Mechanism Of Respiration Intensity On The Lower Respiratory Tract Exposure Of Particulates

According to the statistics of the World Health Organization(WHO),about 7% of the world's population,or 4 million people worldwide,died of viral respiratory infections every year.Many epidemiological studies have shown that the exposure to particles in air is closely related to human morbidity and mortality.Therefore,when paying attention to the health problems related to respiratory system,it is very important to determine the dose of particulate matter during the respiratory transport process.The exposure of lower respiratory refers to the total amount of particulate matter that can reach the lower respiratory tract(the lower respiratory tract is a respiratory structure including bronchioles and alveoli).Respiratory activity is the most basic physiological function required for the human body to maintain vital characteristics,and it is also one of the major factors that affect the exposure of particulate matter in the human respiratory tract.Therefore,it is very important to study the influence of respiratory intensity on the exposure to human lower respiratory tract.Based on the 300 CT scans of the upper and lower respiratory tracts of the real human body,this article establishes a respiratory tract model with up to 8 generations of the lower respiratory tract,and uses the software of medical software Mimics17 to perform three-dimensional reconstruction on the basis of CT scan data.The respiratory tract model is highly similar to the real human respiratory tract geometry boundary.During the experiment,the respiratory tract model was connected with an artificial lung which could provide continuous airflow,and the number of the respiratory zone and the terminal particles of the respiratory model were measured in a full-size and ultra-clean environment chamber when particles of a single particle size were released.This was used to characterize the particulate matter exposure in the lower respiratory tract.In this paper,the parameters of breathing intensity were determined by minutes ventilation and breathing frequency.Breathing intensity corresponded to the breathing parameters of males and females in lying,sitting and standing respectively.The qualitative and quantitative study of respiratory intensity and exposure of particulate matter to lower respiratory tract were studied.relationship.The respiratory system was divided into different control areas,and a mathematical model was established based on the concentration balance equation for particulate matter transport in the respiratory tract.MATLAB software was used to solve the particulate matter exposure analysis.The results show that the theoretical solution is basically consistent with the measured values,indicating that the mathematical model established is reliable.This mathematical model can be used to further calculate the predecessor's sedimentary research results on particulates in the respiratory tract to obtain lower respiratory exposures,and to provide dose reference for ventilation control,disease prediction,and inhaled drug delivery.In this paper,a new method is proposed to determine the exposure of particles in the human respiratory tract.The exposure of particles to lower respiratory tract of men and women under different active conditions is obtained by experimental study.It was found that for 5?m particles,the ratio of the respiratory tract exposure to the total number of particles in the respiratory zone is less than 4%.It is believed that the 5?m particles is close to the upper limit of the exposure in the lower respiratory tract;in the three active states of lying,sitting and standing,the increase in breathing intensity is also increased in the lower respiratory tract for women.While for men,an increase in breathing intensity does not necessarily bring an increase in particles exposure in the lower respiratory tract;the amount of exposure to the lower respiratory tract and the amount of deposition to the respiratory tract are not equal to the amount of the particles from inhalation,but a mathematical model can be used to predict the exposure of the particles of the lower respiratory tract with a given settlement ratio.