[Phys-L] How Oakland (CA) school children are returning to class rooms

[Brian Whatcott <betwys1@sbcglobal.net>]

> bernard cleyet <bernard@cleyet.org>> To:phys-l@phys-l.org>Tue, Jul 27 at 1:20 AM>> https://portside.org/2021-07-26/how-oakland-teachers-took-control-our-return-school ;<https://portside.org/2021-07-26/how-oakland-teachers-took-control-our-return-school> 
> > Excerpt of above: > By conducting these safety walkthroughs, we soon realized that our contract language for safe ventilation was too vague. >  Covid is airborne and our students’ simple cloth masks  wouldn’t filter aerosols, so this was a big concern for us. 
(bolding is my addition.) 
During the early days of the pandemic, I considered what it takes to provide protection from inhaling small particles. I purchased woven copper cloth, woven glass fiber screen and battery high voltage generators. 
I finally discarded the idea of wearing a device of this kind  which carries several thousand volts albeit  at very high impedance,  in a moist environment - but I recall that a useful test environment for masks is smoke  driven at low pressure differential in strong cross lighting. ( Cigarette smoke has been used). 
It turns out that "depth" filtering is as effective in an air medium as in oil filtration. One such effective medium is blue non-woven industrial wipes; more effective than N95.