COVID-19 And Aerosols—Here's What We Know

by Karen Johnson
Peter Dazeley/Getty Images

When we think of polio and measles and typhoid, it seems like all that happened in another world, doesn’t it? We know that polio took lives and permanently disabled many others. We know that measles is terrifyingly contagious and can cause brain damage, hearing loss and long-term immune system issues. And we know that typhoid is a deadly bacterial infection caused by contaminated food and water.

We know all that now, and cannot imagine a time of not knowing it. But at one point, real people like you and me were living through outbreaks of these infectious diseases and learning new information every day. They were scared and had to adjust their lives regularly as new safety measures were introduced, because that’s how science and medicine works.

We will never forget COVID-19. We will never forget the terror this virus raged on our world. And our grandkids will know all about it—how it was transmitted, how it was treated, and how to prevent it from happening again. But we’re the ones living in it right now, as so many have lived through novel viruses and diseases and pandemics before. We are learning new information every day that we must absorb and use to keep ourselves and loved ones healthy, even if it contradicts information we previously thought to be true.

One of the latest pieces of info, which is extremely relevant as states formulate plans to re-open schools, is about the longevity of this virus in air particles called aerosols. According to a New York Times article, research is now revealing that, while the virus does not travel far or remain viable for very long out in the open air, that it can stay “aloft in the air for hours” if contained indoors.

So what exactly is an aerosol? NPR reports that an aerosol is a “microscopic virus-packed particle that’s expelled from an infected person’s mouth when breathing, speaking, coughing or sneezing.” Infected air droplets will fall to the floor within a few feet of the person who expelled them, but a smaller “aerosol particle” can remain suspended in the air for a long time.

Imagine a crowded space like an indoor concert, or a bar or restaurant, or a political rally, for example. Imagine all the aerosols floating through the contaminated airspace, and how many people could potentially breathe this infected air in.

The New York Times warns, “In a crowded indoor space, one infected person can release enough aerosolized virus over time to infect many people, perhaps seeding a superspreader event.”

That means you can be a superspreader of COVID-19 by grabbing a drink with a friend at a bar. You don’t know you’re carrying this contagious virus, because maybe you don’t have symptoms yet. By merely breathing out of your mouth, laughing, chatting about your kids or spouse, maybe letting out a cough or two or clearing your throat, you’ve possibly infected (and definitely exposed) the entire room.

Or, you’re not carrying COVID-19, but you risk going out because you’re tired of staying home. You attend a big get-together where 25 people are packed inside one house with no masks. You catch up with friends and family, move throughout the crowd, and inhale contaminated air. Now this virus is likely inside your body, which means you could become sick and/or spread it to even more people.

Or, you are more careful and social distance. You only go to work and even there, stay six feet from others. You don’t wear a mask because it’s annoying, but it’s okay because you’re not near anyone, right? You walk across the room to get something out of the printer and breathe in aerosols an infected coworker exhaled a half hour ago. You’re now infected.

Now picture a school. Suddenly that image seems a whole lot more terrifying, doesn’t it? Hundreds of kids and teachers indoors, sitting at desks, or moving throughout hallways, breathing in microscopic infected particles of air. Particles that, researchers are saying, can stay contagious for up to three hours. Taking that air into their lungs, into their immune systems. And bringing it home to their moms and dads and grandparents and siblings. Imagine how easy it will be to have a superspreader inside school buildings this fall.

These aerosols will “continue to float and follow the air streams in a room,” says atmospheric chemist Kimberly Prather in an NPR article on COVID-19. We now know that the air around us can become contaminated, and we must address this risk as we make the safest choices for our families.

So what can we do? For one, we should be outdoors as much as possible if in public. That means if you really think it’s important to visit in person with a friend or relative, sit outside. And wear a mask anyway, even though you’re in the open air. If you do need to be indoors, always wear a mask, try to stay 6 feet apart, and open windows if that is an option. Also, The New York Times recommends upgrading the filters in air conditioning systems or adjusting the settings to use more outdoor air than recirculated air.

Again, when we look at schools, what options will they have? Most buildings with central A/C, especially newer school buildings, do not have windows that open. Do school districts have the money to purchase different filters that allow more fresh air in? Well, since many districts around our country cannot buy teachers the basic school supplies they need, that seems highly unlikely.

We must acknowledge that aerosols are yet another route of transmission—one that cannot be stopped by hand washing or even social distancing. This is why we need to wear masks. This is why people are judging you if you have a party or hit a crowded club on Saturday night. And this is why having our kids return to a traditional school setting will be catastrophic.

More than 230 scientists have come together to sign a document imploring WHO to recognize aerosols as a method of COVID-19 transmission. Currently, WHO only recognizes air droplets (which are larger, and heavier than aerosols, and thus do not linger in the air) as a method of airborne transmission. But, as is the case with all diseases, researchers learn new information with each passing day, week, and month as more and more cases are studied.

The latest is this: the air around us is not safe until we’ve rid the world of COVID-19. The air inside buildings is extremely unsafe as infected, contagious aerosols linger in the air and can enter our air waves as we inhale. Face masks and better ventilation are crucial to slowing the spread. Merely social distancing is not enough.

Now that we know about aerosols floating and lingering in the air for hours, school districts might have to re-evaluate their plans for opening their doors this fall to hundreds of students and staff. Their students’ and faculty’s lives are at stake.