I agree... I have a bunch of cheap indoor air quality measuring devices, and they all consistently read temp, pressure, and humidity close together. My CO2 mete

I agree... I have a bunch of cheap indoor air quality measuring devices, and they all consistently read temp, pressure, and humidity close together. My CO2 meter measures exactly what I'd expect -high levels with windows closed, correct outdoor levels with windows open. My cheap PM2.5 air quality meter reads almost exactly what I see in purple air when I take it outside. Basically, I purchased a bunch of diverse cheap air quality sensor products that I have verified all read correctly, and are not scams. I don't think this article is accurate.