Conventional air purifiers, such as active charcoal, only absorb, but do not decompose the pollutants. As a result, it can only on average last about 3 months. Once the filter is saturated, the absorbed pollutants will be released back into the air and cause “secondary pollution”, which can be very harmful to your health. In contrast, NCCO decomposes pollutants, bacteria, and virus, and can last 12 years without being replaced.