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Guide | December 20, 2023

How to reduce your exposure to bushfire smoke

Bushfires are caused by natural phenomena and human activity, and bushfire season in Australia can have devastating effects. One of the major consequences of bushfire smoke is its impact on air - but how do bushfires affect air quality?

Bushfire smoke can travel long distances and linger for hours, days and sometimes weeks, and pose a risk to those near it. Leading air quality and health expert Professor Sotiris Vardoulakis and Dyson engineer David Hill provide advice on how to reduce your exposure to bushfire smoke. Ahead, see four measures that you can adopt to help protect yourself and your family against bushfire smoke health effects.

  • Sydney Air Quality

    Sydney Air Quality

  • Melbourne Air Quality

    Melbourne Air Quality

What is bushfire smoke?

Bushfire smoke is made up of different sized particles, water vapour, gases and other particle pollutants:

  • Carbon monoxide
  • Carbon dioxide
  • Nitrogen oxides
  • Polycyclic aromatic hydrocarbons

  • Importantly, bushfire smoke health effects are contributed to via burning plants and building materials that are picked up along the way1. When particles in the air increase, they can become visible, leading to smoke haze and the orange skies that are synonymous with bushfire season.

    But in other cases, air pollution can be much less visible. While you may not see the same smoke haze inside your home, it is likely that some of that air pollution is making its way inside. In fact, outdoor PM2.5 - such as those particles found in bushfire smoke - is known to have a higher infiltration rate into homes, compared to the course and ultrafine PM size ranges.2

    How do bushfires affect air quality?

    When air quality index levels sit between 100-149, the air can pose a risk to sensitive groups. When levels hit 100-149, the air is unhealthy to all, and levels of 200+ are considered hazardous3. During the Australian 2019/2020 bushfires, the mean population Air Quality Index (AQI) recorded "poor" to "hazardous" air quality levels across eastern-Australia4.

    When levels of bushfire smoke are high, individuals should avoid going outside. Professor of Global Environmental Health, Sotiris Vardoulakis, at the Australian National University (ANU) Research School of Population Health explains, "Bushfire smoke inhalation symptoms can include irritated eyes, nose and throat. Very small particles can penetrate deeper into our respiratory system, reach our lungs and even translocate into the blood stream. This can cause inflammatory responses and affect several body organs. Smoke from fires also contains toxic gases, such as carbon monoxide and nitrogen oxides."

    What is the difference between haze and smoke?

    Smoke haze is a visible indicator of bushfire smoke. Particle pollution is a mix of coarse and fine particles, and a build of larger particles result in the appearance of smoke haze. The air will look smoky, hazy, or foggy and sigh lines can become limited. So, what are the effects of smoke haze on our health? Smoke damage from bushfires presents a public health risk, and inhalation of smoke can cause several health conditions. During bushfire season, people in affected areas should avoid going outside as much as possible.

    When smoke haze is present, it's likely that air quality is affected by high levels of smoke. Exposure to this is linked to respiratory issues, irritated eyes, coughing, difficulty breathing, and cardiovascular issues5.

    What are the health effects of bushfire smoke?

    "Uncontrolled fires can produce larger quantities of smoke that can travel very long distances in the air and affect people living hundreds of kilometres away from the fires. Smoke from backburning typically has a more localised impact, which can also affect the health of communities living in the area" says Vardoulakis.

    Whether uncontrolled or organised, bushfire smoke health effects apply to everyone. Children and older adults are at higher risk of more severe issues6, while young and middle-aged adults are lower risk. Individuals with certain health conditions like asthma and cardiovascular issues, pregnant women, and outdoor workers also sit in the higher risk category7.

    How can you reduce your exposure to bushfire smoke?

    Healthy measures don’t only apply when bushfire smoke is present. As Professor Vardoulakis says, “People should consider adjusting their daily behaviours to mitigate the risks associated with air pollution, even outside of the bushfire season. Try avoiding busy highways, commute to work differently, increase ventilation when cooking, use more environmentally friendly cleaning products or use a purifier with a HEPA filter inside the home.” Dyson Design Engineer David Hill shares how to adopt four key measures to reduce your exposure to bushfire smoke and haze. See his tips as well as air purifiers for bushfire smoke below.

    1. Stay indoors as much as possible

    Unless you are asked to evacuate your area, staying inside can reduce your exposure to bushfire smoke, ashes and other air pollution. Bushfire smoke health effects apply to animals as well as humans, so it’s a recommended to keep pets indoors as well8.

    It’s important to remember though that indoor air can still be impacted by outdoor pollution – including bushfire smoke and haze. In fact, studies have shown that some air pollution can infiltrate indoors even through closed windows9 To protect your indoor space, a HEPA standard air purifier can help to maintain clean air.

