One of our most popular air purifiers is called Guardian Air. While other systems are passive systems which only clean air that passes through the filter, Guardian Air is an active system. This means that it generates oxidizers that actually travel through the air, killing germs before they have a chance to spread. In an independent sneeze test, Guardian Air was proven to kill 78% of the bacteria within three feet of the sneeze. Fairview customers who choose a Guardian Air purifier will enjoy cleaner, healthier air in their homes.