*** This article was updated after publication with additional details on the Singapore meeting ***
Introduction by Croakey: Experts on climate and public health have been gathering in the Asian region this week to talk about how to respond to intensifying global heat and accelerating climate change extremes.
In Singapore, the World Health Organization’s Asia-Pacific Centre for Environment and Health in the Western Pacific and Nanyang Technological University co-hosted a regional forum on the combined impacts of heat and air pollution (more details are in these posts from Dr Sandro Demaio).
Air pollution and climate-related heat remain major causes of illness and premature death across the region, according to the WHO Centre, but many countries still lack capacity to assess local health risks and translate scientific evidence into effective policies.
The regional action forum was designed to build regional capacity in health impact assessment, increase understanding of the combined impacts of air pollution and heat on health and to boost evidence-based policy action on air quality.
The forum’s host told Croakey they used the event to launch the WHO Western Pacific Region road map on air quality and health, with the aim of cutting air pollution-related deaths by half by 2040, as well as setting up an HIA regional community of practice. It will support ongoing collaboration, peer learning and training, and practical implementation across countries, using WHO analytics and planning tools such as AirQ+, CLIMAQ-H and GreenUR.
Meanwhile, the World Meteorological Organisation also launched its 2025 State of Climate in Asia report showing that atmospheric carbon dioxide is at its highest level for two million years, after the largest yearly increase in concentration since modern measurement began in 1957.
It also indicated that the region has warmed faster than the global average in recent decades, with ocean heat at a record high. In the northern hemisphere, Japan, China and the Republic of Korea all experienced their hottest year on record.
“Across Asia and the Pacific, heat is intensifying multi-hazard risks, intersecting with food systems, public health, infrastructure and oceans and placing new pressures on health and livelihoods,” said Armida Salsiah Alisjahbana, Under-Secretary-General of the United Nations and Executive Secretary of the Economic and Social Commission for Asia and the Pacific.
“Early warning and early action save lives when alerts are timely, messages are trusted and last-mile delivery reaches the vulnerable. Resilience is built over time, through a sustained culture of preparedness.”
In Australia, that preparedness involves strategies to address the coming El Niño-influenced summer weather and the risk of an early bushfire season. Health and community services are also being urged to prepare for extreme heat this summer, as Croakey recently reported.
Many areas are experiencing multi-year rainfall deficiencies and the Bureau of Meteorology is forecasting lower than average winter rains for eastern and south-west Australia. Parts of the Pilbara and north east New South Wales are at risk of winter fires.
This early warning of bushfire hazard presents an opportunity to prepare better protection against some of the long term health effects of smoke exposure, beyond the conventional focus on particulate pollution.
For the feature article below, Croakey’s Dr Fiona Martin spoke to researchers working on new ways to calculate smoke exposure risks and mitigation approaches for volunteer firefighters, who make up nearly 80 percent of our bushfire response efforts nationally, and for pregnant women or those with newly born children.
Fiona Martin writes:
In these cooler months it’s hard to envisage the choking haze of heavy bushfire summers. Yet hot and dry conditions, with increased fire risk for much of the country, are expected in the months ahead.
This is a critical time for emergency and health services to explore how we can better protect an ageing and shrinking volunteer firefighting force.
Smoke exposure poses acute and chronic health risks to firefighters, including respiratory and cardiovascular effects and risk of cancer. Yet volunteers are also less likely than professionals to be compensated if they develop what are called ‘presumptive cancers’ – those that are legally presumed to be work-related.
Recent Western Australian public health research has shown volunteer firefighters are exposed to high levels of carbon monoxide (CO) and volatile organic compounds, particularly from burning eucalypts, but that they may have limited personal protective equipment (PPE) and a limited understanding of the cumulative risks they face from smoke inhalation.
On the other side of the country, Dr Maximilien Desservettaz from the University of Wollongong has been using atmospheric chemistry to assess the scope of that risk, and to propose better protective measures for fire-fighting services.
Complex compound impacts
Desservettaz has spent years studying the complex chemical composition of bushfire smoke, from the emissions from Northern Territory savannah burns to southern state hazard reduction burns and urban pollution from woodfire smoke during winter.
