Home Ventilation system Building ventilation as important as vaccination, masking: the experts

Building ventilation as important as vaccination, masking: the experts


While vaccines and masking continue to be important in stopping the spread of COVID-19, experts say proper ventilation and filtration are also essential and companies need to take them into account as they continue to develop. ” develop return-to-work plans.

Employees should ask what additional protocols have been put in place, said Krystal Pollitt, assistant professor of environmental health sciences and chemical and environmental engineering at Yale University.

Pollitt, who has also worked with the Ontario COVID-19 Scientific Advisory Table, said employees should ask themselves how close they will be to other employees and what the company’s hiding policy is.

“You may be wondering about the type of ventilation in the first place. So is there a mechanical ventilation system that supplies air centrally through the building via an HVAC system? ” she said.

“If so, you should ask yourself what is the filter in this system? Is it a HEPA filter? Is this a MERV 13 filter? “

MERV is the technical term for an air filter rating developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

Pollitt said a MERV 13 filter was recommended as a minimum standard for filtering out COVID-19 particles. A HEPA filter has a rating higher than MERV 16.

Every space is different

Pollitt said another question to ask is how many times per hour this air is exchanged to prevent transmission – the goal is six.

Many HEPA filters, like this one, are in use in Ontario schools this year. (Sara Jabakhanji / CBC)

But she also said that every space is different, a feeling shared by Stéphane Bilodeau, a ventilation specialist who teaches at the University of Sherbrooke. He said buildings constructed in the past 20 years would be required to have ASHRAE ventilation standards, but even so, improvements may still be needed.

“The filtration level of your system may not be sufficient to capture aerosols, so very small droplets are not captured by regular filters,” he said, adding that new buildings usually only need ‘a MERV index of seven or eight.

Too much cleaning?

For older buildings, he said there are other options such as portable HEPA filters – which many Ontario schools are using this year – or, if you have access to outside air, you can install an air exchanger, which replaces the stale air inside with fresh air. from outside.

“It’s something that can be done on a smaller budget and a smaller time frame.” he said.

But it can be just as important for companies to bring in an expert before purchasing new equipment, said Dorothy Wigmore, an occupational hygienist who added that it was necessary to move from cleaning surfaces to cleaning the machine. air.

“You get someone who can help you figure out where to put them, how much do you need,” she said.

Even the CDC (Center for Disease Control in the United States) acknowledges this. In April, they said, ‘Oh, that doesn’t look like surface transmission or contact transmission, that was really happening or that is really rare, ”she mentioned.

“Especially when most of the disinfectants people use, be they the most popular… contain really toxic ingredients, many of which can cause or trigger asthma.”

Instead, Wigmore recommends cleaning surfaces once a day with soap and water and a microfiber material, unless someone has been ill or if you work in a healthcare facility where a disinfectant would be. more appropriate. But she pointed out that there are also less toxic disinfectants, such as hydrogen peroxide.

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