Our study on the adverse impact of a polluted environment on children's health was made in Chorzów, a town commonly regarded as a region of ecological disaster. The percentage of infants with birthweight below 2500g is highest and average birthweight lowest in the most polluted districts of the town. Placental dysfunction as a negative effect of air pollution is the immediate reason of drastically diminished aerobic oxydation assessed on the basis of cytochrome c oxydase activity in the placental micro structure. High absorption of lead by nursing children was determined when data were compared with WHO's recommended admissible blood lead levels. The effect of air pollution on the Peak Expiratory Flow of children was studied in the most polluted districts of the town, where PEF values in healthy children were statistically lower.