A woman pushes a wheelbarrow stacked with firewood near a village in Giyani, Limpopo. Picture: Sharon Seretlo
Johannesburg - Household occupants from four villages in Giyani, Limpopo will be exposed to higher indoor apparent temperature (AT) in a warmer predicted climate that will present a greater risk of adverse health impacts, including heat cramps, heat exhaustion and heatstroke.

This is among the findings of a 2018 study that aimed to consider the relationship between temperatures in indoor and outdoor environments in a rural residential setting in the current climate and warmer predicted future climate.

Climate change has resulted in rising temperature trends associated with changes in temperature extremes globally, states the study, “Current and Potential Future Seasonal Trends of Indoor Dwelling Temperature and Likely Health Risks in Rural Southern Africa”.

“Attendees of the Conference of the Parties (COP) 21 agreed to strive to limit the rise in global average temperatures to below 2°C compared to industrial conditions, the target being 1.5°C.

“However, current research suggests the African region will be subjected to more intense heat extremes over a shorter time period, with projections predicting increases of 4-6°C for the period 2071-2100, in annual average maximum temperatures for southern Africa.”

Increased temperatures may exacerbate existing chronic ill-health conditions such as cardiovascular disease, respiratory disease, cerebrovascular disease, and diabetes-related conditions, say the authors from the SA Medical Research Council’s environment and health research unit and the Universities of Pretoria, KwaZulu-Natal and Johannesburg.

Exposure to extreme temperatures has also been associated with mortality.

Temperature and humidity measurements were collected hourly in 406 homes in four villages in Giyani in summer and spring and at two-hour intervals in 98 homes in Winter. Ambient temperature, humidity and windspeed were obtained from the nearest weather station. Regression models were used to identify predictors of indoor AT and to estimate future indoor AT using projected ambient temperatures.

“A large percentage of households live below the upper bound of the poverty line, with many homes receiving grants for children and the elderly,” says the study, published in the International Journal of Environmental Research and Public Health.

Those with pre-existing health conditions, the elderly, and young children - as well as economically disadvantaged communities are particularly vulnerable to heat-related illnesses.

The ability of households to alleviate heat stress depends on the assets they can afford such as fans and air conditioners.

The researchers found only 4.2% of sampled homes used air conditioners in hot weather and only 39.2% used fans.

“This shows the majority of homes are likely exposed to high temperatures that could affect the health of occupants due to the lack of resources to adapt to heat.

The most prevalent perception of indoor conditions during hot weather was that 48% of households felt hotter indoors than outdoors.

“Diurnal patterns showed that indoor AT in the sampled homes often exceeded 32°C in summer and spring, therefore it is possible that occupants could be experiencing perceived heat-related symptoms such as tiredness, low concentration, and breathing difficulties.”

Indoor conditions are an important micro-environment because of the amount of time people spend at home. “The elderly, children and disabled people are particularly vulnerable to extreme indoor temperatures and may experience heat stress or heatstroke, among other heat-related health outcomes.”

Their results show that for the period 2080-2099, ambient temperatures will increase by a mean of 4.6°C.

“Previous studies have found that in Limpopo temperatures will increase by 4-7°C for the period 2080-2100. This increase will reach a regime never observed before in the recorded climate of this region.

“The high indoor ATs observed during the study are cause for concern because a recent study using AT to assess heat exposure found a notable increase in daily mortality for each 1°C increase in mean AT during the warm season. Furthermore, warming in winter was projected to be greater than warming in summer and spring.”

The high measured and projected outdoor and indoor temperatures emphasise the need for national and provincial comprehensive heat response and education and awareness programmes.

“The possibility of establishing emergency cooling shelters should be investigated. Studies have shown that spending only a few hours in an air-conditioned environment reduces heat-related illnesses and death.”