1. In February the Chinese state ordered their citizens who were abroad to buy up all the N95 masks they could in those countries and ship them to China. Their goal was millions of masks according to the article. https://www.bloomberg.com/news/articles/2020-02-07/china-implores-employees-and-clients-to-scour-world-for-masks

2. China already has monopolised production of these N95 masks. They manufacture 97% of the masks in the USA. They only monopolised this recently and quickly. See the following article. "Within one year, nearly the entire production of N95 masks went from Made in USA to Made in China. The U.S. Strategic Stockpile currently holds just 12 million N95 masks, a small fraction of the 3.5 billion the DHS estimates we would need in the event of a pandemic. " https://amgreatness.com/2020/03/10/wuhan-virus-exposes-the-danger-of-reliance-upon-china/

3. On March 4th, the Chinese state press agency, Xinhua, reported (translated below) what a strategic advantage it would be to ban the export of masks to the US, stockpile masks, and cause US to be devastated by coronavirus:

If China retaliates against the United States at this time, in addition to announcing a travel ban on the United States, it will also announce strategic control over medical products and ban exports to the United States. Then the United States will be caught in the ocean of new coronaviruses.

According to the US CDC officials, most masks in the United States are made in China and imported from China. If China bans the export of masks to the United States, the United States will fall into a mask shortage, and the most basic measures to prevent the novel coronavirus can’t do it.

Also according to the US CDC officials, most of the drugs in the United States are imported, and some drugs are imported from Europe. However, Europe also places the production base of these drugs in China, so more than 90% of the US imported drugs are related to China. The implication is that at this time, as long as China announces that its drugs are for domestic use and banned exports, the United States will fall into the hell of the novel coronavirus epidemic.

• Since they already have control over manufacturing the masks, those extra masks they had their citizens stockpile and mail back made little difference. They can increase their output or just use them a little less. Everyone is using masks all day in China, but in the West even some medical staff are at risk of running out. They know this