Ambient air pollution and cardiorespiratory outcomes amongst adults residing in four informal settlements in the western province of South Africa

Few studies have investigated the relationship between ambient air pollution and cardiorespiratory outcomes in Africa. A cross-sectional study comprising of 572 adults from four informal settlements in the Western Cape, South Africa was conducted. Participants completed a questionnaire adapted from the European Community Respiratory Health Survey, and the National Health and Nutrition Examination Survey questionnaire. Exposure estimates were previously modelled using Land-Use Regression for Particulate Matter (PM2.5) and Nitrogen Dioxide (NO2) at participants' homes. The median age of the participants was 40.7 years, and 88.5% were female. The median annual NO2 level was 19.7 microg/m(3) (interquartile range [IQR: 9.6-23.7]) and the median annual PM2.5 level was 9.7 microg/m(3) (IQR: 7.3-12.4). Logistic regression analysis was used to assess associations between outcome variables and air pollutants. An interquartile range increase of 5.12 microg/m(3) in PM2.5 was significantly associated with an increased prevalence of self-reported chest-pain, [Odds ratio: 1.38 (95% CI: 1.06-1.80)], adjusting for NO2, and other covariates. The study found preliminary circumstantial evidence of an association between annual ambient PM2.5 exposure and self-reported chest-pain (a crude proxy of angina-related pain), even at levels below the South African National Ambient Air Quality Standards.