The Dangers of Microplastics in the Air: Australian Researchers Develop Model to Track their Movement Through the Respiratory System

2023-06-13 17:01:01

Microplastics can be found everywhere. So you shouldn’t even think it’s crazy that you also get a lot of it. Still, it sounds very nasty: we breathe in no less than the equivalent of a debit card per week. And these microplastics contain all kinds of toxic substances.

We don’t yet know exactly how harmful they are to our health, but they could pose a serious risk. So it’s super important to understand what happens when the plastic enters our airways. That is why Australian researchers have developed a model that allows them to track exactly how the microplastics move through the respiratory system and where they ‘hang’ in the upper respiratory tract.

Plastic in the airways
“Millions of tons of these plastic particles have been found in water, air and soil. Worldwide, the production of microplastics is increasing rapidly and the density of microplastics in the air is also increasing,” says researcher Mohammad Saidul Islam. “For the first time, microplastics have been found deep in people’s respiratory tracts in 2022, which raises fears of serious health problems.”

At Scientias.nl he explains: “The microplastics range in size from 1.6 to 5.56 microns. They have been found in the lung tissue of thirteen of the twenty deceased who were autopsied. In total, 87.5 percent consisted of synthetic polymer particles while 12.5 percent were microfibers. That is why we also chose this particle size in the study. The particles also consisted of different shapes.”

Preference for the nasal cavity
Together with his colleagues, he looked at the movements of microplastics when breathing is slow or fast. Microplastics often collect in certain places in the nasal cavity or in the back of the throat. “The complex and very asymmetrical shape of the airways plus the way the air flows through the nasal cavity and throat causes the microplastics to deviate from the flow and remain in those areas,” says Islam. “In short, the flow rate, the inertia of the particles and the asymmetrical anatomy lead to many plastic particles becoming lodged in the nasal and pharynx.”

In addition, when breathing faster, i.e. when the airflow has a greater speed, fewer particles remain in the airways than when breathing more slowly. The largest particles also remained in the airways more often than the smaller particles. “Higher microplastic deposition is observed in the nasal cavity than in the trachea and other areas. The flow rates, shape and size of microplastics influence the overall deposition pattern. A higher flow rate leads to a lower deposition efficiency for all forms of plastic,” says the researcher.

Danger to health
The study makes it clear, he says, that there are legitimate concerns about exposure and inhalation of microplastics, especially in areas with a lot of plastic pollution or industrial activity. He therefore argues for more awareness and better monitoring. This study highlights the potential health impact of microplastics in the air we breathe.

In the future, the researchers hope to analyze the transport of microplastics through the airways on a larger scale, also looking at the influence of humidity and temperature. “I discovered a high concentration of microplastics at various deposition hotspots. Depending on how long the plastic stays there, it can lead to diseases such as lung cancer. In a follow-up study, we will investigate the toxicity based on the time the plastic remains in the lungs. We also want to look more closely at specific forms of microplastic and how they end up in the lower respiratory tract,” the researcher continues to say about future research.

Advice to avoid microplastics
Finally, there is the question of whether we can do something ourselves to protect ourselves against microplastics. “Filter the air indoors, ventilate your living areas, minimize the use of plastic and avoid activities that release microplastics. Choose natural fibers and be careful when washing clothes”, is the advice he gives. But also: “Although all this helps, it is difficult to completely eliminate all microplastics from your environment. Therefore, a broader perspective is needed. It is essential that we reduce plastic pollution in general.”