Poor air quality increases covid risk in high-rises


Apartment residents are at the most risk of COVID-19 cross-infections via both the poor air quality in so many units and the contamination of air in common areas, particularly lifts, experts have said, writes Sue Williams.  

They’re now recommending the installation of sophisticated air purifiers to mitigate the dangers.

“Air purifiers are valuable because they’re one of the few ways of reducing the risk of cross-infection,” said Professor Geoff Hanmer, a member of the global expert team on buildings and disease, the International Code Council’s pandemic task force.

“It can be difficult otherwise to improve the quality of the air without making conditions uncomfortable. But the major risk of cross-infection is in apartment buildings with their common areas and lifts. You often can’t prop doors open to improve the circulation of air and it could be a good idea to plug in air purifiers in lifts.”

With the original Alpha form of coronavirus, it became conventional wisdom to wipe down all regular touch surfaces with sanitiser to protect people. But with the airborne Delta variant, that’s just not enough.

For homes, and particularly apartments, the only real solutions are opening windows and doors to make sure there’s plenty of fresh air to dilute any viruses, and to bring in air purifiers – particularly ones with HEPA (High Efficiency Particulate Absorbing) filters that remove large viruses and bacteria.    

There has been work done already on outlining measures to improve air quality in workplaces, aged care homes, schools and shops, but up until now little attention has been focussed on people’s homes.

“It’s good to have air cleaners if someone is out doing a job that could expose them to the virus and then coming back home” said Professor Bruce Milthorpe, former dean of science at UTS.

“Those with HEPA filters are good for reducing the viral load and keeping windows open is a good idea. That may compromise the energy efficiency, but everything is a compromise these days.”

Old-style units in simple walk-up blocks built in the 1920s are now considered among the safest kinds of apartments for a pandemic future, as they tend to have elements open to the air, vents in walls to let air in and out, and aren’t airtight to maximise energy savings. Some modern apartments, especially those which rely on air conditioning and windows that are rarely opened, could now be considered in a different light.

Long-term, apartment building regulations need an urgent overhaul as the modern construction of air-tight homes, with closed common areas, to improve energy efficiency is providing the perfect environment for the spread of COVID-19 through blocks.

Many apartments now have inadequate natural ventilation and little air circulation which can prove deadly when one household member or visitor comes down with the Delta variant.

“We’re already moving to try to make changes to the regulatory suite but unfortunately the Australian Building Codes Board haven’t been so quick off the mark,” said Professor Hanmer.

“Before, they said there wasn’t enough evidence that COVID-19 was airborne so they didn’t need to do anything. Now there is a huge amount of evidence, so there’s a requirement for them to do something. But a change in the rules for the future will still do nothing for the 99 per cent of the housing stock that are existing buildings.”

At the Master Builders Association of NSW, executive director Brian Seidler said this should now be considered.

“Now, with the approach of COVID, it needs to be more about ventilation and air circulation, and that’s even more applicable with apartments. There, sometimes you can’t even open windows much because of safety concerns and you’re sitting with air conditioning recirculating bad air. It’s a significant issue that needs thought.”

At Master Builders Victoria, CEO Rebecca Casson says she welcomes robust policy discussions about building regulations that address areas for a better built environment for the community, but it can be problematic.

“For example, achieving better ventilation may conflict with objectives for better energy-efficiency performance such as tighter building sealing that becomes more dependent on mechanised airflow systems,” she said. “As governments grapple with the new COVID-19 policy challenges, MBV will continue to contribute to the discussion on these types of critical issues.”

Another developer of HEPA air purification systems for commercial spaces has just launched its new offering in Australia on Monday (sept 13) for residential homes, Radic8’s VIRUSKILLER, which distributor Rentokil Initial claims independent tests have found kills 99.9999 per cent of coronavirus in the air. Tests are about to be undertaken locally by UTS.

“With air purifiers, if they don’t have a HEPA filter, they’re not worth buying,” said Professor Hanmer. “There’s not good evidence for ionisers. It wouldn’t surprise me either if people started buying CO2 monitors to test the quality of air.

“But these are all short-term measures. Long-term, we need changes to the building code.”

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