| The air quality is closely related to human health. Particulate matters which carry various bacteria become the primary pollutant. Study on particulate matter purification is imperative. Currently the main indoor control technology is air filter, but there commonly are high resistance and energy consumption and secondary pollution resulting from harmful byproducts. Thus the national support project is proposed to research low resistance and high efficieny filter purificying PM10and PM2.5, which comes from "12th five-year plan". Individual protection mask takes human respiratory force (typically30-50Pa) as purification power and has the charateristics of low resistance relative to the minimum primary resistance (190Pa) requirement of current high efficiency particulate air filter. The topic seeks low resistance and high efficiency filter through study on the PM2.5purification characteristic of mask filter materials, not only to purify PM10and PM2.5, but also to reach the purpose of energy saving.As the tested background concentration, the air quality and particulate matter of the whole country and Shanghai from2008to2012and2013is surveyed. The concentrations of PM2.5under different weather conditions in an urban and suburb of Shanghai is tested. The results show the PM2.5concentration of suburb is lower than that of urban under the same weather conditions. And when the weather is different, the concentration is different under the same place.A static filter performance test bed is designed according to the test requirements. The United States TSI8530type DustTrakTMⅡ aerosols intelligent detector is used to test the PM2.5concentration before and after filter and the TSI9555-P type velocity pressure anemometer to test the filtration velocity and media resistance. Testing three class masks:Class A cotton masks, Class B non-woven masks and Class C masks with static layer.The results show that:the efficiency and resistance of Class A mask filter is the minimum and respectively17.9%～50.3%and2.3～291.1Pa. Class B is better than Class A. The range of efficiency and resistance is34.3%～82.7%and10.4～563.OPa. Class C is the best. The range of efficiency and resistance is87.1%～99.9%and with the increasing of flow, the filtration efficiency is more than85%. The resistance is20.6-1060.4Pa. Comprehensively considering the efficiency of resistance and finding that current masks belong to low efficiency or high resistance.When the flow is graeter than30L/min, they are difficult to meet people’s demand for breathe comfort and clean air.The performance for PM2.5purification of different thickness of the combination of gauze and electret filter are tested.The results show that with the increasing of filter material thickness, the filtration efficiency increases but the resistance also increases.There is the best media thickness values or range.When respiratory flow belows30L/min,T70is the best; and when flow is greater than30L/min,T200is the best.Contrasting the comprehensive performance of commercially available mask and "electret filter" and found that it is high efficiency and low resistance filter material.In order to study whether the low resistance characteristics of mask media applies to the building environmental filter or not, contrasting the performance of electret filter material to that of air filter and results show that during the scope of work speed, all electret filter meet the requirements of efficiency. For the resistance, meeting the requirements (≤50Pa) of primary efficiency material are T70and T100can meet, and meeting the requirements (≤80Pa) of medium efficiency are T70, T100, T150and T200.All tested materils meet the requirements (≤190Pa) of higher efficiency. They can be used to solve the filter material problem of high resistance and low efficiency. |
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