Heat-related health impacts on primary schoolchildren's health: measured and estimated risks in Gauteng, South Africa

Background: Schoolchildren spend a substantial amount of time in classrooms and therefore, the classroom environment should be acceptable and tolerable with an aim to support their welfare and comfort. Globally, temperatures are projected to increase between 1.4 °C and 4.4 °C; however, Southern Africa will likely experience a temperature increase at twice the global rate, resulting in the prevalence of extreme temperatures and more intense heatwaves. An increase in the frequency and intensity of heat waves can lead to overheating in classrooms. This study aimed to describe classroom thermal conditions and understand possible impacts on schoolchildren's health. Methods: A cross-sectional quantitative study was conducted among 904 grade 4 primary school children. The study collected meteorological data, i.e, hourly temperature and humidity data from the South African Weather Service's (SAWS) weather station closest to the participating schools and took place during summer. This data was used to calculate apparent temperature to determine the perceived human body temperature when exposed to the combined effects of temperature and humidity and analyse the potential health implications linked to the symptoms category developed by the United States National Weather Service and the National Oceanic and Atmospheric Administration. Schoolchildren also participated in this study by completing a self-reported hourly heat-related health symptom questionnaire. Data was analysed using STATA. Linear regression was used to investigate the association between apparent temperature and heat-related symptoms. Results: The hourly temperature (mean of 34 °C) and humidity levels (maximum of 80.38 %) exceeded the World Health Organization and the United States Environmental Protection Agency's recommended levels. Out of the 456 apparent temperature range, 203 (44,5 %) of the readings was associated with no health risks, 226 (49,6 %) ranges fell within the caution category and 27 (5,9 %) within the extreme caution category these ranges were associated with health effects such as heat cramps, heat exhaustion and a heat stroke were possible with prolonged exposure. Regression results showed that for every 1 °C in apparent temperature, a 0.05 unit increase in the number of learners who report feeling tired between 8:00–9:00 is predicted; however, this was not statistically significant. Conclusions: Future research should incorporate physiological measures to better assess the direct impact of heat on learner health and longitudinal and intervention-based studies are encouraged to evaluate the effectiveness of school-based heat adaptation strategies in low-resource settings.