Risk Assessment of Outdoor Micron Particulate Matters Inhaled in the Respiratory System of a Standing Mannequin in a Room Ventilated by a Wind Catcher

Background and Objective:In this study the potential of inhaled micro particles in the respiratory system of a mannequin standing in the middle of a room ventilated by a wind catcher was assessed. Methods:The realistic model of a nasal route up to the nasopharynx was obtained from Computed tomography (CT) scan images, and then attached to the nostrils of a standing mannequin.The mannequin was positioned in the middle of a room ventilated by an optimum wind catcher.Micro particles ranging from 1 m to 10 m were released from the wind catcher opening with the same velocity as the air fluid flow through a UDF and the inhaled particles were evaluated. Results:The results show that the maximum and minimum inhaled particle percentage belong to the particles with 1-m and 5-m diameters with the value of 0.0164 and 0.0136, respectively.Also, the aspiration fraction for these particles is 82 and 68 percent.The minimum and maximum percentage of inhaled particles passing the nasopharynx and going out of the nasal route are 88.35 and 71.50 percent that are associated with 1-m and 10-m particles. Conclusion:Based on the obtained results and according to the number of particles delivered to the outlet of the nasal cavity, the most detrimental particles to the respiratory system in the order are: 1, 2 , 2. 5, 3, 4, 7, 9, 6, 8, 5, and 10.This order according to the mass of particles delivered is: 10, 9, 8, 7, 6, 5, 4, 3, 2.5, 2, and 1.The results of this study provide the required data for specialists to evaluate inhalation toxicology and implement necessary measures regarding wind catchers.