My biggest takeaway from traveling for a month with an #Aranet4 to monitor CO2 levels as a proxy for #covid risk, is that air conditioning gives you a false sense of security.

I was on a packed subway train that was stuck for 20 mins, and while the train was stopped with the doors open, the CO2 levels didn't go above 700ppm, despite feeling hot and stuffy. When the doors closed and the AC kicked in, the CO2 levels tripled, despite feeling like there was much more ventilation.

#CovidIsNotOver

#AskFedi #IAQ #CleanIndoorAir #HVAC folks:
My apartment's HVAC system, which is connected to an individual rooftop unit with its own fresh air intake ducts--is currently down. My understanding is that the issue is with the control module that is connected all the in-apartment on this floor, so all of our units are turned off.
I have a CR box air purifier, and a small portable one with miniature #HEPA filters, and an #Aranet4 air quality monitor.

Maintenance have installed a one-hose portable AC unit, with thermal tape around the edges of the open window. From the perspective of minimizing aerosol concentration, what is the best approach with respect to fan speed/mode options, i.e., always on, or only when cooling; blocking the undercut in the door, and opening a window in a different room?

I had also considered not using the portable AC at all; minimizing opening of the door and venting via windows with colder air at night.

Really happy with the ventilation at #Drupalcon! CO2 levels in the sessions have been barely above the baseline outdoors. Look at how much lower the levels were when giving my session compared when I was sleeping overnight alone in a room.

#CovidIsNotOver #Aranet4

[trop tard]

Quelqu'un aux alentours de #Lyon voudrait acheter un #Aranet4 ? Je vais peut-être faire une commande et on a une réduction si on en prend deux, jusqu'à ce soir ! #Covid
@arra #boost #BonPlan #Aranet

Welchem CO2 Sensor glauben wir jetzt?

🫎 #Ikea #Alpstuga mit 401 ppm
🏛️ #ApolloSensors #MSR2 mit 327 ppm
🔺 #Aranet4 mit 496 ppm

🌋 Mauna Loa Observatory, Hawaii: 429.29 ppm

Kann es sein das 6. Stock, Stadt und ca 3 C Temperatur die Messung verzerren?

Wie kalibriert man am besten?

Ich war am Wochenende im Theater. Es war sehr schön. Diesmal hab ich daran gedacht, den Aranet CO2-Sensor nicht an der Garderobe abzugeben sondern in den Saal mitzunehmen.

Das Maximum zu Beginn der Vorstellung im Publikum waren 5.693 ppm. Der Wert war während meines gesamten Aufenthalts im Gebäude nie unter 2.800 ppm.

Das ist halt ein bisschen ungesund. Und auch schade, wenn sich das Publikum schlechter konzentrieren kann und immer wieder ein Gähnen unterdrücken muss.

#luftqualität #indoor #indoorAir #saubereLuft #aranet #aranet4 #co2 #atemluft #wien