Investigation And Modeling On The Impact Factors Of Indoor PM_2.5 Concentration In An Office Building In Wuhan

In recent years,the multiple-pollutant haze weather,with PM10 and PM2.5 as the main pollutants,bursts out in large area in China for a long time.PM_2.5 has become the primary pollutant of atmospheric particulate pollution in China.Modern people spend 80%⁹0%of their time indoors.However,indoor PM_2.5 concentration is affected by many factors at the same time.Therefore,it is necessary to discuss how these factors affect the indoor PM_2.5 concentration,so as to futher achieve the purpose of controlling indoor PM_2.5 concentration.Firstly,a one-week fied monitoring on the indoor and outdoor PM2.5concentration was conducted in office A.During the test,local outdoor meteorological data were collected and the indoor personnel activities were recorded.Based on the above data,the influence factors on PM_2.5 concentration variations were discussed.It was concluded that that indoor and outdoor PM_2.5 has a strong positive correlation;indoor PM_2.5 concentration differs greatly under different weather conditions;indoor PM_2.5 concentration is negatively correlated with outdoor temperature,and slightly positively correlated with air humidity and U-shaped correlated with weed speed;the prevailing wind direction has a cleaning effect on the indoor PM_2.5;the external window opening affects the indoor PM_2.5 concentration to the outdoor;the split air conditioner filters have limited impact on the indoor PM_2.5;the behavior of indoor personnel has a greater impact on the change of indoor PM2.5concentration than the number of indoor personnel.Then,in office B,orthogonal experiment was carried out to study the influence of multiple indoor factors on PM_2.5 concentration.The experimental data was combined with the outdoor meteorological data to establish a database.Multi-linear regression analysis and stepwise regression analysis were carried out with indoor PM_2.5 concentration as the independent variable.The regression process eliminated the independent variables with invariant dependent variables,and established the optimal regression equation for the influencing factors of indoor PM_2.5 concentration.The equation represents indoor PM_2.5.The equation indicates that the main influencing factors of indoor PM_2.5 are outdoor PM_2.5 concentration,outdoor wind direction,number of indoor personnel,open area of south window,and outdoor weather conditions.Then,based on the measured data analysis,the indoor PM2.5 mass concentration balance was used to establish a comprehensive mathematical physical model of the indoor PM2.5 concentration.The model considers the infiltration of outdoor PM2.5through the openings of the enclosure structure,the generation and settlement of indoor PM_2.5,the behavior of indoor personnel and the air supply of the air conditioning system.Finally,the validity of the indoor PM2.5 concentration model is verified by the software simulation method and numerical analysis method.The verification results show that the model has good accuracy.