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Like every other parent with a school-age child, I want schools to reopen in the fall — including the one I’m attending.

On the best of days, my son can be described as “spirited.” After four months of being cared for by his grandparents, he is practically feral. He needs the physical and social outlet that school provides, and I need the anatomy lab to reopen because human dissection is an irreplaceable part of my medical education.

But I am also an epidemiologist, and after reading the Centers for Disease Control and Prevention’s guidelines for school reopening and the various accompanying news coverage and think-pieces, I can’t convince myself that following its rules will keep my family — or yours — safe.


Why? Because the primary way Covid-19 is transmitted is through respiratory droplets that careen through the air, and yet the capricious nature of air circulation and the lack of filtration systems in our already underfunded public school systems is absent from the conversation.

Since New York state started reopening, I have received emails from my medical school’s working group about the plan to bring us back to campus. Its plan is to follow the basic script seen in school reopening strategies all over the country: frequently sanitized high-touch surfaces, 6-foot distances, unidirectional hallways, reduced capacity elevators and classrooms, health questionnaires, and contact-free temperature checks upon entry (more on that in a minute).


My school is not negligent, but like many other educational institutions, its efforts are dangerously misdirected. We are collectively engaging in what Derek Thompson describes in the Atlantic as “hygiene theater,” in which organizations looking to reopen focus intensively on arduous decontamination strategies to mitigate surface transmission — even though that is not the primary route for Covid-19 transmission, and some scientists argue that there is no direct evidence the virus spreads this way at all. I’d also like to add temperature checks to the hygiene theater playbill, as they too fail to successfully screen potential Covid-19 carriers, but have somehow made their way onto every screening list I’ve seen.

Why is this happening? The CDC is supposed to determine the national priorities for American health.

Of the eight bullet points in its “staff safety” section, four address surface transmission. The three bullet points dedicated to respiratory droplets warn people to stay 6 feet away from each other, cough into their elbows, and wear a mask.

The current CDC guidance about ventilation is as follows, “Ensure ventilation systems operate properly and increase circulation of outdoor air as much as possible, for example by opening windows and doors.” But if opening windows or doors increases the risk of asthma, or falling out the window, the guidelines go on to advise that they should be closed. That is all the guidance has to say. It does not mention air filtration, or the fact that we have pretty good data to suggest that without addressing air filtration and circulation, the 6-feet rule does not prevent transmission indoors.

Here are the things that caught my attention as an epidemiologist as schools played Tetris with classroom furniture and agonized over hybrid schedules.

On May 6, Erin Bromage, a microbiologist at the University of Massachusetts at Dartmouth, published a widely read article detailing the role of air circulation at three major indoor transmission events: a call center in South Korea, a restaurant in Guangzhou, China, and the infamous choir practice in Washington state. Each of these events taught us that transmission happens when you spend significant time indoors. Being 50 feet apart with “a low dose of the virus in the air, over a sustained period, was enough to cause infection and in some cases, death.” This happens because infectious particles from individuals are pushed by the ventilation system to the other side of the room. Bromage’s post appeared 127 days before the first day of school in New York City.

HEPA filters are able to effectively capture particles the size of SARS-CoV-2. The CDC currently recommends their use for this purpose in hospitals, but their capacity to prevent the spread of Covid-19 in other public buildings remains under-explored. Though the CDC has stayed silent on the use of HEPA filters outside hospitals, on May 25 a group of ENT doctors made the case for installing them in doctors’ offices where “aerosol generating procedures” are being performed, because of evidence they can help prevent the spread other infections such as SARS-CoV-1, measles, and influenza. That was published 108 days before the first day of school in New York City.

On May 27, a group of 36 scientists from around the world in a variety of fields penned an article in the journal Environment International titled, “How can airborne transmission of Covid-19 indoors be minimised?” As they wrote, “Here, in the face of such uncertainty, we argue that the benefits of an effective ventilation system, possibly enhanced by particle filtration and air disinfection, for contributing to an overall reduction in the indoor airborne infection risk, are obvious.” It’s obvious to me as well, and deserves to be our primary concern in reopening schools, far more urgently than distance or Lysol. That was 106 days before the first day of school in New York City.

McKinsey & Company reviewed research regarding airborne spread of SARS-CoV-2 and on July 9 posted an article suggesting possible upgrades to existing heating, ventilation, and air conditioning (HVAC) systems. A key recommended change was to increase the number of times HVAC systems exchange air per hour, which would push the infectious particles outside and prevent them from being blown across the room. This article appeared 63 days before the first day of school in New York City.

When I mentioned these possibilities to a friend who teaches in the New York City schools, she replied, “Don’t worry about our HVAC systems. They’re all broken.”

Instead of using limited time and funding to engage in hygiene theater, we should be investigating how to address ventilation. Or at the very least, be honest with the public about some institutions’ inability to make interior spaces safe.

