A white box fan is shown inside a room.
A fan serves well to pipe in fresh air from nearby windows, a great strategy to cut down on contamination. (For Spectrum Health Beat)

Americans have by now fine-tuned their core approaches to good health amid the COVID-19 pandemic—washing hands, maintaining physical distance and wearing masks.

But one other area may be worth a starring role in this saga: air quality.

With cold temperatures on the way, experts say we may want to think carefully about the air we breathe at indoor locations where people gather.

A crowded and poorly ventilated space may up the odds of contracting COVID-19 or other viruses, such as the seasonal flu.

Proper ventilation can be a challenge, even in the most high-tech of contemporary buildings.

“Ventilation is essentially when you intentionally introduce fresh air—external air—into a space to dilute the potential particles that could be harmful,” said Gustavo Cumbo-Nacheli, MD, a Spectrum Health pulmonologist.

“In terms of COVID-19, we know transmission occurs from respiratory droplets, which can spread several feet before falling to a surface,” Dr. Cumbo-Nacheli said. “But the virus can also become airborne—and those particles can spread farther.”

In a poorly ventilated and crowded area, these transmission problems can multiply exponentially—and quickly.

It takes just one or two contaminated people to spread the virus to many others.

This is why in the past few months we’ve heard much about super-spreader incidents, wherein large numbers of people contracted COVID-19 after attending the same event.

First-line measures

Masks, social distancing and hand-washing remain leading defenses against the spread of COVID-19.

Wear a mask indoors if you’re exposed to air others have breathed.

Masks work.

Secondly, aim to limit the number of people gathered in a space. Take steps to minimize physical interactions, being ever mindful of proper social distancing guidelines.

The CDC recommends taking a careful look at work areas and classrooms to identify areas where people may come into close contact.

Then, modify seating arrangements, furniture and workspaces to maintain at least 6 feet of distance between individuals.

This sort of analysis can happen on a regular basis, with newcomers always brought up to speed on best practices.

Transparent shields and other physical barriers at workstations also cut down on transmission.


In the battle against viruses, air quality is nothing to sneeze at.

In most structures, adequate ventilation happens mechanically.

Heating, ventilating and air-conditioning systems—referred to as HVAC—pipe in fresh air from the outside while also expelling stale air.

This is the building’s breathing system.

Experts measure this dynamic by looking at the air-exchange rate—the more fresh air brought into a building, the better.

A rule of thumb? A 10-by-10-foot room with three to four people in it should get six air exchanges per hour. And that should be higher during a pandemic, according to a report from Shelly Miller, a professor of mechanical engineering at the University of Colorado Boulder.

The science here can be tricky.

In residential homes, for example, it can be “a Herculean task” to adequately gauge the air-exchange rate, said Liam Sullivan, DO, an infectious disease specialist with Spectrum Health.

“While air exchange is a big deal in keeping people healthy, it’s also expensive,” Dr. Sullivan said. “It often involves running more fans—and running them at increased speeds.”

Fortunately, we can lean on some common-sense approaches to improve indoor air quality.

The CDC recommends increasing the total airflow supplied to occupied spaces as much as possible.

How? A few examples:

  • Consider using natural ventilation by opening windows, if it can be done safely.
  • Disable automated ventilation controls that reduce air supply based on a room’s temperature or occupancy. The goal should be to introduce fresh air as much as possible.
  • Inspect filtering systems to ensure they’re operating efficiently.
  • In high-risk areas, consider using portable high-efficiency particulate air (HEPA) filtration system.
  • Consider running the HVAC system at maximum airflow for two hours before and after occupied times.

These types of steps can help reduce germ transmission and cut down on exposure to viral particles.

Another out-of-the-box tip: Don’t pack away your box fan. On days that aren’t too cold, you can place the fan in your window, positioning it to blow stale indoor air to the outside.

Take advantage of bathroom and kitchen range fans, too, which vent air outside.