Second this. It's possible that the 3000 reading is triggered by something else. They should try rubbing sanitiser on their hands and then holding the device - if it goes crazy then it's not directly sensing CO2.
I sort of did this test last night. I assume that VOCs include ethanol, so I mixed up some drinks near the monitor. VOCs went from ~60ppb to a peak of 579ppb. CO2 remained constant at about 640ppm.
I am less surprised than other people that making an open fire indoors increases CO2 levels. Where do the combustion byproducts go if not into the air.
I am less surprised than other people that making an open fire indoors increases CO2 levels. Where do the combustion byproducts go if not into the air.