The Evaluation Of Indoor And Outdoor PM_2.5 Concentration And Exposure Characteristics In Typical Campus Of Beijing

The Beijing of aerosol pollution is mainly the pollution of fine particles.Fine particles also be referred to as PM2.5,it have great harm to human health.the smaller the diameter of fine particles,the parts of the deeper into the respiratory tract.the diameter of fine particles is less than 2 um,which can penetrate to the bronchioles and alveoli and directly affect people’s health and quality of life.The school is a crowded public places.Teachers and students spend most of their time in the school,so the indoor air quality of school is critical to the health of teachers and students.Therefore,it is very important to study the concentration level of campus indoor fine particles and the evaluation of human exposure.In this paper,the author takes the typical campus of Beijing as the research area,and takes the campus crowd as the object,and makes an investigation and Analysis on the time activity pattern of the campus crowdIn this paper,the concentration of fine particles in indoor and outdoor environments were monitored in the typical school four seasons of spring,summer,autumn and winter.The correlation between the concentration of fine particles in indoor and outdoor was analyzed,and the chemical components were analyzed.According to China exposure parameters manual respiration rate,evaluation in spring and summer,autumn and winter four seasons campus crowd micro environment comprehensive exposure and the average exposure and potential exposure dose and average potential exposure.The main conclusions of this paper were shown as follows:（1）According to the daily campus crowd time activity pattern analysis of the results of the questionnaire,the campus crowd daily on campus each micro environment in time to stay in the classroom,campus crowd daily stay in the dormitory is 5.40 h,the residence time of 11.00 h in the library,the residence time is 3.80 h,stay in the office time is 0.36 h in the playground,residence time is 0.96 h,in the basement of the residence time of 0.07 h,in the supermarket on campus residence time of 0.43 h.（2）The micro environment of campus winter daily average concentration is 184.5 μg /m³,the outdoor indoor environment micro daily average concentration of 74.0 μg /m³;the average concentration of each micro environment outside the campus in the fall of 106.3 μg /m³,the micro environment of indoor daily average concentration is 58.3 μg /m³,the average concentration of the summer campus micro environment outdoor 54.0 μg /m³,the average daily micro the concentration of indoor environment is 23.0 μg/m³,the daily average concentration of each micro environment outside the campus in the spring of 73.5 μg/m³,the daily average concentration of micro indoor environment is 32.0 μg/m³.Obviously,winter indoor and outdoor indoor and outdoor daily average concentration > autumn > spring daily average concentration of indoor and outdoor daily average concentration > summer indoor daily your concentration,winter indoor and outdoor daily average concentration is higher,the daily average concentration is much higher than the outdoor standard value of 75.0 μg/m³,average daily concentration of indoor air is close to 75.0 μg/m³,the average outdoor daily average concentration of four a season is 105 μg/m³,the average daily indoor concentration is 47.0 μg/m³（3）The SPSS correlation analysis of 88 samples collected in spring,summer,autumn and winter in the last four seasons showed that the correlation coefficient R was about Pearson,which was close to the maximum of 1.The results showed that the concentration of fine particles was mainly affected by the concentration of fine particles in the four seasons（4）Through the analysis of the monitoring data,it can be concluded that the average concentration of water soluble ion Cl-in fine particulate matter is 0.68 ug/m³,The average concentration of SO₄^2-is 2.00 μg/m³,the average concentration of NO₃^-is 0.76 μg/m³,the average concentration of Na⁺ is 0.20 μg/m³,the average concentration of NH⁴⁺ is 0.37 μg /m³,the average concentration of K⁺ is 0.06 μg/m³,the average concentration of Mg²⁺ is 0.33 μg/m³,the average concentration of Ca²⁺ is 0.94 μg/m³.The concentration of water soluble ion concentration is arranged in order as follows: SO₄^2-> Ca²⁺> Cl-> NH⁴⁺> Mg²⁺> NO₃^-> Na⁺> K⁺（5）In this study,we evaluated the exposure of campus population in four different seasons,and found that the potential exposure dose and the average comprehensive exposure dose were the highest in winter,followed by autumn and spring,and the lowest in summer.May also be related to the summer weather,hot weather in the summer,almost all of the campus crowd is a minor activity,less respiratory related.Based on the evaluation of the exposure of the four seasons,the concentration of outdoor fine particles was higher in winter,and the potential exposure dose was higher in the school population.Therefore,when the outdoor concentration is high,it will reduce the combined exposure and the potential exposure dose.The differences of the comprehensive exposure and the comprehensive potential exposure dose of the school population in different seasons were different in the outdoor concentration level.