Effect of short-term exposure to air pollution on daily cardio- and cerebrovascular hospitalisations in areas with a low level of air pollution

Exposure to air pollution is associated with increased cardio- and cerebrovascular diseases. However, the evidence regarding the short-term effect of air pollution on cardio- and cerebrovascular hospitalisations in areas with relatively low air pollution levels is limited. This study aims to examine the effect of short-term exposure to different air pollutants on hospital admissions due to cardio- and cerebrovascular diseases in rural and regional Australia with low air pollution. The study was conducted in five local Government areas of Hunter New England Local Health District (HNE-LHD). Hospitalisation data from January 2018 to February 2020 (820 days) were accessed from the HNE-LHD admitted patients’ dataset. Poisson regression model was used to examine the association between the exposure (air pollutants) and outcome variables (hospitalisation due to cardio- and cerebrovascular disease). The concentrations of gaseous air pollutants, Sulphur Dioxide (SO 2 ), Nitrogen Dioxide (NO 2 ), Ozone (O 3 ), Carbon Monoxide (CO), and Ammonia (NH 3 ) were below national benchmark concentrations for every day of the study period. In single pollutant models, SO 2 and NO 2 significantly increased the daily number of cardio- and cerebrovascular hospitalisations. The highest cumulative effect for SO 2 was observed across lag 0–3 days (Incidence Rate Ratio, IRR: 1.77; 95% Confidence Interval, CI: 1.18–2.65; p -value: 0.01), and for NO 2 , it was across lag 0–2 days (IRR: 1.13; 95% CI: 1.02–1.25; p -value: 0.02). In contrast, higher O 3 was associated with decreased cardio- and cerebrovascular hospitalisations, with the largest effect observed at lag 0 (IRR: 0.94; 95% CI: 0.89–0.98; p -value: 0.02). In the multi-pollutant model, the effect of NO 2 remained significant at lag 0 and corresponded to a 21% increase in cardio- and cerebrovascular hospitalisation (95% CI: 1–44%; p -value = 0.04). Thus, the study revealed that gaseous air pollutants, specifically NO 2 , were positively related to increased cardio- and cerebrovascular hospitalisations, even at concentrations below the national standards.