As a result of months of misapplied focus on surface disinfection, the importance of air circulation and the potential use of filtration is missing from the national debate on school reopening. My son’s school and mine are both concerned with delivering our education safely. My son’s preschool director was worried sick about not being able to adequately decontaminate on a daily basis because she loves both the kids and her school.

It shouldn’t be her responsibility to research ventilation theory and filtration techniques and air flow patterns. It’s not my job as a medical student to Google these things trying to get enough information to decide what to do about my son’s school, and mine, starting imminently. And it’s not up to the administrators at my school, who I know have been working around the clock these last few months, to figure this out.

This is supposed to be done by the CDC. Here we are, about a month before public schools are supposed to begin, and the CDC is still failing to signal the crucial importance of addressing ventilation.

We need to include air circulation patterns and filtration options in the conversation. If we’re not willing or able to fund necessary upgrades to school ventilation systems, let’s admit that. Until we have that public discussion, I am not comfortable exposing my family to schools. Because if I can’t trust that the people making these decisions are reading the literature, how can I trust them with my family’s health?

Alexandra Feathers is an epidemiologist and first-year medical student at SUNY Downstate.

  • Open Air Schools. Look to American Educational history!
    In the early 2900’s tuberculous among other diseases was seen to becoming truly problematic and there was a she served that socio- economic status had some sort of involvement. Cleveland Public School
    System created a school based program of ventilation and open windows ALONG WITH a on site physician and weekly exams a nurse who did home visits and healthy food and snacks. This was done in the Tremont neighborhood near the Cleveland hive of steel industry and mills. Most families were immigrants and money was an issue. Mertick House was the settlement house near the Public Baths.

    • If our schools cannot afford a sub-$30 DIY air cleaner (20×20 Box Fan plus MERV-13 filter) we are in deep trouble. If our schools cannot replace the filters in air-handling units with MERV-13 filters (or the maximum filter the unit can handle), we are in deep trouble (they are supposed to change filters every 90 days – the cost of MERV-13 vs MERV-6 or MERV-8 is a very small up-charge). If they cannot increase the outside air-flow (just a configuration change) into the air handling system, we are also in very deep trouble. All three of these things are extremely inexpensive….certainly less than litigating the future lawsuits for failure to do these things.

  • In trying to minimize the possibility of contamination floating around in my classroom, I am considering using a series of small fans to facilitate air circulation. My question is, do I want to move the air OUT of my classroom, or increase the flow of air from the hall INTO my classroom?
    Or, would I be better off directing airflow towards the carpet in hopes of sinking aerosols?
    (Interior classroom, no windows, one door at back corner of a square room).

    • Georgia,

      If you are going to put fans in your classroom, choose inexpensive box fans (20″ x 20″) and attach (duct tape) a MERV-13 filter to each one. This will convert your small fan into a DIY air cleaner.

      What you want to do is move virus laden air out of your classroom, dilute virus laden air with clean air (preferably outside air), and clean (filter) air. In order to have the safest air, do all three. And, even if you do all three, that doesn’t mean you are 100% safe. There is no way to get to 100% safe.

      For additional mitigation ideas, I just posted “What does ‘good’ look like” at

      Best regards,
      Eric Svetcov

  • But there is. ASHRAE, the American Society of Heating, Refrigeration and Air Conditioning Engineers released a position paper in April this year that discussed the intersection of occupational ventilation and aerosolized viruses in non-healthcare-related environments, (

    They specifically point out:
    “ Similar strategies may be appropriate for non-healthcare spaces, such as public transit and airplanes, schools, shelters, and prisons, that may also be subject to close contact of occupants.”

    The Collaborative for High Performance Schools (CHPS) put out this paper in June:

    I don’t think there’s a lack of research in this area or discussion as it relates to schools. As the CHPS paper above points out, there is going to have to be a deliberate statewide effort and financial outlay in every state to have school HVAC systems and air quality evaluated by certified air quality/HVAC engineers.

    I wouldn’t necessarily lay this at the feet of the CDC. Instead there should be a collaborative effort between the research at NIH with the CDC, EPA, and OSHA to carefully craft a single coherent strategy for school air quality and ventilation requirements to mitigate the spread of infectious disease.

    The EPA already relies on standards set by ASHRAE.

    Each school’s administrator will have to be point people on ensuring their school’s HVAC system has been evaluated and recommended applications provided to them along with cost estimates to renew/repair these systems.

    But there is no way that this will be a panacea. Behavioral modifications and, yes, surface sanitization will still have to be part of any COVID mitigation strategy.

  • Having taught art for twenty years, I cannot tell you the battles that I have lost to get adequate ventilation and proper functioning of HVAC systems for the safety of my students.

    The schools are not safe, and there is no funding or plan to make them safe.

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