Three studies published or presented in 2026 have compared microplastics in lung samples from people with and without lung cancer. Each found differences, but none can show whether microplastics contribute to lung cancer.
Microplastics are small pieces of plastic measuring less than five millimetres. They have already been found in human lungs, but their effect on lung health remains unclear.
What do recent studies say about microplastics and lung cancer?
The evidence is still limited, but several findings now point in the same direction.
Microplastics have been detected in lung-wash and tissue samples from people with and without lung cancer. Two recent European studies found them more often, or in larger amounts, in samples from people diagnosed with lung cancer.
A separate study also found a higher average count in lung cancer tissue. However, that difference was not statistically significant. This means it could have occurred by chance.
These studies show an association. They do not show that microplastics cause lung cancer.
What did the new European research find?
The latest findings come from research being presented at the European Respiratory Society Congress 2026 in Barcelona.
According to the European Respiratory Society report, researchers studied 100 people undergoing bronchoscopy at the University Hospital of Larissa in Greece. Fifty were later diagnosed with lung cancer and 50 were not.
Everyone provided a lung-wash sample. During this procedure, a small amount of saline solution is used to collect cells and other material from the lungs. Researchers also collected a tissue sample from half of the people taking part.
They found 232 microplastic particles across all the samples. Microplastics were detected in at least one sample from 70% of the people studied.
People diagnosed with lung cancer were more likely to have detectable microplastics when the samples were considered together. They also had a higher overall microplastic burden.
The difference was also seen in the lung-wash samples. Microplastics were detected in:
66% of people diagnosed with lung cancer
46% of people who were not diagnosed with lung cancer
The study did not measure whether exposure to microplastics increased anyone’s risk of developing cancer.
Which types of microplastic were found?
Polypropylene and polyethylene were the most common plastics identified.
Both are used widely in packaging, textiles, household materials and consumer products. Finding these plastics does not show which products the particles came from or how each person encountered them.
Microplastics can enter the air as larger plastic products wear down. People may then breathe in some of these particles. However, exposure is difficult to measure and can vary between homes, workplaces and wider environments.
How were microplastics distributed in the lungs?
The researchers found an unexpected difference between lung-wash and tissue samples taken from the same person.
People with more microplastics in their lung-wash sample tended to have fewer in their tissue sample. The reverse was also seen.
A lung wash collects material from the air spaces. A tissue sample captures particles embedded within the lung. The result suggests that microplastics may not be distributed evenly throughout the lungs.
This could be important when researchers compare studies that use different types of samples.
Have microplastics been found in lung cancer tissue before?
Yes. The new findings follow two peer-reviewed studies published earlier in 2026.
A February 2026 research letter in the American Journal of Respiratory and Critical Care Medicine compared 10 lung cancer tissue samples with 10 non-cancer samples.
Microplastics were detected in all 20 samples. The median count was higher in the cancer samples, at 39 particles per approximately 100 milligrams of tissue compared with 31.5 in the control samples.
This numerical difference was not statistically significant. Researchers did find differences in the size, shape and types of microplastic present.
In August 2026, a separate study led by Ilias Dimeas was published in the Journal of Clinical Medicine. It examined tissue from 50 people undergoing diagnostic thoracic surgery.
Microplastics were detected in 32 of the 50 people. Detection was more common among those with a primary lung malignancy than among those without one, at 81.8% compared with 50%.
The association remained after the researchers adjusted their analysis for age and smoking exposure. However, the study was small and the statistical estimate was imprecise.
The ERS research is separate from this published paper. It adds information from lung-wash samples and compares different respiratory samples.
Earlier this year, Lung Cancer Europe also looked at the wider evidence on plastic pollution and lung health, including questions about inflammation and occupational exposure.
Can microplastics cause lung cancer?
No study has shown that microplastics cause lung cancer.
The three studies are observational. They show what researchers found in samples, but they cannot establish what caused the differences between the groups.
Microplastics could affect inflammation or other biological processes in the lungs. Laboratory research has suggested several possible effects, but this does not prove that the same processes cause cancer in people.
We also do not know whether the microplastics were present before the cancer developed.
Could lung cancer change how microplastics are retained?
This is another possible explanation.
Lung cancer can change tissue structure, inflammation and the way the lungs clear material. Lungs affected by cancer may therefore trap or retain microplastics differently.
People undergoing investigations for lung symptoms may also differ from the wider population in other ways. Environmental exposure, occupation, age and other health conditions could all affect the results.
Researchers do not yet know what a normal background level of microplastics in human lungs would be.
What evidence is still missing?
Researchers need larger studies involving people from different countries and environments.
Future research will also need:
consistent methods for collecting and analysing samples
detailed information about environmental and workplace exposure
suitable comparison groups
studies that follow people over time
laboratory research into how different plastics interact with lung cells
clearer information about typical microplastic levels in healthy lungs
The research team behind the ERS study has begun further laboratory work. It is also studying samples from people with chronic lung diseases.
The current evidence gives researchers good reason to continue investigating microplastics and lung cancer. It does not yet tell us whether microplastics increase the risk of developing the disease.
Sources and further reading
Ilias E. Dimeas et al. High respiratory microplastic burden across paired airway and tissue samples in patients with lung cancer. ERS Congress 2026, abstract PA1663.European Respiratory Society report on the new researchIlias E. Dimeas et al. Microplastics in Human Thoracic Tissues: Increased Burden in Patients with Lung Malignancy. Journal of Clinical Medicine, 2026.Morteza Gholami et al. Microplastic accumulation in the human lung: distinct signatures in lung cancer vs normal tissue. American Journal of Respiratory and Critical Care Medicine, 2026.
Source note: The European Respiratory Society report published on 4 September gives figures of 100 people and 232 microplastic particles. The publicly available conference abstract contains different figures of 50 people and 186 particles. This article uses the newer figures reported by the European Respiratory Society.