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Humans inhale the equivalent of a credit card in microplastics each week

A recent study led by the University of Technology Sydney (UTS) has found that humans might inhale approximately 16.2 bits of microplastics each hour, or the equivalent of a credit card per week.

Microplastics are tiny debris in the environment generated from the degradation of plastic products. These particles often contain highly toxic chemicals that pose significant health dangers.

“Millions of tons of these microplastic particles have been found in water, air, and soil. Global microplastic production is surging, and the density of microplastics in the air is increasing significantly,” said lead author Mohammad S. Islam. He is an expert in Materials and Process Engineering at UTS.

“For the first time, in 2022, studies found microplastics deep in human airways, which raises the concern of serious respiratory health hazards.”

How the microplastics research was conducted 

To prevent and treat respiratory diseases caused by inhaled microplastics, understanding how they travel in the respiratory system is crucial. 

By developing a computational fluid dynamics model, the experts analyzed the transport and deposition of microplastics with different shapes (spherical, tetrahedral, and cylindrical) and sizes (1.6, 2.56, and 5.56 microns) in the upper airways, under both slow and fast breathing conditions. 

What the researchers discovered about inhaled microplastics 

The analysis revealed that inhaled microplastics tended to collect in several areas of the nasal cavity and oropharynx, or back of the throat.

“The complicated and highly asymmetric anatomical shape of the airway and complex flow behavior in the nasal cavity and oropharynx causes the microplastics to deviate from the flow pathline and deposit in those areas. The flow speed, particle inertia, and asymmetric anatomy influence the overall deposition and increase the deposition concentration in nasal cavities and the oropharynx area,” Islam explained.

Both breathing conditions and microplastic size played significant roles in the overall microplastic deposition rate in airways. For instance, a higher flow rate led to less deposition, and the largest microplastics were deposited in the airways more frequently than the smaller ones.

Further research is needed on inhaled microplastics

These findings highlight the dangers of exposure to and inhalation of microplastics, especially in regions with high levels of plastic pollution and industrial activity.

In future research, the scientists plan to investigate microplastic transport in a large-scale, patient-specific whole lung model. This includes environmental parameters such as temperature and humidity. This will be done in order to help inform the development of targeted drug delivery devices and improve health risk assessment.

“This study emphasizes the need for greater awareness of the presence and potential health impacts of microplastics in the air we breathe,” concluded co-author YuanTong Gu, a professor of Mechanical, Medical, and Process Engineering at the Queensland University of Technology.

The study is published in the journal Physics of Fluids. 

Microplastics and human health

Microplastics are tiny particles of plastic, usually less than 5 millimeters in size. They can originate from a variety of sources, such as broken-down plastic waste, synthetic textiles, and even personal care products containing microbeads.

The ubiquity of microplastics in the environment, especially in marine and freshwater systems, has raised concerns about their potential impacts on human health.

Research into the effects of microplastics on human health is still in its early stages, with many unanswered questions. However, several potential health risks have been suggested:

Physical impact of inhaled microplastics

Microplastics ingested or inhaled can potentially cause physical damage. This might occur directly, due to the physical presence of the plastic particles in the body, or indirectly, due to the release of harmful substances.

Chemical impact of inhaled microplastics

Plastics are often made with additives such as phthalates and bisphenol A (BPA), which can leach out of the plastic particles. Both phthalates and BPA are endocrine disruptors, meaning they can interfere with the body’s hormone systems.

Furthermore, microplastics in the environment can adsorb other pollutants, such as heavy metals and persistent organic pollutants (POPs), which could be released in the body after ingestion or inhalation.

Microbial impact

Microplastics can carry bacteria, including potentially harmful species, which could influence the gut microbiota if ingested.

Ingestion is the most commonly discussed exposure pathway for humans, particularly through the consumption of seafood and freshwater fish that have ingested microplastics. However, microplastics are also found in other foods, drinking water, and the air, suggesting that inhalation and drinking could be significant exposure pathways too.

More research is needed to fully understand the risks and impacts of microplastics on human health. For now, reducing plastic pollution and improving waste management are key strategies to limit the spread of microplastics in the environment.

Microplastics and the Earth

The ubiquity of plastics and their durability is causing an increasing amount of these microplastics to contaminate both terrestrial and aquatic environments across the globe. Here are several ways microplastics impact the earth:

Wildlife Impact

Microplastics pose a threat to a wide range of animals. They can be mistaken for food and ingested by creatures ranging from tiny plankton to large marine mammals. This ingestion can lead to physical harm, including internal injury and death. Microplastics can also cause starvation by creating a false sense of fullness.

Ecosystem Disruption

By affecting individual organisms, microplastics can ultimately disrupt entire ecosystems. For example, if smaller creatures that form the base of the food chain, such as zooplankton, are harmed, this can affect larger animals that rely on them for food, resulting in cascading effects throughout the ecosystem.

Human Health

Microplastics have the potential to impact human health as well. They can accumulate in the food chain and end up in the food we eat. Additionally, microplastics can absorb and concentrate harmful chemicals from the environment, which could be released into organisms upon ingestion. While the health impacts of microplastics on humans are not yet fully understood, studies are ongoing to determine potential risks.

Soil Health

Not only are microplastics a problem for marine and freshwater environments, but they’re also increasingly being found in soils. They can affect the health of the soil by disrupting the soil microbe community, potentially reducing the fertility of the soil and affecting plant growth.

Climate Change

Plastics, including microplastics, are made from fossil fuels, so their production contributes to greenhouse gas emissions and hence, climate change. There’s also emerging research suggesting that microplastics in the ocean may interfere with the carbon cycle by disrupting processes by which carbon is sequestered in the deep ocean, potentially contributing to global warming.

Mitigating the impact of microplastics involves reducing overall plastic use, improving waste management systems, conducting further research on the impacts of microplastics, and considering legislation to limit the production and use of certain types of microplastics (like those in personal care products). Public education to raise awareness of the problem and promote responsible behavior can also play a key role.


By Andrei Ionescu, Staff Writer

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