Screens showing CO2 level set up at venues to lessen virus risk : The Asahi Shimbun
▻http://www.asahi.com/ajw/articles/13832094
The CO2 concentration level in the air is shown on a large screen at a live concert in Tokyo’s Chiyoda Ward. (Provided by Yo Ishigaki, a specially appointed associate professor at the University of Electro-Communications)