"Pura air works to target odor at the source, decreasing dust and removing odor. The Pura air uses infrared thermal system technology to sensitively and accurately identify when your pet enters the detection range. For 60 seconds following detection, the negative ion generator within the PURA AIR releases high-activity negative ions to deactivate bacteria. The negative ions work by absorbing dust and inhibiting bacteria growth, this decrease in dust purifies the air. Each PURA AIR is equipped with five odor removal air ducts at different tilt angles to ensure maximum coverage. The high polymer solid air freshener extracted from 20 pure plants is safe and non-toxic, it can remove odor and refresh air as well as decompose the odor molecules such as nitrogen and hydrogen supplied, etc. In addition, it also helps to promptly suppress the decay of microorganisms contained in odors and prevent bacteria growth. PURA removes odor automatically when pets enter the detection range; as well as running every 6 hours automatically to help promote fresh air all day & night. "