Effect Of Negative Ion Air-cleaner On Particulate Deposition In Respiratory Tract

With the development of epidemiology in recent years,researchers have found a significant correlation between particulate exposure in the air and respiratory morbidity and mortality.Therefore,when paying attention to the causes of respiratory diseases,it is important to determine the dose of particulate matter entering the human respiratory system with respiration.Exposure to the lower respiratory tract of particulate matter(including bronchioles,alveolar tubes and alveolar sacs)represents the total amount of particulate matter that can reach the lower respiratory tract of the human body during respiration.The results show that particle size is an important factor affecting the exposure amount of particles in the lower respiratory tract,which affects the movement mode and deposition area of particles in the respiratory system.However,when the anion air purifier purifies particles,its coagulation effect will bring changes in particle size,so it is very important to study the influence of anion air purifier on particle deposition in the respiratory tract.Some studies have found that the purification efficiency of negative ions is closely related to particle size,and the particles will be affected by gravity deposition,inertia collision and diffusion after entering the human respiratory system.Therefore,combining these two points and on the basis of previous studies,an experiment was designed to measure the exposure of particulate matter in the lower respiratory tract when the anion air purifier was opened.In combination with CT scanning and 3D printing height reduction human respiratory tract boundary and structure of the respiratory tract after the physical model,the model and can simulate human respiration artificial lung connection,in a clean environment tank using dummy to the respiratory tract model release different particle size of monodisperse particles,By measuring the number of particles in the three locations of the source dummy respiratory zone,the model respiratory zone and the model lower respiratory tract,the exposure of particles in the lower respiratory tract can be comprehensively determined.Since particles with particle size of less than 5μm will pass through the upper respiratory tract and enter the lower respiratory tract,forming exposure to the lower respiratory tract and causing great harm to human body,monodisperse particles of 1μm,1.5μm,2.5μm and 5μm were selected as the research objects.The deposition efficiency of the respiratory tract model was compared with ICRP and MPPD to reflect the reliability of the model and the rigor of the experimental results.By comparing the exposure levels of four kinds of particles in the lower respiratory tract when the anion air purifier was opened and closed,it was found that: after opening the anion air purifier,the reduction range of exposure levels in the lower respiratory tract increased with the increase of particle size,from 26% to 62%.However,the reduction of exposure in the respiratory zone ranged from 47% to 54%,which did not change significantly with the change of particle size,but affected the particle size distribution in the respiratory zone and increased the proportion of particles with larger particle size in each interval.The coagulation effect of negative ions on 1 m and 1.5 m particles is more effective,but it does not fundamentally change the lower interception of the upper respiratory tract.Although the coagulation effect on large particles is relatively low,it will increase the interception of the upper respiratory tract.Finally,by comparing the experimental results with the theoretical model,it is found that the respiratory tract model used in the experiment has a high reliability and its results are of certain reference value.