A little-known pollutant may be far more common than expected
Researchers in the Netherlands have reported unexpectedly high atmospheric levels of methylsiloxanes, a class of silicone-based compounds used in products ranging from cosmetics to industrial materials and transportation applications. The findings suggest that these chemicals are not confined to dense urban corridors or obvious industrial sources, but are present across cities, rural areas, coastal regions and forests.
The study, published in Atmospheric Chemistry and Physics by researchers from Utrecht University and the University of Groningen, points especially to larger molecular methylsiloxanes associated with ship and motor vehicle emissions. Those compounds had previously received far less attention than the better-known forms linked to evaporation from personal care products and consumer goods.
From niche chemistry to broad environmental exposure
Methylsiloxanes are valued because they repel water and can function as lubricants or performance additives. That utility has helped them spread across many categories of modern products. But environmental visibility has lagged behind usage. While pollutants such as PFAS and microplastics have become part of mainstream public debate, methylsiloxanes have remained comparatively obscure.
The new work challenges the idea that these compounds are a secondary atmospheric issue. Researchers found the larger methylsiloxane molecules in many different settings, implying that emissions are not only more geographically widespread than assumed but may also persist in the air at levels high enough to demand closer scrutiny.
