Devabhaktuni "Sri" Srikrishna
@sri_srikrishna
Working on how to stop spread of viruses since 2014. Founder http://patientknowhow.com: N95 + air purifier how-to. MS (EECS). Like, share, or retweet ≠ endorse.
Why cleaning air in your classroom/home/bar/work at least 6 to 12 times per hour (6-12 ACH) is not great, but rather the bare minimum to cut down COVID spreading. + 5 steps to get 6-12 ACH with gold-standard HEPA purifiers or cheaply with Do-It-Yourself (DIY) filtration (1/19)
:-)
My GVS sits in its little case in my truck. Just baking all day every day. It is my "oh crap, forgot my N95" emergency respirator. I think I like the case more than the respirator, truth be told. (Make sure you buy the respirator straight from a amazon.com/GVS-Elipse-SMP…
FLAW #7: The risk in 241 is computed "per hour", i.e. 1 hour at a time. That maybe ok for hour long class in high school or college, but useless for guide to stop transmission for 6 hours elementary school classroom, 8+ hours at home 🏠, a hotel room 🛏️, or a hospital stay 🩺.
“Several students and adults reported smelling odors in the building… 7 other people having seizure-like symptoms, "I think it was polyurethane," Dietch said. "I think they were refinishing the wood floor."” wcvb.com/article/8-mass…
Not if but when! We will get there. Tech is ready, standards are ready.
If we sufficiently cleaned indoor air, pandemics could be made improbable A big overlooked need to doing this is diluting clumps of pathogen that cause short-range spread Fans can help but other approaches are needed @sri_srikrishna & I discuss in our @ScienceMagazine eLetter
Interesting tradeoff: fans versus surgical masks which is better for interrupting close-contact transmission? As with many things, probably situation dependent
Short range, masks (even SM, which deflect flow but don't really filter) are probably the best Fans seem to me quite unreliable as you don't quite know air speed & 5 ACH for infectious aerosols is imho a bit low, even if that is heavily dependent on transmission bottleneck size
ASHRAE 241: What to do when a virus spreads through the air. This standard defines how much clean air per person is needed to reduce infection risk - but only during outbreaks. It doesn’t apply all the time. Here’s what it says and why it matter🧵
MEGA STUDY: ASHRAE 241 model just published 🌪️ Kudos to authors and anon peer-reviewers for achieving clarity + precision 🙏🏽. Lot to LOVE in here 🎶. But also some fatally FLAWED assumptions ☠️ Details below. First love 👍 then flaws 👎 h/t @effiegreathouse
Nice summary of a new publication on ASHRAE 241. We have surpassed that Standard in every classroom I have taught in the past several years because Covid transmission is high even during relative lulls.
MEGA STUDY: ASHRAE 241 model just published 🌪️ Kudos to authors and anon peer-reviewers for achieving clarity + precision 🙏🏽. Lot to LOVE in here 🎶. But also some fatally FLAWED assumptions ☠️ Details below. First love 👍 then flaws 👎 h/t @effiegreathouse
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MEGA STUDY: ASHRAE 241 model just published 🌪️ Kudos to authors and anon peer-reviewers for achieving clarity + precision 🙏🏽. Lot to LOVE in here 🎶. But also some fatally FLAWED assumptions ☠️ Details below. First love 👍 then flaws 👎 h/t @effiegreathouse