According to Joseph G. Allen, an associate professor and director of the Healthy Buildings program at Harvard University’s T.H. Chan School of Public Health, there’s no reason any essential worker — and, really, everyone in the country — should go without masks that filter 95 percent.

The power of N95 masks comes in to play when particles have to pass through the material twice — once after being emitted and again before someone breathes them in. Take the example of two 70 percent efficient masks, which combine to reduce 91 percent of particles. Not bad. But two N95s result in greater than a 99 percent reduction in exposure.

We could reduce exposure by 99 percent if everyone wore an N95 mask.

If everyone wore an N95 mask it could be the key to slowing the pandemic and limiting spread from the new more highly transmissible variants until we all get vaccinated. Read the full Washington Post article here.