Review on 🌬️ Optimized Air Quality Particle/Dust Detector/Counter - PerfectPrime AQ9600, PM 0.3/2.5/10 Μm by Paul Barnes

We have a Class 10,000 clean room. The device works well outside the clean room where I measure 25,000 particles/L for 0.3 µm particles. But as soon as the particle concentration in the clean room falls below 7000, the instrument suddenly shows zero for all particle sizes. I expected the reading to be around 1000/L for 0.3 µm particles.