My Philips Air Purifier does not improve the air quality

If the air quality does not improve or the air quality light does not turn blue when using your Philips Air Purifier, 2in1 Air Purifier and Humidifier or 2in1 Air Purifier and Dehumidifier, find out the possible causes and solutions here.

Note: All images shown below are generic representations only; there can be some differences among specific appliances.