For my environment it never ramps up in that mode at all. Ambient levels are never higher than 10ppm or so. I know the sensor works because once there was a sm

For my environment it never ramps up in that mode at all. Ambient levels are never higher than 10ppm or so. I know the sensor works because once there was a small bin fire outside. There was no visible smoke indoors, I only noticed a slight smell. But the purifier immediately ramped up and showed over 200ppm.. So it does work. I'm surprised it's so low as I live at the 2nd floor on a fairly busy street with many diesel buses passing.