Indoor Air Quality in Naturally Ventilated Classrooms. Lessons Learned from a Case Study in a COVID-19 Scenario

Abstract

This paper describes the implementation of a series of ventilation strategies in a nursery and primary school from September 2020, when the government decided to resume the students’ face-to-face activity in the middle of a COVID scenario. Air quality and hygrothermal comfort conditions were analysed before the pandemic and compared for different ventilation configurations in a post-COVID scenario. Ventilation strategies included the protocols issued by the Public Administration, while others were developed based on the typological configuration and use of the school. Results revealed that it is advisable to implement certain strategies that reduce the risk of infection among the occupants of the spaces, without a significant decrease in hygrothermal comfort. Given the importance of maintaining better IAQ in the future within classrooms, and regarding the pre-COVID situation, these strategies may be extended beyond this pandemic period, through a simple protocol and necessary didactic package to be assumed by both teachers and students of the centre.

Monitoring and Assessment of Indoor Environmental Conditions after the Implementation of COVID-19-Based Ventilation Strategies in an Educational Building in Southern Spain

“…In their study, their results showed a 30% improvement in the daily average CO2 concentration compared to the values measured before the COVID-19 disease. In addition, the research conducted by Meiss et al [47] on natural ventilation strategies in classrooms concluded that continuous natural cross-ventilation ensured the lowest CO2 levels compared to the other scenarios studied. Therefore, cross-ventilation with opening windows and doors is recommended for health emergency situations.…”

Elucidating the role of environmental management of forests, air quality, solid waste and wastewater on the dissemination of SARS-CoV-2

“…For example, air quality can be reduced due to higher levels of pollutants from wildfires and other activities, which have shown to lead to strong impacts upon contracting COVID-19 ( Liu et al, 2020a ; Meo et al, 2020 ; Middleton, 2020 ; Curtis, 2021 ; Dragone et al, 2021 ; Kiser et al, 2021 ; Leifer et al, 2021 ; Setti et al, 2020 b; Zhou et al, 2021 a). Furthermore, natural ventilation for optimal indoor air quality is not sufficient to control the potential spread of SARS-CoV-2 ( Li et al, 2004 ; Meiss et al, 2021a ; WHO, 2021a). The host of SARS-CoV-2 may contribute to its spread ( De Wit and Ricketts, 2021 ) through means of water from agriculture ( Coronado et al, 2021 ) or organic human waste ( De Wit and Ricketts, 2021 ), which may affect marine ecosystems ( Guo et al, 2021 ; Mathavarajah et al 2021 ) and individuals through buildings ( Wang et al, 2021 ).…”

“… Lee (2020) estimated a particle size of 4.7 μm carrying SARS-CoV-2. Indoor NO 2 , PM 1 , PM 2.5 and PM 10 may indicate potential presence, but do not directly represent SARS-CoV-2 ( Bianconi et al, 2020 ; Li et al, 2020a ; Baboli et al, 2021 ; Bazzazpour et al 2021 ; Li et al, 2021a Meiss et al, 2021a ; Nor et al, 2021 ). Similarly to SARS-CoV, approximate temperatures of 20°C - 28°C and relative humidity of 20% - 80% are reported to be optimal conditions for the presence of SARS-CoV-2, but do not directly lead to its transmission ( Casanova et al, 2010 ; Spena et al, 2020 ; Baboli et al 2021 ; Raines et al, 2021 ; Razzini et al 2021).…”

“…The use of natural ventilation has been reported to reduce SARS-CoV-2 transmission (Meng et al, 2020; Xiao et al, 2020b ). However, the sole of natural ventilation was stated as a plausible reason for SARS-CoV transmission due to it leading to uncontrolled air flow and direction ( Li et al, 2004 ; Meiss et al, 2021a ; WHO, 2021a). Therefore, a minimum ventilation rate is recommended to be achieved prior to use of natural ventilation (WHO, 2021a).…”

Towards a Living Lab for Enhanced Thermal Comfort and Air Quality: Analyses of Standard Occupancy, Weather Extremes, and COVID-19 Pandemic

“…Furthermore, COVID-19 pandemic has prompted renewed interest in the assessment of deficient indoor air quality conditions, especially in educational buildings. Notably, recent studies point to the need for indoor air quality monitoring and prediction solutions based on IoT and machine learning capabilities (Mumtaz et al, 2021) as well as reassessing ventilation protocols (Alonso et al, 2021;Meiss et al, 2021). Accordingly, we further discuss the insight gathered from the data collected during the COVID-19 pandemic.…”