When it comes to eliminating gases and other air pollutants, it's important to choose an air purifier with both a HEPA filter and an activated carbon filter. Not all carbon filters are created equal, however, and many basic air purifiers only contain a minimal amount of activated carbon, providing only a small amount of protection. High-efficiency particulate air (HEPA) filters were developed in the 1940s and are now used in many cell processing facilities. Portable air purifiers require proper care and maintenance to continue to work effectively and filter the air.
To maximize their filtering and particle retention capabilities, these filters are usually made up of multiple alternating layers of aluminum screens with a high MERV rating. Ionizing air filters use a pre-filter to capture large particles before they reach the main filter. The air then passes through an ionizer which gives suspended particles an electrical charge. Washable electrostatic air filters are made of a woven polypropylene or polyester filter medium.
This medium is used to compare the performance of air filters and determine how well they provide good air quality. HEPA filters are incredibly effective at capturing particles of almost any size, with an efficiency of more than 99.5%. For even smaller particles, Ultra-Low Particulate Air Filters (ULPA) can remove particles up to 0.12 microns in diameter with an efficiency of at least 99.99%. When installing HVAC filters in residential spaces, it is recommended to use oven filters with a MERV rating lower than 13 due to their operation based on air flow.