yah it's hard to verify whether or not the thing has true absolute accuracy. However once I started experimenting in real world scenarios where I was able to co

yah it's hard to verify whether or not the thing has true absolute accuracy. However once I started experimenting in real world scenarios where I was able to corroborate my own subjective interpretation of my senses the numbers did correlate and scale proportionally as hoped. When it was noticeably smoky outside the numbers registered high, the higher the smoke smell the numbers reflected proportionally so. I would do experiments like vacuuming and seeing what showed up. Cooking with smoke being generated, the numbers would grow. Mine has some VOC mode too, when I took the thing to the gas station that number went way up which was pretty illuminating how much VOCs we breathe in at the pump. Another angle to the experimentation was with and without the HEPA filter being ran. When smoke would infiltrate the indoor numbers would be like 10 or 12. Run the HEPA for say 20 min the numbers get down to 2 or 3. To me that thing was doing what I expected and served us well in the wildfires.