Thread by @CorsIAQ

1/ Return to university (part A)

I have heard from faculty at universities across the US about what their universities are planning for return to school in just over a month.

2/ I am fascinated by the large spectrum of actions that will be taken, or in some cases frightened by actions that will not be taken, to assure the health and safety of their university communities. We will learn a lot from this grand experiment. What worked and what did not?

3/ Which universities took actions that protected their on- and off-campus communities, and which failed? To be sure, there will be COVID-19 outbreaks on university campuses across the US. Some people will die, and the local community around a university will be impacted.

4/ The goal of every university should be to reduce on-campus and off-campus exposures to the SARS-CoV-2 virus. That means developing and starting to act on a plan three months ago. I hope that something that I write in this thread of tweets helps your university in some way.

5/ I understand that universities cannot control the actions of their students while off-campus. As such, my comments in this thread are focused on a number of steps that can be taken on campus to reduce risk.

6/ I assume that members of every campus community will develop COVID-19 and there will likely be dozens to hundreds of infected individuals who come to campus every day, many unaware of their infection but perhaps at the height of infectiousness.

7/ My hope is that universities also work closely with the communities in which they are immersed to reduce impacts on residents, merchants, and others.

This is Part A of a long multi-part thread. Additional parts (masks, distancing, controls) will be posted on 7/22.

8/ This list described herein is not all-inclusive. Lack of mention of a risk-reduction strategy does not mean it is not important. I have also focused this tweet thread on the classroom, understanding that there are many other indoor environments in universities, ....

9/ from dorms to library, coffee shops to gyms, and more. And at many urban universities, students will travel to campus on mass transit. Universities and students should understand protections being taken and precautions to be taken in transit as well.

10/ Much of what I have written here can be extrapolated to these other environments, with obvious additional nuances required in each. My focus is largely on close contact and airborne pathways for exposure to SARS-CoV-2.

11/ Source reduction. When discussing risk reduction related to indoor air quality it is prudent to look back to one of the acknowledged founders of the #IAQ field and the namesake of the most prestigious award in the field, Max von Pettenkofer.

12/ In 1858 von Pettenkofer stated - “If there is a pile of manure in a space, do not try to remove the odor by ventilation. Remove the pile of manure.” Wise words!

13/ Source reduction should ALWAYS be the first goal of improving indoor air quality. No source, no problem (at least with that pollutant). With respect to SARS-CoV-2, this means trying to remove the source (infected individual, or “infector”) from a building.

14/ This means some form of testing on a regular basis and quarantine of those individuals who might be infected. Standard (Cadillac) testing of all students, teachers, staff, and visitors will not be possible for most universities.

15/ Group testing or randomized testing of a smaller population might provide some benefit, albeit less than rigorous community-wide testing. Other measures should include .....

16/ a relentless campaign of education for campus community members, including reminders of high risk activities to avoid, common symptoms of illness, and not going to class or other on-campus activities if not feeling well.

17/ IR thermometry and/or smell tests on campus can provide some level of screening that is not fool proof, but has some benefit to identify those who need further testing and quarantine. These tests are also quick and relatively inexpensive.

18/ Certain activities are high emission activities and should be avoided, especially indoors. These include singing, use of wind instruments, speaking or yelling with significant amplitude, and ....

19/ aerobic activities that lead to breathing rates that far exceed average and that can lead to higher emissions from an infector or dose in a receptor.

20/ An additional source minimization strategy is to simply reduce density on campus. This can be done by various means, e.g., hybrid courses, staggered courses, remote teaching for many courses, etc.

21/ If student attendance is cut to 50% of normal, that will effectively reduce by 50% the probability that an infector is in the classroom and also reduce the number of infections if an infector is present.

22/ I know of at least a couple of universities that are aiming for lower attendance percentages in classrooms, e.g., 30%, which reduces risk of a source being present even lower.

23/ While the suggestions listed above will likely reduce infection sources on campus and in the classroom to some extent, they will not reduce sources to zero. Von Pettenkofer would not be pleased. As such, additional steps are critical to reduce exposure and dose.

24/ I focus the remainder of this thread on inhalation dose from both close contact (near field) and the airborne (far field) pathways.

25/ Masks. The benefits of everyone wearing a mask are clear and unambiguous. If everyone wears a mask in a classroom or other communal location, exposure to both large droplets and aerosol particles are reduced, as is risk of infection. to be continued.