Summary
Fires pose serious but often overlooked health risks from smoke pollution, both outdoors and indoors. The number and severity of landscape fires is increasing and with it, the risks posed by air pollution, especially to vulnerable segments of the population.
Fire-related air pollution is episodic and fast-changing. Public health advice is often to stay indoors to avoid smoke exposure but homes and buildings are not always safe havens. A management and data gap exists, preventing rapid, tailored responses to events.
This article explores the use of new low-cost air sensors and modelling tools to improve real-time responses. To protect public health, these tools must be paired with coordinated response plans, improved public guidance, and wider access to indoor air filtration solutions such as portable air cleaners and HEPA systems.
Recently, Aotearoa New Zealand has had several significant fire events, from bush fires in Hawkes Bay, Tongariro, Waipoua and Port Waikato to urban blazes, including the Glenfield recycling plant fire in Auckland, the Loafers Lodge tragedy in Wellington and at Taupo-nui-a-Tia College. While immediate threats to life and property are well understood, what’s less often discussed is the hidden danger of airborne pollution and the consequences on people’s health.1
Rising exposure to air pollution from landscape fires
The annual number of wildfires in New Zealand rose from around 3,000 to nearly 5,000 over the 30 years to 2021, with the length of the fire season predicted to increase 83% due to climate change by 2090.2 Globally, 1·53 million all-cause deaths per year were attributable to wildfire air pollution with around 3800 in Australasia.3 The risk of being hospitalised with respiratory conditions increases with increasing wildfire air pollution. According to a 2024 study across eight countries, including New Zealand, hospitalisation risks for all-cause respiratory illness increase 0.36% for every 1 µg m−3 increase in wildfire-specific PM2.5,. The study also found that in Australia and New Zealand wildfire-specific PM2.5 was associated with elevated risks of asthma hospitalisations compared to non-wildfire PM₂.₅ exposures. 4
Smoke can travel vast distances carrying a mixture of gases and fine particles, including carcinogens, and compounds that cause respiratory and cardiovascular harm.5 Fire smoke is particularly hazardous to infants and children, and short-term exposure during pregnancy may lead to persistent cognitive changes and decreased immune system and lung function later in life.6,7 Those with asthma may also be at risk, with adults over 65 years more susceptible to asthma related hospitalisation due to landscape fire smoke.8 Urban fires are especially concerning, as burning synthetic materials, such as plastics, release even more toxic chemicals than those from landscape fires. The World Health Organization has noted, every major fire should be treated as a chemical incident.9
The indoor risk - not as safe as you think
In fire events, public health advice is often to stay indoors to avoid smoke exposure. But homes and buildings are not always safe havens. Smoke can infiltrate indoors through small gaps and ventilation systems, meaning indoor air may be as hazardous as outdoor air. In these cases, simply shutting windows isn’t enough.
Recently, the concept of “safe spaces” has been promoted to protect vulnerable people from smoke,10 but a review found very limited published evidence evaluating their establishment, use or effectiveness.11 HEPA filters and portable air cleaners can play a crucial role in protecting indoor environments,12,13 but only if people have access to them and know when and how to use them, supported by pollutant measurement, evaluation of effectiveness and feedback into planning.
Speed matters - why rapid response is essential
One of the biggest challenges with fire-related air pollution is the episodic and fast-changing nature of these events. Wind direction and intensity can shift smoke plumes quickly across cities, creating localised but severe air quality issues.
Traditionally, in New Zealand air quality assessments rely on monitoring stations managed by regional councils. However, these stations are limited in number, often not located near affected areas, and many don’t provide real-time data. Te Whatu Ora (Health NZ) released guidance for managing public health risks during such incidents.14 But even with guidance in place, the reality is that without rapid data, responses remain largely generic and reactive. Currently, warnings are not triggered by air quality monitoring. Management of fires is the responsibility of the fire service and health warnings are issued by Te Whatu Ora or by the local regional civil defence emergency management group.
A technological turning point in air quality monitoring
Fortunately, we now have the tools to improve monitoring using low-cost, internet-connected air quality sensors, which are increasingly accessible to individuals and communities. These low-cost sensors transmit data to the cloud, allowing immediate public access through interactive online maps. This real-time, local information allows communities to monitor air pollution in their areas and enables timely responses to air quality issues, including evaluation of the effectiveness of actions and subsequent management plans in a way that cannot be achieved otherwise.
In Canterbury, after the Port Hills fires, some residents purchased sensors to track smoke exposure. This kind of crowdsourced, real-time monitoring offers a valuable layer of detail, especially when combined with weather forecasting and smoke dispersion modelling. Together, these technologies can help assess risk more accurately and quickly, allowing tailored health advice based on actual exposure.
From data to action
However, technology alone isn't enough. To protect public health during fire-related air pollution events, there must be a clear, coordinated response plan. This means assigning responsibility to specific agencies, including a requirement for access to and assessment of real-time air quality measurements, ensuring real-time modelling tools are ready to go when fires start, and integrating efforts across emergency services, health authorities, and local councils. The American Environmental Protection Agency’s Fire and Smoke Map is a strong example combining official and citizen-sourced data to give a real-time, nationwide picture of air quality during fire events.15,16
Conclusion
Current response systems struggle to keep up during short but high-impact air pollution events, such as those caused by fires. There is a lack of real-time air quality data and unclear responsibilities between agencies, leaving communities without timely information or coordinated support to protect their health. The next big fire isn’t a matter of if, but when.
Many of the tools and strategies needed to manage smoke-related health risks already exist. What’s needed now is investment in research, planning, education, and coordination. By enabling communities to monitor air quality, respond effectively and feedback results, we can move beyond simply “closing the windows” and truly protect people’s health.
What this Briefing adds
- Fire-related air pollution poses serious public health risks, exposing communities to harmful smoke from both landscape and urban fires. This smoke contains carcinogens and respiratory irritants that can significantly impact health, especially for vulnerable populations.
- Current response systems are limited, with gaps in real-time air quality data and unclear agency responsibilities during short, high-impact pollution events, leaving communities without timely guidance or protection.
Implications for policy and practice
- Expand real-time air monitoring networks using low-cost sensors in both urban and rural communities.
- Integrate citizen-sourced sensor data with public health alert systems.
- Develop a national smoke incident response plan, including clear roles for health, emergency, and environmental agencies.
- Commission research to improve planning and evaluate responses.
Authors details
Dr Guy Coulson, Director at the Air Quality Collective, Auckland
Associate Professor Julie Bennett, Department of Public Health, Ōtākou Whakaihu Waka, Pōneke | University of Otago, Wellington
Dr Caroline Halley, Department of Medicine, Ōtākou Whakaihu Waka, Pōneke | University of Otago, Wellington
Dr Joel Rindelaub, Department of Chemical Sciences, Waipapa Taumata Rau | University of Auckland
Gustavo Olivares, Director at the Air Quality Collective, Auckland
Dr Ian Longley, Director at the Air Quality Collective, Auckland
Declaration of interests
The Air Quality Collective is a recently formed (2024) research and consultancy company, specialising in urban air quality and climate. Members of The AQC pioneered the use of low-cost air quality sensors in Aotearoa New Zealand for both indoor and outdoor exposure studies.
