1/ More good support that indoor dining is challenging (no masks indoors = risky). Nice article by @RoniNYTimes, w/ comments from knowledgeable folk following a recent CDC #MMWR report.
2/ “You have decreases in cases and deaths when you wear masks, and you have increases in cases and deaths when you have in-person restaurant dining,” said #CDC director Dr. Rochelle Walensky
3/ Unfortunately, the Nat'l Restaurant Assoc called the #CDC report “an ill-informed attack on the industry hardest-hit by the pandemic.”
I feel for restaurant owners & workers. I honestly can't imagine the difficulty through the pandemic. But the challenge & risk is legitimate.
"Association of State-Issued Mask Mandates and Allowing On-Premises Restaurant Dining with County-Level COVID-19 Case and Death Growth Rates — United States, March 1–December 31, 2020" cdc.gov/mmwr/volumes/7…
5/ Add'l reports supporting risk of indoor dining not at all surprising, given the extensive data along those lines. For example, here's a nice, similar study from early November.
3/ I was pleased to see early mention that "Wearing a well-fitting, multi-layer mask helps prevent virus particles from entering the air or being breathed in by the person wearing the mask."
"Right now, schools are looking to CDC and they are not getting the answers to the kinds of things we are talking about." "All of them look to CDC." said @CorsIAQ
"If you look at all the high profile outbreaks -- same underlying factors -- no masks, low ventilation. It doesn't matter if it's spin class, ice hockey, camps, classrooms, choir practice or restaurants, (it's) the same underlying factors" said @j_g_allen
The more I read this story of #superspreading in a Chicago gym, the more outrageous it is, especially this late in the game. A few amazing quotes below.
So preventable: distance, wear good masks, improve ventilation & filtration.
"Overall, 43 (78%) attendees with COVID-19 participated in multiple classes while potentially infectious.* Twenty-two (40%) attendees with COVID-19 attended on or after the day of symptom onset."
"Patrons brought their own mats and weights and were stationed ≥6 ft apart."
"Mask use, temperature checks, and symptom screenings were required on entry"
"however, patrons were allowed to remove masks during exercise." 🤦♂️
1/ Here's a quick bite (< 2.5 minutes) of overview on infectious respiratory aerosol emissions, #ventilation, and using #CO2 monitors as a tool in the fight against COVID & for healthy indoor air.
2/ I recently gathered several interesting stories from recent CO2 measurements as well as a simple example of how I had fun measuring the ventilation rate in my house.
3/ Measuring #CO2 to estimate ventilation rate is a quick way of approximating the amount of "rebreathed air" (the portion of air you breath that has already been in someone else's lungs).
2/ They explored a variety of respirators and masks. As expected, the collection efficiency of the N95 & surgical masks did very well. Masks with filters next, lowest filtration quality when only single-ply material used.
3/ The "fit factor"/FF (higher = better) is also critical. Look at the difference between the N95 and surgical masks in terms of fit (left).
Also see how much fit factor increased when more tightly fitted (below on right w/ ear loop adjusters to make snug).
1/ More great work by @smogdr & team to test the performance of various kinds of #masks.
The (re)introduce mask "protection factor" (PF) as a fraction of particle mass that makes it through & also evaluate breathability, effect of mask construction, etc. pubs.acs.org/doi/10.1021/ac…
2/ This is the thread of main points that @SmogDr put together associated with the now-published & #OpenAccess paper.
3/ And if you haven't already played around with the mask-testing data, @SmogDr & team built this interactive site (months ago) to look in detail at results from various masks. jv.colostate.edu/masktesting/