No safe level of long-term exposure to bushfire smoke says ANU expert

Michael Weaver 27 December 2019 25
Professor Sotiris Vardoulakis

Professor Sotiris Vardoulakis from the ANU Research School of Population Health says exposure to bushfire smoke is “like smoking a few cigarettes a day”. Photo: Lannon Harley, ANU.

Leading environmental health expert from the ANU Professor Sotiris Vardoulakis says advice to stay indoors and reduce strenuous physical exercise outdoors is impractical for dealing with long-term exposure to bushfire smoke.

The warning from Professor Vardoulakis comes as Canberra’s air quality was measured at 500 per cent worse than the hazardous threshold on 20 December.

Bushfire smoke contains fine particles, also called PM2.5 (or particulate matter) that irritate the respiratory system and can have serious health effects. A reading of 200 is classified as ‘hazardous’. Air quality on 20 December showed particulate matter levels ranging from above 400 PM2.5 to over 1000 at Florey.

Professor Vardoulakis says people should learn about PM2.5 levels and become accustomed to checking air pollution readings, particularly during the bushfire season.

While studies are yet to conclude what constitutes long-term exposure to particulate matter, he said there was no safe level of exposure to bushfire smoke.

“More nuanced advice that encourages individuals to be guided by air quality forecasts and the pattern of PM2.5 levels is needed,” Professor Vardoulakis said.

“People need to not only understand this information but also use it to plan their daily activities in a way that minimises their exposure to pollution.”

Air quality readings on 20 December

Air quality levels in Canberra on 20 December. Image: ACT Health.

He said people can use bushfire smoke alerts, real-time air quality data and forecasts, and related health advice to reduce exposure to hazardous air pollution.

“Bushfire smoke is a major public health concern. These very small particles in bushfire smoke can penetrate deep into the respiratory system inducing inflammation and even translocate into the bloodstream,” said Professor Vardoulakis.

“Mortality rates have been found to increase in Sydney on days with high bushfire smoke pollution.

“For most people, it is like smoking a few cigarettes a day – it is increasing the risk of developing lung and heart disease in their lifetime.

“But some people, such as those with asthma, the elderly, young children and pregnant women, are at a higher risk and it is important to know how to minimise their exposure to air pollution.”

Although he says there is no safe level of exposure to PM2.5, Professor Vardoulakis noted there were certain times of the day in Sydney when the levels were lower than 25 micrograms per cubic metre.

“In early December, PM2.5 levels were lower in most locations in Sydney in the early morning,” he said.

“Exercising outdoors, and cycling or walking to school or work within this time-window, if possible, would help maintain good physical activity levels without substantially increased exposure to smoke.

“However, if you are pregnant, elderly or have a pre-existing respiratory condition, it will be important to avoid exposure.”

Professor Vardoulakis says his research shows some Australian homes are “leaky” and bushfire smoke is able to penetrate indoors and it is also able to pass through ill-fitting facemasks.

“Facemasks are not the best option,” he said.

“Their effectiveness depends on the make and the fit. Surgical masks often have a poor facial fit and professional P2/N95 facemasks aren’t comfortable to wear over prolonged periods or made for children,” he said.

“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 high-efficiency particulate air filter (HEPA) is probably the best option for most families.

“As the climate in Australia is becoming hotter and drier, we need to be prepared for more extreme bushfires and days with very poor air quality ahead,” he said.

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25 Responses to No safe level of long-term exposure to bushfire smoke says ANU expert
lynehamovaluser lynehamovaluser 6:57 pm 30 Dec 19

Went to the Dr, who listened to my lungs and listened again and frowned. I’ve had asthma maybe 2 times in the past 2 years, until the fires. Now I’ve used my puffer over 5 times in 2 weeks (I’m lucky) and the Dr’s put me on a preventative inhaler (cortisone of course!). I hate that I can’t control the level of particles in the air and can’t live in an hermetically sealed safe environment. I hate that I have to choose between cortisone inhaler or long term lung damage (or rather, worse long term damage). EVERYONE is at risk, so please don’t be the idiots I see sitting outside cafes, thinking that they can’t see smoke so it must be OK. Or exercising, because they’re ‘tough’. LONG TERM DAMAGE is a real risk of p2.5 particles. You won’t be enjoying your exercise or coffee when you’re struggling to just breath.

Clive Stott Clive Stott 6:03 pm 30 Dec 19

Professor Vardoulakis says people should learn about PM2.5 levels. This is correct but it is hard to even get a grip when mainland states post results in AQI.
Try searching on “what are the PM2.5 ug/m3 levels in Canberra?” Hope you have better luck than me!
Professor Vardoulakis also mentions the equivalent number of cigarettes smoked. Gemma Rose has to be guided by her GP that her symptoms are smoke caused. If I was smoking the equivalent number of cigarettes to Canberra’s particulates I too would have a raspy irritated throat which is one of the first side effects.
For those who are interested in cigarette equivalents, here is the rule of thumb: one cigarette per day is the rough equivalent of a PM2.5 level of 22 ?g/m3. Double that level, and it is equivalent to 2 cigarettes per day. Of course, unlike cigarette smoking, the pollution reaches every age group.
At 1700 hrs on the 24th December 2019 the rolling 24 hour average at Florey A/Q station in Canberra was 500.
If you were exposed to this smoke today you smoked a pack!

