Personal and demographic factors and change of subjective indoor air quality reported by school children in relation to exposure at Swedish schools: A 2-year longitudinal study

摘要

This paper studies changes in subjective indoor air quality (SIAQ) among school children and relates these data to repeated exposure measurements during a two-year follow-up period. Data on SIAQ and demographic information were gathered by a questionnaire sent to 1476 primary and secondary school pupils in 39 randomly selected schools at baseline and after two years (follow-up). Exposure measurements were applied after questionnaire data were collected at baseline and follow-up in approximately 100 classrooms. The arithmetic mean values for baseline and follow-up were: for indoor air temperature 23.6 ℃ and 21.8 ℃ and for outdoor air flow rate 5.4 L/s and 7.9 L/s. Older children, those with atopy at baseline, and those in larger schools reported impaired SIAQ during follow-up. Installation of new ventilation systems, higher personal air flow rate and air exchange rate, and better illumination were associated with improved SIAQ, Higher CO_2 levels were associated with impaired SIAQ, In conclusion, sufficient ventilation and illumination in classrooms are essential for the perception of good indoor air quality.