    2. Use an air purifier indoors

    As Professor Vardoulakis explains, “Air purifiers with HEPA filters, when appropriately used, can reduce exposure to smoke particles and significantly improve indoor air quality. Air purifiers with sealed HEPA filters combined with activated carbon filters can provide added protection from smoke as well as keep the air clean of everyday pollutants found in our homes.”

    The best air purifier for bushfire smoke needs the highest standard of filtration technology. This is partly due to bushfires having the ability to release high amounts of carbon dioxide (CO₂) into the air, combined with other particles which should be avoided. Dyson’s air purifying technology improves indoor air quality by using HEPA filtration alongside the highest standard of materials and pioneering features such as air quality monitoring, to protect the inhabitants of your home and workplace:

  • Our purifiers are whole machine sealed to HEPA H13 standard10, to prevent pollutants from re-entering the room.

  • We test our machines beyond industry standards, to make sure that they benefit real homes and spaces. Each air purifier is engineered with Air MultiplierTM technology to draw in distant pollutants and project purified air into the corner of every room.

  • Dyson air purifiers monitor and track the quality of your indoor air, and can automatically sense airborne particles before displaying real-time reports. The Dyson Purifier Big + Quiet Formaldehyde - Advanced Technology has an additional CO2 sensor to monitor carbon dioxide and limit your exposure

  • Explore the range of Dyson Air Purifiers

    3. Limit indoor pollution

    Other factors alongside bushfire smoke and smoke haze can affect the health quality of your indoor air. Air pollution can be contributed to by a range of outdoor and indoor sources - such as cleaning sprays , exhaust fumes and building materials. To help improve the health of spaces like homes and workplaces, Dyson's engineers have committed to understanding the science of air and what impacts it. It can be helpful to avoid smoking and using gas stoves, wood-burning fireplaces, gas logs, and candles where possible, as those contribute to indoor air pollution.

    4. Wear a facemask when outdoors

    It's not advisable to go outside when bushfire smoke is present, but if you must, be sure to protect yourself by wearing an effective mask. According to Professor Vardoulakis, planning our daily activities to reduce exposure to outdoor pollution, and creating a clean air space in our own homes by keeping doors and windows shut and using an air purifier with a HEPA filter is probably the best option for most families.

    Professor Sotiris Vardoulakis has been working with Dyson on its air quality backpack study in Sydney. Reworking existing technology used in its air purifiers, two Dyson prototype air quality backpacks were given to two Australian families to detect the air quality around them during their daily lives. The results from one of the participants, a Sydney-based mother, found spikes in air pollution including PM2.5, NO2 and VOCs during routine activities such as cooking, cleaning and travelling by car.

    While outdoors, this form of air quality protection can also be experienced through the Dyson ZoneTM. Although face masks are effective, the air purifier visor provides a stream of purified air to both the nose and mouth through a sealed filtration system to remove city fumes4.

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    2 Liu et al (2003). Particle Penetration through Building Cracks. Aerosol Sci Technol 37:565-573; Liu et al (2001) Modeling pollutant penetration across building envelopes. Atmos Environ 35:4451-4462; Long et al (2001) Using Time- and Size-Resolved Particulate Data to Quantify Indoor Penetration and Deposition Behaviour. Environ Sci Technol 2001 35:2089-2099 When air quality index levels sit between 100-149, the air can pose a risk to sensitive groups. When levels hit 100-149, the air is unhealthy to all, and levels of 200+ are considered hazardous3. During the Australian 2019/2020 bushfires, the mean population Air Quality Index (AQI) recorded “poor” to “hazardous” air quality levels across eastern-Australia4.
    4 Graham AM, Pringle KJ, Pope RJ, Arnold SR, Conibear LA, Burns H, Rigby R, Borchers-Arriagada N, Butt EW, Kiely L, Reddington C, Spracklen DV, Woodhouse MT, Knote C, McQuaid JB. Impact of the 2019/2020 Australian Megafires on Air Quality and Health. Geohealth. 2021 Oct 1;5(10):e2021GH000454. doi: 10.1029/2021GH000454. PMID: 34723045; PMCID: PMC8536818. 5 Filter tested in an external lab (NO2, SO2, Ozone) in a laboratory setting (3m3 chamber at 23oC and 50% RH) at max air flow setting. Capture rates may differ depending on real life usage
    10 Wang et al (2016) Indoor-outdoor relationships of PM2.5 in four residential dwellings in winter in the Yangtze River Delta, China. Environ Pollut 215:280-289
    11 Particle challenge by DEHS oil specified in EN1822 within a chamber specified in ASTM F3150. Tested in Max Mode at IBR US, for whole machine efficiency above 99.95%