By Rachel McDonald, the Australian Science Media Centre

In our houses and in our cars, we're likely breathing in tiny plastic particles every day, according to an international study. The French research team collected air samples from their own apartments and cars to look for microplastics - plastic particles measuring less than 10 micrometres across. These particles are smaller than a speck of dust, which makes them small enough to be inhaled deep into the lungs, raising questions about their potential health impacts.

The researchers say across their 16 air samples, the average concentration of microplastics was 528 particles per cubic metre for the apartment samples, and 2238 for the car samples. Combining this finding with previous research on the subject, the researchers estimate we could be inhaling about 68,000 of these particles each day.

Professor Thava Palanisami from the Australian Plastic Research and Innovation Lab at The University of Newcastle told the AusSMC that this study suggested plastic particles were more prevalent in indoor areas than previously thought.

"By employing high-resolution Raman spectroscopy, this study provides the first robust quantification of inhalable PM₁₀ microplastics (1–10 μm) in indoor air, revealing exposure levels that are an order of magnitude higher than previously estimated," Prof Palanisami said.

He said this showed it was important we do more research on where these plastics are going once inhaled and what risks they pose.

"These small particles can penetrate deeply into our lungs, raising new concerns about how prolonged exposure to everyday plastics may impact our health over time," he said.

This particular study focused only on the prevalence of plastic particles, without looking specifically into the health impacts these particles could be having on the people living and driving in these spaces.

Professor Ian Rae, an expert on chemicals from the University of Melbourne, said the experiment was "very well done" but it was difficult to make hard and fast conclusions from the results.

"The results show a scatter of plastic types that make interpretation of the results difficult," Prof Rae said.

He said the paper showed significant differences in the types of plastics likely to be collected in cars compared to those collected in apartments, and a great deal of variation between the different cars and apartments used in the study.

"No overall view can be formed from these few examples; it’s hard to know why these interior atmospheres are so different. Materials of construction could have a lot to do with it (the authors note the kind of furnishing fabrics used in cars), but other things in these spaces and the way they are used by occupants could be important, too," he said.

While he said the inconsistencies in plastics found in the samples throw some doubt on how well this research translates to houses and cars more broadly, the finding of nearly five times as many particles in car air compared to apartment air stood out.

"There is no information about health effects, but if there are health effects, it’s clearly better to walk or cycle when you go down to the shops than it is to jump into the car!" he said.

You can read the full Expert Reaction here

This article originally appeared in Science Deadline, a weekly newsletter from the AusSMC. You are free to republish this story, in full, with appropriate credit.

Contact: Rachel McDonald

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Email: info@smc.org.au