Microplastics are tiny plastic particles less than 5 millimeters in size, found everywhere in the environment, and capable of accumulating in human and animal lung tissues. They can disrupt hormone balance, cause chronic inflammation, create oxidative stress, damage gut health, and even cross the placenta and blood-brain barrier.

Story at a glance:

• Microplastics are tiny plastic particles less than 5 millimeters in size, found everywhere in the environment, and capable of accumulating in human and animal lung tissues.
• A 2025 study found microplastic particles in every lung sample from 51 bird species, with an average of 221 particles per bird’s lungs. These findings suggest similar widespread contamination in humans.
• Previous research has shown that microplastics are present in human lung tissues, with particles from common plastics like polypropylene and polyethylene terephthalate (PET).
• Microplastics disrupt hormone balance, cause chronic inflammation, create oxidative stress, damage gut health, and even cross the placenta and blood-brain barrier.
• To reduce your microplastic exposure, switch to reusable bags, store food in glass containers, avoid using single-use plastics, choose natural home products and improve your indoor air quality with an air filter.

Microplastics are small plastic particles that are less than 5 millimeters in size. They form when large plastic materials, such as packaging, textiles, tires and industrial coatings, break down through heat, friction or wear.

These particles do not degrade; instead, they persist in the environment. Their size makes them especially dangerous because they’re small enough to bypass your body’s defenses and accumulate in your tissue.

In 2019, the world produced 460 million tons of plastic, and that number is projected to triple by 2060. So it’s no surprise that microplastics are everywhere — polluting our oceans, contaminating our food and even filling the air we breathe. One of the starkest warnings now comes from birds.

Birds are considered environmental sentinels because they show early signs of ecological damage. A recent study published in the Journal of Hazardous Materials found microplastics embedded in the lung tissue of dozens of wild bird species.

The fact that plastic has accumulated inside their lungs means the same is likely happening to you — perhaps even to a greater degree.

New study reveals airborne microplastics in bird lungs

A 2025 study published in the Journal of Hazardous Materials analyzed lung tissue from 51 different bird species living near Chengdu Tianfu International Airport in China.

The goal was to see whether microplastics (tiny plastic particles between 1 micrometer and 5 millimeters) and even smaller nanoplastics (less than 1 micrometer) were present, and if so, in what quantity.

Plastic particles were found in every single bird tested

Across all 51 species, the researchers found a total of 11,281 plastic particles. On average, each bird had about 221 particles in its lungs, or roughly 416 particles per gram of lung tissue. Some birds had only a few particles, like the Little Bunting, which had 11. Others, like the Grey Heron, had over 1,400.

Two types of plastic showed up most often 

Out of 32 types of plastic detected, chlorinated polyethylene and butadiene rubber were the most common. These plastics are often used in packaging, cables and tires. Most of the particles were shaped like films or small pellets and measured between 20 and 50 microns.

Certain types of birds had higher plastic levels

The researchers noticed that some birds, especially those that live on land, eat other animals or are larger in size, tended to have more plastic particles in their lungs. These differences likely reflect how much time the birds spend in polluted areas and how their habits affect exposure.

Nanoplastics were found in several species

In addition to microplastics, the team looked for even smaller particles called nanoplastics in five of the bird species. Their tests revealed nanoplastics made of materials like nylon 66, polypropylene and polyvinyl chloride or PVC, all commonly used in clothing, packaging and building materials.

The study ranked plastic particles by ecological risk 

Using something called the Polymer Hazard Index, the researchers evaluated the types and amounts of plastic found to estimate their potential environmental harm. Most bird lung samples were ranked at level III or IV on this scale, meaning they carried a higher risk to wildlife.

Bird findings suggest shared risk for humans 

This study is the first large-scale study to confirm widespread plastic contamination across dozens of bird species.

Previous research had only looked at a few species at a time. According to Shane DuBay, assistant professor of biology at the University of Texas at Arlington and part of the research team:

“Our research highlights an urgent need to address plastic pollution in our environments, as these contaminants can have far-reaching impacts on ecosystem health, as well as human health. Our findings call for further research, funding and action to mitigate the harmful effects of plastic pollution and ensure a healthier environment.”

