Data update: Short-term health impacts of the 2019–20 Australian bushfires

As the effects of climate change become increasingly apparent, Australia is seeing an increase in the intensity and frequency of extreme fire weather, a trend that projections suggest will continue to rise (BoM & CSIRO 2018).

Prolonged drought and the hottest and driest year on record formed the backdrop for the 2019–20 bushfire season (BoM 2020). Fires started during the winter of 2019 and continued to burn until the beginning of March 2020, burning millions of hectares of land, resulting in:

• the death of 33 people as a direct result of the fires
• more than 3,000 houses destroyed
• hundreds of communities being threatened or displaced
• burning of the habitat of an estimate of almost 3 billion vertebrate animals
• billions of dollars in damage (Royal Commission into National Natural Disaster Arrangements 2020).

Particulate matter of diameter 2.5 micrometres or smaller (PM2.5) is associated with a range of health impacts when these particles are in high enough concentration (See Chapter 2 of Australian bushfires 2019–20: exploring the short-term health impacts for further information on air pollution and health). Arriagada and others (2020) found that, within their study area in eastern Australia, at least one monitoring station recorded a PM2.5 concentration exceeding the 95th percentile of historical daily mean values on 125 of the 133 days between 1 October 2019 and 10 February 2020. It should be noted that extreme heat often co-occurs with bushfire and has significant impacts on a range of health conditions and mortality.

During the first half of January, population-weighted PM2.5 levels in eastern Australia were substantially above the national air quality 24-hour PM2.5 standard of 25 micrograms per cubic metre (µg/m³) of air, peaking at 98.5 µg/m³ on 14 January 2020, which is more than 14 times the historical population weighted mean 24 hour PM2.5 value of 6.8µg/m³ (Arriagada et al. 2020).

Bushfires and bushfire smoke are associated with a range of health conditions and health impacts, including loss of life. Public health is affected by bushfires through smoke pollution, impacts on water supplies and destruction of major infrastructure, such as roads and powerlines (Johnston 2009). The impacts of bushfire smoke are the most widespread. Johnston and colleagues (2020) estimated the smoke-related health costs of the 2019–20 bushfire season, due to premature deaths (all causes), hospital admissions for cardiovascular diseases and respiratory diseases, and emergency department attendances for asthma, to be $1.95 billion. For further information on the health impacts associated with bushfire and bushfire smoke pollution, see Australian bushfires 2019–20: exploring the short-term health impacts.

What is included in this report?

This report is an online update to the Australian Institute of Health and Welfare (AIHW) report released in November 2020, Australian bushfires 2019–20: exploring the short-term health impacts. The original report provided a detailed background and analysis of data relating to New South Wales Emergency Department presentations (preliminary data), pharmaceutical prescriptions and sales, general practitioner visits and use of bushfire-specific mental health Medicare Benefits Scheme items.

This update includes national data relating to admitted patient hospitalisations, emergency department presentations (all jurisdictions), use of Medicare-subsidised mental health services, and outdoor physical activity for the Australian Capital Territory based on activity tracking data. With the exception of some mental health data, all analyses cover the 2019–20 bushfire season (1 September 2019 to 29 February 2020 for the purposes of this report). For additional information on the geographical units of analysis used in this report, see Technical notes.

The AIHW holds perinatal health data within the National Perinatal Data Collection. At the time of writing, this data collection included data to the end of 2019. As the smoke exposure that occurred in the first quarter of 2020 was deemed critical in presenting a comprehensive picture of any effect of the 2019–20 bushfire season on perinatal outcomes, these are not presented in the current report. Analysis of perinatal data once 2020 data become available could provide further insight into the relationship between bushfire smoke exposure and perinatal outcomes.