Three Australian cities are among the top 10 global cities with the lowest levels of air pollution, according to analysis of nearly 400 cities worldwide.
Hobart (third), Darwin (fourth) and Canberra (10th) topped the list, based on air pollution data analysed by Auto Trader, an online vehicle trading site.
However Prof Fay Johnston, a public health physician and environmental epidemiologist who leads the Centre for Safe Air, said the approach was flawed and the findings conflicted with measurements by local environmental authorities. Darwin, where smoke from savanna fires was a major source of air pollution, was a “case in point”, she said.
“The EPA have monitored air quality in Darwin for 20 years, as environmental agencies do all around the country,” Johnston said. “Consistently over that time, Darwin has had the worst air quality in Australia.”
From Funafuti in Tuvalu (first) to Shanghai in China (393rd), Auto Trader ranked cities based on an “air quality index” score, reflecting concentrations of hazardous air particles, sulphur dioxide, carbon monoxide, ozone, and nitrogen dioxide, collected from Open Weather Map data at twice a year over a three year period.
Sydney (150th) was the worst-ranked Australian city, recording a poorer air pollution score than London (90th), which Johnston said was also incorrect.
“Sydney has never been worse than London, on empirical data,” she said, adding that local measurements over time analysed by experts in the field provided more meaningful results than “a global model that got interpreted by car salesmen”.
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Clare Walter, a public health and air pollution researcher based at the University of Melbourne, warned against complacency.
“Air pollution impacts our health, at any level,” she said. Asthma, lung cancer, respiratory infections, diabetes, stroke and heart disease had all been linked to the problem.
“Air pollution gets into our blood stream. It causes systemic inflammation. When your body is under stress, in an inflamed state, it can lead to a very wide range of health impacts.”
Vehicle emissions were the main source of chronic air pollution in Australian cities, she said. Wood heaters also make a substantial contribution in some cities, particularly during winter.
Walter said Melbourne’s inner west was subject to high levels of air pollution, largely due to diesel trucks travelling between the port and container yards.
Melbourne (52nd) recorded a similar score to US cities Miami and Texas, whereas Perth (95th) and Brisbane (96th) had similar levels of air pollution to Pittsburgh.
While a blanket rating might drive some cities to try to improve, the narrative that “air quality is good in Australia” was a barrier to changes required for improvement, Walter said.
Dr Kate Charlesworth, a public health physician and Climate Council health expert, agreed.
“Australians tend to think we have pretty good air quality, but when you look at the air pollution in the places where we spend a lot of time, the levels are actually quite concerning,” she said.
A previous report by the Australian Conservation Foundation found towns outside capital cities that had large mining operations or power stations were the worst locations for air quality.
A recent Climate Council report found one in six childcare centres and schools nationally were within 100 metres of a busy road. That exposure was a concern, Charlesworth said, given children could be spending up to seven hours a day at school, and up to 10 hours at childcare, and were most at risk from the health impacts of air pollution, particularly asthma, respiratory infections and developmental delays.
“We’re now understanding just how harmful that can be in the longer term,” she said. The Global Burden of Disease Study showed in 2021 that air pollution caused more ill health in children than passive smoking, Charlesworth said.
Gains could be achieved relatively quickly, she said, through a combination of anti-idling policies, clean air zones, supporting walking and cycling to school and public transport. Stronger fuel efficiency standards and the increased uptake of electric vehicles would also help.
“You can’t move schools and childcare centres, but you can clean up the air,” Charlesworth said.
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Erin Baker, a director at Auto Trader, said: “We hope this study inspires both individuals and policymakers to take steps towards improving air quality in all our cities, making them healthier for everyone.”
According to the report, Hobart’s high ranking reflected the city’s proximity to the ocean, small population and less traffic, while places like Bilbao in Spain had achieved lower pollution through high public transport use and shifting taxi, delivery and council fleets to electric vehicles.
In London, phasing out diesel vehicles and introducing the ultra-low emissions zone and initiatives to make school streets safer had been associated with reduced asthma-related emergency department attendance, Walter said.
In Australian cities, anti-idling policies, wood heater restrictions in urban environments and prioritising active and public transport could all dramatically reduce air pollution and improve public health, she said. “There are lots of things we could and should be doing.”