Microplastics have also been detected in human lung tissue

Even in humans, microplastics have been found deep in the lungs. The researchers behind the bird study pointed to a 2022 investigation as a comparison.

Published in Science of the Total Environment, this study analyzed lung samples from 11 patients in the U.K. who were undergoing surgery at Castle Hill Hospital.

The researchers reported the following findings.

Microplastics showed up in almost every sample

Out of 13 tissue samples tested, 11 contained microplastic particles. A total of 39 individual fragments were identified using a method capable of detecting plastics as small as 3 microns, which is small enough to be invisible to the eye but large enough to enter and stay in lung tissue.

Plastic particles were present in all areas of the lung 

Samples were taken from the upper, middle and lower lobes, and plastic was found in each region. The lower lobes had the highest levels, with an average of 3.12 plastic particles per gram of tissue. By comparison, the upper lobes had 0.80 per gram and the middle lobes had 0.41.

Twelve different plastic types were identified 

The most common plastics were polypropylene (used in packaging and textiles), PET (commonly found in drink bottles) and resin. Others included polystyrene, PVC and polyurethane, all materials frequently used in construction, insulation or consumer goods.

Particles came in different shapes and sizes 

The fragments varied widely, from small fibers and films to larger irregular pieces. Some were just 12 microns long, while others stretched over 2,400 microns. The largest was a PET particle measuring 2,475 microns in length and 12 microns across.

For a deeper look at how airborne microplastics affect health, check out “Airborne Microplastics Linked to Multiple Health Problems.”

What are the other health problems linked to microplastic exposure?

Microplastics do not just stay in the lungs. Once these particles enter your body, they interact with your cells, organs and hormones. Here are five key areas where microplastics have been shown to interfere with human biology:

Disruption of hormone balance

Plastic particles carry compounds known as endocrine-disrupting chemicals, such as phthalates and bisphenol A (BPA).

These chemicals disrupt hormonal balance by mimicking or blocking natural hormones. They bind to estrogen and androgen receptors and disrupt key functions related to metabolism, fertility, mood and thyroid regulation.

In addition, when combined with natural estrogen, exposure to endocrine-disrupting chemicals leads to estrogen overload and initiates a series of harmful events. Learn more about the effects of endocrine-disrupting chemicals in “Exposing Toxic Chemicals in Consumer Products.”

Chronic inflammation and immune activation 

Your immune system treats plastic particles as invaders. When those particles lodge in tissues, they set off an inflammatory response. Research has shown that microplastics increase immune activity and inflammatory markers.

Over time, this raises your risk for autoimmune issues, ongoing low-grade inflammation, and chronic illnesses.

Oxidative stress and mitochondrial dysfunction 

Microplastics are linked to increased production of reactive oxygen species, which damage DNA, proteins and cell membranes.

This oxidative stress is particularly harmful to mitochondria, which in turn impairs cellular energy production. This compromises metabolic function, cognitive performance and your ability to recover from stress or injury.

Disruption of gut health and digestion

Microplastics irritate and inflame the intestinal lining, which weakens the gut barrier and allows harmful substances to enter the bloodstream.

They also disrupt your gut microbiome by reducing beneficial bacteria and encouraging the growth of harmful strains. This imbalance affects nutrient absorption, digestion and immune regulation, which contribute to bloating, sensitivities and chronic gut inflammation.

Crossing into protected areas of the body

Nanoplastics have been shown to cross the placenta and the blood-brain barrier. That means they reach fetal tissues and the central nervous system. This raises serious questions about long-term neurological and developmental effects.

If you’re pregnant, trying to conceive or raising children, minimizing microplastic exposure should be a priority.

Read “Microplastics Continue to Threaten Public Health” for a deeper look at how these particles disrupt biological systems and impact long-term health.

Adblock test (Why?)