Researchers from the University of New South Wales discovered that the upper respiratory tract is the most prone area for the accumulation of larger microplastics.
The researchers utilized computational modeling to investigate the areas of the respiratory tract that are most affected by inhaling toxic microplastics. They published their findings in the journal Physics of Fluids, with a report by Live Science on June 19.
Microplastics exist in the air and throughout the oceans. (Photo: C&EN).
Mohammad S. Islam, the lead author of the study at the University of New South Wales in Sydney, and his colleagues developed a computational model to analyze the tiny plastic particles and where they typically move and accumulate within the respiratory system. Through analyzing this circulation under both fast and slow breathing conditions with three shapes of plastic particles (spherical, tetrahedral, and cylindrical), the research team found that the largest microplastics, measuring about 5.56 microns (equivalent to 1/70 the width of a human hair), are the most likely to become trapped. They tend to drift toward the upper respiratory tract, such as the nasal cavity and the back of the throat.
In 2019, a group of scientists estimated that up to 16.2 microplastic particles enter the respiratory tract every hour, meaning that humans could inhale an amount of toxic microplastics equivalent to a credit card each week. Islam and his colleagues based their calculations of how microplastics move throughout the respiratory system on those findings.
Microplastics are tiny plastic particles less than 5 millimeters in length, according to the U.S. National Oceanic and Atmospheric Administration (NOAA). They are remnants of industrial waste and consumer goods, found both in the atmosphere and across the oceans. The full impact of microplastics on the human body is not yet fully understood. However, microplastics can damage human cells, cause intestinal inflammation, and reduce fertility in mice. They can also carry viruses, bacteria, and a variety of other harmful chemicals.
The researchers indicated that the next step is to understand how microplastics accumulate within the lungs by examining factors such as humidity and temperature. According to them, microplastics are becoming increasingly pervasive. “Millions of tons of microplastic particles are found in water, air, and soil. Global production of microplastics is skyrocketing, and the concentration of microplastics in the air is also significantly increasing,” Islam stated.
