Every time we breathe, we could be inhaling tiny fragments of plastic. In recent years, concern about plastic pollution has grown, especially due to its accumulation in the oceans. However, what many people still don't realize is that plastics are also present in the air we breathe.

An adult can inhale more than 48,000 microplastic particles a year without even noticing. These particles, imperceptible to the naked eye, float in the air like invisible dust that seeps through our windows, settles on our furniture, and, most disturbingly, enters our lungs.

This year, World Environment Day (June 5) focuses on plastic pollution. And perhaps it's time to look not just at the land and sea, but also at the sky.

The air route of microplastics

When we think of plastic pollution, we usually imagine bottles on the beach or bags floating in the sea. But plastics also break down over time—due to solar radiation, wind, or use—into particles smaller than 5 mm: so-called microplastics .

These are known as secondary microplastics , because they originate from the degradation of larger plastic objects. However, there is another subject Microplastics that do not originate from this decomposition, but are manufactured directly as tiny particles: primary microplastics . These are used intentionally in numerous industrial and commercial sectors. For example, as ingredients in cosmetics and skincare products. staff , such as exfoliants or makeup. They are also common in textile coatings, paints, detergents, slow-release fertilizers, and even as industrial abrasives.

These particles can end up in the air through various pathways: direct emissions into the environment, tire wear on roads, the washing and drying of synthetic clothing, urban dust, being blown out by waves at sea , or lifted and carried from the ocean by severe storms . Once there, they can be carried by the wind for thousands of kilometers.

Microplastics are now commonly detected in densely populated urban areas. In Spanish cities, it has been estimated that between 2,000 and 28,000 microplastic particles per square meter are deposited from the atmosphere each year , with the highest levels in cities such as Madrid and Barcelona. But what is truly worrying is that they have also been detected in remote locations such as the cima from Mount Everest , in cloud water samples taken from mountaintops in Japan , or in the atmosphere of both the Arctic and Antarctica . In other words, it doesn't matter whether we live by the sea, in the mountains, or in the center of a city. Microplastics are already part of the atmospheric cycle.

What enters through the nose does not stay in the wind

The big challenge now is to understand the effects these microplastics have on our health. We already know that they can reach the respiratory system, and that some, due to their size and shape, could even penetrate the deepest lung tissues.

And it's not just the plastic itself that matters. Many microplastics travel "loaded" with chemical contaminants: heavy metals, pesticides, or toxic additives that can be released once inside the body. It's as if we're not just breathing dust, but also an invisible cocktail of unwanted substances.

programs of study Recent studies have shown that certain plastic particles can cause inflammation, oxidative stress and even altered immune responses in lung tissues exposed to laboratory . However, the long-term effects in humans remain a matter of debate. research .

The concern becomes greater when we think about the exhibition daily, especially in vulnerable people: children, the elderly, or those living in areas with high air pollution. Are we facing a new subject of invisible pollution that could chronically affect our health?

What can we do if we don't even see them?

Faced with this problem, the solution isn't (only) to stop using straws. We need to consider how we produce, consume, and dispose of plastics. As citizens, we can reduce the use of synthetic clothing, opt for public transportation (to limit tire wear), strategically ventilate, or support initiatives that promote biodegradable materials and public policies to combat pollution.

From a scientific perspective, we continue to investigate how much plastic is in the air to better understand how and where it originates, how it is transported, what factors drive these processes, and what consequences they have. In my case, I'm dedicated to studying atmospheric microplastics because I believe we can't protect what we can't see if we don't first understand it.

This June 5th, as we celebrate World Environment Day, let's remember that plastic pollution doesn't just float in the ocean: it also floats, silently, among us. And breathing should be a clean and safe act.

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Yasser Morera Gómez researcher of the Biodiversity and Environment Institute BIOMA of the University of Navarra. 05.06.2025