Every day, new research reveals that tiny plastic particles, known as microplastics, are being found in places where they shouldn't be—such as our bodies, food, water, and air.
However, detecting and identifying microplastics is extremely difficult, particularly because they are so small. The size of a single microplastic varies from that of a ladybug to one-eighth the size of a red blood cell.
Furthermore, because microplastics exist virtually everywhere, it is difficult for researchers to avoid unintentionally contaminating samples. Consequently, these studies are likely overestimating the amount of microplastics present.
In a new study published in March 2026, our research team discovered that even when following established protocols, results can be contaminated when using certain environmental microplastic measurement methods.
Microplastics are tiny pieces of plastic that break off from plastic waste. They are found in the environment, waterways, and even the human body.
We are a collaborative research team of chemists from the University of Michigan. We began this study to investigate the amount of microplastics inhaled outdoors by Michigan residents and the differences based on their residential areas. We adhered to all standard protocols during the sample preparation process. We banned the use of plastic in the laboratory, wore plastic-free work clothes, and even used a special chamber to reduce the possibility of laboratory air contamination.
Despite these precautions, airborne microplastic concentrations were found to be more than 1,000 times higher than previously reported levels. Something felt off, and what could be the cause?
The culprit was none other than laboratory gloves.
After a long journey to identify the source of contamination, we discovered that laboratory gloves, which are recommended for use by the scientific community, can transfer microparticles to sample surfaces, particularly to the small metal pieces used to collect airborne precipitates. Furthermore, these microparticles resulted in an overestimation of microplastic concentrations in the study.
Here is how it works: These particles, which we identified as stearates, play a role in helping the gloves separate cleanly from the mold during the manufacturing process. When handling laboratory equipment with the gloves, these particles are transferred to everything the gloves come into contact with.
Stearates are similar to soap molecules. While consuming large amounts may not be good for your health, it does not cause serious harm to the environment like microplastics do.
Stearates themselves are not microplastics, but they are structurally similar to polyethylene, the most commonly found plastic in the environment. Due to this structural similarity, they are difficult to distinguish using the standard methods scientists use to determine whether particles are plastic.
Researchers use vibrational spectroscopy to identify microplastics, which measures how particles interact with light to create characteristics that scientists call a "chemical fingerprint."
Because polyethylene and stearates have very similar structures, they also interact with light in similar ways.
Consequently, in at least some cases, particles from gloves are misidentified as microplastics. As more researchers use automated methods to speed up analysis, the likelihood of glove residue being mistaken for microplastics is increasing, which can result in reported environmental microplastic concentrations being higher than they actually are.
How widespread is this contamination?
To investigate the extent of this contamination, we examined various types of gloves. By simulating the use of seven different types of gloves when handling laboratory equipment, we measured the amount of microplastics that would be reported as being released into the environment when following the most common analytical methods.
As a result, we found that when particles from gloves are misidentified as microplastics, more than 7,000 particles per square millimeter can be generated. This means that researchers may unknowingly overestimate environmental microplastic concentrations when handling samples while wearing gloves.
Even more concerning is the fact that the size of most of these particles is less than 5 μm. Microplastics of this size have a greater impact on human and ecosystem health because they can penetrate cells more easily. The use of laboratory gloves may exaggerate the levels of microplastics in this size range, potentially jeopardizing research necessary for establishing future policies and regulations.
Moving forward
To prevent contamination, scientists are advised to refrain from using gloves when conducting microplastic research. If wearing gloves is unavoidable—for example, when handling biological samples, where researchers must wear them for self-protection—it is recommended to use stearate-free gloves, such as those used in electronics manufacturing.
To recover data sets that may have been contaminated in the past, we developed a method to distinguish chemical characteristics.
Science is an iterative process. New fields of research, including environmental microplastics, present new challenges to the scientific community. In the process of addressing these new challenges, one may encounter obstacles such as unexpected contamination.
Related Article: Research Finds Takeout Coffee May Contain Thousands of Microplastic Fragments
Although the initial data set had to be discarded, we hope the lessons learned from this study on glove contamination will be helpful to other scientists. Additionally, we plan to continue our research on Michigan atmospheric microplastic contamination without wearing gloves.
Even if the amount of microplastics in the environment is less than researchers initially predicted, it must be kept in mind that even small amounts can be problematic because microplastics have a negative impact on human health and ecosystems.
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