[istorical]

Have you tried a cursory Google search? I don't know if you refer specifically to the negative effects of microplastics in lungs or microplastic exposure in general, but a search for "microplastics human effects" will provide you with weeks of reading material if you'd like to be depressed.

[WithinReason]

Microplastics in general. Maybe my googling skills are failing me, but all I can find is about "potential" risks, "possible" harm and unquantified in vitro studies, nothing showing actual harm. Which leads me to believe that if so many people are looking so hard for so long, maybe there is nothing to find.

[headmelted]

That seems incredibly optimistic.

Asbestos exposure often takes up to 50 years to have a detectable impact, then kills in short order.

Lead poisoning can take an incredibly long time to identify unless you find the source of exposure up front.

Plastics haven’t even existed for a century, and have been ubiquitous only in the last few decades.