Effect of photochemical air pollution on acute respiratory symptoms in children

In the spring and summer of 1989, an epidemiologic study of the acute effects of photochemical air pollution on the respiratory health of 300 children 7 to 11 yr old was conducted. The children studied were a general population sample of the children living in two rural towns in the Netherlands. For these children, small pulmonary function decrements associated with ambient ozone concentrations were reported previously. In this paper, the association between photochemical ambient air pollution and acute respiratory symptoms is evaluated. Occurrence of acute respiratory symptoms was registered by the parents of the children in a diary on a daily basis. The association of symptom prevalence and incidence with air pollution was evaluated using a logistic regression model that took auto-correlation of the residuals into account. Several photochemical episodes occurred in the study period of 102 d. Hourly maximum ozone concentrations ranged from 14 to 114 ppb. Daily average PM10 concentrations ranged from 11 to 136 micrograms/m3. Levels of acid aerosol were low. No associations of daily symptom prevalence or incidence with same-day or previous day concentration levels of ozone, PM10, fine particle sulfate, or nitrate were observed.