A study of the effects of air pollution on children.
D000041:Absenteeism; D000397:Air Pollution; D002140:California; D002648:Child; D004782:Environmental Health; D005767:Gastrointestinal Diseases / Q000453:epidemiology; D006261:Headache / Q000453:epidemiology; D006801:Humans; D012140:Respiratory Tract Diseases / Q000453:epidemiology; D012572:School Health Services