This is What Happens When You Breathe in Microplastics

A map and model of where plastic particles travel inside the lungs help us better understand the health effects

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We know that plastics are everywhere. For decades, we’ve manufactured countless products out of synthetic polymer materials and now tiny bits of the stuff have ended up in places they were never meant to be. Our food, water, and air are littered with micro- and nano-plastics. A surge of studies have shown it’s inside our own bodies too. Every testicle sampled in one recent research endeavor harbored microplastics. And that's far from the only organ involved: our lungs, blood, brains, kidneys, livers and breastmilk have also all been found to contain plastic. Emerging research suggests this prolific plastic pollution may carry some serious health consequences, from increased heart disease risk to a higher incidence of some cancers.

Much of this research has focused on ingested plastics — the kind we’re exposed to through our food and water. But airborne exposure is another common route. So where does plastic end up when you breathe it in? A recent study sought to track the path of plastic particles through the human respiratory system. The researchers found that how you breathe, fragment size, and particle shape all impact where plastic pieces pile up. The findings, published May 1 in the journal Environmental Advances, could help doctors and scientists better understand the likely, varied effects of inhaling micro- and nano- plastics on the lungs.

Plastic, Plastic, Everywhere

To track the course of inhaled microplastics and their even smaller counterparts, nanoplastics, the study authors constructed a detailed computer model of the human respiratory system from the nose to deep inside the lungs. They simulated what happens to various types of particles at resting, normal, and active breathing rates.

The researchers found that slower breathing rates, like the kind most people display while sleeping or resting, carry more micro- and nanoplastics farther into the lungs than faster breathing rates, meaning most of the damage happens when we’re least active. Overall, larger microplastics aggregate more in the upper airways while nanoplastics travel deeper, infiltrating multiple layers of branching bronchioles inside the lungs. Different parts of the lungs accumulate different quantities of plastic particles, and oddly shaped (cylindrical and tetrahedral) particles have a propensity for penetrating even further into the respiratory system than spherical ones — potentially triggering distinct health harms.

“These findings highlight the imperative consideration of breathing rates and particle sizes in health risk assessments,” write the study authors. Or, in other words, the study data could improve our understanding of how, why, and when airborne plastic is likely to make someone sick.

The study model didn’t include all aspects of the respiratory system. For instance, the researchers excluded the movement of the airway walls in their analysis. Further research is needed to see how, exactly, the model compares to real people. Nonetheless, it's an illustrative and concerning set of results.

What You Can Do About Plastic In the Air

Plastic particles are found in both indoor and outdoor air — from sources as diverse as synthetic fabrics to the aerosolized ocean spray that carries on a coastal breeze. And though plastic pollution is a planet-wide problem, the inside of your house is likely to be where you’re breathing in the most particles.

We can’t stop breathing to avoid microplastic exposure, but there are steps you can take to improve your at-home air quality. Avoiding synthetic fibers in your clothing, flooring, and furniture reduces sources of plastic pollution. Regular ventilation, cleaning and vacuuming can also help. And installing air purifiers with certain types of filters (the smaller gauge, the better) can mitigate all sorts of indoor air contaminants.

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