Do you ever wonder if the air inside your home is polluted? If so, you may want to consider using an air purifier with a HEPA filter. HEPA stands for High Efficiency Particulate Air, and it is the industry standard for air purifiers. It is designed to remove at least 99.97% of particles measuring 0.3 microns in diameter in a laboratory environment. HEPA filters are particularly effective at filtering out allergens such as pet dander, pollen, and dust mites.
They can also trap other particles, although they may not be as effective. To ensure that your air purifier is effective, it should use a true HEPA filter in combination with activated carbon. When particles enter the fibers of a HEPA filter, they become trapped by two processes: direct impaction and interception. Direct impaction occurs when large particles travel directly to the filter and collide with the fibers, where they are trapped.
Interception occurs when particles enter the fibers of a HEPA filter and remain attached to the fibers. You can tell if an air purifier is effective by looking for certain signs. One sign is the use of a high-efficiency particulate air (HEPA) filter. Another sign is indicator lights that tell you when it's time to replace the filter.
HEPA filters are very effective at trapping allergens, but they cannot eliminate VOCs (Volatile Organic Compounds). VOCs are simply too small to be trapped by a HEPA filter. In theory, HEPA filters can remove 99.97% of dust, bacteria, mold, pollen and other particles from the air, but their effectiveness will depend on factors such as the age of the filter. Air and HVAC filters can also help reduce airborne contaminants, including viruses, in a small building or space. A study among smoking households with nonsmoking pregnant people found that while the HEPA air purifier reduced particles in the air, it did not reduce nicotine in the air. Do-It-Yourself (DIY) air filters are indoor air filters that can be assembled from box fans and square HVAC (or oven) filters.
Diffusion occurs when small particles attempt to travel through the filter, but are captured by the fibers.