Air purifier filtration.
When choosing an air purifier, consumers can pay attention to the following filtration efficiency reference indicators.
Filter:
1. HEPA filter: the "High-efficiency Particulate Air filter is mainly used to intercept the tiny dust contained in the filtered air. HEPA is a standard rather than a name: according to the definition of the U.S. Department of Energy, HEPA is a filter that is able to block more than 99.7% of suspended particles with a size of 0.3 microns (μm), regardless of whether the filter is made of paper, non-woven fabric or glass fiber. As long as the filtration efficiency meets this value, it can be considered a HEPA filter. In EU countries, it is subdivided into several different grades according to the filtration rate. Generally speaking, only H13 and H14 in European standards can be considered HEPA.
2. Whether antibacterial and antiviral materials are used: In recent years, viruses and bacteria have been rampant, and antibacterial technology has been applied to the filter screens in air purifiers, including copper ion, silver ion, or copper and silver ion technology, which is more effective. When the air passes through the filter, viruses will pass through the antibacterial coating or antibacterial materials, which can weaken or kill bacteria and viruses to exert its antibacterial function.
Mechanical functionality:
1. CADR value: CADR value (Clean Air Delivery Rate), refers to the ratio of clean air output by air purifiers tested by the American Home Appliance Manufacturers Association (AHAM) in accordance with strict testing standards. The higher the CADR value, the higher the purification efficiency of the purifier.
2. Air Exchange per hour: Air Exchange per hour, also known as Air Exchange Rate, refers to the number of air changes per unit time, calculated by dividing the air volume entering the room per unit time (m3/h) with the room area (m3). If the ventilation mode of the room is uniform air supply or complete mixed air supply, the number of air changes is an index to evaluate the frequency of indoor air exchange. In many cases of indoor ventilation, the air in the room is neither uniform nor mixed, and the percentage of air exchange in a room depends on the efficiency of the air exchange and the ventilation method. In the case of complete mixing ventilation, when the air change rate is 1 time/h, 63.2% of the air will be replaced after one hour. In order to maintain the balance of air pressure, the air supply volume and exhaust air volume must be equal.
