I bought three Vindriktnings when they came out, and on a day when we had some wildfire smoke making outdoor air quality around 150 put all three outside. Two w

I bought three Vindriktnings when they came out, and on a day when we had some wildfire smoke making outdoor air quality around 150 put all three outside. Two went yellow then red, while the third stayed green... I guess I'd prefer a false positive to a false negative personally. It's true, they only cost me $13 each, so not a huge loss but it does suggest there are quality control problems with either the sensor or the whole device.