How the Findings Were Reported 

The study received significant media attention, often with striking headlines such as:  

• Microplastics found deep in lungs of living people for first time, The Guardian   
• Once Thought Impossible, Microplastics Found in Live Human Lungs for First Time, Bloomberg 
• Microplastics Have Now Been Found in The Deepest Part of The Human Lungs, ScienceAlert 

None of these headlines, which were typical of news coverage of this study, reflected key uncertainties with the underlying science. Specifically, media coverage often overlooked key details, such as the potential for laboratory contamination, the biological implausibility of large particles reaching deep lung tissue, and an entire field of research that differentiates how inhaled fibers and fragments behave.

For example, ScienceAlert reported that particles as large as 2,475 micrometers (μm, ~2.5 mm) were found in lung regions that are known to be too small for particles of this size to fit. The article even noted this size is “too large to be present, yet present nonetheless.” Instead of asking whether this discrepancy pointed to contamination, methodological limitations, or known differences in how fibers move through the respiratory tract, (Lizal et al., 2022), the reporting concluded that people must be routinely inhaling particles orders of magnitude larger than what pulmonary biology supports. 

This example underscores an important point for reporters covering microplastics: don’t take conclusions at face value. Put the study’s limitations in context and consult experts who weren’t involved in the research—including those in related disciplines like particle and fiber inhalation toxicology. Doing so helps prevent the overstatement of early or uncertain findings.

What the Study Said 

Jenner et al. (2022) looked for microplastics in lung tissue samples collected from 11 people undergoing surgery. The researchers found the largest concentration of microplastics was found in the lower regions of the lung, finding fibers, fragments, and films with an average length of 223.10 μm and an average width of 22.21 μm. However, these findings are implausible as decades of medical science indicate particles >10 µm have a negligible probability of entering the deep lung tissue (Brown et al., 2013).

Based on the information presented by Jenner et al., several issues with the methodology raise doubts about the reliability and relevance of the data presented: 

• Particle size and lung biology. The fragments are too large to reach the deep lung tissues reported by Jenner et al. Pulmonary science shows that there is a 50% cut-size (the size where half the particles would get into the lungs) for entering the lungs for spherical and fragmented particles at around 3 µm in adults and 5 µm in children (Brown et al., 2013). All fragments reported in the lung tissue by Jenner et al., however, are typically greater than 10 µm, sizes which have a negligible likelihood of being deposited through normal breathing, raising concerns with respect to the plausibility that such large particles would dominate the detection of microplastics in the lungs. 
• Background contamination. A more reasonable explanation for the observations reported by Jenner et al. is that they detected and quantified microplastics that contaminated their tissue samples. Typically, procedural and sample blanks (i.e., tissue free samples) are collected to determine how much background contamination is present when collecting the tissue or in the laboratory. The significant variability in background contamination levels in this study points to issues in handling, environment, or materials. Even more importantly, when the blanks were compared to the tissues collected, only one tissue sample could be distinguished from the background contamination further calling the conclusions into question. These results make it difficult to tell whether the researchers were accurate or simply measuring background levels of microplastics (i.e., contamination).
• Microplastics can be present at high levels in the surgical environment. Particles detected in surgical samples can come from the operating room itself. Despite being viewed as a clean environment, microplastics are present in operating rooms and contamination during procedures is difficult to avoid (Field et al,Field et al. 2022), making it hard to determine whether microplastics were present in the body before surgery or if the samples were contaminated by the surgical environment.
• Small sample size. The study by Jenner et al. is limited to 13 samples from 11 patients. No information regarding the details of the individuals, such as smoking status, occupation, or area of residence, was included in the evaluation of the data. While the limited amounts of data obtained could be considered exploratory and help inform future research, they are not sufficient to make any general conclusions about population-level exposure. A more reasonable conclusion is that additional research is needed to establish the reliability of the sampling and analytical methods that were adopted. This is particularly true given that only one sample had concentrations that were quantifiable after the high background contamination was considered.  

Conclusion

Results from exploratory studies with novel findings should be evaluated cautiously. As with any new area of science, the uncertainties and methodological limitations often prevent researchers from making definitive statements about the results. The Jenner study contradicted well-established biology, lacked statistical reliability, and the samples were subject to known pathways for contamination. Together, these issues make it difficult—if not impossible—to determine whether the particles detected were present in lung tissue or introduced during sampling and analysis.    

This study underscores the importance of relying on rigorous methods, replication, and expert context before drawing conclusions about human health. Without that rigor, headlines risk overstating findings and confusing the public about what the science actually shows.  

References  

Brown, J. S., Gordon, T., Price, O., Asgharian, B. (2013). Thoracic and respirable particle definitions for human health risk assessment. Part Fibre Toxicol, 10, 12. https://doi.org/10.1186/1743-8977-10-12. 

Field, D. T., Green, J. L., Bennett, R., Jenner, L. C., Sadofsky, L. R., Chapman, E., Loubani, M., Rotchell, J. M. (2022). Microplastics in the surgical environment. Environ Int, 170, 107630. https://doi.org/10.1016/j.envint.2022.107630. 

Jenner, L. C., Rotchell, J. M., Bennett, R. T., Cowen, M., Tentzeris, V., Sadofsky, L. R. (2022). Detection of microplastics in human lung tissue using muFTIR spectroscopy. Sci Total Environ, 831, 154907. https://doi.org/10.1016/j.scitotenv.2022.154907. 

Lizal, F., Cabalka, M., Maly, M., Elcner, J., Belka, M., Lizalova Sujanska, E., … Jicha, M. (2022). On the behavior of inhaled fibers in a replica of the first airway bifurcation under steady flow conditions. Aerosol Science and Technology, 56(4), 367–381. https://doi.org/10.1080/02786826.2022.2027334.