A recent study has raised concerns about the increasing deposition of microplastics in the human respiratory tract and the potential health risks associated with it. The study highlights that humans may inhale approximately 16.2 particles of microplastic per hour, equivalent to a credit card's weight over the course of a week. The study, published in the journal Physics of Fluids, emphasises the importance of understanding the travel patterns of inhaled microplastics in the respiratory system for the prevention and treatment of respiratory diseases.
Conducted by researchers from the University of Technology Sydney, Western Sydney University, Urmia University, Islamic Azad University, the University of Comilla, and Queensland University of Technology, the study utilises a computational fluid dynamics model to analyse the transport and deposition of microplastics in the upper airway.
According to Mohammad S. Islam, the density of microplastics in the air is significantly increasing. The discovery of microplastics deep within human airways raises concerns about potential respiratory health hazards. The researchers investigated the movement of microplastics with different shapes (spherical, tetrahedral, and cylindrical) and sizes (1.6, 2.56, and 5.56 microns) under slow and fast breathing conditions.
The study revealed that microplastics tend to accumulate in hotspots in the nasal cavity and oropharynx (back of the throat). The complex anatomical shape of the airway and the intricate flow behavior in the nasal cavity and oropharynx cause microplastics to deviate from the flow path and deposit in these areas. Factors such as flow speed, particle inertia, and asymmetric anatomy influence the overall deposition and increase the concentration of microplastic deposition in the nasal cavities and oropharynx.
Breathing conditions and microplastic size impact the deposition rate in the airways. Higher flow rates resulted in less deposition, while larger microplastics (5.56 microns) were deposited more frequently than smaller ones.
