The Research On Influential Factors Of Indoor Particulate Matter Concentration Change And Purification Method

With the frequent weather haze,the concentration of outdoor PM2.5 seriously exceeded the standard,causing the air quality deteriorated day by day,meanwhile,in recent years,the way of people's live and work have changed a lot,and the time of people staying indoors almost account for 80-90%,but the indoor air is inseparable with the part of the atmospheric environment,over the long term,human health will be harmed.At present,although people have a certain understanding of the sources of PM2.5 and some prevention measures,the study on factors affecting indoor PM2.5concentrations focused on indoor and outdoor sources,while other factors were less studied.The lack of this study make people can't perceive the impact of various factors on indoor air quality,and can't take air purification measures correctly and efficiently.The effects of indoor relative humidity,room air-tightness,indoor and outdoor pressure differential on the concentration of fine particulate matter in the room were studied by experiment and numerical simulation.Also this paper studied the purification effect of the split type purifier and fresh air purification system on indoor fine particulate matter concentration.The results show that humidification could reduce the concentration of fine particles in the room by changing the grain size composition and accelerating sedimentation,and for the hygroscopic particles,the coarser the particle size,the better the effect of humidity.The phenomenon of re-suspension of particle after humidity was weak.The higher the indoor PM2.5 concentration,the better the effect of humidity.When there are more than 1000?g/m³ in the environment,the humidity could be controlled at about 60%,while less than 1000?g/m³,we could improve the humidity to 70%-80%by a short time so as to reduce indoor PM2.5 concentration quickly.I/O value,linear fit and penetration coefficient can reflect the influence of air tightness on indoor PM2.5 concentration relationship from different angles.The higher the room air tightness grade,the lower effect by the outdoor pollutants on indoor air quality,and have the higher outdoor pollutants concentration limit.To a room with 0.78 air tightness,the relationship between the room blocking ability of outdoor PM2.5 and indoor to outdoor pressure was positively correlated,while to a room with 0.54 air tightness,the gap was significantly reduced,and to a room with0.42 air tightness,the room blocking ability of outdoor PM2.5 was basically not affected by indoor to outdoor pressure.The purification effect of integrated filter of adsorption,electrostatic,and filtration was the best,which could also reduce the filter replacement cost.For the global pollution,the purifier should be placed about 2m distance from the target location,with its outlet facing the target position,and the inlet avoiding indoor objects.For local pollution,pollution sources should be away from the target position,and the purifier should be placed near the sources,with its inlet facing the pollution sources,and the outlet facing the target location as far as possible.In the residential fresh air purification system,in order to improve indoor airflow effect,it is advisable to set the return air outlet in each fresh air room,then the return air is discharged to the outdoor through the total exhaust pipe,but the offset phenomenon of new air and return air should be avoided.