| In recent years,with the gradual advancement of the concept of ecological civilization development that "clear waters and green mountains are golden hills and silver mountains",China’s environmental air quality has been significantly improved.However,atmospheric particulate matter pollution is still a common problem facing all mankind.PM10 and PM2.5in atmospheric particulate matter are closely related to human health.Severe particulate pollution can increase the incidence of respiratory,cardiovascular and immune diseases in humans and affect human lifespan.Most people spend more than four-fifths of their day indoors,and that’s where the harm from particulate matter pollution occurs.The particulate matter in the outdoor atmosphere mainly penetrates into the indoor environment through the cracks in the building envelope with the osmotic wind.The penetration factor is an important parameter to characterize the penetration ability of particulate matter.Particulate penetration is affected by many factors,such as gap condition of building envelope,pressure difference between indoor and outdoor,particle size and so on,which has many uncertain factors.Therefore,this paper focuses on the law between indoor and outdoor particle concentration under multiple influencing factors and the change law of penetration factor under various working conditions.In this paper,based on the artificial climate chamber,the experimental research method was adopted to build an experimental platform for measuring the concentration of particulate matter.By creating an outdoor pollution environment with artificial particulate matter source,the simulated indoor and outdoor particulate matter concentration test experiments were carried out.The validity and rationality of the experimental data were screened and verified by SPSS software.Based on the experimental results,the influence of the air tightness level of the external window,the pressure difference between indoor and outdoor,and the range of particle size on the concentration of indoor and outdoor particles was explored by using the method of drawing analysis,and the change rule of the penetration factor under each influencing factor was calculated and analyzed.The study shows that for the external window with the air tightness level of 4～8,with the improvement of the air tightness level of the external window,the indoor particulate matter concentration increases slowly,and the penetration factor growth rate decreases by3%～10%.When the pressure difference between indoor and outdoor is 0～10 Pa,with the increase of the pressure difference between indoor and outdoor,the growth rate of indoor particulate matter concentration is accelerated,and the growth rate of penetration factor is increased by 3%～12%.For particles with different particle size ranges,small particle size is strongly affected by Brownian diffusion,while large particle size is greatly affected by gravity sedimentation.The overall penetration factor decreases with the increase of particle size,but the penetration factor of 2.5 μm particle size is slightly increased by the superposition of U-shaped gap in the external window.On the basis of experimental and theoretical analysis,the penetration factor was analyzed by parameterization,and the penetration factor model under different air tightness levels of external Windows was established.The indoor PM2.5 and PM10 mass concentrations were predicted by measuring the outdoor wind speed and querying the real-time outdoor PM2.5 and PM10 mass concentrations.In order to determine the reliability of the penetration factor model under different air tightness levels of external Windows,a practical office building was selected to verify the established particle penetration factor model,and the error rate was ±12.5%.The results of this study can effectively predict the mass concentration of indoor PM2.5 and PM10,and provide a reference for the prevention and control of indoor air pollution.It is of great significance to maintain indoor air quality and protect human health. |
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