Â鶹ÒùÔº

New measurements of fine microplastic particles suspended in the air in homes and cars suggest that humans may be inhaling far greater amounts of lung-penetrating microplastics than previously thought. Nadiia Yakovenko and colleagues at the Université de Toulouse, France, present these findings in the open-access journal .

Prior research has detected tiny fragments of plastic known as microplastics suspended in the air across a wide variety of outdoor and indoor environments worldwide. The ubiquity of these airborne pollutants has raised concerns about their potential health effects, as small-sized inhaled microplastic particles may penetrate the lungs and could pose risks of oxidative stress, immune-system effects, and organ damage.

However, prior research on airborne microplastics has mostly focused on larger particles ranging from 20 to 200 micrometers in diameter, which are less likely to penetrate the lungs than particles of 10 micrometers across or less.

To help improve understanding of the risk of microplastic inhalation, Yakovenko and colleagues collected air samples from their own apartments, as well as from their own cars in realistic driving conditions.

A technique called Raman spectroscopy enabled them to measure concentrations of microplastics, including those from 1 to 10 micrometers across, in 16 air samples.

They found that the median concentration of detected microplastics in the apartment air samples was 528 particles per cubic meter, and in the cars, 2,238 particles per cubic meter; 94% of the detected particles were smaller than 10 micrometers. (While car levels were higher than apartment levels, the difference was not statistically significant because of high variability of microplastic concentration in both environments.)

The researchers then combined their results with previously published data on exposure to indoor microplastics, estimating that adults inhale about 3,200 microplastic particles per day in the range of 10 to 300 micrometers across, and 68,000 particles of 1 to 10 micrometers per day—100 times more than prior estimates for small-diameter exposures.

These findings suggest that health risks due to inhalation of lung-penetrating microplastics may be higher than previously thought. Further research will be needed to confirm and expand on these results.

• 

• 

The authors add, "We found that over 90% of the microplastic particles in indoor air across both homes and cars were smaller than 10 µm, small enough to be inhaled deep into the lungs.

"This was also the first study to measure microplastics in the car cabin environment, and overall, we detected indoor concentrations up to 100 times higher than previous extrapolated estimates, revealing indoor air as a major and previously underestimated exposure route of fine particulate microplastic inhalation.

"Everywhere we look, we find microplastics, even in the air we breathe inside our homes and cars. The biggest concern is how small these particles are completely invisible to the naked eye. We inhale thousands of them every day without even realizing it. Deep inside our lungs, microplastics release toxic additives that reach our blood and cause multiple diseases."