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Experts prescribe better ventilation for offices during coronavirus times; key to staying safe on the job

Boston office towers are mostly empty nowadays. Experts are asking building owners to provide cleaner air to workers when they eventually return.David L. Ryan/Globe Staff

With the coronavirus pandemic still a threat, many Americans have not yet gone back to the office. But when they do, they might find there’s literally change in the air.

Health experts and building engineers are pushing for better airflow in offices to help protect workers from virus particles floating through the air.

“We’ve been yelling from the rooftops since early February that buildings should be the first line of defense against this novel coronavirus. We’re now in September. It’s great that people are starting to recognize that airborne transmission is happening. These are controls that should have been in place months ago. If someone hasn’t been thinking about them yet, they need to think about them now,” said Joseph Allen, a professor at Harvard T.H. Chan School of Public Health and director of the school’s Healthy Buildings Program.


Recommendations from the US Centers for Disease Control and Prevention and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) include opening air dampers wider to bring in more fresh air and installing denser filters to screen out virus particles better.

Other recommendations include running systems longer, as much as 24 hours a day, to keep freshening the air; disabling systems that automatically reduce the amount of fresh air when fewer people are in a building; considering the use of portable air purifiers with high-grade HEPA filters; and considering the use of ultraviolet light technologies to kill the virus.

The recommendations are key, Allen said, because “time spent indoors in underventilated places, overcrowded places, is a critical risk factor for the spread of this virus.”

The mostly behind-the-scenes measures will accompany the more-visible safety precautions returning office workers are likely to encounter, such as spaced-out desks, stepped-up surface cleaning, mask-wearing, and an abundance of hand sanitizer.


How hard it will be to freshen the air in office buildings will vary, experts said.

“For some of them, it will be much easier. Others already had a deficit of ventilation before COVID,” said Memo Cedeño Laurent, associate director of the Healthy Buildings Program.

Laurent noted that office buildings built at different times have different design characteristics. Buildings constructed in the period right after the 1970s energy crisis were “known to be very tightly sealed,” for example, to save energy. The way heating, ventilation, and air conditioning (HVAC) systems have been operated and maintained is also a factor in how difficult it will be to freshen up the air, he said.

The Healthy Buildings Program recommends a minimum of 30 cubic feet per minute of fresh or highly-filtered air per person. The current ASHRAE design standard for typical office building occupancy is about half that, Allen said. The CDC has not issued a recommendation.

If that air filtering recommendation can be met by bringing in more outside air, there’s no need to do anything else, said Laurent. If that can’t be done, the next option is to put in higher-efficiency filters, rated MERV-13 or greater, that do a better job at screening out virus particles. If more air cleaning is needed, portable HEPA air purifiers are recommended, he said. (Even with all those measures, experts still recommend that workers wear masks at their offices, Laurent noted.)

Changes will cost money, experts acknowledged. During hot weather and cold weather, extra fresh air piped in will need to be cooled or heated to be comfortable; new filters will need to be purchased; and more energy will be needed to push the air through the denser filters.


But Allen said the costs of making changes are not as high as people might think — and are far outweighed by the costs of not making them.

“It’s a common misunderstanding that the strategies are expensive. The costs of not implementing are increased risks of someone getting COVID … and increased risks that no one will come back to your building,” he said. “Who is going to go back to a building that isn’t a healthy building? The costs are trivial to what’s at stake."

Allen said building owners are stepping up. “There’s no question. Across sectors of the economy — finance, biotech, commercial real estate, the arts, universities, hospitals — I talk to CEOs every day who are implementing these healthy building strategies because they get it. They get it that this is the new minimum to operate.”

Wade Conlan, commissioning and energy manager at Springfield, Ill.-based Hanson Professional Services Inc. and an ASHRAE director-at-large, said building owners are in different stages of addressing ventilation issues.

“I would say right now that the majority of building owners are evaluating their systems to see what they are doing and what they can be doing,” said Conlan, who works out of Florida, evaluating new and existing HVAC systems.

Tamara Small, chief executive officer of NAIOP Massachusetts, the Commercial Real Estate Development Association, said that in this state, “Improving ventilation has been a huge focus for building owners."


“Flushing buildings with more fresh air than in the past began happening in the spring. When most workers were at home, property managers were investing in making work environments safe for tenants when they returned,” Small said in an e-mail. “While the size and age of HVAC systems affects which filter is best, most buildings are installing MERV-13 filters which trap more particles. Energy efficiency suffers (particularly when it’s extremely hot or cold), but right now the focus is on ensuring health — and fresh air is key.”

“The top priority is keeping tenants and making sure they know they are safe,” she said. “Any costs associated with air filtration and filters are worth it to them.”

Small estimated that the occupancy rate for many office towers in downtown Boston is still in the single digits, while in the suburbs, the office occupancy rate is about 15 percent and the lab occupancy rate is about 20 percent.

With few school districts going back full-time and still no vaccine available, she said, “we do not expect a huge shift by the end of this year.”

Conlan said the HVAC industry is coming out with new products or “twists of ideas" to eliminate the virus from the air, but ASHRAE is still evaluating them.

“I’m taking it with a grain of salt,” he said. “I would love for a new technology to come out and be a magic bullet, but it’s still going to take time.”


When people return to their offices, how will they know if their air is meeting recommended standards? Employees should ask their companies to tell them what steps have been taken, the experts said.

“There isn’t any HVAC systems police,” said Conlan. “You should be asking your employer, ‘OK, what are they doing with our HVAC system to help mitigate transmission of the virus?' And I would expect the business owner to talk with the building owner or operator to find out what’s going on.”

Allen said, “Building owners and companies need to communicate” to their workforces about what’s been done to improve ventilation.

"It’s up to employees to ask about it,” he said.

Jeremiah Manion of the Globe staff contributed to this report.

Martin finucane can be reached at martin.finucane@globe.com.