Architects will need to be more creative in equipping commercial buildings for the challenges of climate change, which is likely to increase both bushfire smoke prevalence and pandemic risks, a leading researcher says.
Dr Arianna Brambilla, a lecturer in building engineering at the University of Sydney's architecture school, said while mechanical ventilation can manage the impact of air pollution, like smoke, it would not be the best pandemic response.
Natural ventilation, however, was the preferred method of reducing the indoor spread of microbes and viruses, such as the COVID-19-causing novel coronavirus.
Dr Brambilla said her answer before the pandemic would have focused on sophisticated mechanical ventilation systems as the right response to better equipping buildings.
"But then there are other cases, like the pandemic, COVID-19. We recognise that natural ventilation is the good response in that case, for example, because of the issues with bacteria and diffusion of the airborne infection through ventilation systems," Dr Brambilla said.
"So It's about how we can actually manage the two. Natural ventilation on one side and HVAC systems on the other side. And there's still the layer of energy efficiency as well.
"It's not as straightforward, but clearly the implication is probably - what I would say to an architect or a designer that is approaching this thing, just to try to challenge our presumption in the design."
Dr Brambilla led research into the concentration of bushfire smoke in a Canberra government-style office building, with findings that challenged the public health messaging of staying indoors.
The research suggests the Australian built environment was not equipped to cope with the duration and magnitude of the 2019-20 bushfire season and current health advice was unreliable.
Indoor concentration of air pollutants peaked up to 12 times higher than the recommended critical thresholds, and those peaks often came after outdoor peaks had passed.
The two-storey building in the case study, which had space for offices and laboratories, housed about 450 workers, and had a 15-year-old heating, ventilation and air-conditioning system. Researchers said the building represented the typical Australian office building.
An analysis of the building's air quality data from the 2019-20 summer showed the filtering system struggled to cope with the prolonged high pollution levels.
The paper, published in the peer-reviewed journal Buildings & Cities, said current public health policy assumed staying indoors on hazy days would offer better protection from pollutants, but Australian buildings were in fact leaky and generally lacked appropriate ventilation systems.
Even when buildings had an appropriate mechanical ventilation system, occupants were unprepared and lacked instruction on how to best manage the system during extreme weather events, the paper said.
"Considering that the likelihood of these extreme events is increasing due to climate change, understanding how buildings behaved during this period is of utmost importance to identify a suitable strategy to reduce the health risks associated with fire-related air pollutants," the paper said.
More than a third of Canberra's summer days in 2019-20 recorded air quality levels above the hazardous threshold. At the height of the bushfire crisis, on January 1, 2020, air pollution levels reached 250 times the hazardous level.
A study published in the Medical Journal of Australia found the heavy smoke haze which blanketed the city may have caused 31 deaths in the ACT.
There were 176 smoke-related presentations to Canberra Hospital's emergency department between December 20 and January 12, according to government figures.
The study estimated there were, in the ACT, 31 excess deaths, 82 cardiovascular hospital admissions, 147 respiratory admissions and 89 asthma related emergency department attendances from the smoke haze. More than 410 were likely linked to the smoke across NSW, Victoria, Queensland and the ACT.
