Formaldehyde in high school classrooms

Abstract

Schools have a unique place in the fabric of America. Yet there is growing evidence that poor indoor air quality (IAQ) leads to increases in student illnesses and absenteeism, decreases in academic performance, and increased upper-respiratory problems in teachers. Past studies of IAQ in schools have been deficient in many ways. Only four of 735 published papers have involved actual measurements in high schools in North America. There has been little progress in determining the actual agents responsible for adverse effects when ventilation is inadequate. Few studies have focused on irritating oxygenated VOCs (OVOCs) and their sources. The objectives of this thesis were to better understand the levels and temporal variation of one OVOC, formaldehyde (HCHO), in 46 high school classrooms in Central Texas, to explore differences in HCHO concentrations between portable and traditional classrooms, and to compare differences between two HCHO measurement methods. Results indicate that HCHO concentrations in high school classrooms are in the range of those found in past school studies. There were statistically no differences in HCHO concentrations between portable and traditional classrooms. Formaldehyde concentrations at night exceeded those during the occupied day as a result of mechanical systems being switched off at night to conserve energy. Finally, when HCHO concentrations were above 10 ppb, a continuous colorimetric HCHO analyzer compared favorably with a more standard DNPH-based passive sampler. This finding is important in that the continuous analyzer can provide valuable information regarding temporal variations in HCHO, which may lend knowledge regarding the role of building-related factors on HCHO concentrations and control.