Do HEPA filters really improve air quality? Research has shown that they can reduce fine particles by up to 55 percent and contamination from outside particles entering inside by 23 percent. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has a Minimum Efficiency Reporting Value (MERV) system for evaluating the efficiency of an air filter. HEPA filters are designed to capture particles between 0.3 and 10 microns (µm) in size, making them effective at removing larger particles such as pet dander, pollen, and dust mites. Unfortunately, they are not able to remove mold, VOCs, viruses, bacteria, or particles smaller than 0.3 microns from the air.
The Clean Air Supply Rate (CADR) indicates the volume of filtered air delivered by an air purifier per unit of time, with three separate scores for smoke, pollen and dust. The higher the CADR number for each pollutant, the faster the unit filters the air for contaminants in a given size range. Fibrous air filters are found in some of the most popular air purifiers and work to physically filter contaminants by capturing particles through the filter fibers. If your main concern is to calm allergies and their symptoms, air purifiers that use HEPA filters are a good option.
All air filters require regular cleaning and filter replacement to work properly. Follow the manufacturer's recommendations for maintenance and replacement. The EPA warns that while air purifiers can help reduce airborne pollutants indoors, cleaning the air alone is not enough to protect people from exposure to coronavirus. In fact, other particles that accumulate and fill the filter begin to act as nutrients and allow mold spores to grow in and through the filter membrane and eventually release new spores into the air.
If there is nowhere for contaminating molecules to adhere, the filter will not remove them from the air. With proper care and maintenance, a portable air purifier will continue to work properly and filter the air. The EPA warns that the functionality of air purifiers is limited in terms of filtering gases and that you must replace filters frequently for optimal functionality, usually about every three months. In conclusion, HEPA filters can be effective at reducing larger particles such as pet dander, pollen, and dust mites from the air. However, they are not able to remove mold, VOCs, viruses, bacteria, or particles smaller than 0.3 microns from the air. It is important to follow manufacturer's recommendations for maintenance and replacement of filters in order to ensure optimal performance.