title: The effects of ambient air pollution on school absenteeism due to respiratory illnesses.
abstract: We investigated the relations between ozone (O3), nitrogen dioxide (NO2), and respirable particles less than 10 microm in diameter (PM10) and school absenteeism in a cohort of 4th-grade school children who resided in 12 southern California communities. An active surveillance system ascertained the numbers and types of absences during the first 6 months of 1996. Pollutants were measured hourly at central-site monitors in each of the 12 communities. To examine acute effects of air pollution on absence rates, we fitted a two-stage time-series model to the absence count data that included distributed lag effects of exposure adjusted for long-term pollutant levels. Short-term change in O3, but not NO2 or PM10, was associated with a substantial increase in school absences from both upper and lower respiratory illness. An increase of 20 ppb of O3 was associated with an increase of 62.9% [95% confidence interval (95% CI) = 18.4-124.1%] for illness-related absence rates, 82.9% (95% CI = 3.9-222.0%) for respiratory illnesses, 45.1% (95% CI = 21.3-73.7%) for upper respiratory illnesses, and 173.9% (95% CI = 91.3-292.3%) for lower respiratory illnesses with wet cough. The short-term effects of a 20-ppb change of O3 on illness-related absenteeism were larger in communities with lower long-term average PM10 [223.5% (95% CI = 90.4-449.7)] compared with communities with high average levels [38.1% (95% CI = 8.5-75.8)]. Increased school absenteeism from O3 exposure in children is an important adverse effect of ambient air pollution worthy of public policy consideration.
authors.affiliation: Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles 90033, USA.
authors.forename: F D
authors.initials: FD
authors.lastname: Gilliland
authors.forename: K
authors.initials: K
authors.lastname: Berhane
authors.forename: E B
authors.initials: EB
authors.lastname: Rappaport
authors.forename: D C
authors.initials: DC
authors.lastname: Thomas
authors.forename: E
authors.initials: E
authors.lastname: Avol
authors.forename: W J
authors.initials: WJ
authors.lastname: Gauderman
authors.forename: S J
authors.initials: SJ
authors.lastname: London
authors.forename: H G
authors.initials: HG
authors.lastname: Margolis
authors.forename: R
authors.initials: R
authors.lastname: McConnell
authors.forename: K T
authors.initials: KT
authors.lastname: Islam
authors.forename: J M
authors.initials: JM
authors.lastname: Peters
mesh_terms: D000041:Absenteeism; D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution / Q000009:adverse effects*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D009569:Nitric Oxide / Q000032:analysis; D010126:Ozone / Q000032:analysis; D012140:Respiratory Tract Diseases / Q000453:epidemiology / Q000209:etiology*; D012574:Schools
chemical_list: D000393:Air Pollutants; D009569:Nitric Oxide; D010126:Ozone