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. With poorly insulated homes and electricity scarcity, the practice of burning wood to heat homes extends across all income groups. In higher-income groups, these fireplaces are used for comfort and ambience and are typically open, but some are enclosed, slow-combustion stoves of varying quality. According to the World Health Organisation, prolonged exposure to particulate matter, specifically PM2.5, levels over 15 µg/m3 for more than three days a year adversely affects health and development. This study reports indoor air quality parameters, specifically particulate matter, in seven affluent homes in Stellenbosch, South Africa, which has a moderate climate. The measurements were taken 130 times daily to capture transient effects, spanning the colder five months of the southern hemisphere. Results are compared with the ambient weather conditions. Our analysis focuses on PM2.5 levels in the two types of fireplaces, exploring their correlation with outside ambient temperatures. Results indicate that PM2.5 levels exceeded the WHO guidelines in only five months, with frequent transients greatly exceeding 15 µg/m3. Findings reveal a discernible relationship between the ambient temperature and PM2.5 levels and show that PM2.5 concentrations are only marginally higher for open fireplaces than enclosed ones.