Opinion

Every time we breathe, we could be inhaling tiny fragments of plastic. In recent years, concern about plastic pollution has grown, especially because of its accumulation in the oceans. However, what still goes unnoticed by many people is that plastics are also present in the air we breathe.

An adult can inhale more than 48,000 microplastic particles per year without even noticing it. These particles, imperceptible to the naked eye, float in the air as invisible dust that sneaks 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 the time has come to look not only to the ground or the sea, but also to 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 fragment over time - due to solar radiation, wind or use - until they become particles of less than 5 mm: the so-called microplastics.

These are known as secondary microplastics, because they originate from the degradation of larger plastic objects. However, there is another type of microplastics that do not originate from such 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 cosmetic and personal care products such as scrubs or make-up. 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 by various routes: direct emissions into the environment, tire wear on roads, washing and drying of synthetic clothing, urban dust, being expelled by waves at sea or being ripped up and washed from the sea by severe storms. Once there, they can be carried by the wind thousands of kilometers away.

It is already common to detect microplastics in densely populated urban areas. In Spanish cities it has been estimated that between 2,000 and 28,000 microplastic particles are deposited from the atmosphere per square meter per year, with the highest values in cities such as Madrid and Barcelona. But what is really worrying is that they have also been detected in remote places such as the summit of Mount Everest, in cloud water samples taken at the summits of the mountains of Japan or 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 goes in through the nose doesn't stay in the wind

The great challenge now is to understand what effects these microplastics have on our health. It is already known that they can reach the respiratory system, and that some, because of their size and shape, could even penetrate into the deepest tissues of the lung.

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 is as if we are not only breathing in dust, but also an invisible cocktail of unwanted substances.

Recent studies have shown that certain plastic particles can cause inflammation, oxidative stress and even altered immune responses in laboratory-exposed lung tissues. However, the long-term effects in humans are still under investigation.

The concern becomes greater when we think about daily exposure, especially in vulnerable people: children, the elderly or those who live in areas with high air pollution. Are we facing a new type of invisible pollution that could affect our health in a chronic way?

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

Faced with this problem, the solution is not (only) to stop using straws. We need to think about 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), ventilate strategically or support initiatives that promote biodegradable materials and public policies against pollution.

From science, we continue to investigate how much plastic there is in the air, in order to better understand how and from where they originate, how they are transported, what factors favor these processes and what consequences they have. In my case, I am dedicated to the study of atmospheric microplastics because I believe that we cannot protect what we do not see if we do not understand it first.

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

This article was originally published in The Conversation. Read the original.