| With the rapid development of economy and the rapid advance of urbanization,we have been through great changes in our lives.Indoor and outdoor air quality are showing an increasingly severe trend in China,which had led to a series of healthy problems.Pollution source control,ventilation dilution and air purification are the basic measures to improve the quality of indoor air.Currently,it is a long way to control the indoor and outdoor pollution sources.Especially when the outdoor source is the main source of typical indoor contaminants,it is difficult to achieve the desired effect through the source control method in the short term.Because of the serious situation of outdoor air pollution,the effect of ventilation is not obvious.When the outdoor air pollution is much higher than indoor,ventilation may increase the risk of deterioration of indoor air quality.In the case of severe outdoor air pollution,air purification is a more reasonable and effective way to improve indoor air quality.Most studies on the effect of air purifier are focused on the performance parameters in chamber test.Due to the specific experimental conditions of the chamber environment,it cannot accurately reflect the effect of the air purifier in the actual environment.There is a small amount of foreign research on the efficiency of air cleaner in the real environment,but the main concern of these studies is the impact of the air cleaner on typical indoor pollutants,ignoring the impact of outdoor pollutioin source on the indoor environment.The existing researches are concentrated in Europe and the United States.Compared with Europe and the United States,the outdoor air pollution is more serious in China.The effect of the air cleaner in the real environment is influenced by the outdoor environmental parameters,the air exchange rate and so on.Therefore,based on the actual situation of outdoor air pollution in China and the effect of air cleaner in residential buildings,this paper analyzes the role of air cleaner in the process of outdoor air pollution impacting on the indoor environment and the contribution of air cleaner to decrease indoor pollutant concentration.In this study,20 residential buildings were selected for field testing in Chongqing.The indoor and outdoor parameters(temperature and humidity,O3 concentration,particle concentration,elemental carbon and organic carbon in PM2.5)were tested when the air cleaner fixed with and without the HEPA filter.Based on the tested data,the present situation of the main pollutants in Chongqing was analyzed,and the infiltration factor was calculated by one-way linear regression.The contribution of outdoor pollutants to indoor environment was quantified by comparing the changes of the infiltration factor before and after the installation of HEPA filter.Finally,the contribution of the air cleaner in real environment was calculated.When the air purifier is not installed with HEPA filter,the rate of PM1,PM2.5,PM10 and TSP from outdoor contaminating the indoor air is more than 90%.When the air purifier is installed with high efficiency filter,the outdoor particles from outdoor contaminating the indoor air is is reduced from 7.47% to 8.18%.Before and after the installation of high efficiency filter membrane,there is no significantly difference in the contribution of outdoor ozone to indoor environment,and outdoor ozone impacting on the indoor air about 50%.The contribution rates of air purifiers to indoor PM1,PM2.5,PM10 and TSP were 36.25%,36.03%,35.60% and 35.16%,respectively.As the I / O ratio increases,the contribution rate of the air purifier to purify the particles is decreases.The use of air purifiers can reduce indoor concentrations of pollutants.The reduction in the proportion of outdoor pollutants entering and depositing indoor can effectively reduce the exposure of indoor personnel to outdoor pollutants and reduce the risk of health.Outdoor weather,indoor and outdoor pollutant concentration,ventilation and air purifier location can affect the air purifier contribution rate.So whether to open the window or to use the air purifier depends on the pollution sources both indoor and outdoor.And furthermore,the location of the air purifier should be choosed accordingly. |
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