Respiratory function (forced vital capacity-FVC; forced expired volume in one second-FEV1; maximal mid-expiratory flow-DEMM; peak flow-DP; maximal expiratory flow at 75-50-25% of vital capacity CV-DEMx) was studied in children of comparable age, sex and height (9 to 12 years) in a polluted zone (the exposed group n = 223) and a neighboring non-polluted zone (the control group n = 211) in the north of Lorraine. There was no significant difference in ventilatory function between the two groups. Amongst other factors capable of influencing the ventilatory function in the children we found an influence of parental smoking habits (particularly the mothers) identifiable in the non-exposed zone, above all in boys. A sub-segment analysis identified that in the absence of parental smoking, there was a negative influence of open coal fires. The discordance between the results of the measures of respiratory function and the prevalence of different respiratory symptoms, of acute infections and absenteeism from school, is probably explained by the interference of other factors which were not controlled in this study (e.g., ethnic factors and physical activity) and by the moderate level of the pollution; an over-reporting of respiratory symptoms by parents in the exposed zone could not be excluded.