Air Pollution Mapping in Melbourne

Air pollution is the third leading cause of death worldwide, and most large cities, have fine particulate matter (PM2.5) levels above WHO health guidelines. Here, we take a look air pollution mapping in Melbourne to better understand the current situation, and where things may be heading. 

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In the early years of the industrial revolution, essentially during the length of the 19th century, air pollution in most countries came from coal-spouting chimneys and a vile mix of noxious odors from factories. 

During this time, Melbourne went from a small settlement, acquired from aboriginal peoples by a business syndicate, to the full-fledged capital city of Australia, though only for a short time. The 1870’s were a mini golden age with a 20+ year economic boom during which it was dubbed “Marvellous Melbourne”. The population grew from 280,000 to 445,000 in the 1880-1890 decade and it gained the reputation of the richest city in the world. It certainly was one of the largest, with a typical American-Australian suburban sprawl, granting to each their “promised quarter-acre” of the time. 

Of course, rapid urban expansion came hand in hand with increased levels of pollution, including fouled waterways, streets and air. Some of the most illustrative records of Australian urban air pollution at the time come from local poetry. Andrew “Banjo” Peterson’s 1888 Clancy of the Overflow put it so:

“I am sitting in my dingy little office, where a stingy

Ray of sunlight struggles feebly down between the houses tall, 

And the foetid air and gritty of the dusty, dirty city

Through the open window floating, spreads its foulness over all”

He was writing about Sydney, but Melbourne, spearheading Australian industrial development at the time, was in similar conditions. 

The earliest action against air pollution in the country were Health Acts like the Smoke Nuisance Abatement Act in 1902 in New South Wales, which was quickly mirrored by similar provisions in most Australian States. It was mostly ineffective however, as records show little to no proceedings based on the act in the following decades. Better provisions came later, such as one placing a limit of three minutes of thick smoke emissions per half hour, leading to many successful prosecutions, but still not much change. 

Overall, little action was taken against air pollution until the London disaster of 1952, during which an ominous smog blanketed the city and caused around 4000 deaths within a few days. This was a wakeup call for many large cities around the world, where pollution had been obvious but solving it was not a priority.  

On the 1st May 1957, the Honourable Buckley Machin introduced the first specific air pollution legislation (rather than Health Acts), citing concerns shared by a physician friend who was alarmed at the apparent link between cancer and air pollution. Quoting his friend to King George VI in a letter, he said: “Lung Cancer is predominantly a disease of the city and urban dweller.” The reports went on to blame Melbourne’s power stations for the terrible conditions of those living around it, citing homes covered in soot and dead gardens.

With increasing evidence of unacceptable levels of pollution thanks to a growing number of measurements, the state of New South Wales passed the Clean Air Act in 1961. It enforced the use of the “best practicable means” for preventing air pollution, giving it quite some scope. Contemporary practices of “dilution is the solution to pollution”, like tall smoke stacks, were not good enough anymore. It still took years before truly effective technologies enabled cleaner production and reduced pollution at the source, but this was the beginning of true change in Australia’s air quality. 

Motor vehicles were also growing in numbers around this time, as was the awareness of their nefarious carbon monoxide emissions. Surprisingly, they were considered more of a nuisance than a danger to public health, so no further action was taken, a strange conclusion to reach considering the way things were going. Unfortunately, while progress was made in regulating industrial emissions, monitoring techniques in the 1970s proved completely inadequate in identifying the growing problem of vehicle pollution. 

A big shift in how air pollution was monitored came with the Environment Protection Authority’s (EPA) commitment to high-standard monitoring in 1973. From then on, more effort was put into developing and standardizing measurement techniques, equipment and scheduling around the country. This gave way to major air pollution studies, of which many were around Melbourne, characterizing its meteorological nature, and how ozone, smog and particulate haze behaved in it. With better evidence, it is easier to drive policy in an informed direction, so it isn’t surprising that more decisive legislation followed, of which here are a few: 

• Tighter regulation on domestic backyard burning. This actually made a big difference. 
• Better urban planning to reduce traffic congestion
• Taking up European emissions standards for vehicles
• Putting an emphasis on indoor air pollution and fine particles, since a study showed that Australians spend 95% of their time indoors.

The EPA’s continued monitoring since the 1970s shows that carbon monoxide, nitrogen dioxide and sulfur dioxide have decreased significantly, but ozone and particulate matter remain problematic depending on the time of year. With this, the public health burden is greatly reduced, as fine particulate matter  (PM2.5) has many similarities to cigarette smoke in terms of health effects. Using the most recent census data, and Berkeley Earth’s PM2.5 to cigarette equivalence in terms of health effects, we mapped what air pollution looks like in Melbourne to give you a better picture of the situation. 

Air pollution mapping in Melbourne. PM2.5 data from NASA-SEDAC (2016).

What you see above is a very low average yearly pollution compared to most large cities in the world. Some of the key reasons for this are decades of attention to industrial emissions and a relatively early shift to natural gas thanks to the 1973 coal crisis, followed by low population density, meaning less cars. When compared to the heavily polluted Delhi’s ~11,000 inhabitants per kilometer square, Melbourne’s 1,500 makes it much easier to avoid congestion. 

Cities with higher population density and unfortunate meteorological conditions have a taller task ahead of them to solve air pollution, and it will only come from a combination of better urban planning, public transport and cleaner energy sources. 

This article was written by Owen Mulhern.

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