For what it's worth I'm flying back home to the US from the UAE and at the airport as I was waiting to check my bag I saw many (10+) groups of Chinese tourists checking entire boxes of 3M N95 masks. My guess is that they're running out at home and these tourists saw an opportunity to make some money or help people out (or both).

Can an N95 mask prevent viral infection? Those things are typically for particulates and are charged so things like dust attach to the fibers. I’m not sure they’re effective for aerosolized particles

I did research this topic many years ago during the bird flu panic, and the short answer is yes, a PROPERLY USED N95 mask prevents infection. The properly used part is quite tricky though, for example you touch the outside of the mask with your fingers when you remove it, and then rub your eyes... There's a reason those guys are in a full suit and not just a mask.

But even if it's not 100% effective, even if it's just 90% it's still a massive win.

There's very little evidence N95 masks work better than surgical masks, which are cheaper and easier to use.

Umm, properly used N95 masks have been shown to filter particles <10 nm...

N95 masks are better when there's dust, or smog, but don't make preventing getting sick any better than surgical masks. The idea behind surgical masks is to prevent you from getting sick when people sneeze, cough, etc. So the effectiveness is basically the same providing you use them properly.

Never touch the front of the mask. Wash your hands after removing. Dispose of mask after use.

And repeated studies have failed to show that N95 masks reduce transmission more than surgical masks do.

One of many studies: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868605/

- Wearing masks is normal because of air pollution. A lot of people wear really loose non-N95/n99 masks though, but there's definitely an uptick in people wearing better masks because of the virus.

- An acquantince of mine went to a supermarket today. Everything seems fine (they live not too far from Beijing where there are confirmed cases).

- There are still people entering Wuhan to see family. (https://youtu.be/cmgPVhubmQA?t=208)

I'm not saying people don't care. My family is worried for me because I left Hanoi the same day an infected individual arrived in Hanoi. I have friends that are worried for their families back home. But I still see a lot of friends celebrating the new year, albeit not in any quarantined areas.

There's reports of people leaving the quarantined areas with symptoms. I wish they would team up with Tencent to flag individuals who have been active in the quarantined regions and left such regions since then.

In Shanghai (at least, Pudong and Puxi), mask usage has jumped dramatically since last week. I haven't actually kept score, but my impressions of usage from walking around a lot are:

- Summer/spring (lower pollution — Chinese AQI around 60–100, with spikes to 150): 5-10% of people wear masks outdoors. The indoor rate is lower (2-3%?).

- December/early January (AQI typically above 120): 20-30% outdoors. The indoor rate is much lower.

- As of January 23/24: 80-90% outdoors. The indoor rate is at least as high. This time period includes a couple of anomalously low-pollution days (AQI 30 — the lowest I've ever seen in Shanghai), when I might otherwise expect mask usage to be even lower than that 20–30% from before the Wuhan events escalated.

This is just people walking around and shopping. As of a few days ago, some businesses, such as Starbucks and Didi (Chinese Uber/Lyft), require employees to wear respirators (and they've messaged to customers on WeChat and in the Chinese Starbucks and Didi apps).

This is consistent with my observations in the Jiading area - low pollution days but mask usage around 80% for general populace and 95% for service workers (store clerks, etc).

We’ve decided to leave China before things get any worse. I’m not looking forward to bringing my family through the airport this week though...

Good luck and safe travels!

Masks are sold out the couple of places I've been to in Beijing. Girlfriend's family cancelled CNY celebrations for fear of the virus.

People are taking it very seriously.

> An acquantince of mine went to a supermarket today. Everything seems fine

What would it look like if it wasn't fine...?

Massive shortages from people mass panic buying?