We are all linked together whether we like it or not.
The planet can be covered in man-made walls, but they will not make any difference because every country has different resources including the amount and types of labor and we will be forced to trade and exchange what is of value.
According to a correspondent on National Public Radio, we get most of our surgical masks from China. These are not the germicidal masks providing limited protection that you purchase in the drug store or the throw-away masks that the doctor's offices provide to protect their patients from YOUR sneezing if you are polite enough to wear them when you are ill. No. These are the tight-fitting disposable masks with two filters so that the doctor and nurse can breathe while not contaminating or getting contaminated by the germs in the operating room. Medical personnel will not operate without these masks due to lawsuits.
Most of these masks are in very limited supply in the United States now. We get our masks from China. China has shut down their factories. We get most of our generic drugs from China and we also get most of the basic chemical ingredients to make such drugs elsewhere from China. We can hope we have seen the worst of this epidemic. (We get lots of other stuff as well, but the medical supplies are most important.)
Below is a photo of one of the American doctors that traveled with us to China as a tourist. She has on a traveling mask with the double filter and she wore it because of the pollution in Beijing.
She and her doctor husband wore the masks during days that the pollution levels were beyond a certain point. They checked the data on their watches each day. Most of the rest of us did not. One other woman had asthma and they gave her one of their masks.
The times that I saw locals wearing masks was when they went to the temples where there was lots of smoke from incense burning and smoke from the yak butter candles. Mostly people were maskless.
China is known for shutting down its schools because of air pollution and this was bemoaned by our tourist guide who waited for the day China would have clean air regularly. China is one of the worst polluters of the air on the planet. Above is Tiananmen square on a fairly hazy day. I am sure is mostly empty today.