This would fit in well with the thermometer and humidity icons, since CO2 is another variable IoT smart house devices can measure. Could be something along the lines of a cloud with CO2 written inside it.
I.E.

It's pretty hard fitting text into a cloud, but this should do.
In my opinion though, it would be more readable if the text was standalone, and not in a cloud. :cat2:
I too believe that it should stand alone, not in a cloud. And since it's a chemical compound, I don't believe that we need to worry about linguistic differences since The IUPAC (The International Union of Pure and Applied Chemistry) has their main language as English.
@GreenTurtwig Could you provide a visual without the cloud and make the text a bit bigger?
Also agreed that it should just be "CO2" without the cloud.
And @MrGrigri is correct that there is no language conflict, which can be confirmed here.
Huh, I did upload a plain text version along side the cloud, wonder why it didn't show.
Anyway, here's the plain text version:


co2.zip
@MrGrigri The text on this one is regular height, well apart from the subscript "2". :cat:
Icon name should be CO2 (cee - oh - two), not C02 (cee - zero - two).
Fixed, watching the new MTK3 on Netflix apparently is a bit distracting. Not even sure how I did that. 馃槅
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Huh, I did upload a plain text version along side the cloud, wonder why it didn't show.
Anyway, here's the plain text version:
co2.zip
@MrGrigri The text on this one is regular height, well apart from the subscript "2". :cat: