Standard air quality measurements for big cities could be "misleading" indicators as they fail to take into account significant variations within suburbs and sometimes even in the same street.
Key points:
- The NSW government provides air quality data taken at nine locations in Sydney, which is available online and updated hourly
- A UTS academic says the data is misleading, and the city's air quality should be looked at like "a mosaic"
- UTS students measured air quality in five suburbs across 20 locations in each, and found lower air quality tended to match lower socio-economic status
University of Technology Sydney (UTS) students have collected air quality data showing changes across short distances depending on tree canopy, levels of construction and traffic, and time of day.
The NSW government provides air quality data taken at nine locations in Sydney, which is available online and updated hourly.
While Sydneysiders generally enjoy some of the world's cleanest air, the quality is affected by dust, traffic fumes and bushfire smoke.
Associate professor at the UTS faculty of design, architecture and building Nimish Biloria said the available air quality data was "misleading" and did not adequately reflect the complex make-up of a city.
"We should look at the city as a mosaic, and it's really critical to look at it that way rather than simply saying that this is one policy that fits all," Dr Biloria said.
Mapping air quality
Dr Biloria last year led students to create sensory maps of Sydney suburbs according to how they felt, sounded or smelt.
This time, students added air quality data to the sensory maps.
Students focused on five suburbs — Burwood, Redfern, Kyeemagh, Pyrmont and St Peters — recording the air quality at 20 locations in each.
That data was then combined with information about land use, resident demographics, and students' observations of noise, smells, and how they felt at each location.
Dr Biloria said air quality added to our understanding of multi-dimensional environments, with strong links revealed between the data and the experience of being in that place.
Lower air quality tended to match lower socio-economic status.
"This inequity in terms of the air quality, which is actually circulating around you, was so apparent that it was quite surprising, to be honest," Dr Biloria said.
In Burwood, for example, air quality worsened in the more dense areas close to the busy train station or Parramatta Road where housing is cheaper and denser.
Grace Lee, studying interior architecture, had never been to the inner-west suburb, which is home to 40,000 residents, but chose to study it because of its mix of urban and suburban settings.
Ms Lee said the area close to the station was more lively and home to younger people, but there were downsides such as noise and lower air quality.
That was in contrast with the more leafy, quiet streets with bigger houses.
"In those suburban areas where the air quality was generally a lot better, we saw a wealthier demographic and they were towards the older scale, full-time working and aged 40 years and above," Ms Lee said.
Car ownership
In Kyeemagh, a small beachside suburb between the airport and Brighton-Le-Sands, students correlated the data with car ownership figures.
Architecture graduate Adrian Ristevski said the average was two to three cars per household, reflecting the area's poor public transport links and increasing congestion on the road.
Air quality deteriorated when they were closer to traffic, such as Endeavour Bridge, where there is little distance between the footpath and roads.
Mr Ristevski said the correlation between air quality and the group's emotional state along busy roads or near construction showed the link between mental health and urban development.
"For people living close to the main roads, especially, you really wonder how you are able to sustain living in these areas without feeling tense, it impacts so many things really," he said.
"You go: 'Wow, you actually put up with this every day.'"
UTS interior architecture student Elissa Topher and her group examined 20 locations in Redfern, taking an hour and a half to cover 5 kilometres.
"We were really trying to tune into the smell, there were definitely parts where the air quality smelled worse, or we could smell smoke, or we could smell those construction sites," she said.
Ms Topher said one of the surprising findings was the correlation between air quality and road speed limits.
She said this was likely because lower speed limits were found around redeveloped residential areas, which included trees and vegetation and higher speeds near the train station and older housing.
Next steps
Dr Biloria said the next step was to also measure physiological signs, such as heart rate, to work out the impact of the urban environment on people's health.
Dr Biloria said more detailed work was also being done to understand the impact of different factors, including building design and type of trees, on air pollution levels.
"We need to understand why different factors need to be addressed in different places, and when spikes can occur," he said.
"Therefore, it's really important that health services, urban planning authorities, architects, and the government start working hand in hand towards improving these factors."