All Quiet in the Quarantine Zone

China is rolling out a new mobile phone application, called Alipay Health Code, which is being used to enforce quarantine measures. The app indicates whether the owner of the phone should be quarantined or not and is being used to determine whether people can use public transit, or be allowed into malls and other public spaces. The app uses a color coded system to indicate an individual's health status. People who have been assigned yellow or red are having their movements severely restricted. The New York Times has also discovered that the application is sharing each user's information, including their location, with the Chinese police.

One effect of these stringent quarantine measures being imposed across China is a drop in transportation passenger numbers and a fall in economic activity. Two weeks ago the New York Times created an impressive side-by-side animated map visualizing the huge drop in air traffic over China since the outbreak of coronavirus. In response to the outbreak of the virus airlines have canceled more than 200,000 flights - both domestically, within the country, and internationally, to & from China. In 13,000 Missing Flights the NYT visualized the scale of this reduction in air traffic by animating a day's flights over China on January 22nd (before the outbreak) and a day's flights on February 13th (after the outbreak).

The imposition of quarantine measures and the restrictions on travel have not only affected air traffic. The reduction in road traffic and economic activity in China has also led to a huge drop in air pollution. Over the weekend NASA released a visualization comparing NO2 over China during January and at the end of February. Airborne Nitrogen Dioxide Plummets Over China shows how levels of NO2 have plummeted since the introduction of the coronavirus quarantine in China. According to NASA this fall in NO2 pollution was first apparent near Wuhan, but has now spread across the whole country.