Hopefully mankind's addiction to single-use plastics and the negligent disposal of all plastics can be stopped before exposure to, inhalation of, and ingestion of large quantities of microscopic shards of poly-whatever start shredding and poisoning our bodies from the inside.
And smaller microplastic particles, which all larger particles eventually become, can float through the air.
It is not unreasonable to assume that the problem is going to keep getting worse and worse as time goes on until it gets to a point where every breath we take is contaminated shards of plastics: https://www.researchgate.net/figure/Photographs-of-microplas...
I'm not a doctor, or a plasticsologist, or a breathing-things-in-ologist, but breathing in large quantities of plastic shards seems less healthy than not doing so and just from a layman's perspective it seems that exposure to microplastics in the air and water should be minimized to the greatest extent possible.