Why do the PM2.5 readings vary when using multiple Xiaomi Smart Pet Care Air Purifiers?

Question

Accepted Answer

In actual environments, dust moves with the airflow, so even in the same room, it is difficult to ensure that the dust levels are identical in all areas. Since the Xiaomi Smart Pet Care Air Purifier's sensors are highly sensitive, differences in readings could occur. A PM2.5 difference between two devices (calculated by the formula: (average value - reading) / average value) within 10% is considered normal. Additionally, electronic devices have tolerances, which can cause slight differences in sensor voltages, leading to discrepancies in the readings. If the PM2.5 difference is large, the sensor compartment will have accumulated dust, which can be cleaned. The different colors of the air quality indicator are due to differences in the PM2.5 values detected by the sensors. If the readings are close to the threshold, one purifier could be above the threshold while the other is below, leading to different indicator colors.