The Interlinkages Between Ambient Temperature and Air Pollution in Exacerbating Childhood Asthma: A Time Series Study in Cape Town, South Africa

Background: Given the rapid global increase in asthma cases, understanding the impact of climate change on respiratory health is necessary for evidence-based policymaking, particularly in low- and middle-income countries (LMICs). Objectives: To estimate the short-term associations between temperature (mean and diurnal range), particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), ozone (O3), and childhood asthma exacerbations in Cape Town, South Africa. Methods: We analysed daily hospital records (n = 7753; 2009, 2014, 2019) alongside citywide air quality and meteorological data using negative binomial mixed-effects models and distributed lag non-linear models to capture delayed effects. Results: NO2 and PM10 were consistently associated with a higher exacerbation risk, with additional delayed effects observed for PM2.5, PM10, and NO2. Mean temperature and diurnal temperature range were also linked to an increased risk at short (lag 0–1) and medium (lag 4–5) delays. Conclusions: Temperature variability and traffic-related air pollution contribute to childhood asthma exacerbations in urban LMIC settings. The findings support child-centred early warning systems and stricter air quality controls aligned with WHO guidance.