| In recent years,with the acceleration of the country's industrialization process,China's economy has maintained a rapid growth,and at the same time,China is also facing more and more serious problems of atmospheric pollution.The problem of PM2.5and PM10 pollution in atmospheric particulates has become the primary issue of atmospheric pollution in most cities.According to the survey results of some cities,the composite air pollution problem formed by PM2.5 and O3 had seriously affected the production and life of local residents.Therefore,the problems concerning airborne particulate matter pollution,especially the research on PM2.5 contamination of fine particles in the atmosphere,have attracted the attention of researchers at home and abroad.The state has also established relevant standards for indoor and outdoor air particulate matter concentrations,and stipulated the weight concentration limits for PM10 and PM2.5.However,most of the air filters on the market are classified according to counting efficiency,thus causing difficulties in the selection of filters based on the existing design calculation.In addition,the research of domestic and foreign scholars on air filter materials mainly focus on the research of the filtration effect of PM10 and PM2.5.There is relatively little research on the classified filtering efficiency of existing filter materials for particulate matter which have different particle sizes.This article focuses on the above issues and conducts targeted research on the subject.GRIMM1.109 portable aerosol particle size spectrometer and TSI7525 indoor air quality instrument were used to conduct an on-site sampling of the air quality in Xi'an city.And the log-normal distribution function was used to analyze and process particulate matter of different particle sizes in the atmosphere aerosol.The results showed that during the tested period,the mass concentration of PM10 and PM2.5 in Xi'an downtown were higher than the concentration limit specified by the state,so the study on filtering effect of filter materials is very necessary.In order to test the filtering effect of filter materials on atmospheric particulate matters,GRIMM1.109 portable aerosol particle size spectrometer and HD2114 P.0differential pressure gauge were used to design a set of experimental devices by the author.The filtration performance of filter materials which are commonly used in the market were tested with particulate matter of different particle sizes in atmosphere aerosol within the range of filtration velocity selected by the author.The experimental results showed that,within the range of filtration velocity selected by the author,the optimal filtration velocity of Coarse filter was 1.1m/s,the performance of counting filtration efficiency on particles within the size range of 5?m?d?10?m was better,and the efficiency was between 77.7% and 85.6%.The optimal filtration velocity of medium efficiency filter was 0.8m/s,the performance of counting filtration efficiency on particles within the size range of 2.5?m ? d ? 10?m was better,and the efficiency was between 79.4% and 90.0%.The optimal filtration velocity of high efficiency filter was0.05m/s,the performance of counting filtration efficiency on particles within the size range of 1.0?m ? d ? 10?m was better,the efficiency was between 70.8% and 97.3%.The counting filtration efficiency on particles which the size range of ? 1.0?m was also relatively high.In addition,through experiments,the classified filtering efficiency of different particle sizes of atmospheric particulate matter at each grade was obtained.So,from the perspective of practical engineering application and based on the experimental results,the suggestions on the selection of filter materials for different occasions and the best filtering effect of the filter materials at different filtration velocity were given,these suggestions will be very important reference values for practical engineerings to design. |
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