Impact of elevated fine particulate matter (PM 2.5 ) during landscape fire events on cardiorespiratory hospital admissions in Perth, Western Australia.

Background: Australia has experienced extreme fire weather in recent years. Information on the impact of fine particulate matter (PM _2.5 ) from landscape fires (LFs) on cardiorespiratory hospital admissions is limited.
Methods: We conducted a population-based time series study to assess associations between modelled daily elevated PM _2.5 at a 1.5×1.5 km resolution using a modified empirical PM _2.5 exposure model during LFs and hospital admissions for all-cause and cause-specific respiratory and cardiovascular diseases for the study period (2015-2017) in Perth, Western Australia. Multivariate Poisson regressions were used to estimate cumulative risk ratios (RR) with lag effects of 0-3 days, adjusted for sociodemographic factors, weather and time.
Results: All-cause hospital admissions and overall cardiovascular admissions increased significantly across each elevated PM _2.5 concentration on most lag days, with the strongest associations of 3% and 7%, respectively, at the high level of ≥12.60 µg/m ³ on lag 1 day. For asthma hospitalisation, there was an excess relative risk of up to 16% (RR 1.16, 95% CI 1.00 to 1.35) with same-day exposure for all people, up to 93% on a lag of 1 day in children and up to 52% on a lag of 3 days in low sociodemographic groups. We also observed an increase of up to 12% (RR 1.12, 95% CI 1.02 to 1.24) for arrhythmias on the same exposure day and with over 154% extra risks for angina and 12% for heart failure in disadvantaged groups.
Conclusions: Exposure to elevated PM _2.5 concentrations during LFs was associated with increased risks of all-cause hospital admissions, total cardiovascular conditions, asthma and arrhythmias.
Competing Interests: Competing interests: None declared.
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