Wildfire-sourced PM2.5 and cause-specific emergency department visits in Victoria, Australia from 2014 to 2019

Wildfires-sourced (WS) fine particulate matter (PM_2.5) is known to adversely impact human health, while evidence regarding the burden of emergency department (ED) visits attributable to WS-PM_2.5 at the local community level remains limited. This study used a time-series design, utilizing daily cases of ED visits and gridded WS-PM_2.5 concentrations, estimated by a chemical transport model and machine learning techniques, in each statistical area level 2 (SA2) in Victoria State, Australia from Jan 1, 2014 to Dec 31, 2019. A two-stage time series model was employed to assess the association between daily mean WS-PM_2.5 concentration and ED visits. Health and economic burden of WS-PM_2.5-related ED visits was quantified. We found that for each 1 μg/m³ increment in WS-PM_2.5, the risk of ED visits for all-cause, cardiovascular and respiratory diseases increased by 0.27 % (95 % confidence interval: 0.22 %, 0.31 %), 0.45 % (0.23 %, 0.67 %) and 0.47 % (0.30 %, 0.64 %), respectively. The associations of daily ED visits with WS-PM_2.5 exposure showed higher risk in the south-eastern part. Subgroup results suggested that more pronounced effects were found in population residing in urban communities than those in rural communities. The total cost of ED visits attributable to WS-PM_2.5 was A$145.49 (120.24, 170.24) million, with A$17.09 (8.97, 24.65) million and A$17.74 (11.66, 23.56) million due to cardiovascular and respiratory diseases, respectively. Overall, short-term exposure to WS-PM_2.5 was significantly associated with increased risks for cause-specific ED visits, with varied health burden of WS-PM_2.5 related ED visits in SA2 communities.