We recommend that you choose an air purifier to consider the following main air flow: good air purifier ventilation speed must be fast, that wind capacity in the product specification to (m3 / h) to represent, the better the value. Purification efficiency: choose clean and efficient products, specifically to see the removal of the solid particles, the removal of volatile organic compounds, formaldehyde removal, these three indicators are usually expressed as a percentage, the better the value. Filter: the mainstream air purifier filters for each layer for different pollutants, such as: pre-filter can absorb small dust particles and hair; deodorizing filter multi-finger activated carbon filter can remove sweat smell, pet odors such as smell; formaldehyde removal filter is designed for formaldehyde; HEPA dust filter is used to remove dust mites, pollen, bacteria, secondhand smoke, dust and other tiny particles requires special attention is filter replacement frequency and filter cost, how long to replace one, in fact, according to the frequency and extent of the contamination. Noise: As long as no more than 30 db, would not affect sleep at night in the bedroom, then choose a mute function or sleep mode products. Non-silent mode noise'll sleep under the influence Application area: Each air purifiers are marked Approximate area. It can be used as an optional reference. It is noteworthy also taking into account storey house, if the size of the standard height of more than 2.8 meters, then you should take into account this factor, buy a larger area of ??suitable products. Security: look for 3C certification, buy the regular manufacturers. A perfect after-sales service of the product manufacturers. Fifth floor: HEPA high efficiency HEPA filters are High Efficiency AirFILTER (high efficiency particulate air filter) acronym, is internationally recognized as the best high filtration material, according to its unique fiber structure, through efficient control of microorganisms antibacterial fiber processing one of the HEPA filter, effectively inhibit air allergens, such as dust mites, pollen, bacteria, secondhand smoke, dust and other tiny particles, the purification efficiency up to 99%, the smallest particles purify up to 0.0003mm. Sixth layer: photocatalytic filter degrading toxic gases in the air, effectively kill a variety of bacteria. The sterilization rate and TVOC removal efficiency of 97.6% and 97.3%, respectively. Seventh layer: UV ultraviolet light disinfection technology is a major pathway leading air diffusion spread of influenza, clean air is an effective measure to prevent influenza. Using UV air sterilization technology, environmental natural bacteria kill rate of up to 97.6%. Eighth floor: negative ion technology