1.5 million negative ion Negative ion is good for our health. It can help increase our blood oxygen, absorption and utilization so as to improve our body immunity. 2.HEPA filter can clear smok, particles and pollen, kill bacteria as high efficiency as 99.97% 3. Release small amount of ozone, kill bacteria and viruses; 4. Dispel formaldehyde & benzene  and eliminate unpleasant smell;