More than 1000 tonnes of microplastic particles are raining down on the Western US each year.
That figure, which is the equivalent to more than 123 million plastic water bottles, has been estimated by a team of scientists at Utah State University.
Assistant Professor Janice Brahney and her team, used data and identified samples of microplastics and other particulates collected over 14 months in 11 national parks and wilderness areas.
The findings reported in the journal Science, estimate a staggering 4% of the atmospheric particulates collected from remote locations were plastic polymers.
Scientists also note most of the plastics in both wet and dry samples were microfibers, sourced from both clothing and industrial materials.
Approximately 30% of the particles were brightly coloured manufactured solid plastic particles but not those associated with personal care products.
These microbeads were acrylic and likely derived from industrial paints and coatings.
Other particles were fragments of larger pieces of plastic.