What affects air quality in Docklands?

Can you see the air quality on high rise buildings? Environmental Protection Agency (EPA) Victoria senior scientist Paul Torre can.

“On a clear day you can see the vertical dispersion on a building – a greyed area, on top of it is blue. It’s sometimes above the building or sometimes below,” he said.

Mr Torre said an area’s air quality standard depended largely on meteorology and how close it was to general pollution sources.

But the CBD area has a better standard than most would think. The EPA monitors particle pollution. The particles can be up to 30 times smaller than the width of a human hair.

A “low” standard is up to 8.9 micrograms per cubic metre. The CBD last year averaged 8.1, in comparison to inner city suburbs like Footscray that averaged 7.9.

The level of “vertical dispersion” Mr Torre referred to largely depends on weather and pollution activity together.

“Generally, what you find is during the morning you get a build-up in the peak hour – when it’s cold you get poor dispersion and dilution,” he said. “When it warms up you get more mixing and it goes up higher, rather than getting trapped, and at night it comes down again.”

For that reason, air quality is generally slightly worse in winter.

Mr Torre said it was only about seven days last year that the air quality in the CBD exceeded the standard. In Alphington, for example, there were eight days – probably because of more wood fired heating in the suburbs.

But the biggest negative influence on air quality in the inner city are bush fires and planned burns from out of Melbourne.

“They can go for weeks; you can have a really big impact from that.”