Lifting the Unseen Smokescreen on Indoor Air Quality Due to Amenity Indoor Fireplaces in South African Homes

South Africa’s fondness for fire is not limited to barbecuing. During the winter months, many Saffers will heat their homes and braai using indoor fireplaces. Unfortunately, this quintessential South African activity poses a significant health risk, as it results in the inhalation of particulate matter that is harmful to the occupants. 

In their recently published paper, PhD candidate Rita van der Walt and Professor Thinus Booysen (Department of Electrical and Electronic Engineering) and PhD candidate Rentia Jacobs and Professor Sara Grobbelaar (Department of Industrial Engineering) measured the levels of particulate matter inside a handful of houses with both open and closed fireplaces during the 2023 winter. This research was funded by MTN South Africa. The results clearly show to what extent indoor air pollution exceeds acceptable levels for both open and closed fireplaces.


Domestic fuel burning constitutes a major source of air pollution in Africa, particularly in South Africa, where wood burning is practised for a variety of purposes, ranging from cooking to ambience. With over 21% of South African children suffering from asthma and emerging evidence linking air pollution to birth defects, the need to monitor and mitigate HAP becomes increasingly urgent.

The World Health Organization (WHO) has elevated air pollution to the ranks of major global health threats like poor diets and smoking. Household air pollution (HAP), in particular, has been linked to a heightened risk of respiratory infections, a leading cause of mortality among young children in developing nations, and chronic conditions like heart disease, cancer, and diabetes. In 2019 alone, over 2 million deaths worldwide were attributed to HAP from burning solid fuels like wood, with South Africa accounting for over 5,500 of these fatalities. Alarmingly, the incidence of such deaths appears to be significantly higher in countries with lower socioeconomic status.


Fig. 1. Typical open and enclosed fireplaces

Particulate Matter: A Microscopic Menace

Particulate matter (PM), minuscule particles and droplets suspended in the air that can inflict significant harm upon inhalation, is of particular concern in the context of IAQ. According to the Global Burden of Disease study, even zero exposure to PM from solid fuel use is considered the safest level.

Against this background, this study examines indoor air quality, specifically fine particulate matter (PM2.5), within seven upscale homes in Stellenbosch, South Africa, a region with a moderate climate.  Measurements were taken 130 times daily over the five colder months of the southern hemisphere’s winter to capture fluctuations in PM2.5 levels. These levels were then compared with outdoor weather conditions. Our analysis focuses on how PM2.5 concentrations from two different types of fireplaces correlate with ambient temperatures.

Results and Future Research

High-level results indicate that burning wood indoors creates harmful air pollution, even when fireplaces are used infrequently. This pollution can linger even when no one is home. Both open and closed fireplaces cause unhealthy air, but open fireplaces may be worse. The study found that people may not be aware of the danger, but are willing to change their behaviour once informed. Further research is needed with a larger group and in more locations. The study suggests that showing people the air quality in their homes may encourage them to change their behaviour.

To download and read the full research paper, visit: