March 25, 2025 – Recent research has revealed that microplastics are not only prevalent in the environment but also accumulate significantly in the lungs of birds, primarily originating from tire wear. This discovery further solidifies tires as a major contributor to air pollution. Scientists express concern that, given the overlapping habitats of birds and humans, the impact on human organs could be comparable to that observed in birds.
Researchers analyzed the lungs of 51 bird species, discovering microplastics in every bird, regardless of size, habitat preference, or feeding habits. On average, there were a staggering 416 particles per gram of lung tissue. The study also indicated that terrestrial birds had a higher microplastic burden than waterfowl, and larger birds had more microplastics than smaller ones. Predatory and omnivorous birds exhibited the heaviest burden, suggesting that habitat and foraging locations are critical pathways for bird exposure to microplastics.
According to Color Masterbatch Industry Network, these microplastics consist of 32 different types of plastic fibers, films, and particles, including polyethylene, polyurethane, polyvinyl chloride, and butadiene rubber. These plastics are widely used in tire manufacturing, and tire wear may release butadiene rubber particles into the air, though further research is needed to confirm this source.
The research points out that 5%-28% of the plastics entering the oceans come from tire wear. However, tires, as a source of microplastics and a significant contributor to air pollution, are often overlooked. Researchers warn that this is a global issue. Birds were chosen as the study subjects because they inhabit nearly every corner of the Earth and often share habitats with humans, making them crucial indicators of environmental health. Additionally, birds are highly active, with generally higher respiratory rates than humans and faster air circulation in their lungs, making them more susceptible to air pollutants. Scientists caution that since birds and humans breathe the same air in shared locations, humans are also exposed to airborne plastics.
Microplastics are persistent substances, and the significant accumulation found in bird lungs underscores the ubiquity of pollution. Microplastic contamination of the atmosphere clearly poses problems for both animal and human health. A 2021 study in Switzerland revealed that over 10,000 chemicals are used in plastic production, more than 2,400 of which are harmful to human health. A 2022 study of 13 human lung samples found 39 microplastic particles representing 12 different types of polymers.
This bird study echoes similar findings of microplastic “hotspots” in human lungs and nasal passages, highlighting the impact of airborne particle drift and emphasizing the urgency of addressing plastic pollution in the environment. Researchers also note that microplastics in the air cannot be cleaned up and must be prevented at the source.
The field of research on the health impacts of microplastics is only a decade old. While most researchers acknowledge that microplastics may affect human health, there is currently a lack of high-quality studies and consistent methodologies to demonstrate their harm to humans. Currently, researchers are exploring other pathways for microplastics to enter birds, such as through food ingestion, to identify different exposure routes and gain a broader understanding of the multifaceted impacts of microplastics on organism health.