(no subject)

[timelets]

This is really clever:

CO2, a substance found in the breath in large amounts, spreads easily in the atmosphere, so changes in the CO2 concentration are a useful indicator to identify how closed and crowded the space is.

For that reason, the Japan Society for Occupational Health states the CO2 level of 1,000 ppm or lower suggests the room is well ventilated based on the building hygiene control law and other criteria.

Under its recommendation, a room with a reading of higher than 3,500 ppm has an extremely bad ventilation capability, so the facility should not be used as a countermeasure against the novel coronavirus.
..
The measured CO2 concentration is combined with data on the population density and degree of noise, allowing whether the space boasts the three-Cs settings to be determined.


http://www.asahi.com/ajw/articles/13832094