When was the last time you had that sensor calibrated properly with a can of test gas and a multimeter?
replyTake it outside, as long as it measures 400-450 it's probably good.
replyMetrology calibration is necessary if you want accuracy better than 10%, but most of us don't care at all about that, instead we care about increments of 200ppm or more.
Haha yes. 400-450ppm is fine. We’re doing just fine here. Everything is okay.
replyThe comment was about the accuracy of the sensor, not about raising CO2 levels across the globe.
replySure. It just draws attention to the fact that a throwaway piece of advice for checking calibration of a CO2 sensor is ‘it should read 400-450ppm outside’ when a few short decades ago that advice would have been ‘it should read 300-350ppm outside’.
replyIt’s like if someone said ‘you can check if your chatbot’s news feed is complete and up to date by asking it for ‘recent mass shootings’. There should be two or three in the past seven days’. It’s true and a valid methodology but holy crap does it say something dark about where we are.
Local factors can make your CO2 fluctuate by 200ppm. If you're near a busy road with not a lot of wind 600 ppm is possible. But it's not that important if you open your window at 1000 ppm or 1200 ppm.
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