We should also be grateful for the bakers and cooks, whose risk of death rose more than 50 percent. And for maids and truck drivers, who saw a 30 percent increase in death risk. And construction workers and shipping clerks, up more than 40 percent.
Those numbers come from a new report out of California that shines a light on the shocking risk to covid-19 by occupation. It also shows how necessary it is that we ramp up protections for essential workers. The best way to do that: better masks.
In the scrambling for information and tools in early days of the pandemic, it was acceptable to just say any cloth mask will do because it’s true. Any face covering is better than none.
But we’ve learned so much since then, and we need to adjust our strategy. A typical cloth mask might capture half of all respiratory aerosols that come out of our mouth when we talk, sing or just breathe. A tightly woven cloth mask might get you to 60 or 70 percent, and a blue surgical mask can get you to 70 or 80 percent.
But there’s no reason any essential worker — and, really, everyone in the country — should go without masks that filter 95 percent.
The masks I’m referring to, of course, are N95s. These are cheap — pre-pandemic they cost about 50 cents — and easy to manufacture. Yet our country has failed to invoke the Defense Production Act to produce enough masks for health-care workers and other essential workers. That needs to change, as my colleagues at Harvard Medical School have written.
To see the true power of masks as a public health tool, we have to examine them in the context of everyone wearing them, where the power of each mask doubles. That’s because the 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.
Think about that for a minute. We could reduce exposure by 99 percent for what should be $1 a mask. (Prices are higher now because of the failure to produce an adequate supply.) Throw in better ventilation and some distance between people, and you have hospital-grade protections.
How well a mask works isn’t just about filtration; it must also fit well. A mask with a good set of filters doesn’t do much good if your breath can escape out the sides or top. The mask needs to go over the bridge of your nose, down around your chin and be flush against your cheeks.
Americans should become familiar with ways to test a mask’s fit. Every time you put on a mask, do a “user seal check.” Put your hands over the mask to block the air moving through it, and exhale gently. You shouldn’t feel air coming out the side or up toward your eyes. Then, test to make sure it stays in place by moving your head side to side and all around. Read passages of text, like the “Rainbow Passage” that’s commonly used for respirator fit testing, and see whether the mask slides around too much when you talk.
Beyond the basics of filtration and fit, consumers will need to navigate a confusing market. Is a KN95 mask acceptable? How about KF94? Does country of origin matter? What about counterfeits? A formal federal program could help by offering clear guidance on hi-fi masks.
Until that happens, here’s my cheat sheet: If you can find an N95, go for it. These are certified in the United States. Barring that, I’d go for the certified mask used in South Korea, the KF94. Next I’d choose KN95s, but there is a catch: The government reports that KN95s out of China might not meet standards unless the manufacturer holds a “NIOSH (National Institute for Occupational Safety and Health) Certificate.”
If you can’t find one of these masks, or if you’re not sure whether they meet the standards, there’s something you can do right now with confidence: Double-mask with a surgical mask and a cloth mask. The surgical mask gives you good, certified filtration, while the cloth mask on top helps improve the fit. Research shows this can achieve greater than 90 percent filtration.
Many people ask if they need an N95 on their morning runs or while sitting on a park bench. The answer to both is no. Choose masks based on the level of risk for that activity. If you’re out for a jog with no one around or on a walk outside with a friend, a simple two- or three-layer cloth mask is fine. But use a hi-fi mask or double-mask if you head indoors. If you’re an essential worker, a hi-fi mask is critical.
I’m not alone in calling for better masks, and certainly not the first. But I am joining the chorus calling for them. This could be the key to slowing the pandemic and limiting spread from the new more highly transmissible variants until we all get vaccinated.