Short-term joint effects of PM10, NO2 and SO2 on cardio-respiratory disease hospital admissions in Cape Town, South Africa

Background/Aim: In sub-Sahara Africa, few studies have investigated the short-termassociation between hospital admissions and ambient air pollution. Therefore, this study exploredthe association between multiple air pollutants and hospital admissions in Cape Town, South Africa.Methods: Generalized additive quasi-Poisson models were used within a distributed lag linearmodelling framework to estimate the cumulative effects of PM10, NO2, and SO2up to a lag of21 days.We further conducted multi-pollutant models and stratified our analysis by age group, sex, andseason. Results: The overall relative risk (95% confidence interval (CI)) for PM10, NO2, and SO2at lag0-1 for hospital admissions due to respiratory disease (RD) were 1.9% (0.5-3.2%), 2.3% (0.6-4%), and1.1% (−0.2-2.4%), respectively. For cardiovascular disease (CVD), these values were 2.1% (0.6-3.5%),1% (−0.8-2.8%), and−0.3% (−1.6-1.1%), respectively, per inter-quartile range increase of 12μg/m3for PM10, 7.3μg/m3for NO2, and 3.6μg/m3for SO2. The overall cumulative risks for RD perIQR increase in PM10and NO2for children were 2% (0.2-3.9%) and 3.1% (0.7-5.6%), respectively. Conclusion: We found robust associations of daily respiratory disease hospital admissions with dailyPM10and NO2concentrations. Associations were strongest among children and warm season for RD.