In the news this week, there have been stories about members of car clubs gathering up unused N95 respirator masks and donating them to hospitals. Plus, hardware stores have signs on their doors stating they have no N95 masks in stock.
Why would a bunch of motorheads and hardware stores have N95 respirators? Originally, the masks were made for mechanical/industrial use, not medical purposes.
According to the Food and Drug Administration (FDA), “The ‘N95′ designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (0.3 micron) test particles.”
The N95 is a descendant of gas masks created by scientists in World War I and II; soldiers used them to clean the air supply. Miners used similar masks, which utilized fiberglass as a filter, to prevent black lung disease. Although they did the job of filtering out small particles, they were huge, heavy, and hot—masks wrapped around the whole head and were usually made of rubber. “All the respirators were these giant, gas mask-looking things,” Nikki McCullough, an occupational health and safety leader at 3M, which manufactures N95 respirators, said is a recent interview with Fast Company. “You’d wash them out at night and you could wear them again.”
The first masks were efficient, but not so easy to use or wear. Scientists at 3M went back to the drawing board to develop something a little more user-friendly, and, on May 25, 1972, the modern N95 respirator mask was approved. The single-use masks used a melted polymer that was air blasted into layers of very small fibers. When viruses, vapor, or silica particles are caught in the fibers, they get caught in the maze. In addition, 3M added an electrostatic charge to the material, so even smaller particles get pulled in.
Masks then and now: Vintage reusable mining respirator (left) and modern, single-use N95
The new N95 respirators are comfortable and breathable, but they are single use. Why? Because the masks are overachievers—they get more efficient as they’re worn; new particles stick to particles already caught in the mask, which is extremely efficient, however, after a while, it becomes hard to breathe.
That’s why the lifespan—the optimum wearing time for the N95—is about 8 hours. Then the respirators are pretty much full. And, unlike their predecessors, you can’t wash them out and put them on again.
N95 respirators were used in industrial applications such as in car painting, mining, and construction, years before they were adopted and adapted for medical use. Medical applications didn’t occur until the 1990s, when doctors started wearing them to stop the airborne spread of drug-resistant tuberculosis. In China, the N95s were worn by citizens during the SARS outbreak (2002–2004) and by people in Beijing to protect themselves from the air pollution. Today, they are rarely used in hospitals—only when outbreaks of severe respiratory viruses, like COVID-19, call for this kind of top-grade respirator.
The N95 is efficient but not perfect—it has to seal onto the face to work, rendering it inefficient for children and men with beards. But right now, it’s the best tool medical personnel, including doctors, nurses, respiratory therapists, and others in the healthcare field have to protect them against COVID-19 to protect themselves—and their patients—from the virus.
Federal legislation signed on March 18 now allows makers of N95 respirators to produce tens of millions of masks starting immediately and get them out to U.S. health care workers as soon as possible.
Like the models before it, the design of the N95 is evolving. Right now, 3M, Honeywell, and other companies that manufacture the N95 are tweaking and re-tweaking the technology to improve the current model’s efficiency, technology, and wearability. Although the N95 respirator looks the same on the outside, the microscopic world on the inside is changing for the better. “We’re always improving the technology,” says McCullough. “We have thousands of scientists at 3M working on [it].”
NOTE: As of this writing on March 26, 2020, the Centers for Disease Control and Prevention (CDC) does not recommend that the general public wear N95 respirators to protect themselves from respiratory diseases, including coronavirus (COVID-19). The best way to prevent illness is to avoid being exposed to this virus.
