Microplastic levels in the air have been overestimated, but are still a big concern

"Many human activities - from improper disposal of waste to the degradation of car tyres - release small plastic particles, which have infiltrated the atmosphere, oceans and other ecosystems. These include nanoplastics - particles measuring less than 1 micrometre across - and microplastics, which range from 1 micrometre to around 5 millimetres. They've entered our bodies and brains, and scientists are still working to understand their effects on people's health."

"Studies that have estimated the concentration of microplastics in the atmosphere show high levels of variability, with results ranging across several orders of magnitude. And studies that have taken measurements from a region in the western United States have been used to infer global emissions."

""This doesn't mean we don't have a lot of microplastics in the atmosphere," says Ioanna Evangelou, an environmental scientist at the University of Vienna. But it does point to a need to broaden and standardize the measurements of microplastics globally, she adds. Research on the biological effects of microplastics is still in its infancy, which means that it is not clear whether the levels humans are exposed to - whatever those levels are - are safe."

Atmospheric microplastic concentrations may be substantially lower than some estimates, potentially by orders of magnitude. Measurements vary widely, often spanning several orders of magnitude, and some inferences have used data from limited regions such as the western United States to estimate global emissions. Human activities, including improper waste disposal and tyre degradation, release micro- and nanoplastics into the atmosphere, oceans, and ecosystems. Microplastics range from 1 micrometre to around 5 millimetres; nanoplastics are under 1 micrometre. Microplastic particles have been detected in human bodies and brains, and the biological effects and safety of current exposure levels remain unclear, requiring broader standardized global measurement efforts.

Read at Nature