated from a simple growth model which was validated using measured pulmonary function growth data from a longitudinal study. A decline of pulmonary function (FVC, FEV1 and PEF) from predicted baseline levels was observed, starting on the last day of the episode. Two weeks after the episode, FVC, FEV1, PEF and MMEF were all decreased, and three and a half weeks after the episode, there was still a deficit compared to predicted baseline levels for FVC and FEV1.