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Silicon Valley, Ca
In history of surgical mask part I, I described history of surgical masks development. It was discovered that plaque pathogen was transmitted not by body contact as thought earlier in Europe. Rather it was transmitted by airborne pathogen. Dr Wu was credited for the discovery of transmitting medium and creatively developed an improved surgical mask at very affordable price(0.25 Yuan) with layers of gauze and cotton to filter the air contaminants electrostatically.
N95 mask is a descendant of Dr Wu’s design from Spanish flu days[ref to 1 ]. N signifies filter is not oil resistant and is closely fitted to one’s face filtering out 95% of particles that are larger than 0.3 micro-meters in size.
Earlier all the respirators were those giant, gas mask-looking masks. As a child I got scared looking at these photographs. They were heavy and cumbersome to wear. Many workers in the mining and construction industry ignored the use of them and putting on hood coverings the head was hot for people working in the sun and those defy the use ended up with serious health problem. They were often coal miners, and workers handling asbestos contract lung cancers.
Face mask and a N95 surgical mask (3M) -1961
Around 1950s, a décor editor for House Beautiful magazine named Sara Turnbull consulted for the 3M’s gift-wrap division. To make stiff gift ribbons, 3 M had developed a technology to take melted polymer and air-blast it into tiny fibers. Turnbull realized another application was invented from this process. She began experimenting with the material for women blouse shoulder pads, leveraging connections in the fashion industry. In 1958, she gave a presentation at 3M titled: “Why,” which explained why 3M should go into this business of non-woven products more. She presented over 100 product ideas for the technology, and was assigned to design a molded bra. Turnbull, who spent time visiting sick family members in hospitals and came up with another new invention: A “bubble” surgical mask that 3M released in 1961. It takes its inspiration from the cup of a bra. When 3M learned it could not block pathogens, the mask was re-branded as a “dust” mask. That is the only kind of dust prevention mask one could find at local home improvement. In fact, a painter recently complained to me he can not sandblast and do paint preparation anymore because all dust masks have been purchased as emergency facial masks for this Corona-virus epidemics.
The first single-use N95 “dust” respirator as we know it was developed by 3M, and was approved by OSHA in 1972. Instead of fiberglass, the company repurposed that technology it had developed for making stiffer gift ribbons into a proper filter. Under a microscope, they look like a bunched twisted strands—and they have ample spaces for breathing. The particulates, whether silica (sand) or Covid 19 viruses, flown into this maze of strands, they are being trapped. 3M also added an electrostatic (ESD) charge feature to the material act like electrodes on an electrostatic precipitator, so smaller particles are adhered to the gift wrap fibers and they become more efficient over use. N95 mask after 8 hours of use is efficient but breathing holes are plugged. It is time for a replacement or a rejuvination from a cleaning inside a steamer. This is exactly what a professor from University of Tennesse developed using household rice cooker used in many countries by millions today.
N95 respirators were used in industrial applications for about 20 years before the need for a respirator circled back to clinical settings in the 1990s with the rise of drug-resistant TB. HIV resulted in 32 million death, but TB infected many health care workers also. Respirators were not often used in hospitals until it’s only outbreaks like Covid-19 that necessitate more protection. Debating among our president, politicians and governors is not productive. I wonder why they do not consult health experts based on past use.
The cup face mask design is a fit-it-all for those who have a Roman nose like Barbara T. as opposed to Sam's flat nose. It allows a reservoir to store oxygen. However, the use of the rubber bands makes 3M design not as comfortable as Dr Wu's cloth loose fit design.
The face masks are particularily useful in countries that do not have room for social distancing. However, there is ample evidence wearing a mask saved millions lives. I will explain in the next blog how other people effectively use surgical masks to conduct regular business today.
Effective use of wearing surgical masks with no social distance practiced in crowded world.
Compiled by Sam Shueh, your local realtor (408) 425-1601 SamShuehRealtor at Gmail.com http:www.SiliconValleyRealtors.info