In my last post, I pinned down what I did and didn’t know about microplastic. And, while I don’t (yet) think this spells the end of civilization, what I learned has given me pause.
With the just-prior post as background, I spend this post homing in on the questions that I should be asking.
They are:
1) What are my likely sources of greatest exposure?
2) How does this stuff break down? What is the half-life of microplastic, particularly fibers, in various environments (including human tissue).
2B) Are we seeing this topic frequently in the popular press because microplastic has been building up in the environment (that is, it’s now a much greater hazard than in the immediate past), or because we’re looking for it and/or we now have the means to find it?
3) Are nano-scale (really tiny) fibers a particular concern?
I’m only going to address the first question, in this post.
Understand my background as a health economist. Surgeons have been implanting chunks of plastic and metal into people for more than 70 years. (The first pacemaker implant took place in the late 1950s. Modern metal-and-plastic hip replacements go back somewhat further.) So the right materials, properly chosen, won’t interact with the body at all. OTOH, there’s a long list of materials that were tried and rejected, because they were not so inert.
So my prejudice is that incorporating random bits of plastic into your body is probably a bad idea. The only question is, how bad is it? And can you avoid it?
Wall-to-wall paranoia
The first question to ask for any environmental health hazard is, 1) What are my likely sources of greatest exposure?
For airborne fibers, if I walk through it logically, my greatest source of exposure almost certainly has to be the wall-to-wall carpeting in my home. It’s indoors, it contains a huge amount of fiber, it’s clearly synthetic fiber, and it is constantly being abraded by walking on it. And it’s “clipped”, that is, every strand of carpet yarn has been sheared off, so that it’s an entire floor surface consisting of the cut ends of synthetic yarn. In my house, every floor surface save bathroom, kitchen, and foyer is covered in the stuff.
For me, it’s a big, fiber-generating surface that I shuffle my feet across, every time I change locations within my house.
Reading up on it, I’m guessing it has maybe 60 ounces of carpet pile per square yard, a.k.a., “face weight” 60 carpeting. Doing the math, that means my house contains somewhere around 700 pounds of carpet fibers. In the form of short pieces of yarn, with their cut ends exposed, for me to walk on. I’m pretty sure that outweighs all other cloth in this household, by a wide margin. True, on any given day, most of it just sits there. But so does most of the clothing in my closet.
I can only think of two things arguing against this being my greatest source of airborne synthetic fiber exposure.
The first is that, whatever it’s made of (I have no clue), it’s made to resist abrasion. It was here when we moved into this house in 2007, and it looks about the same now as it did then. (To within my ability to tell. What I mean is, no obvious new wear spots have developed in the past 15 years.)
The second is a potential “inverse-square-law” for inhaled fiber concentrations. That is, for a given rate of fiber shedding, the closer you are to the source of the airborne fibers, the more of them you may be likely to inhale. If that’s true, then the fibers shed from stuff that’s right under your nose — shirts, sweaters, scarves, coats — might matter more than the fibers shed at your feet.
And if I put all that together, I come up with the obvious conclusion that crawling around on wall-to-wall carpet may not be smart. Not that I’m planning to do that any time soon, if I have any say in it. But the point being that having infants crawl around on your wall-to-wall carpeting might require a rethink. Putting that differently, if you’re not worried about your kids crawling around on wall-to-wall carpet, I don’t see much point in being worried about this topic at all. Because, outside of a factory, it’s hard for me to imagine where you could get a higher concentration of inhaled artificial fibers than in crawling across modern wall-to-wall carpeting.
We have met the enemy, and he is us.
In my case, I’m going to start by trying to figure out what my carpet is made of. It was here when we moved in, and I have no clue what the fiber is. Nylon is a good guess, and everything I read says that nylon, in particular, is a fiber that you’d like to avoid breathing in, owing to what it produces as it slowly breaks down.
And I may be a little more diligent in vacuuming. Given that the vacuum (in theory) has a HEPA-level filter on it, that (in theory) couldn’t hurt.
Conclusion: What to do when you’re flying blind
From the prior post, it was absolutely clear that routinely inhaling a lot of nylon fiber is bad for you. There’s even a name for the resulting condition — flock worker’s lung.
But so what? Inhaling high levels of almost any fiber or powder is bad for you, be it coal dust, silicon dust, cotton dust, copier toner, wood dust, or what have you.
It’s still an open question as to whether or not there are identifiable health effects from absorption of microplastic at levels commonly found in the environment.
But, from my own perspective, given how picky medical device manufacturers are about the materials they will use for implantable medical devices, it’s a pretty good bet that inhaling and ingesting random plastic bits and fibers is probably not good for you. How bad, exactly, we can argue about. But almost surely not a good thing.
My first thought, in a situation like this, is to test for it. Measure it. See what my exposure is.
But I don’t think that’s possible, practically speaking. I already have a “PM 2.5” meter, bought in response to the Canadian forest fires of 2023. That almost uniformly shows lower airborne particulate levels inside my house than outside. And that responds to all kinds of particulates, of which the tiny minority is likely to be microplastic fibers.
So this is a case of flying blind. I can’t tell how much I’m exposed to and I have no clear idea what harm that exposure might do, anyway.
In that case, I can at least try to identify the easily-avoidable sources of microplastic, and so reduce my exposure until better information develops. I might even go so far as to change what I buy, to avoid funding the production of even more items that shed microplastic. (E.g., avoid synthetics in my next batch of shirts). But I’d want to look at the full implications of that first.
So I’m stuck at the “identify my exposures” stage. My water filter appears to take care of most of the microplastic that might make it into my tap water. (Though I have no idea what it does with the very smallest particles). And for airborne fiber, my biggest exposure has to be wall-to-wall carpet. But this house was built for it, and replacing the existing wall-to-wall with hard-surface flooring would be ludicrously expensive.
Time to step back and let this percolate a bit.
