Abstract
We studied the effect of ventilation as a measure for decreasing the levels of two aldehydes and forty-six volatile organic compounds (VOCs) in the indoor air of schools. A technical high school in Saitama Prefecture was chosen as the investigation facility during a long summer vacation. The levels of chemical compounds in the indoor air were measured prior to and after ventilating the classrooms.
Prior to ventilation, formaldehyde levels exceeding the guideline values for indoor air quality were detected in four of the five classrooms that were measured. After ten minutes of passive ventilation the formaldehyde levels in the classrooms decreased by 72%, bringing the levels below the guideline values for indoor air quality. The acetaldehyde levels in the classrooms decreased by 50%.
In the windowless laboratory aldehyde levels were reduced using an electric fan for mechanical ventilation.
For VOCs, 15-17 compounds were detected in the classrooms and 21 compounds were detected in the laboratory prior to ventilation. After ventilation only 2-5 compounds were detected in each room, and in all cases the levels decreased considerably compared to the levels before ventilation. As a result, ventilation decreased the total volatile organic compounds (TVOC) by approximately 80-90%.
