Ductless air cleaners, also known as portable air purifiers, can be effective at improving indoor air quality, but their effectiveness depends on several factors. These devices typically use filters, such as HEPA (High-Efficiency Particulate Air) filters, activated carbon filters, or UV light, to remove pollutants from the air.
HEPA filters are highly effective at capturing particles as small as 0.3 microns, including dust, pollen, and pet dander, with an efficiency rate of up to 99.97%. Activated carbon filters are useful for adsorbing gases and odors, such as volatile organic compounds (VOCs) and smoke. UV light can help inactivating certain bacteria and viruses, although its effectiveness depends on exposure time and intensity.
The effectiveness of ductless air cleaners is influenced by the size of the room, the air change rate, and the specific pollutants present. For optimal performance, the air cleaner should be appropriately sized for the room, with a Clean Air Delivery Rate (CADR) that matches the room's square footage. A higher CADR indicates a faster rate of air purification.
However, ductless air cleaners have limitations. They are less effective at removing larger particles that settle quickly, such as dust and pet hair, and they do not address pollutants embedded in surfaces or those originating from continuous sources, like mold or tobacco smoke. Additionally, their effectiveness can be reduced if filters are not regularly maintained or replaced.
In summary, ductless air cleaners can significantly improve indoor air quality by reducing airborne particles and some gaseous pollutants, but they should be used as part of a comprehensive approach to indoor air quality management, including source control and adequate ventilation.