USB Air Purifier with Negative Ionizer Captures airborne allergens like pollen, smoke, dust, pet dander or any particles as small as 0.01 micron by means of silent electrostatic Generates millions of negatives ions to the flow of clean air Super quite fan prompts a better airflow without distraction noise No costly filters to replace and simply removes the steel collection blades and wipe clean with a damp cloth Energy efficient and inexpensive to operate Power supplied by a USB adapter in connection with a USB booster Power input types optional: car lighter adapter/mains AC adapter (all not included) ESP (electrostatic precipitator): yes Negative ionizer: yes Negative ions output: >1,000,000 ions/cm3 Ozone concentration: < 0.05ppm