TRANSCRIPT
Air pollution is not something we think about too often in Australia.
And why would we? According to air quality indexes, Australia ranks among the best places for air quality worldwide.
While air pollution isn't considered a threat in Australia, some experts say even low levels of pollution are unsafe and may even have long term effects on our brains.
Rachel Tham is a research fellow in environmental epidemiology at the University of Melbourne's Department of Medicine and Melbourne School of Population and Global Health.
“For the cognitive health impacts, they're predominantly from exposure, long-term exposure to air pollution, and it can be lower levels of air pollution right through to the higher levels, depending if you're thinking about if you compare a city like Melbourne or Sydney to Delhi in India where the levels are chronically so much higher than here, and yet we still are able to pick up the long-term cognitive health impacts of people who live closer to areas with high levels of air pollution. So if we're thinking about living near major roads or in areas where there is much more industry”
One key indicator of air quality is the density of what is known as particulate matter, or PM.
Particulate Matter refers to a mixture of solid and liquid droplets found in the air.
When small enough, these particles can get deep into our lungs.
But while we often associate air pollution with lung health, evidence suggests our brains are also at risk.
“The actual air pollutants themselves when we breathe them in, some of them go through our nose and are able, they're small enough like those tiny particles I was talking about, small enough to cross the back of our nose straight into the brain. And so when they enter the brain, they set off an inflammatory reaction in the brain, which then over time can lead to the changes in brain structure. There's much more research being done about understanding that long-term exposure with things like Parkinson's disease and Alzheimer's disease.”
Air pollution is one of the greatest environmental risk factors to public health globally.
In fact, it's said to be the greatest external threat to human life worldwide.
The World Health Organisation estimates the combined effects of ambient pollution and household air pollution causes around 7 million premature deaths every year.
Elaine Luthi is the UNICEF Regional Chief of Communication for East Asia and the Pacific, she says air pollution in the region is disproportionately impacting children.
“It’s the children whose families are living in poverty, who can’t afford clean-cook stoves, who can’t afford masks, who can’t afford air purifiers. They are ones that are paying the price for the air pollution crisis and these children are paying the price with their health, with their education and with their very futures and we need to do better.”
According to the 2023 IQ-Air World Air Quality Report; Bangladesh, Pakistan, and India experience some of the worst air pollution in the world.
Out of the 134 countries ranked, from worst to best, Australia sits comfortably at number 128.
But that doesn't mean we are immune.
Recently, a study published in the journal Nature Communications found that even brief exposure to air pollution can impact a person's ability to focus on everyday tasks.
With higher air pollution in more industrial areas, Dr Tham says people in lower-socioeconomic areas are often at greater risk.
She says as well as older and immunocompromised people, pregnant women and children are among the most vulnerable to air pollution.
“We've also done research that's looked at children's cognitive function at schools and measured by the NAPLAN scores. And we found across Australia that children that were in schools that were in lower socioeconomic areas closer to major roads, there was a trend towards lower NAPLAN scores. So there could be some academic impacts as well for children.”
Studies conducted in the United States and Denmark have also shown links between exposure to traffic related pollution and lower cognitive functioning and academic performance.
Though research is still being done in the area, some studies also suggest prolonged exposure to polluted air is a risk factor for dementia.
Fay Johnston is a public health physician and environmental epidemiologist, she's also the lead investigator at the Centre for Safe Air.
Dr Johnston says that when air quality is bad, our body triggers its immune defences.
“If air quality is chronically a little bit bad, then those reactions will be going on in the background, but they're small compared to all the other things that shape your health and your brain health, like diet, like exercise, like your genetic makeup. So it's one of many things that affects overall health and wellbeing. And through that mechanism it can make you more likely to develop sorts of diseases like heart disease. But in the brain over time, over many years, it's a higher risk of dementia or a higher risk of getting a stroke.”
So even low level air pollution can, over time, have an impact.
Outdoors, things like traffic fumes and dust storms create low level pollution in the air, whereas inside, gas appliances and indoor wood fires also pose a risk.
The Centre for Safe Air estimates that wood heater smoke in Australia is linked to between 558 and 1555 earlier than expected deaths each year.
Dr Johnston says better policy is needed.
“We've got more than a million wood heaters. They're very inefficient. They make a lot of pollution for the amount of energy they give you compared to say a diesel engine. So having policies to reduce that chronic source of pollution through winter. There's many places, even though Australia has clean air, there's many places where air is really poor for months and that has a measurable impact.”
When we think of climate change related deaths, it's the immediate and direct fatalities caused by natural disasters that often come to mind.
During the Black Summer bushfires five years ago, air pollution in and around the affected areas saw air quality drop to levels far worse than what's regarded as 'hazardous'.
A report from the Grattan Institute estimated the pollution from those fires sent around 2000 people to hospital with respiratory problems.
The bushfire smoke alone was responsible for 417 deaths that summer.
Dr Johnston says as the frequency of bushfires increases, we may start seeing longer term impacts on health.
“The longer it goes on for, all the accumulation over the years is much more important for your health than a single say, a smoky day. A bit like your diet, if you only regulate sugar at parties, it's what you eat every day that really shapes your health. And it's the same with air. But if a bushfire smoke episode is bad and goes on for a week or so, then in people who are at higher risk, we can even years, a couple of years later, it's still measurable the slight impacts.”
In the longer term, air pollution in Australia and around the world is continuously worsened by the burning of fossil fuels.
Experts suggest that at an individual level, face masks, HEPA air filters, and using more active methods of transportation like walking and cycling can all help reduce our exposure to air pollution.
But Dr Johnston says that one of the most effective ways to avoid worsening air quality is better policy around climate action.
“Overwhelmingly, we have to do our bit to address climate change and reduce carbon pollution, CO2, shift to electrical sources and get off combustion wherever we can. If there's an opportunity to generate energy, not using combustion, we should be doing it. That's the overwhelming main message. But then very specifically for air pollution, there's lots of other kind of policies that can help us promoting active transport, public transport to reduce use of cars, promoting electric vehicles.”
