Urban ecosystems and human health in South Africa : examining the relationships between housing, energy, indoor air quality and respiratory health

Abstract

In South Africa one of the strongest influences on domestic indoor air quality is the type of energy used for heating, cooking and other household purposes. Emissions from fuel combustion, along with housing factors, can result in respiratory infections, a leading cause of death in the country. In this study I examine the relationships between energy types, patterns of use, housing conditions such as improper ventilation and overcrowding, indoor air quality and respiratory health in poorer communities of Msunduzi Municipality, South Africa. These variables were examined using an ecohealth perspective through the integration of data concerning individual time-activity budgets, housing materials and structure, energy sources used for heating, cooking and lighting, respiratory symptoms and continuous real time monitoring of indoor air pollutants (particulate matter (PM), carbon dioxide (CO2), carbon monoxide (CO) and sulphur dioxide (SO2)). A total of 20 dwellings, displaying large variability in housing structure and energy patterns, were sampled for 24 hours (hr) over a period of 60 days. The mean 24-hr average indoor concentrations measured were as follows: PM2.5= 16 ± 11 µg/m3, PM10= 78 ± 46 µg/m3, CO= 5 ± 6 ppm and SO2= 0.18 ± 0.27 ppm. Mean indoor concentrations measured were significantly greater than mean outdoor concentrations (p<0.0001 (PM2.5), p=0.017 (PM10), p<0.0001 (CO), p<0.0001 (SO2)). Although PM concentrations increased with the use of increasingly inefficient-burning fuel types (gas < paraffin < wood), no significant differences in the means were found across these fuel types. It is thought that the high degree of variability among dwellings and the small sample size in this study obscured any statistically significant relationships. No significant differences in mean concentrations were found across different housing types either. Indoor exposures were, on average, highest among very young children (ages 0-5) and elders (ages 51+). All age groups reported experiencing high levels of respiratory symptoms, with the elder group (ages 51+) reporting the highest percentages for each symptom. This study will be used to inform local governments and NGOs of local indoor air pollution and exposure risks, so that policy and resources can be allocated accordingly to improve physical environments.