![Dr. Alex Huffman on Twitter: "11/ My strategy to measure #ventilation rate was to use dry ice (solid #CO2). Cheaply, easily adds high CO2 to a room, them slowly exchanges with outside Dr. Alex Huffman on Twitter: "11/ My strategy to measure #ventilation rate was to use dry ice (solid #CO2). Cheaply, easily adds high CO2 to a room, them slowly exchanges with outside](https://pbs.twimg.com/media/EonME0GVoAc7gyN.jpg)
Dr. Alex Huffman on Twitter: "11/ My strategy to measure #ventilation rate was to use dry ice (solid #CO2). Cheaply, easily adds high CO2 to a room, them slowly exchanges with outside
Dr David Berger, Absurdist Chronicler on Twitter: "@Qantas this ventilation level is completely unacceptable. Immediate CO2 ppm rise from 515 outside to 2154 on boarding. Aircraft on APU. 2755 on engine start.
![Dr David Berger, Absurdist Chronicler on Twitter: "@Qantas this ventilation level is completely unacceptable. Immediate CO2 ppm rise from 515 outside to 2154 on boarding. Aircraft on APU. 2755 on engine start. Dr David Berger, Absurdist Chronicler on Twitter: "@Qantas this ventilation level is completely unacceptable. Immediate CO2 ppm rise from 515 outside to 2154 on boarding. Aircraft on APU. 2755 on engine start.](https://pbs.twimg.com/media/E0P6FmDVoAM4lSB.jpg)
Dr David Berger, Absurdist Chronicler on Twitter: "@Qantas this ventilation level is completely unacceptable. Immediate CO2 ppm rise from 515 outside to 2154 on boarding. Aircraft on APU. 2755 on engine start.
![Linsey Marr on Twitter: "CO2 was >1200 ppm after 2.5 hr in classroom, but dropped <600 ppm after kids went to recess and teacher opened window, placed fan in it. Kept window Linsey Marr on Twitter: "CO2 was >1200 ppm after 2.5 hr in classroom, but dropped <600 ppm after kids went to recess and teacher opened window, placed fan in it. Kept window](https://pbs.twimg.com/media/EoWJh3aXMAAwC8L.jpg)
Linsey Marr on Twitter: "CO2 was >1200 ppm after 2.5 hr in classroom, but dropped <600 ppm after kids went to recess and teacher opened window, placed fan in it. Kept window
![Wartungsaufkleber mit Ihrem Firmenlogo Personalisierte Wartungsaufkleber mit Logo für Ihren SHK-Betrieb. Prüfplaketten, Firmenaufkleber uvm. … | Event, Event ticket Wartungsaufkleber mit Ihrem Firmenlogo Personalisierte Wartungsaufkleber mit Logo für Ihren SHK-Betrieb. Prüfplaketten, Firmenaufkleber uvm. … | Event, Event ticket](https://i.pinimg.com/originals/c5/60/b8/c560b852f41eaa7525901a976563a707.jpg)
Wartungsaufkleber mit Ihrem Firmenlogo Personalisierte Wartungsaufkleber mit Logo für Ihren SHK-Betrieb. Prüfplaketten, Firmenaufkleber uvm. … | Event, Event ticket
![100 Stück Wartungsaufkleber / Kesselaufkleber für Heizung -> Gasthermen mit Firmeneindruck : Amazon.de: Baumarkt 100 Stück Wartungsaufkleber / Kesselaufkleber für Heizung -> Gasthermen mit Firmeneindruck : Amazon.de: Baumarkt](https://m.media-amazon.com/images/I/71g6nbGewXL._AC_SY606_.jpg)