Concentration Distribution Cbaracteristics Of Particles In Two Typical Indoor Sites Of School

With the improvement of living standards,the problem of air quality has gradually become the focus of attention.The majority of people spend 70-90%of their time staying indoors,so it is of great significance to investigate concentration distribution characteristics of the inhalable particle inside rooms.In this work,the indoor particle number and mass concentrations of the two typical school environments which are canteen and conference room are measured by GRIMM 1109,a particle size measuring instrument.Using experimental design and correlation analysis,the sources of indoor particles are discussed,and the distribution and transmission process of indoor particulate concentration are explored to provide basic data and prevention methods for indoor air environmental control.The results are shown as follows:The canteen has the source of indoor particulate matter.In view of the different structure of kitchen decoration,the particulates of the two different types of canteens,such as open cafeteria and traditional student canteen,are measured.The results show that the enclosed or open-style cooking plays an important role in the concentration of particles.The particle number concentration is mainly contributed by the particles smaller than 1 μm.For the mass concentration at the same place,PM10 is the top contributor,while PM1 can be negligible.The number and mass concentrations of the particulate matters decrease with increasing the distance from the cooking source.The mass concentration of PM10 in the open-style cafeteria can arrive at even 0.45mg/m3,which is 8.5 times as many as that in the traditional student canteen,and exceeds the maximum allowable concentration of 0.16mg/m3.In contrast,the traditional student canteen with the enclosed cooking units is superior to the open-style cafeteria.It is recommended to enhance the ventilation to reduce the harmful effect of particulate matters on human health in the open-style dining hall.The concentration distribution of indoor particles in the conference room is obtained,and the particle concentration ratio of indoor to outdoor is analyzed.The results show that the outdoor particle concentration plays an important role in the indoor concentration distribution in case of no indoor particle source,no matter the windows are open or closed.The particles with the diameter less than 1μm are easier to enter the room,and the effects of outdoor particles on the indoor concentrations of big particles become weak.With increasing the distance from the window,the ventilation effects on the indoor particles can be negligible.The air purifier may effectively restrain the indoor air pollution,especially for PM10,but cannot work well for PM1,either under smoking conditions or not.