Effect of Ambient Ozone on Peak Expiratory Flow of Exercising Children in the Netherlands

The potential effects of elevated ozone concentrations in The Netherlands were evaluated by the measurement of peak expiratory flow (PEF) of exercising children. Peak expiratory flow was measured with mini-Wright peak flow meters, both before and after out-door sports training. The relationship between PEF and ozone was investigated with individual regression analysis. The difference of PEF after and before training (delta PEF) and the PEF after training were used as dependent variables. The ozone concentration during the training and the 1-h maximum ozone concentration of the same and the previous day were used as independent variables. The highest observed 1-h maximum ozone concentration was 236 micrograms/m3. delta PEF was unrelated to the ambient ozone concentration during training. Peak flow measured after the training was positively correlated with ambient temperature. The high correlation between ozone and temperature prevented the evaluation of effects of the maximum ozone concentration of the same day on PEF after training. A small negative association of borderline statistical significance between PEF after training and previous-day maximum ozone was observed.