Now working with the NSW Bushfires and Natural Hazards Research Centre, he is researching firefighter exposure to CO and toxic gases using portable monitors which are worn while hazard burning.
Calculating CO levels, Desservettaz said, allows tight estimation of exposure to other dangerous substances that are released when eucalypts burn, including potential carcinogens like acrolein, naphthalene, benzene, styrene and formaldehyde.
These volatile organic compounds combine with other toxic gases, fine particulates and, depending on what has been burnt, heavy metals such as lead and mercury.
So rather than tracking the health impact of exposure to individual compounds, he said it’s important to assess the combined effect of atmospheric “species” which harm the same part of the human body.
“Several gas and particulates will have a carcinogenic effect”, he said, “while several gases will irritate the lungs, the upper and the lower tract.”
His work has shown that if we take all these factors into account, “maybe the current safe work procedures around CO are still too high, because actually it’s not just CO, it’s everything that can be contributing” to negative health impacts.
Improving protective measures
Working with NSW Fire and Rescue Agency, Desservettaz and colleagues have also followed up a national assessment of health and safety measures, to answer firefighters’ questions about how their personal protection could be improved to deal with carbon monoxide, volatile organic compounds and gases.
Their study said volunteers need a better knowledge of the strengths and limits of PPE, improved decontamination protocols, better real-time smoke exposure monitoring and more effective exposure reduction policies.
While there is no single mask or respirator that can protect people against all particulate and gas hazards in extreme fire conditions, Desservettaz’s study said firefighters need to be clear about the best breathing equipment to use and how to fit it.
For example, N95 or P2 masks can only protect against particulate matter, not against toxic gases. Half face respirators, even where they are worn with P3 filters and eye protection, are liable to leak around the nose. Critically, if the wearer has a mask on over their beard, a respirator will not seal effectively against gases. Desservettaz also found a lack of current evidence about how long filtration cartridges were effective.
The study recommends use of full-face masks over half-face masks with eye protection, though it acknowledges the former restricts both communication and range of sight in the field.
It also recommends better PPE and vehicle decontamination processes, particularly to deal with polycyclic aromatic hydrocarbons (PAHs), a group of hazardous chemicals formed by partial burning of organic substances, which leave a sticky residue. These can adhere round the openings in protective clothing, particularly the neck and wrists.
Helmets, face masks, overalls, gloves, socks and boots should be taken off immediately, and stored away from the crew on the return journey from the fireground while they ‘off-gas’, or release toxic compounds.
Desservettaz’s study supports advice that PPE be washed at work, not at home, and for vehicles to be thoroughly cleaned after fireground work to avoid cross-contamination.
He said that sweat “is a very good conveyor of those toxics into the body…through the skin barrier,” so using wet wipes after a shift and immediately showering in cold water, to reduce absorption through the pores, is important.
National guidelines and standards needed
Volunteer firefighters need greater clarity too, Desservettaz said, about how they can balance safety and job demands, for example in using CO monitors to signal when to pull back from a fire.
He has heard that firefighters sometimes ignore or turn off CO monitor alarms, because they are triggered by brief bursts of high concentration on the fire front, rather than measuring the risk of total exposure.
Desservettaz wants to see development of real-time exposure monitoring tools capable of measuring this harm, and that of a wider range of smoke components.
In the meantime, using CO monitors, he has also started studying the relative smoke exposure that Aboriginal people experience doing cooler traditional burns. Working in cooperation with Yuin Nation leaders on Country between Nowra and Ulladulla, he is comparing this exposure to that of rural fire service volunteers doing hazard reduction work.
He said preliminary results suggest that Aboriginal fire workers are exposed to about four times lower concentrations of carbon monoxide than Australian firefighters, on average, experience at hazard reaction burns, possibly because there is less complete combustion of fuel in cultural burning.
Australia’s firefighters also need national personal protection and safety guidelines and exposure standards, Desservettaz stressed.
