Elementary school absenteeism and air pollution.

This study assessed the association between ambient air pollution and daily elementary school absenteeism in Washoe County, NV, between 1996 and 1998. All 57 elementary schools in Washoe County in northern Nevada were included in the data set. There was a total of 27,793 student enrollments during this study period. The daily average absence rate was 5.09% (+/-1.54%). Air pollutant values including PM(10), O(3), and CO were obtained from seven air monitoring stations. Weather variables were collected from five of seven stations and from the Western Regional Climate Center. The daily average concentrations of PM(10), CO, and O(3) were 32.44 microg/m(3), 2.73 ppm, and 37.45 ppb, respectively. Student absenteeism was regressed on the three air pollutants, weather variables, and other confounding factors, using autoregression analysis. After adjusting for the effects of weather variables, day of the week, month, and holiday indicators, and time trend, we found that CO and O(3) were statistically significant predictors of daily absenteeism in elementary schools. For every 1.0 ppm and 50 ppb increase in CO and O(3), the absence rate would increase 3.79% (95% CI 1.04-6.55%) and 13.01% (95% CI 3.41-22.61%), respectively. However, PM(10) values were negatively correlated with school absenteeism.