Carbon Dioxide Concentration Levels and Thermal Comfort in Primary School Classrooms: What Pupils and Teachers Do

Abstract

The current climate emergency concerns and the COVID-19 pandemic demand urgent action to maintain healthy indoor environments in energy efficient ways. Promoting good indoor environments, in particular, increasing ventilation levels, has been a prominent strategy to mitigate the risk of COVID-19 transmission indoors. However, this strategy could be detrimental to thermal comfort, particularly during the heating season in buildings located in temperate climate zones. This paper presents research conducted in two primary schools in South Wales (UK) where the temperature, relative humidity and the carbon dioxide (CO2) concentration levels were monitored. The study monitored six classrooms and two communal spaces in the two schools during the academic year 2021/2022, the first academic year back to teaching and learning in school buildings after home-schooling and educational disruptions due to COVID-19 lockdowns. The study investigated the actions taken by teachers and pupils to balance the thermal comfort needs while minimising CO2 concentration levels. We conducted user studies to explore the comfort perceptions by pupils and teachers in relation to the thermal conditions and the freshness of air in the monitored classrooms. The paper identifies opportunities where end-users, teachers and pupils engaged with the management of the indoor environmental conditions and adopted actions to balance the requirement of reducing CO2 concentration levels while promoting thermal comfort. This research offers lessons and insights related to end-users’ agency and their understanding of indoor environments and thermal experience in schools.

A Review of Energy Efficiency Interventions in Public Buildings

“…In recent years, the emphasis on energy-saving retrofits for educational buildings has gained significant traction [20][21][22][23]. A case study for a thermos-modernization of a school in Poland [24] reported significant energy savings.…”

Indoor Environmental Quality, Pupils’ Health, and Academic Performance—A Literature Review

“…Physical, biological, and chemical factors, as well as ventilation and the extent of human activities, all act to contribute to the levels of pollution in any given indoor environment [47]. A high concentration of CO 2 in classrooms reflects inadequate ventilation [50,51]. The number of occupants in a building has been associated with CO 2 concentration.…”

“…This can result in dissatisfaction among the people entering such rooms. Improving ventilation reduces indoor CO 2 levels [49,51], and the higher the CO 2 concentration indoors, the lower the ventilation rate per student. Some countries have recommended ventilation rates for classrooms.…”

“…Ventilation has been found to be inadequate in many classrooms [18,51,66,67]. This may be due to overcrowding, ventilation system type, climatic condition, and school building type.…”