While advice is available on managing bushfire smoke exposure from peak body the Australian and New Zealand National Council for Fire and Emergency Services, approaches vary from agency to agency, with each having differing capacities to respond to safety expectations.
Determining risks for children
In another innovative approach to longer term bushfire smoke risk, Curtin University economist Dr Jacquelyn Zhang from the Bankwest Curtin Economics Centre has been studying the causal effects on the health and cognitive development of babies in the womb and after birth.
As the ABC reported recently, the contaminants in bushfire smoke are particularly dangerous for babies in utero, entering the mother’s bloodstream and crossing into the placenta. However, Zhang’s work also illustrates the dangers to the newly born.
She found, for example, that babies directly exposed to smoke plumes are more likely to demonstrate delayed cognitive function development later in life, especially in working memory, and weaker performance in NAPLAN tests.
Existing public health studies have inferred strong correlations between smoke exposure and negative health effects on child development, but Zhang said she hopes to influence public policy by demonstrating clear casual health effects and quantifying risk.
To do this, she has drawn on existing satellite data about fire sites, as well as wind dynamics such as wind direction and speed, to determine potential smoke exposure in specific areas. She also calculated the toxicity of the smoke plume through daily fire volume data, ensuring she captured information about the impact of fresh smoke rather than as it decays and dilutes.
Zhang then used longitudinal data from an Australian survey of over 4,000 children to investigate birth outcomes and children’s physical development and cognitive performance in these areas. The results were controlled for confounding factors such as gestation length, maternal mental health, smoking and alcohol consumption.
Bushfire smoke exposure in utero, she found, is linked to increased risks of low birth weight and preterm birth.
Pre-natal exposure is also linked to asthma and persistent effects on children’s respiratory health. Some impacts are more pronounced for boys than girls, in line with research showing “the male foetus is more vulnerable to environmental toxin stress in the womb”, she said.
Reducing smoke exposure
Zhang advises pregnant and new mothers with babies to avoid bushfire smoke exposure as much as possible. She is particularly concerned that parents be made aware of the neo-natal risk to cognitive development.
While she said the use of N95 or P2 rated masks can be helpful to reduce particulate pollution effects, they do not address the risk of exposure to toxic gases and heavy metals.
Instead, she said, her research points to the need for Australians to use air purification technologies in hospitals, homes and workplaces.
The CSIRO has found that high-efficiency particulate air (HEPA) filters can improve indoor air quality by 30-74 percent during prescribed burns and bushfires.
Zhang’s advice is also supported by new research from a RACE for 2030 project at Echuca Regional Health. It showed that upgrading hospital ventilation systems can help services maintain high indoor air quality during bushfires, and lower energy demand.
The trial, run during the January 2026 Victorian bushfires, compared two similar hospital air handling units operating side-by-side: one using full outdoor-air ventilation with conventional filters and the other operating with reduced outdoor air, supported by advanced air treatment provided by a bioHEPA filter.
The study found the new air filtration system was able to reduce the amount of smoke entering the hospital by 1,000-fold, while also lowering energy consumption by 34 percent.
It challenges a long-standing assumption underpinning ventilation design – that using outdoor air is cleaner and safer than recirculating indoor air in hospitals. During bushfires, that assumption is increasingly tested, as smoke can persist for days and often coincides with periods of high heat and energy demand.
“What this study demonstrates is that indoor air quality can be stabilised during these events without increasing exposure to external pollutants contained in bushfire smoke,” said Professor Dino Pisaniello, Adjunct Professor in Occupational and Environmental Hygiene at Adelaide University’s School of Public Health.
“This is increasingly important as climate extremes become part of normal operating conditions.”
Further reading
Brian Oliver, The Conversation: How to protect yourself from bushfire smoke
Victoria Department of Health: Supporting people when air quality is heavily impacted by bushfire smoke – guidance for local government
Kiam Padamsey et al (2024) Characterising the Chemical Composition of Bushfire Smoke and Implications for Firefighter Exposure in Western Australia, Fire 7(11), p. 388; https://doi.org/10.3390/fire7110388
See Croakey’s archive of articles on air pollution and on heat
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