The SmartFilter comprises one particle filter layer and one active carbon filter layer. The activated carbon in the SmartFilter removes gas, odours, smoke, VOCs, exhaust, smog, and chemicals from the air. The two parts of the SmartFilter are attached at the top, so when removing it, you can fold it over like a booklet to keep dust and pollutants from escaping. The built-in intelligent chip tracks the use of the filter and notifies you through the Blueair app when it is time to replace it. The SmartFilter must be replaced every 6 to 12 months, depending on your environment.