How bad is bushfire smoke for your health?


How bad is bushfire smoke for your health?

More hazy days mean more breathing problems for some people. What is it about bushfire smoke that's bad for you, and what can you do about it?


Bushfire smoke has continued to intermittently shroud some of Australia's major cities as bushfires rage around the country.

Sydney has said goodbye to blue skies as a blanket of haze, of varying degrees of thickness, has made life unpleasant for some and downright dangerous for others over the summer period.

Canberra's smoke haze was so bad at one stage that it briefly overtook Asia's polluted megacities in the air pollution stakes, and the National Gallery had to close to protect priceless artworks from being damaged by all the smoke particles in the air.

Visitors to Parliament House were forced to wear face masks after smoke from bushfires made Canberra's air quality hazardous in early January.


In Melbourne, the smell of smoke peaks when the wind dies down and the temperature rises, causing smoke bands higher in the atmosphere to descend on the city and suburbs. In January, residents were breathing smoke from fires burning in East Gippsland, along with smoke from NSW and from as far away as Western Australia, said the state's chief health officer, Brett Sutton.

Even New Zealanders have been feeling the effects of our bushfires – after New Year's, the sky in Auckland turned an eerie orange thanks to a cloud of smoke so big it could be seen from space, which had travelled 2000 kilometres across the Tasman Sea.

But is bushfire smoke particularly bad for our health, what lasting impact does it have, and what can we do to minimise its harm?


What health risks do you face from bushfire smoke?

By the time bushfire smoke reaches densely populated areas, the main factor that can cause harm is the presence of minuscule solid particles within it, says the head of the environmental health group at the Menzies Institute for Medical Research, Associate Professor Fay Johnston.

These particles are classed as PM2.5, which means particulate matter less than 2.5 micrometres in diameter, she says.

A cyclist rides by Sydney Harbour with the Opera House barely visible in the distance.

A cyclist rides by Sydney Harbour with the Opera House barely visible in the distance.Credit:Bloomberg

“Most of them are even smaller than that again, so we’re talking something really tiny, smaller than a red blood cell,” Associate Professor Johnston says.

These tiny particles are treated like a foreign object by your body, which will trigger a defensive response with inflammation (think itchy eyes and a sore throat).

These particles are so small, they can travel deep into the lungs and enter the bloodstream.


Does the state of your health make a difference?

This degree of prolonged exposure to bushfire smoke is unprecedented. University of NSW Professor Bin Jalaludin says previous bushfire events have subjected civilians to smoke pollution for "a couple of days, a week at most", and it will be years before we know what long-term health impacts people will suffer.


For healthy people the impacts could be low, he says, but experts already know the inflammation caused by the tiny particles can exacerbate a number of existing health conditions, particularly lung conditions such as asthma and emphysema, as well as heart problems.

Associate Professor Johnston says: "These changes are actually quite tiny ... but, for example, if you’re already at very high risk of a heart attack, it can be the precipitant that sets off the heart attack.”

Recent research also found that short-term exposure to PM2.5 fine particles was sending people to hospital for conditions not previously known to be linked to air pollution, including kidney failure and urinary tract infections.

Bushfire smoke has also been found to be more harmful to people with asthma than normal air pollution, according to another study.


Poor air quality has also coincided with a jump in hospital admissions and ambulance call-outs. In the first nine days of December alone, there was a more than 30 per cent increase in emergency department presentations for heart and breathing problems compared to the same period last year, the Australasian College of Emergency Medicine reports.

“The main thing is to make sure people know how to protect themselves,” says Dr Adi Vyas, who is NSW Health's medical adviser at Environmental Health.

Melburnians are now having to get used to haze too.

Melburnians are now having to get used to haze too.Credit:AAP

Should you use face masks?

Some are resorting to wearing paper or cloth masks but Dr Vyas says those are not really going to help protect you from the smoke.

One type of mask, called a P2 mask, is made to filter out small particles, but Associate Professor Johnston says those masks only work if you can get an airtight seal between the mask and your face. The federal government has distributed millions of P2 masks to people in bushfire-affected areas.

“[That] is actually quite hard and you’ve got to be a bit fanatical, but the minute it leaks around the outside it’s close to useless,” she says, adding that facial hair such as a beard would make that close to impossible.


Smoke affects pets too

The Australian Veterinary Association says pets could feel the effects of smoke and haze to a greater extent than humans.

"They can get heart and lung diseases that can make breathing difficult on smoky days," AVA President Dr Julia Crawford says.

Some animals, such as pugs, have very narrow airways, protruding eyes and can get irritated and distressed with the smoke.

"The smoke will aggravate heat stress. Dogs and cats do not thermo-regulate as humans do. If we feel hot, they will feel hotter and succumb to heat stress."

Dr Crawford says owners should keep their pets indoors; look for any distress such as panting, coughing, or difficulty breathing; and to ring the vet if concerned.

– Matt Bungard

What can people do to stay healthy?

There are three main things people can do to minimise their exposure to smoke, Dr Vyas says, and therefore reduce any negative health impact: stay indoors, do less strenuous exercise outside and – for those with health conditions – make sure their treatment plans are up to date.

While staying inside with the windows and doors shut sounds simple, Dr Vyas says it is “really effective”.

Air-conditioning systems set to recirculate air can also help as they provide another way to reduce the amount of outside air getting in.

Haze lingers over Sydney.

Haze lingers over Sydney.Credit:Nick Moir

On the flipside, Associate Professor Johnston says, it is important to air your home once the smoke dissipates to release any trapped pollution.


With exercise, she says even healthy people should avoid anything too strenuous when air quality is this poor. Your breathing naturally increases when you are exerting yourself and can therefore exacerbate any symptoms, she says.

“Even if you’re healthy I wouldn’t recommend it.”

For those with conditions including asthma, coronary problems or diabetes, Dr Vyas says having an up-to-date treatment plan is important.

“Make sure you have your reliever puffer available,” he says.

With Kate Aubusson, Craig Butt and Dana McCauley

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