Research also shows that humidity can be effective at reducing the infectiousness of the viruses in general, according to Frank. "That is going to be very carefully weighed with the engineering in balancing all of this," she says. "If you increase filtration rates, you're going to increase energy use. That can have a negative consequence on air quality."

Increasing humidity can also cause mold, which brings its own set of issues. In addition to focusing on ventilation, building operators also need to monitor surfaces. That should include "increased cleaning protocols in high-touch areas, whether that's an elevator, the shared kitchen or the bathroom," Frank says.

To ensure that surfaces are disinfected, building operators need to create protocols that address minor details, such as the percentage of alcohol in the cleaning solution used.

"It will be essential that building operators and managers could communicate how they are addressing those major areas—the airborne transmission and the things oppressing the transmission," Frank says. "As a building occupant or the tenant, you are unlikely to be in control of those processes, and it will be very hard for you to know if they're being done effectively."

For that reason, building owners and operators need to share information about their filtration system and air quality policy. Fitwel has strategies around having an indoor air quality policy and testing the indoor air quality. It also has a strategy around sharing the data.

"We see that used very infrequently because there's risk attached to when you share the data about your air quality," Frank says. "If there's an issue with the air quality, you need to be in a position that you can act on it. When it comes to building trust, it's going to be important that you don't just develop strategies, but you communicate how you are achieving them."