Indoor air contains thousands of microplastics small enough to penetrate deep into our lungs, study finds

By Sandee LaMotte, CNN

(CNN) — Thousands of microplastics so small they can penetrate deep into the lungs are in the air you breathe in your home and car, a new study has found.

The particles are likely the result of the degradation of plastic-filled objects such as carpet, curtains, furniture and textiles and the plastic parts of car interiors, according to the study published Wednesday in the journal PLOS One.

“People spend an average of 90% of their time indoors, including homes, workplaces, shops, transportation … all the while they are exposed to microplastic pollution through inhalation without even thinking about it,” senior study author Jeroen Sonke and lead author Nadiia Yakovenko said in a joint statement.

“Microplastics in the air, especially indoors, may be an invisible threat we are only beginning to understand.”

Sonke is a research director at the National Centre for Scientific Research, which is affliated with France’s University of Toulouse. Yakovenko is a postdoctoral researcher of environmental geosciences at the university.

“While research is still ongoing, there is concern that long-term exposure to microplastics and their additives may contribute to respiratory problems, disrupt endocrine function and increase risk for neurodevelopmental disorders, reproductive birth defects, infertility, cardiovascular disease, and cancers,” the two said.

The study found adults may inhale some 68,000 microplastic particles of 1 to 10 micrometers per day from indoor air — an estimate that is 100 times more than expected, according to Sonke and his team.

In comparison, a red blood cell is 6.2 to 8.2 micrometers, while E. coli bacteria may be 1 to 2 micrometers long.

“This adds to the body of knowledge we have that microplastics are everywhere and getting into humans in every way imaginable,” said microplastics researcher Sherri “Sam” Mason, director of Project NePTWNE at Gannon University in Erie, Pennsylvania, via email. She was not involved in the study. (NepTWNE is short for Nano & Polymer Technology for Water and Neural-networks.)

Scientists have detected microplastics in human testes and the penis, human blood, lung and liver tissues, urine and feces, mother’s milk, and the placenta. A February study found nearly a spoon’s worth of microplastics in human brain tissue. A March 2024 study found people with microplastics in their carotid artery tissues were twice as likely to have a heart attack, stroke or die from any cause over the next three years than those who had none.

“The size of these particles are especially concerning as the smaller the particle, the bigger the impact on human health,” said Mason, one of the first scientists to measure microplastics in bottled water.

Kimberly Wise White, vice president of regulatory and scientific affairs at the American Chemistry Council, which represents the plastics industry, expressed concerns about the study’s methodology.

“This study is based on a very small sample size and acknowledges a contamination rate of 18%, which raises questions about the accuracy of the findings,” White said via email. “Additional work using validated methods and standardized exposure assumptions is essential before drawing conclusions about potential health impacts.”

Cars are a significant source of microplastic pollution

To do the study, Sonke and his team took indoor air samples from their apartments and while in their cars driving between cities in France. In the United States, AAA Foundation for Traffic Safety statistics have shown the average American spent about 60 minutes a day inside a car in 2023.

Car cabins can be a significant source of microplastic exposure because they are small, enclosed spaces filled with plastic-based materials — dashboards, steering wheels, door handles, seat fabrics, carpets and carpet liners are all made with plastics, Sonke and Yakovenko said.

“These materials can shed tiny plastic particles over time, especially by solar irradiance, friction, heat and daily use,” they said. “Unlike homes, car cabins often have limited ventilation, allowing microplastic particles to accumulate and concentrate in the air. As a result, they can be inhaled in higher amounts during regular commutes or long drives.”

Testing found some 2,238 microplastics particles per cubic meter of air inside the cars — much more than the 528 particles found in a similar amount of air from inside homes.

“We often associate plastic pollution with oceans or industrial areas,” Sonke and Yakovenko said, “but our findings showed that the everyday indoor environment where we spend most of our time can be a major source of human exposure.”

To measure the plastic concentrations, the team used Raman microscopy, a newer and powerful technique that can measure down to about 1 micrometer. This technique is different from those applied in past studies, which have used methods that can only measure larger particles down to 20 micrometers, they said.

“Their analysis is sound,” said Wei Min, a professor of chemistry at Columbia University in New York City who specializes in developing next-generation microscopy techniques. He was not involved in the study.

“They were using a commercial instrument, and the limit of detection is at its best condition (around 1 micrometer),” Min said via email. “This allows them to capture (1 to 10) micrometer population, which had remained largely undetected in previous studies of in-door air.”

However, the study was unable to measure even smaller particles, called nanoplastics, which are measured in nanometers instead of micrometers. It takes 1,000 nanometers to make 1 micrometer — in comparison, an average human hair is roughly 80,000 to 100,000 nanometers in diameter.

“The present study provides important information but also speaks to the need for advancements in the technology to assess even smaller polymer particles, both in the air and in our bodies,” said microplastics researcher Matthew Campen, regents’ professor and professor of pharmaceutical sciences at the University of New Mexico in Albuquerque.

Nanoplastics are the most worrisome type of plastic pollution for human health, experts say. That’s because the minuscule particles can invade individual cells and tissues in major organs, potentially interrupting cellular processes and depositing endocrine-disrupting chemicals such as bisphenols, phthalates, flame retardants, perfluoroalkyl and polyfluoroalkyl substances, or PFAS, and heavy metals.

Ways to cut back on plastic

There are many steps individuals can take to reduce their exposure to plastics and their plastic footprint, experts say. In February, CNN spoke to pediatrician Dr. Philip Landrigan, lead author of a March 2023 report from the Minderoo–Monaco Commission on Plastics and Human Health, a global consortium of scientists, health care workers and policy analysts charged with following plastics from creation to final product.

In that report, the consortium determined plastics are associated with harms to human health at every single stage of the plastic life cycle.

“I say to people, ‘Listen, there are some plastics that you can’t escape. You’re not going to get a cell phone or a computer that doesn’t contain plastic.’ But do try to minimize your exposure to the plastic that you can avoid, especially single-use plastics,” said Landrigan, a professor of biology who directs the Program for Global Public Health and the Common Good and the Global Observatory on Planetary Health at Boston College.

It’s hard to avoid foods wrapped in plastic film because they are so ubiquitous, Landrigan said, but you can take food out of the plastic wrapping before cooking or putting it in the microwave.

“When you heat plastic, that accelerates the movement of the microplastics out of the wrapping into the food,” he said.

Invest in a zippered fabric bag and ask the dry cleaner to return your clothes in it instead of those thin sheets of plastic, suggests the Natural Resources Defense Council, an environmental advocacy group. Bring a travel mug to the local coffee store for takeout and silverware to the office to cut back on plastic cups and utensils.

“Don’t use plastic bags when you go shopping. Use a cloth bag or a paper bag or a recycle bag,” Landrigan said. “Try to avoid plastic water bottles, if you can possibly do so.”

A January 2024 study found 1 liter of bottled water — the equivalent of two standard-size bottled waters typically purchased by consumers — contained an average of 240,000 plastic particles from seven types of plastics. Some 90% of those were nanoplastics.

“Use a metal or glass drinking cup instead of a plastic cup. Store your food in glass containers instead of in plastic ones,” Landrigan said. “Work in your local community to ban plastic bags, as many communities around the United States have now done. There is a lot you can do.”

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