Objective and Subjective Indoor Air Quality and Thermal Comfort Indices: Characterization of Mediterranean Climate Archetypal Schools After the COVID-19 Pandemic

Abstract

The COVID-19 pandemic has prompted renewed interest in indoor air quality (IAQ). Poor ventilation habits, energy obsolescence, and the lack of cooling equipment in schools, combined with increasing temperatures due to climate change, are leading to situations of thermal stress in classrooms. Changes in school operation, following the COVID pandemic, have made it necessary to establish an accurate understanding of the current situation. This research work presents an assessment of winter and summer IAQ and thermal comfort (TC) for a sample of 7 archetypal secondary schools in 5 Mediterranean climate variants in southern Spain in a postpandemic situation. IAQ was assessed through CO₂, PM2.5, PM10, and CH₂O, while static and adaptive models were used in the case of TC. Surveys were also used to assess both of these. The main novelty is the use of IAPI (indoor air pollution index) and IDI (indoor dissatisfaction index) objective global dimensionless indices to optimize the joint assessment of both variables. Poor objective IAQ results, especially for CO₂ and PM2.5, were obtained for both seasons and all climate variants. Global IAPI is between 6.2 and 8.1, with an index of 10 considered unacceptable, while time percentages exceeding established limits are more variable in winter, ranging from 7% to 31.9%, than in summer, ranging from 14.3% to 20.9%. TC objective results varied, and the summer percentage of hours outside the comfort bands reached 40%–47% due to excess heat in the hottest regions. This discomfort was reported by 58.3% of users.