Ventilation conditions and their influence on thermal comfort in examination classrooms in times of COVID-19. A case study in a Spanish area with Mediterranean climate

M T Miranda; P Romero; V Valero-Amaro; J I Arranz; I Montero

doi:10.1016/j.ijheh.2021.113910

Ventilation conditions and their influence on thermal comfort in examination classrooms in times of COVID-19. A case study in a Spanish area with Mediterranean climate

Int J Hyg Environ Health. 2022 Mar:240:113910. doi: 10.1016/j.ijheh.2021.113910. Epub 2021 Dec 23.

Authors

M T Miranda¹, P Romero², V Valero-Amaro³, J I Arranz², I Montero²

Affiliations

¹ Department of Mechanical Engineering, Energy and Materials, School of Industrial Engineering , University of Extremadura, Avenue Elvas s/n, 06006, Badajoz, Spain. Electronic address: tmiranda@unex.es.
² Department of Mechanical Engineering, Energy and Materials, School of Industrial Engineering , University of Extremadura, Avenue Elvas s/n, 06006, Badajoz, Spain.
³ Department of Business Management and Sociology, School of Industrial Engineering, University of Extremadura, Avenue Elvas s/n, 06006, Badajoz, Spain.

Abstract

Current evidence and recent publications have led to the recognition that aerosol-borne transmission of COVID-19 is possible in indoor areas such as educational centers. A crucial measure to reduce the risk of infection in high occupancy indoors is ventilation. In this global pandemic context of SARS-CoV-2 virus infection, a study has been carried out with the main objective of analyzing the effects of natural ventilation conditions through windows on indoor air quality and thermal comfort during on-site examinations in higher education centers during the winter season, as this implies situations of unusual occupation and the impossibility in many cases of taking breaks or leaving classrooms, as well as the existence of unfavorable outdoor weather conditions in terms of low temperatures. For this purpose, in situ measurements of the environmental variables were taken during different evaluation tests. As the main results of the study, ventilation conditions were generally adequate in all the tests carried out, regardless of the ventilation strategy used, with average CO₂ concentration levels of between 450 and 670 ppm. The maximum CO₂ concentration value recorded in one of the tests was 808 ppm. On this basis, the limit for category IDA 2 buildings, corresponding to educational establishments, was not exceeded in any case. However, these measures affected the thermal comfort of the occupants, especially when the outside temperature was below 6 °C, with a dissatisfaction rate of between 25 and 72%. Examinations carried out with outside temperatures above 12 °C were conducted in acceptable comfort conditions regardless of outside air supply and classroom occupancy. In these cases, the dissatisfaction rate was less than 10%. The results obtained have made it possible to establish strategies for ventilation in the implementation of future exams, depending on the climatic conditions outside.

Keywords: Carbon dioxide; Indoor air quality; Thermal comfort; Ventilation; Ventilation rate.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollution, Indoor* / analysis
COVID-19*
Carbon Dioxide / analysis
Humans
SARS-CoV-2
Schools
Ventilation

Substances

Carbon Dioxide