Good ventilation the key for safe return to the office, says OzSAGE

OzSAGE, an Australian network of experts formed in response to the COVID-19 pandemic, has highlighted the need for workplaces to have appropriate ventilation in order for employees to safely return to the office once lockdowns lift.

In a statement released yesterday, OzSAGE said safe, clean indoor air (not to be confused with ventilation of COVID-19 patients in intensive care units), must be prioritised in a post-COVID world.

“SARS-CoV-2 spreads through the air. The risk of COVID-19 infection is higher in indoor spaces, and it’s even higher when those indoor spaces are poorly ventilated,” OzSAGE said.

“Respiratory aerosols from breathing and speaking accumulate in indoor spaces, much like cigarette smoke but invisible. Risk of infection increases risk over time. Spending 10 minutes indoors in a poorly ventilated room is less of a risk than spending hours in there – so homes and workplaces are high risk.

“Good ventilation is one of the most effective ways to reduce the risk of COVID-19 infection, in concert with other mitigations, including density limits, the use of PPE and the use of air purifying devices.”

OzSAGE said high risk of COVID-19 transmission can be identified with the three V’s and T (any of these is a red flag, and more than one indicates a higher risk):

• Venue: Multiple people indoors, where social distancing is often harder.
• (Poor) Ventilation: Staying in one place with limited fresh air.
• Vocalisation: Talking, shouting or singing will increase aerosolisation of the virus.
• Time: The amount of time spent in the venue in relation to the risk. Less time is better.  

In order to mitigate these risks, OzSAGE proffers the following solutions:

• Test: Use a CO2 meter to check and to monitor ventilation in the space.  This tells you how much of other people’s exhaled breath you are inhaling. If it is a public space, consider making the reading visible to the public. Don’t guess, test. CO2 meters are cheap and easily accessible.
• Remediate: Act as required to improve ventilation to the target level of less than 800 ppm.
• Ameliorate: If immediate ventilation improvements are impractical, ameliorate conditions using air purifying devices. At a minimum, these should have a HEPA filter and the size of the unit should be matched to the space. Alternatively, relocate activities outside or to a better-ventilated venue.

“Think of COVID as spreading like deadly cigarette smoke – it builds up and is removed in the same way, but you can’t see it. Just as workplaces must be free of smoke, we must provide fresh air and sometimes filters and masks to protect workers and visitors,” OzSAGE’s Professor Geoff Hanmer said.

“By ensuring we breathe fresh air, we can avoid most COVID transmission. Where we can’t freshen up rooms, we need good masks, filters to clean the air, and less people.

“Something as simple as opening windows and not recycling air inside vehicles can make a tremendous difference.”

Updated at 12.39pm AEST on 7 September 2021.

This update is brought to you by Employment Hero.

Click here to go to Employment Hero’s Covid-19 Resource Hub for essential resources to help employers, managers and HR specialists navigate the ongoing pandemic.