Health and economic impacts associated with smoke from summer bushfires in Australia, 2000-2020

Abstract

Background: Summer bushfires are an integral feature of temperate forests in Australia, which are largely dominated by eucalypts. Global warming is changing the pattern of bushfire activity by increasing the frequency of weather conditions associated with extreme fires. Objective: To quantify health impacts and associated economic costs attributable to bushfire smoke-related PM2.5 produced during Australian fire seasons (1st October - 31st March) since 2000/2001. Methods: We included all regions in temperate climate zones in Australia with long term air monitoring networks, covering approximately 90% of the population. We applied standard methods for health impact assessments to estimate the number of premature deaths, cardiorespiratory hospitalizations and asthma emergency department (ED) attendances attributable to bushfire smoke-related particulate matter (PM2.5). Health costs were quantified using the value of a statistical life for mortality and average health care costs for morbidity outcomes. We did a sensitivity analysis on the PM2.5 cut-off points used to identify fire smoke affected days, and applied alternative economic valuation methods to estimate health costs. Results: We found large interannual variation. The 2019/2020 fire season was the worst in recent history with estimated health costs of $1.96 billion (AUD), more than 9 times the median estimated costs of the past 19 fire seasons ($204 million). The two next worst seasons were 2002/2003 and 2006/2007 with estimated costs of $552 million and $360 million respectively. For 2019/2020 we estimated smoke-related health impacts of 431 premature deaths, 3240 cardiorespiratory hospitalizations, and 1333 asthma ED attendances. Our sensitivity analysis shows slight differences in magnitude of impacts for each fire season, but the relative importance of these remains unaltered. Conclusions: Bushfire smoke is associated with substantial health economic costs. Our analysis illustrates the potential for major increases in the health burden from air pollution due to increased bushfire risk associated with the changing climate.