1/ Ocean-Going COVID Vessel.

Another reminder this pandemic is far from over. Significantly reduce inhalation dose of virus-laden respiratory aerosol particles to significantly reduce chance of infection (+ spread to family, friends, & colleagues).

abc.net.au/news/2022-11-2…
2/ Vaccinate to lower chance of severe outcome if infected. How do you lower inhalation dose for yourself and others (if you are infected)?
3/ Test before spending time with others or others spend time together for family gatherings, etc., and isolate if +. Meet outdoors if possible. Avoid being in crowded indoor environments - especially around those you do not know (oh, I don't know ... maybe cruise ships).
4/ Wear a high quality mask (N95 or better). Where you have control increase ventilation. Use (if HVAC system can handle it - most can but some cannot) a MERV-13 filter. Make use of right-sized standalone filtration systems, including #HEPA air cleaners & #CorsiRosenthalBox es.
5/ None of this is rocket science. Never has been, folks. Never will be.

And dollars to donuts it is more than 10-15% (article).

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More from @CorsIAQ

Nov 24
1/ Our paper is officially publised and open access

A novel VOC breath tracer method to evaluate indoor respiratory exposures in the near- and far-fields; implications for the spread of respiratory viruses

Grateful for my wonderful co-authors.

nature.com/articles/s4137…
2/ Results should not be generalized to other indoor environments but are relevant to office spaces or small bedrooms ventilated to about 3 ACH. Two important points. Ventilation = top to floor but supply air flow rate allows for good mixing.
3/ For conditions tested the initial ratio of tracer concentration to normalized exhaust concentration is highly variable and after about 30 minutes converges to a relatively constant ratio with near-field (2.5 to 5 ft) higher than background (far field), but not by much.
Read 6 tweets
Nov 18
1/ New study by EPA researchers and Jacobs Tech Inc.

Large-scale evaluation of microorganism inactivation by bipolar ionization and photocatalytic devices

Important findings .....

sciencedirect.com/science/articl…
2/ Pretty clear conclusion:

"None of the technologies tested appreciably impacted particle concentrations, size distributions, or deposition rates, nor did they demonstrate efficacy against MS2 on surfaces in the test chamber."
3/ For context

Clean Air Delivery Rate (CADR) for BPI = 34 cfm & for PCO = 68-125 cfm.

A good HEPA air cleaner can provide 300 cfm for apprx US $250 to $600
Read 5 tweets
Nov 18
Dear @elonmusk,

I write this thread with sincerity and from the perspective of someone who was dragged kicking and screaming to Twitter 10 years ago by two of my graduate students, but who has learned to appreciate its power as a technology for the greater good. 1/
I have tried for the past decade to avoid getting pulled into the world of trolls, haters, and misinformers. I see these as nuisances on a platform that has meant much to so many. 2/
Twitter has served as a means for effective education and sharing, that has brought people together during a dark time across the globe, and that has started movements that benefit the greater good of society and the planet. 3/
Read 11 tweets
Nov 12
1/ Figs 3 & 4b + Table 1. Entirely possible to achieve equivalent ACH of 10 (low flow setting) to 12 (high flow setting) in a classroom w/ addition of a #CorsiRosenthalBox.

tandfonline.com/doi/pdf/10.108…
2/ Even on low flow setting performance 2x a good HEPA air cleaner and w/ less power, similar dB, & lower $. And system effectively removes particles down to 5 microns (smallest measured in this study) w/ high CADR. Not rocket science, folks. It works.
3/ Paper uses a five filter MERV-13 unit. A 4-filter MERV-13 CR Box still outperforms a much more expensive HEPA air cleaner by a significant amount (1.5x on low flow). 3-yr average cost for a good 4 filter unit with a low cost fan in a class of 25 students? Wait for it.
Read 7 tweets
Oct 26
1/ Given a recent tweet about dorm rooms I allude back to a previous tweet about a #CorsiRosenthalBox in a dorm room w/ 2-3 people in close quarters w/o masks for approx 8 hrs/night. Note mistake in previous slide - should be 15-30 ACH primarily from filtration in flight. TypDoh!
2/ Assuming three students in the dorm room described above (with 2 air changes per hour) and typical CO2 emission rates while sleeping, the steady-state rebreathed fraction (achieved after 1.5 hours) based on those in the room only is approximately 12%. That's high, folks.
3/ Using 12% rebreathed fraction and a typical respiration rate for sleeping adults leads to the following "equivalency." Don't read on if you are squeamish. 🫣
Read 8 tweets
Oct 24
1/ COVID PCR Test #29 in past 14 mos. No wait! Hoping for 0 for 29!

Traveled & in a lot of densely occupied indoor meetings this past week and traveling again this week. Testing just in case I am pre-symptomatic to assure I do not infect my wife or others I'll be meeting.
2/ To reduce the spread of COVID-19 and the lingering adverse effects that it causes it's important to lower inhalation dose of virus-laden respiratory aerosol particles. 3Rs - Remove, Reduce, Remediate.
3/ REMOVE sources - Test, isolate/quarantine, stay home if having relevant symptoms. No source(s) in a shared space, no infections will emerge from that shared space.
Read 4 tweets

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