Assessment of indoor and outdoor air quality in primary schools of Cyprus during the COVID-19 pandemic measures in May-July 2021

Corina Konstantinou; Andria Constantinou; Eleni G Kleovoulou; Alexis Kyriacou; Christina Kakoulli; George Milis; Michalis Michaelides; Konstantinos C Makris

doi:10.1016/j.heliyon.2022.e09354

Assessment of indoor and outdoor air quality in primary schools of Cyprus during the COVID-19 pandemic measures in May-July 2021

Heliyon. 2022 May;8(5):e09354. doi: 10.1016/j.heliyon.2022.e09354. Epub 2022 May 2.

Authors

Corina Konstantinou¹, Andria Constantinou¹, Eleni G Kleovoulou¹, Alexis Kyriacou², Christina Kakoulli³, George Milis⁴, Michalis Michaelides³, Konstantinos C Makris¹

Affiliations

¹ Cyprus International Institute for Environmental and Public Health (CII), Cyprus University of Technology, Limassol, Cyprus.
² LELANTUS Innovations Ltd, Nicosia, Cyprus.
³ Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, Limassol, Cyprus.
⁴ PHOEBE Research & Innovation Ltd, Nicosia, Cyprus.

Abstract

Combined pollutant effects from indoor and outdoor sources on children's health, while being at school have not been holistically tackled. The aim of the School Temperature and Environmental Pollutants Study (STEPS) was to perform a school population representative assessment of indoor air quality (IAQ) in primary schools of densely and intermediate populated areas of Cyprus (n = 42). The study took place during May-July 2021 when a school-specific COVID-19 protocol was in place. Questionnaire-based characteristics of schools/classrooms were collected along with 24/48-h long IAQ monitoring of air temperature, relative humidity (RH), particulate matter (PM), carbon dioxide (CO₂) and volatile organic compounds (VOCs), using low-cost sensors. Mixed effect models assessed the IAQ determinants during school hours. Indoor PM, temperature, RH and VOCs increased with progressing school periods in the day, while indoor CO₂ decreased. Indoor RH and CO₂ were negatively associated with % open windows, while indoor PM_2.5 was positively associated. Most of school time (85%), indoor air temperature exceeded the recommended upper limit (27 °C), while a third of indoor PM_2.5 (24-h) measurements exceeded 15 μg/m³. The interplay of clean indoor air with adequate ventilation and adaptation to heat stress in schools is important and its comprehensive characterization requires holistic methodological approaches and tools.

Keywords: COVID–19 measures; Environmental pollutants; Exposome; Indoor air quality; School; Sensors.