Every breath you take at home or in your car could be filling your lungs with plastic.

A new study published in the PLOS One journal has found that humans may inhale up to 70,000 microplastic particles each day indoors, 100 times more than previously believed.

According to researchers, these particles likely come from the slow breakdown of everyday items, such as carpets, curtains, furniture, textiles and car interiors, which slowly shed microscopic plastic into the air.

The scientists from the University of Toulouse found concentrations of up to 528 microplastic particles per cubic metre indoors, while cars had a staggering 2,238 — and 94 percent were smaller than 10 micrometres, just small enough to slip deep into the lungs.

These invisible particles may remain in our bodies permanently and lead to a range of health issues over the long run.