Coway AP-1012GH Smart Air Purifier with HEPA Filter This smart air purifier with pollution level sensor continuously checks particles in the air and adjusts its air flow speed accordingly 4-stage filtration : pre-filter + carbon filter + true hepa filter + ionizer effectively eliminates pollutants Long-lasting 3-year hepa filter fights dust, smoke, pollen, mold and pet dander Air quality indicator provides visible color change, indicating the air quality level detected by particle sensor technology Aham certified and energy star