Our invisible exposure to microplastic particles is driven by the design choices of manufacturers and weak regulation, writes independent environmental scientist Heather Leslie — and simple awareness is the starting point for reducing it.
© Dr Heather Leslie
Amsterdam, April 23, 2026
By Dr Heather A. Leslie, environmental scientist and author of Exploring Everyday Microplastic Exposures
For years, the conversation about plastic pollution has focused on the visible: bottles on beaches, animals tangled in packaging, bags choking rivers. These images are powerful, though they do not reveal another part of the picture — unfolding in tandem — one that is microscopic, continuous and poorly understood.
We are living in an age of invisible exposure to microplastic particles in our homes, workplaces and public spaces thanks to the design choices of manufacturers and weak regulators. These particles are like tiny polymeric skeletons carrying a multitude of chemical additives, some with terrible toxicological track records. My previous research led to the discovery of microplastics in the human bloodstream. Others have found plastic particles in lung tissue, placentas, and hearts. But these studies leave us wondering: where exactly did the microplastics showing up in people come from in the first place?
I wanted to learn about the range of different everyday products that result in microplastics queuing up in our living environments and into positions where they can be breathed in and swallowed. An overview like that could hold clues to preventing at least some microplastic exposures. The first step to solving any problem is to be aware of it.
Around 350 peer-reviewed studies later, I had mapped the breadth of microplastics exposure from a wide range of products and product systems. And this created a foundation for action — which is the happy ending to this story which I'll get to.
What emerged from the research is the realisation: if the product has plastic in it, it will be releasing microplastics. The amount they shed ranges from low to astronomically high. And as a species that is using plastic stuff all day long, we are surrounded by such sources.
Consider what happens when you make a cup of tea. A single plastic teabag, brewed for five minutes, releases around 2.3 million microplastic particles and billions of nanoplastics into your cup. A new plastic kettle can release five to 35 million particles per litre of boiled water.
The total daily dose for humans is still impossible to estimate meaningfully. But we can already see two things: how products drive exposure to different degrees, and that anyone willing to avoid certain products can start reducing their personal exposure.
Understanding where exposure comes from gives you choices. A wooden chopping board instead of plastic, loose-leaf tea instead of plastic teabags, a cotton towel instead of polyester, and tools like the PlasticFreeFuture app can help. Not heating your food in plastic helps too, because hot plastic releases more microplastics.
My scientific review also highlights lesser-known exposure routes. Microplastics can be inhaled from polluted air due to synthetic textiles, tyre wear, and possibly also “stratospheric aerosol injection”. The latter involves spraying particles from planes that fall into our air, onto crops, streets and playgrounds.
Some exposure sources are impossible for individuals to avoid. Addressing these requires collective action, better governance, and redesign by manufacturers.
System change starts with individual and collective actions aligned with a better future. Governments often move slowly and only under strong societal pressure.
If institutions adopted the precautionary principle, research into health impacts would accelerate. Governments could act without waiting for perfect data, and manufacturers would redesign products.
Policy change is slow, like a heavy truck going uphill. People often wait for policy, forgetting their own power. Simply refusing plastic products is like not voting for them. Imagine skipping that plastic-lined coffee cup on your commute — not as a sacrifice, but as a conscious choice. Over time, plastic could lose its default role in design.
The plastic age promised convenience. But growing scientific evidence forces us to reconsider what that convenience has cost. Are we ready to change habits and move toward cleaner food and environments? That sounds like a good future to me.
