Study On The Method Of Determining The Design Concentration Of Ventilation Outdoor PM_2.5

Haze weather occurs frequently in China,PM_2.5.5 has become the primary pollutant affecting the quality of the atmospheric environment.With the increase of outdoor air pollution,the indoor air quality can not be guaranteed.Many air-conditioning systems are equipped with air filter devices to filter the air supply.Thereby reducing the indoor PM_2.5.5 concentration and improving the indoor air quality.Since there are no relevant values for the design parameters in the air filter design selection in China,there are many problems in the design selection of the filter.Most of the early indoor and outdoor air quality standards in China draw on the relevant standards of international or developed countries.The lack of reliable research and conclusions on the control of indoor air quality,the harm caused by air pollutants to the human body is not specifically quantified,so the relevant regulations in China are not In line with China's national conditions or lack of status quo.Firstly,this paper records the air pollutant data of 31 provincial capital cities and municipalities directly under the central government from January 2017 to December2018.According to China's air quality index,it analyzes the PM_2.5.5 pollution level and PM_2.5.5 maximum and year in China.The mean distribution shows that the average annual concentration of PM_2.5.5 in 31 tested cities is between 30 and 100?g/m³.The city with the smallest PM_2.5.5 annual average concentration is Lhasa,the largest is Shijiazhuang;The city with the highest daily average PM_2.5.5 concentration was xi'an,with 560?g/m³.The lowest city is Lhasa,at 72?g/m³.Lhasa is the only city where the daily average PM_2.5.5 concentration meets the national second-level standard.On this basis,based on the statistical data collected,the distribution characteristics of PM_2.5.5 concentration with season,month,day and time and the concentration of PM_2.5.5 and CO,SO₂,NO₂,O₃,PM₁₀0 and other major gas pollutants were analyzed.Correlation,the results show that PM_2.5.5 concentration has a certain correlation with season,month and daily average,and the daily variation distribution of PM_2.5.5 concentration presents a dual peak variation feature;The daily average concentration of PM_2.5.5 has a linear correlation with the concentration of CO,SO₂,NO₂,PM₁₀0 and other pollutants,while it is not strongly correlated with the daily average concentration of O₃.Using Spss software,the multiple linear regression model is established by taking the concentration of pollutants such as CO,SO₂,NO₂ and PM₁₀0 as independent variable.Finally,this paper studies the basic methods and existing problems of air filter selection,statistically analyzes relevant norms and standards at home and abroad,and carries out comparative extension.According to the specifications and related research,the design parameters required for air filter selection are given.The three methods of“non-guaranteed days method”,“guarantee rate method”and“mathematical induction method”were used to determine the atmospheric PM_2.5outdoor design concentration,and the recorded city daily average data were analyzed respectively.The recommended value of atmospheric PM_2.5.5 design concentration under the method.At the same time,the analysis and comparison of the three methods suggest that the use of"mathematical induction"at this stage to estimate the atmospheric PM_2.5.5 outdoor design concentration is appropriate,with the data is recommended to use the"no guarantee days method",does not guarantee the number of days recommended 5 days or 15 days.The determination of atmospheric PM_2.5design concentration provides reference for the design and selection of fresh air filter,which has practical application value.