Air filters trap small particles from the air, thus providing cleaner air. There are various types of air filters. The finer the filters, the better the filter system works, since it thus captures a larger percentage of airborne particles. There are three types of air filters.
HEPA Filters (high efficiency particulate arresting filters) are said to be the best because of their ability to trap up to 99% of particles down to 0.3 microns in size. However, very minute molecules, such as gas and tobacco smoke, are still able to pass through these filters. Pleated filters (also known as 'media filters') use the same materials as the HEPA filter, but are less effective because they are less tightly packed. Gas Phase Filters are less popular, since they only remove odors and fumes, but not any particulate matters.
There are a few guidelines that you need to follow before selecting the right type of air cleaner filters. The most important is to ensure that the filter has UL and Class II FDA approval, which simply means that the product is effective and in good condition. How effective is the filter? What are its capabilities in regards to removing substances and particles? To find out, see if the efficiency rate is in accordance with a 'True HEPA (high efficiency particulate air)' or better.
True HEPA means the filter must be able to capture at least 90% of all particles 0.3 microns or more in diameter. Check out the device's CADR rate (clean air delivery rate). The device should be able to cycle enough air to change every four to six minutes in the particular environment. The filter should be easy to clean and change. Also, compare the rates to replace a worn-out filter A good filter should not be too noisy.
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