It is difficult for air trapped in furniture, upholstery, and fabric to get filtered. Glass Fiber Filters - Trap large particulate more efficiently than small matter. These units typicially stop about half the smoke and odors. Activated Carbon Filters - These filters are designed to trap some particles and gases and are typicially expensive to use, need to be replaced often and slow down air flow. Electrically charged plates attract the particulates.
Particulates receive an electrical charge.
These filters must be cleaned or replaced regularly. They get clogged, reduce airflow, lose efficiency and make the blower motor work harder. Needlepoint ionization is the main selling point of these units. Also, it must be stated that most of these units are energy hogs, using in excess of 200 watts. Living Air's proprietary Ionization System reduces particles, like those found in tobacco smoke.