Buildings upgrading air filtration to address airborne spread of COVID-19

BOSTON — Buildings across the Boston area are upgrading air filters in an effort to prevent the spread of COVID-19 through HVAC systems.

It’s one of a list of steps many properties are taking to prepare for the state’s reopening in phases. There are also plans to flush many properties with outside air 48 hours before officially reopening.

Many of these office spaces have sat virtually empty for the last two months.

“You need to make sure you commission your systems. That’s the air handling system in addition to the water quality system,” said Joseph Allen, assistant professor at Harvard University’s T.H. Chan School of Public Health.

Joseph Allen, co-author of the book “Healthy Buildings,” has been working with properties in the Boston area and across the country on making improvements to air filtration.

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“The number one risk factor for transmission of COVID-19 is time spent indoors. There is no question that we have to put in healthy building control strategies to help minimize the risk of transmission,” Allen said.

Allen told Boston 25 News reporter Drew Karedes that increasing the amount of fresh outdoor air inside buildings is a key step to help keep people safe. He said upgrading the efficiency of filtration systems in buildings is also a crucial component.

“When you recirculate that air, you have to be sure that air is going through a high-efficiency filter. Otherwise, any viral airborne particles will just be transmitted to another part of the building or an adjacent room,” Allen explained.

According to Allen, some property managers also plan to tinker with humidity levels. He said that is based on the concept that dry air in air-conditioned towers can more easily spread the virus.

“Relative humidity in a building is tricky because most building systems aren’t set up in a way that let you adjust relative humidity,” he said. “If you get it wrong, you can introduce conditions that lead to condensation and even mold growth.”

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Allen estimated that the cost to increase ventilation and better filtration is about $40 per person annually.

He said it’s also important for buildings to implement enhanced cleaning disinfection measures to address surface contamination and administrative controls to address exposure from large droplets.

“These are things like keeping six feet away from others, mask wearing and trying to go to touchless bathrooms and automatic doors,” he added.

Boston Properties, one of Boston’s largest office landlords, will be enforcing a policy of only allowing a maximum of four people inside an elevator at a time. This new protocol will apply to some of the tallest office buildings in the city, including the Prudential Tower and 200 Clarendon, the 62-story tower formerly known as John Hancock.

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- Massachusetts Coronavirus Information

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