With Washington now in another lockdown to reduce Covid-19 cases, I’m hearing questions from landlords and commercial building owners who want to take this time to make the indoor air safe for when they bring employees and customers back inside.

Meanwhile health care, biotech, production and manufacturing businesses have remained open during the pandemic and are concerned about improving their indoor air as well.

Nearly a year after so many people started doing their work from home, they are looking forward to the day when they can come back to the workplace.

When bringing workers and customers back inside, the key consideration is safety.

The Centers for Disease Control in October acknowledged that Covid-19 is an airborne virus, something that many have suspected and have worked around for months.

Now that it is official, landlords, tenants and those tasked with building safety must work even harder to protect people from this airborne illness when at work.

They can be the heroes of safely bringing people inside and jump-starting the economy by following the research and guidelines from the CDC, the state and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

Because every building has its own customized heating, ventilating and air-conditioning systems (HVAC) based on the number of floors, layout, age and construction materials, each must have its own expert inspection and customized solution.

With Covid-19, we want to make sure inside air is as safe to breathe as clean outside air. HVAC systems can reduce the airborne concentration of Covid-19 inside, lessening the virus load that individuals are exposed to as they work or learn. By using best practices to bring in as much fresh air as possible, we can create just as safe an environment indoors as outdoors, as long as people continue to social distance and wear masks.

For anyone looking for reassurances about spending time working, dining or learning inside, here are the most important air system adjustments to understand in the age of Covid-19:

• Building ventilation should be adjusted to bring in more outside air. ASHRAE recommends three changes of outdoor air before people come back into a building. Air should be completely flushed at the end of the workday so that employees or students return to clean air the next morning. When people are in the building, air should be flushed more often than in the past, even if it uses more energy and makes occupants a bit uncomfortable because of temperature and humidity fluctuations.
• Control humidity. A study published in the journal PLOS One showed that maintaining humidity levels above 43% cuts the ability of viruses like the flu to spread. While few local buildings have humidity controls, another solution is to place portable humidifiers in high-traffic areas such as a lobby or entrance – especially in the dryer winter months.
• Increase filtration to remove as many virus-collecting particles from the air as possible. Replace filters often with the finest ones that a system will allow. Filters are rated MERV 1 to 20. MERV 13+ filters are recommended for Covid-19. For systems that can’t accommodate MERV 13 filters, MERV 11 are the next best choice. HEPA filters also work to arrest very fine particles but retrofitting an HVAC (Heating Ventilation and Air Conditioning) system not designed for HEPA filtration is difficult. Instead of replacing an entire system, consider setting up a smaller, recirculating HEPA filtration system in high-traffic areas such as a lobby or building entrance.

Bipolar ionization is becoming popular in commercial buildings. The latest versions are safe and don’t emit harmful ozone. Bipolar ionization units flood an area with positively and negatively charged ions that can kill microscopic organisms, such as viruses in the air and on surfaces. When dispersed, ions seek out and bond with particles in the air, creating clusters that are large enough for an HVAC system to filter out.

All these solutions, used along with face masks with social distancing, will increase the safety of working, recreating and learning indoors. They offer ways for building owners and operators to visibly show tenants, employees, parents and students that they are being proactive in reducing the risk for everyone to come inside to help get our economy humming again.

Gus Simonds is president of MacDonald-Miller mechanical contractor, which serves the Tri-City area. Reach him at gus.simonds@macmiller.com or 206-763-9400.