Every breath people take in their homes or car probably contains significant amounts of microplastics small enough to burrow deep into lungs, new peer-reviewed research finds, bringing into focus a little understood route of exposure and health threat.
The study, published in the journal Plos One, estimates humans can inhale as much as 68,000 tiny plastic particles daily. Previous studies have identified larger pieces of airborne microplastics, but those are not as much of a health threat because they do not hang in the air as long, or move as deep into the pulmonary system.
The smaller bits measure between 1 and 10 micrometers, or about one-seventh the thickness of a human hair, and present more of a health threat because they can more easily be distributed throughout the body. The findings “suggest that the health impacts of microplastic inhalation may be more substantial than we realize”, the authors wrote.
“We were quite surprised about the microplastic levels we found – it was much higher than previously estimated,” said Nadiia Yakovenko, a microplastics researcher and study co-author with France’s University of Toulouse. “The size of the particle is small and well-known to transfer into tissue, which is dangerous because it can enter into the bloodstream and go deep into the respiratory system.”
Microplastics are tiny bits of plastic either intentionally added to consumer goods, or which are products of larger plastics breaking down. The particles contain any number of 16,000 plastic chemicals, of which many, such as BPA, phthalates and Pfas, present serious health risks.
The substance has been found throughout the human body, and can cross the placental and brain barriers. Food and water have been thought to be the main exposure route, but the new research highlights the risks in air pollution. Among other issues, microplastics are linked to chronic pulmonary inflammation, which can lead to lung cancer.
The concentrations in indoor air are far higher than outdoor air, which the study’s authors say is worrying because humans spend about 90% of the day indoors. Yakovenko said the concentrations indoors are higher because it is an enclosed environment with high levels of plastic in a small area, and there is generally poor ventilation.
The study measured air in multiple rooms throughout several apartments, as well as car cabins as the authors drove. The source of the microplastics in the apartments is thought to be degrading plastic in consumer products, from clothing to kitchen goods to carpets.
Virtually any human activity will kick up the microplastics because the bits are so light. The levels were much higher in an apartment in which two people lived because of virtually any human activity that kicks up the particles. Smaller particles stay suspended in the air longer because they are lighter, Yakovenko said.
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“Any movement of air, vibrations, your movement, if you walk, sit down, stand up, if you open a window – all this is going to resuspend the particles,” Yakovenko said.
Meanwhile, the concentration of plastic in the cars’ air was about four times higher than in the apartments. Because it is a smaller enclosed environment, cars have a higher concentration of plastic, and the ventilation is not good, Yakovenko said. Researchers matched the microplastic material with that used on the dashboard, door handle, steering wheel and other components.
While it is impossible to avoid all microplastics in the air, exposures can be reduced by eliminating as much plastic from the home environment as possible – buy products made of wood, metal and natural fibers or materials.
Hepa air filtration systems have been found to be effective at removing microplastics, and Yakovenko said regular vacuuming with a Hepa vacuum and dusting can help. Reducing levels in the car is more challenging. Opening windows may ventilate a car cabin, but that could potentially allow in microplastic pollution from tires.