With cutting-edge sensing and purification technology, the Philips Air Purifier Series 2000i is proven to reduce allergens, odors, VOCs, and even certain bacteria. The pre-filter and True HEPA filter remove particles. The Active Carbon filter reduces gases and odors. Designed with a multi-stage active filtration system, which captures up to 99.97% of particles that pass through the filter as small as 0.3 microns – the size of most common airborne allergens, particles, bacteria, and viruses. Benchmarked against a professional-grade sensor, Philips AeraSense technology is highly effective in sensing even the slightest change in indoor air conditions. It continuously monitors the air and automatically adjusts the fan speed when it detects a change in particles.