Kerry-Ann Weirick’s asthma took a turn for the worse when she moved to the western Sydney suburb of St Marys.
“I was going to hospital two or three times a year with really bad breathing problems,” she says.
Weirick’s new place was near the Light Horse interchange, where several main roads cross, including the M4 and M7 motorways.
“From a pollution perspective … it was particularly bad between 7.30am and 9am and probably 3pm to 6pm when most people are commuting in and out of Sydney,” she says. “The traffic was a nightmare.”
Weirick was no stranger to pollution-related asthma problems. As a student, she had been more prone to attacks while commuting in Sydney’s now obsolete red rattler trains, which had open windows.
“As you were moving along, the pollen and dust would come in, and you used to get soot in your eyes,” she says. “Doctors put it down to exercise-induced asthma because I was moving a lot, but we later found out it was pollution causing my breathing problems.”
People with asthma are “the canary in the coalmine” for air pollution, says Michele Goldman, the chief executive of Asthma Australia. “If you’re in an area where there is air pollution, a person with asthma is going to have symptoms … and it’s quite explicit that the air quality’s bad. Whereas with cardiovascular disease, with cancers, with other diseases where air pollution is a contributing factor – they might only manifest years or decades down the track.”
Air pollution has been linked directly to myriad health problems, both as a result of short periods of high pollution – acute exposure – and chronic exposure to lower levels over time. There is no safe level of exposure, experts say.
Of specific concern is small particulate matter, PM2.5 – particles 2.5 microns or less in diameter that can travel deep into the lungs, bloodstream, brain and other organs. Exposure to these particles increases the risk for a long list of conditions: lung diseases such as cancer, chronic obstructive pulmonary disease and pneumonia, cardiovascular disease, strokes, neurological diseases and adverse pregnancy outcomes.
Australia has relatively low levels of air pollution compared with other countries, but the impacts are greater in areas with more socioeconomically disadvantaged people.
Working with academics, Guardian Australia has analysed PM2.5 data for 2015 and 2018, the most recent non-pandemic years without extreme bushfires, to produce an interactive map showing estimated pollution levels in each suburb.
Air pollution tends to be greatest in the centre of cities, but the data also shows isolated pockets of higher pollution. Parts of western Sydney, especially around Bankstown and Parramatta, are hotspots, with some of the highest levels of air pollution in the country.
Australia’s national ambient air quality standards set a limit of PM2.5 air pollution to average 8 micrograms per cubic metre of air (µg/m3) annually. The government has a goal to reduce this to 7µg/m3 annually by 2025.
But many parts of Sydney and Wollongong exceed this level, especially in more disadvantaged areas. The recommended World Health Organization threshold is 5µg/m3.
Prof Matthew Peters, of Macquarie University’s Woolcock institute of respiratory medicine, says the high pollution in western Sydney stems largely from a geographical peculiarity. “The PM2.5 generated by diesel [trucks] in Vaucluse ends up in Campbelltown,” he says. “The areas where it’s generated … are not the areas where it ends up at night-time.
“PM2.5 is generated in the metropolitan Sydney basin. The prevailing wind that blows through summer … is a north-easterly. During the day, hot air rises and the particulates travel … at altitude down towards south-west Sydney. During the night, when things cool, it settles.
“It’s a geographical curiosity that creates a compounding risk for that part of Sydney.”
The composition of the particles varies depending on location. “In the Hunter valley, for example, you get PM2.5 which is not pure carbon – which is some carbon, some sea salt, some agricultural emissions,” Peters says.
Concerning PM2.5, he says, comes from traffic pollution, mining and industrial activity. “Within a background of generally low levels, there’s no question that exposures are significant in and around arterial roads where there’s stop-start diesel traffic in particular, and in some of the mixed mining and coal mining areas.
“There are other industrial contexts where bunker oil [or] diesel is burnt in significant amounts, generating carbonaceous PM2.5 in port and industrial complex areas,” he says.
In Melbourne, PM2.5 is high in Dandenong and Clayton, while in Wollongong the highest levels appear to the south, closer to industrial areas and the port. Port Adelaide similarly shows high levels of particulates.
Local topography, weather, climate, road traffic and industry all affect air pollution levels. Whereas large events such as bushfires can affect everybody in the area, the socioeconomic factors that determine where people live and work also influence their exposure to air pollution.
“The distribution [of air pollution] is unfair,” says Prof Fay Johnston from the University of Tasmania. “Areas near factories and industrial areas have cheaper housing, so those of lesser means tend to end up there, or right by a busy road.”
A 2018 Australian Institute of Health and Welfare study found that the disease burden of air pollution was 2.2 times greater for the most socioeconomically disadvantaged Australians, compared with the least disadvantaged.
“We have an unequal society,” says Dr Edward Jegasothy, a lecturer at the the University of Sydney school of public health. His research shows that exposure to air pollution compounds existing inequality. The more vulnerable – who are the most exposed – are already dealing with inequalities in health, and are least able to reduce exposure by moving, engaging policymakers or renovating their homes.
No easy wins
Experts say some of the effects of human-made air pollution could be ameliorated through better land use and urban planning, such as situating childcare centres away from arterial roads. But Jegasothy says some solutions that seem like easy wins may not help the more disadvantaged.
Tightening up regulations on vehicle emissions may make them less affordable, while moving childcare centres may mean putting them in places where rents are higher or land parcels are smaller.
“What’s worse: having air pollution exposure or no access to a childcare facility?” he asks.
One measure experts insist would help is a transition away from wood burners. Domestic wood heaters in Sydney are the single largest source of small particulate pollution there, according to one study that found they contributed to 19% of primary PM2.5 emissions despite just 4.4% of Sydney residents using them as their main heating source..
A wood heater buyback scheme in Launceston in the early 2000s significantly improved winter air quality and reduced mortality on some measures, according to research led by Johnston.
“I used to live in a suburb of Adelaide where lots of people had combustion heaters and open fires,” says Katherine, a retiree who developed asthma in later life. “For me, it’s not being in the same room as the heater [that causes a problem], it’s the smoke in the air from other people’s combustion heaters.
“It’s streaming eyes, sneezing and coughing, and just generally feeling like I’ve suddenly got a bad cold,” she says. “[Whereas] my poor old husband [who had severe asthma] – he would become really breathless.” She believes they should be banned.
“If I sit in a room with an open wood fire, I love the ambience of it, but I can’t breathe very well,” Weirick says.
After years of breathing difficulties, Weirick eventually decided to move away from western Sydney to the coastal city of Port Macquarie. “Every time I came up here [on holidays] we’d go to the beach and I could just feel that I could breathe better,” she says. “It was just crisp, clean air.”
Her asthma has drastically improved. “I’ve been here eight years and I’ve probably been to the hospital once for my breathing.”
