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Marcel Harmon (he/him) Profile picture
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6 Oct, 4 tweets, 1 min read
A few questions for the UV specialists. 1st, are the studies/modeling that have been done so far relative to Far UVC impacts on eyes/skin sufficient to answer questions regarding a) potential negative impacts from chronic (continuous or repeated) exposure,... 1/
b) age/developmental specific concerns related to short term or chronic exposure, & c) concerns for those w/ pre-existing eye/skin conditions after experiencing short term or chronic exposure?

2nd, have studies been done looking at the impacts on the built environment's... 2/
microbiome, & the subsequent impacts on human health? And for this 2nd question, not just relative to Far UVC, but also for more traditional upper room UVGI systems.

Manufacturers are already marketing fixtures exposing occupants to Far UVC. Do the answers to either of the... 3/
above questions suggest we should be implementing the precautionary principal here for far UVC? And w/ respect to the 2nd question, does the answer suggest that at least for now we should be somewhat judicial in our use of upper room UVGI in general? 4/

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Marcel Harmon (he/him) Profile picture
9 Oct
Our new office policy we're finalizing essentially takes this viewpoint. In 3 of our offices, we've assessed high vaxx rates combined w/ addressing the Delta far field risk via ventilation/filtration is adequate enough for vaxxed employees (almost 100%) to go sans masks. 1/
Even in metro areas currently deemed by the CDC as having high or substantial community transmission.

To have vaxxed employees go sans masks in our other 2 offices, relative to their current lower office vaxx rates, the Delta far field risk needs to be addressed through... 2/
some combination of additional ventilation/filtration improvements, increasing vaxx rates, setting lower occupancy limits, or having non-vaxxed employees WFH - we are still assessing the best path forward for each of those locations.

We estimated the far field risk for... 3/
Read 16 tweets
Marcel Harmon (he/him) Profile picture
8 Oct
"'We were in no way expecting what happened,' says Superintendent Adam Hatfield." @TheKLC

Expression of every aerosol scientist, engineer, etc., who've been promoting #COVIDisAirborne strategies since spring 2020: media.giphy.com/media/A928XcII…. #ksed #ksleg 1/

klcjournal.com/covid-19-schoo…
W/ the #DeltaVariant we knew districts would be taking larger risks than necessary if all relevant mitigation strategies weren't implemented - . That we haven't had more districts close for a period of time is pretty fortunate considering everything. 2/
That we're still arguing over the basics of how to respond to a pandemic driven by a predominantly airborne virus demonstrates a multi-level failure of public health & government, exacerbated by a history of underfunding public health, public education, current levels of... 3/
Read 4 tweets
Marcel Harmon (he/him) Profile picture
15 Aug
This is an all hands on deck moment. In-person school is starting. W/ the #DeltaVariant, even w/ the majority of the relevant strategies in place, it’s going to be difficult to prevent transmission in our schools (linkedin.com/pulse/in-perso…). 🧵1/

#ksed #ksleg
In an elementary classroom w/ unvaxxed students, generally ASHRAE compliant ventilation/filtration, the addition of (1) portable HEPA filter unit, & theoretical 100% mask wearing (double layer cloth mask), max exposure is only about 1.2 hrs before an additional student... 2/
is potentially infected at full occupancy (assuming 1 infected student is present).

Accounting for the potential reality of younger kids not always effectively wearing their masks (50% mask wearing), the max exposure is under an hour before an additional student is infected. 3/
Read 17 tweets
Marcel Harmon (he/him) Profile picture
5 Jan
These are the type of actions our pharmacies, hair salons, retail stores, offices, universities, k-12 schools, individual residences, etc., need to be taking, particularly w/... 1/

@KDHE @LDCHEALTH @lawrenceks @douglascountyks @UnivOfKansas @usd497 @LawrenceChamber #ksleg #ksed
a more transmissible strain spreading in the U.S. & months left before vaccination levels are where needed to be.

CO2 levels can be used to estimate ventilation levels, though it's important to account for factors like the number of people present, the size of,... 2/
the space, & the use of portable air cleaners. Pages 23-24 of this document from @HarvardChanSPH & @j_g_allen provide a means for estimating ventilation rates based on measured CO2 levels. 3/

schools.forhealth.org/ventilation-gu…
Read 16 tweets
Marcel Harmon (he/him) Profile picture
3 Jan
I would challenge your point that “No matter what we do, resources will remain scarce and people will compete over them.” First, there’s an abundance of evidence from the archaeological, historical, & contemporary ethnographic records of individuals & groups cooperating... 1/
(employing some or all of Ostrom’s principles) to survive in environments of scarce resources (& not just hunter/gatherer groups). Not saying the evidence for competition (including violent competition) isn’t also there, or that the competition between groups isn’t also... 2/
what often drives the cooperation among group members (because it does), only that cooperation seems to have been most effective when these principles are applied (even as part of a larger competition between groups).

Cooperating (& squashing toxic individualism) was... 3/
Read 17 tweets
Marcel Harmon (he/him) Profile picture
22 Sep 20
Sure. I think that’s great advice, whether or not we’re in a pandemic. As high performance bldg consultants, we’ve been doing that since last March. Engaging school districts to help them work through building/behavioral strategies for reopening relevant to their situation. 1/
As part of that effort we also developed a viral infection risk estimator to help districts (in conjunction w/us, by themselves, or w/ other consultants) evaluate the most effective strategies room by room. Particularly important when resources are limited. I know other... 2/
consultants have been doing similar things (though perhaps not the behavior focus or developing calculators).

But there are limits to such efforts, or other local partnerships w/ businesses, short of a nationally coordinated effort to reopen schools. Decades of deferred... 3/
Read 14 tweets

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