The great thing about living in a country where air conditioning is mostly non-existent, is that when the weather is nice enough they will just open up all the windows and doors.
Today kid2 and a friend went to an indoor playground thing. It is in an old warehouse. The doors for loading the warehouse were open (2 sets of doors), the skylights were open... there was natural ventilation. Where the CO2 spiked above 800ppm: the toilets.
Our respirators stayed on. Drinks were had right next to the open doors.