Clive Stott Clive Stott 4:10 pm 30 Dec 19

ANU Professor Sotiris Vardoulakis is correct. Locking ourselves inside is not the answer.
Early detection and rapid attack to extinguish these fires is the only way to reduce the smoke. It must be stopped at the source, not by after-market ideas such as face masks, air purifiers, or our lungs.
The AQI system is rubbish and needs to be thrown out. Why do complicated maths to arrive at an AQI figure? Besides there are different AQI formulas around the world!
Smoke is mainly made up of PM2.5. All the population needs is the raw PM2.5 and PM10 data straight off the air monitoring instruments and reported in real time.
This is what Tasmania does and we have pretty much the cleanest air in the world. We don’t go on with all this AQI nonsense. Besides our raw PM2.5 data is being scooped and transposed wrongly into AQI as it is reported around the world. Our PM2.5s at present read 15 compared to AQI reported as 65 across the globe by
Our reading are up today because of smoke coming in from the mainland . See

Vic Srbinovski Vic Srbinovski 12:58 am 30 Dec 19

Might be an opportune time for the government to offer subsidized AC RC unit/s esp to the elderly and perhaps allround.

Donna Garvey Noonan Donna Garvey Noonan 11:56 pm 29 Dec 19

The world screams about the future impacts of current actions and climate change, but do not focus on current contributing health impacts that may help minimize future issues. It is all interlinked. Why does society keep putting in place band aid fixes?!

Graeme Jackson Graeme Jackson 8:23 pm 29 Dec 19

I think plastic bags tied tight can be too.

Bradley Temperley Bradley Temperley 4:06 pm 29 Dec 19

Every air quality app I've seen uses AQI (US) as the unit, which goes up to 500. The values reported in Australia seem to be 2 to 3 times higher than AQI (US). For example, when it reached 1300 in Canberra my app reported 404. I can't find "AQI" or a conversion table to AQI (US).

    Bradley Temperley Bradley Temperley 4:36 pm 29 Dec 19

    Grace Morgan I had read that site. It looks like I need to compare the Air NEPM standard used in Australia to the values used for the AQI (US). Thanks

    Paul Dowden Paul Dowden 4:49 pm 29 Dec 19

    Bradley Temperley bear in mind the source of the US app data is still the ACT Health monitoring stations.

    Alessandra Whiting Alessandra Whiting 5:46 pm 29 Dec 19

    Bradley Temperley the app I’m using is PM2.5 in ug/m3 which is a different measure entirely. Maybe just double check that. (But also download a different app? I’m mostly using AirRater)

    Bradley Temperley Bradley Temperley 5:56 pm 29 Dec 19

    Paul, yes the source data are the same, but I can’t find the AQI value that appears in reports from Canberra (e.g. 1038) on ACT websites, just the component values.

    I use Air Matters app.

    Arianne Schlumpp Arianne Schlumpp 6:35 pm 29 Dec 19

    The underlying data reported are here

    Julie Macklin Julie Macklin 7:08 pm 30 Dec 19

    Grace Morgan What's an air conditioner? "We" don't have one, and have never had one.

Linda Meulen Linda Meulen 3:37 pm 29 Dec 19

Craig Neiberding our homes are leaky 🤨

    Craig Neiberding Craig Neiberding 5:59 pm 29 Dec 19

    Linda Meulen i need a mask, I am over it. My throat is sore

    Bec Primrose Bec Primrose 6:14 pm 29 Dec 19

    same here Craig. It’s so awful, and the cafe door is always open for people coming in and out. Nothing we can do at work 😞

Zoe Ellen Brain Zoe Ellen Brain 3:31 pm 29 Dec 19

3M industrial filter respirator.

    Steve Aust Steve Aust 4:22 pm 29 Dec 19

    Zoe Ellen Brain - what’s the rating? Where did you buy from?

Lin Van Oevelen Lin Van Oevelen 3:24 pm 29 Dec 19

Keeping windows shut was impossible if you didn't have aircon during the heatwave. I felt sick waking up in the morning breathing in that smoke. But it was that or not sleep at all.

This is a serious problem that will need to be considered in the future. Heaps of elderly or otherwise vulnerable people cannot afford aircon.

    Steve Aust Steve Aust 4:21 pm 29 Dec 19

    Lin Van Oevelen - same, last Thursday night was shocking. Needed to run the Evaporative cooling all night on low which was a mistake. Yes the cool air was great & needed but the stink was terrible. Woke up at 5am & was like I ate a ash sandwich...

    Ava Lyons Ava Lyons 5:37 pm 29 Dec 19

    Lin Van Oevelen I keep all windows and doors shot, make sure most windows and glass in doors is covered. No air con at our house but remains cool if all closed up.

    Lin Van Oevelen Lin Van Oevelen 5:47 pm 29 Dec 19

    I close them during the day but it still gradually heats up. Depending on how warm the house is in the morning, it quickly becomes unbearable after a few days of extreme temperatures. So I do whatever I can to get that temperature down overnight.

    I'm having aircon installed tomorrow though.

    But lots will continue to choose smoke over unbearable heat.

    Julie Macklin Julie Macklin 8:25 pm 30 Dec 19

    Ava Lyons No air conditioning at my house and I too have kept my house closed up. So far it's still liveable, because of insulation and concrete walls.

Gemma Rose Gemma Rose 2:20 pm 29 Dec 19

I have no history of asthma, chest infections or other serious respiratory conditions but I currently have a very inflamed throat and have lost my voice. I’m now on day 14 with no improvement at all. I feel like my throat is swollen and it’s hard to clear it. Have done a course of antibiotics to rule out infection as my immune system is compromised already From an autoimmune condition (that’s in remission) but I’ve never experienced anything like this before. My GP was certain it’s the smoke. Anyone else have similar symptoms?

Capital Retro Capital Retro 8:43 am 29 Dec 19

The problem is exacerbated somewhat by the standing inversion layer over many residential areas in Canberra. In hindsight, Canberra should have never been built where it is.

Long term Tuggeranong residents will remember similar conditions when wood heaters were very common in the valley. They were subsequently banned.

There are lots of other invisible nasties floating around too but they never get mentioned.

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