Bushfire smoke deadlier than flames
Smoke from Australia’s recent bushfires killed more than 400 people and forced another 4000 into hospitals for urgent treatment, a study suggests.
Those who died because of smoke inhalation far exceeded the 33 killed in the fires, which raged from September until February and burnt through an area more than half the size of the UK.
Research published in the Medical Journal of Australia estimated that the smoke was responsible for about 417 deaths, 1124 cardiovascular-related hospital admissions, 2027 respiratory-related admissions, and 1305 asthma-related admissions.
Most of the deaths and hospital admissions would have been in New South Wales, the most populous state and the region hit hardest by the bushfires. Thousands fled their homes, at least 2500 houses were destroyed and more than 800 million animals are estimated to have died.
‘‘Weather conditions conducive to extreme bushfires are becoming more frequent as a consequence of climate change,’’ the study’s six authors wrote. ‘‘Such fires have substantial social, ecological, and economic effects, including the effects on public health associated with smoke, such as premature mortality and exacerbation of cardiorespiratory conditions.’’
The researchers arrived at their estimates by modelling how the levels and extent of smoke exposure would have affected the population based on previous experience. Many of the deaths and admissions to hospital are likely to have been older people with heart disease or lung problems, such as bronchitis or emphysema. Severe asthma attacks would probably have killed younger people too, the authors said.
In people with existing cardiorespiratory issues, inhaling smoke can cause inflammation that stresses the body and makes blood more likely to clot, increasing the risk of a heart attack.
The research focused on the four areas of Australia’s east most affected by the fires:
Queensland, New South Wales, Victoria, and the Australian Capital Territory. According to the Department of Home Affairs more than 126,000 square kilometres of woodlands and grasslands were burnt out by the fires.
The study’s lead author, Fay Johnston, an epidemiologist at the University of Tasmania, estimated that 80 per cent of the population of about 25 million was blanketed by smoke at times during Australia’s summer. The 5.2 million people who live in Sydney, the biggest city, experienced 81 days of poor or hazardous air quality in 2019, more than the total of the previous ten years combined, the report said. It added: ‘‘The scale and duration of these bushfires was unprecedented in Australia . . . smoke is just one of many problems that will intensify with the increasing frequency and severity of major bushfires associated with climate change.’’
Separate research has estimated that the summer’s bushfires poured between 650 million and 1.2 billion tonnes of carbon dioxide into the atmosphere. That is far higher than Australia’s usual annual emissions of about 531 million tonnes and the upper figure exceeds total carbon emissions from global commercial air traffic. – The Times