CU Boulder Today chatted with chemistry Professor and CIRES Fellow Jose-Luis Jimenez about why it鈥檚 so important to wear a face covering鈥攅ven when you鈥檙e outdoors. For starters, Jimenez said you can think of the virus like smoke. Imagine people around you smoking cigarettes. If you would be able to smell that smoke, you may not be completely safe.
鈥淲e鈥檝e all seen smoke on a windy day or in a smoky room,鈥� Jimenez said. 鈥淲e need to think about where the smoke would move.鈥� Now, to our questions. (Listen to Jimenez and mechanical engineering Professor Shelly Miller talking about ).
So, just to get this out of the way, do face coverings work?
Face coverings听work. Basically, face coverings听reduce how many viruses an infected person puts into the air, and they also reduce how many viruses a susceptible person will inhale. They reduce both.听
There seems to be growing evidence that, during this pandemic, you鈥檙e safer outside than inside. Is that the case?
There's one study that says a person is 20 times less likely to be infected outdoors than indoors. It's very clear in data collected around super-spreading events, which are these events when one person gets many people infected. There is a database with more than 1,000 events. We see one or two of those that happened outdoors and more than 1,000 indoors. So, it鈥檚 overwhelmingly clear.
With that said, do you still have to be safe outside鈥攌eep your distance from people, wear face coverings?
There are cases of transmission outdoors that have been documented, and they tend to involve people talking in close proximity without face coverings. That鈥檚 really the situation to avoid. You don't want to be talking to someone in close proximity without a face covering. The approach that is closest to a silver bullet is being outdoors, distanced and with face coverings.
You鈥檝e also said that it鈥檚 important not just to wear a face covering, but to wear a face covering听that fits well. How so?
If you鈥檙e thinking about how to block smoke, then you want to block all the gaps, so you want to make sure that you have a face covering听that fits well on your face, has more overlap and doesn't leave any gaps. That is a good fit.听If there are gaps that you can kind of put your finger around, a lot of the air is going to go through there. Air goes where it takes the least work.
How do you know if your face covering听fits well?
When you breathe in, it gets tight to your face. And when you breathe out, it gets further from your face. If it鈥檚 not doing that, that's a sign your face covering听may not fit well.
If we鈥檙e thinking about, say students on this campus, what鈥檚 your best advice for how they can keep themselves safe?
All of these things like being outdoors, wearing face coverings听or keeping your distance, they're what we call layers of protection. Alone, none of them is a silver bullet. But if you do these three at a time鈥攕tay outdoors, wear a face covering听and maintain distance鈥攜ou鈥檝e got the best protection from the virus for yourself and others. Short of just staying at home, of course, but far more enjoyable and productive.
