The Pure Fan Auto has a particle sensor which monitors the air quality in your room. Selecting the Auto Mode means that your Pure Fan Auto will automatically adjust when pollution levels creep up. The fan increases to the right speed based on the sensor readings and slows down when the air is clean again. This ensures that your air purifier is always running at the perfect speed needed to maintain the purity of the air in your home.​
The Blue Pure Fan does not have the Auto Mode. Only the Pure Fan Auto has the Auto Mode.