Air purification systems are used in a variety of commercial and industrial settings, such as restaurants, hospitals, schools, offices, gyms, dental offices, hairdressers, factories, and warehouses. These places require air quality to be maintained for the safety of their occupants. An air ionizer (or negative ion generator or Chizhevsky chandelier) is a device that uses high voltage to ionize (electrically charge) air molecules. In response to the COVID-19 pandemic, people have been installing ionizers in offices and restaurants.
The fan-based ionizer uses its fan to circulate air quickly through the room, but it is noisier and consumes more energy. Fanless types distribute air slowly, taking longer to purify the air, but they are quiet and save more energy. If you prefer a commercial air filter, Health Canada provides a useful guide on how to choose an air filter. Home air purifiers are no substitute for the need for adequate ventilation and are not a long-term solution for spaces with poor indoor air quality. Keep in mind that the manufacturer of a multifunction device, such as an air conditioner that contains an ionizer, must have CARB test and certify it, even if the manufacturer does not advertise the function of the air filter.
Ionizers use electrostatically charged plates to produce positively or negatively charged air ions (for example, N2+ or O2−; these primary ions immediately cluster with other air molecules, such as H2O) to which the particles adhere. Portable air purifiers have two main limitations related to their overall contribution to good indoor air quality and their ability to reduce the onset of diseases. A product whose main purpose is not to purify the air, but that includes an air filter or a component that supposedly cleans the air, is also considered an indoor air purifying device. With respect to the COVID-19 pandemic, portable air filters can be used to reduce the amount of virus in the air and on surfaces. In the case of a respiratory pathogen such as SARS-CoV-2, it is generally recommended that classrooms receive 3 to 6 people each, so that as much as possible is outdoor air and the rest (if necessary) recirculated and cleaned air. Another consideration to consider with portable air filters is that they can create directional airflows within the room that could result in greater exposure for some occupants, depending on their position relative to the air filter compared to the source of the contaminant or pathogen.
Ionization decreases considerably with distance (even in the ducts), so that air ionization is rarely used for this purpose and only for the elements immediately adjacent to the actual ionizer. Using an ionizer may not be helpful if you have asthma or allergies. It is important to note that while ionizers can help reduce airborne particles in certain settings, they are not a long-term solution for spaces with poor indoor air quality. Therefore, it is important to ensure adequate ventilation in any commercial or industrial setting.
