National environmental health risk assessment of short-term air pollution effects on cardiovascular disease in Australia: A systematic review and meta-analysis

Background Although there is substantial evidence linking ambient air pollution to increased cardiovascular disease (CVD) risk, the specific effects of different air pollutants in Australia remain unclear, and quality-assessed evidence is lacking. We aimed to examine the short-term effects of air pollution exposure on the risk of CVD-related health outcomes in Australia and evaluate the quality of available evidence to enable tailored actions. Methods We conducted a systematic review for the impact of air pollutants responsible for CVD in Australia, including particulate matter (PM 2.5 , PM 10 ), nitrogen dioxide (NO 2 ), carbon monoxide (CO), ozone (O 3 ), sulfur dioxide (SO 2 ), and particles measured by nephelometry (bsp). A random-effects meta-analysis was employed to calculate the overall relative risks (RRs) of CVD by each air pollutant. The quality and strength of evidence from Australia on the association between air pollution and CVD were assessed using the Navigation Guide. Results We identified 1683 studies from database searching and finally 30 studies were eligible for meta-analysis. The pooled effects through meta-analysis demonstrated that short-term exposure to PM 2.5 , PM 10 , NO 2 , and CO was significantly associated with elevated risk of CVD-related health outcomes (morbidity and mortality combined). The pooled risk of CVD-related health outcomes increased by 3.8% per 10 μg/m 3 of PM 2.5 , 0.8% per 10 μg/m 3 of PM 10 , 2.4% per 10 ppb of NO 2 , and 7.9% per 1 ppm of CO. Subgroup analysis by locations indicated higher RRs for Brisbane residents exposed to PM 2.5 and PM 10 , and for Melbourne residents exposed to CO and O 3 . Through stratifying by population characteristics, higher RRs were observed among people aged above 65 years exposed to NO 2 and bsp, and among males exposed to PM 2.5 , PM 10 , and CO. Evidence quality varied by air pollutants and CVD-related health outcomes examined. For morbidity, moderate-quality evidence was observed for associations with PM 2.5 , PM 10 , and NO 2 , whereas for mortality, high-quality evidence was found for PM 10 , NO 2 , and O 3 . Conclusion This review provides comprehensive evidence with rigorous quality assessment to confirm that exposure to air pollution is significantly associated with the risk of CVD-related health outcomes in Australia. Variations in risk across population characteristics and locations underscore the importance of targeted preventive measures to mitigate the burden of CVD attributable to air pollution.