Hot under the collar: How heat prevents school kids from learning

Changes in climate affect children and adolescents in unique ways - and this is felt most acutely in "non-brick" school infrastructure in SA.

University of the Witwatersrand scientist Matthew Chersich, in a guest editorial in the South African Medical Journal, says schools should be safeguarded against the health and educational impacts of heat.

In the editorial - titled "Climate change and adolescents in South Africa: The role of youth activism and the health sector in safeguarding adolescents’ health and education" - Chersich said today's youth will inherit a world made hazardous by greenhouse gases.

He said in SA there are around 10-million adolescents (aged between 10 and 19 years), who make up about 20% of the country’s population.

"They already face a gamut of challenges, ranging from HIV infection, sexual and physical violence, teenage pregnancy and substance use to poverty, inequality and gangsterism. Additionally, many schools are unsafe, with overcrowded classrooms and high levels of environmental toxins, and educational outcomes are poor," he said.

Chersich said the effects of climate change on adolescents, and the effects of heat exposure in particular, were not fully appreciated.

"In many schools, classrooms are made out of converted shipping containers or prefabricated sheeting with corrugated iron roofs. Most container classrooms have poor insulation, little natural ventilation and as many as 50 children in a class, who themselves generate a considerable heat load," he said.

In one study in Johannesburg, which has a relatively mild climate, temperatures reached as high as 47.5°C in the containers and the large majority of students reported experiencing heat-health symptoms every day, including drowsiness, poor concentration and thirst.

"These impacts will be even greater in hotter regions of the country, such as [the] Northern Cape and Limpopo provinces," said Chersich.

He said in classes with poor ventilation, levels of carbon dioxide or stuffiness rose together with temperature, causing children to experience symptoms characteristic of "sick building syndrome". These symptoms affected concentration and learning, and even school attendance and rates of asthma attacks.

Chersich said opening windows was a key means of removing heat and carbon dioxide. "However, in towns and cities with high pollution levels, such as Witbank, one of the most polluted towns in the world, doing so would increase exposure to outdoor air pollution," he warned.

Long-term initiatives to make the built environment more heat resistant were critical, said Chersich - especially replacing containers and prefabricated buildings with brick classrooms.

Short-term interventions could include installing air conditioning in those container schools, he suggested.

"In one study in Costa Rica, learning outcomes improved after air conditioning was installed in the classrooms. Studies in high-income countries have also shown that the effects of heat on exam performance can be ameliorated by air conditioning and mechanical ventilation."

He said further research was needed to identify effective interventions other than air conditioning. "These could potentially include providing cold water at regular, prespecified intervals; use of the ancient Egyptian method of applying damp cloths to the body, which cools as the water evaporates; and improved natural ventilation, which also lowers risks of tuberculosis transmission in schools.

"Schools could also consider substituting closed shoes with sandals, using light-coloured, loose clothing, and adapting school hours during the hottest seasons, with either earlier starting times or a longer lunchtime break and later finishing hours."

Planting trees at schools provided shade and cooling, as well as other health and environmental benefits, he added.