For years, scientists were baffled by a deadly mystery. Every fall, after the first hard rains, coho salmon returning to spawn in streams across the Pacific Northwest would die within hours, often before they could lay a single egg. Entire runs were being wiped out, and no one knew why. In 2020, researchers finally identified the culprit: a chemical called 6PPD-quinone, formed when a common tire preservative reacts with ozone in the air. It washes off our roads with the rain, and it is acutely lethal to coho salmon. The source had been hiding in plain sight, under every car on the road: the tires.

Tire wear is now one of the largest sources of microplastic pollution on Earth, and it carries this toxin straight into our waterways. Almost every attempt to deal with it happens far downstream, filtering runoff after it has already spread through storm drains, rivers, and streams. By then it is too late.

TireCapture solves the problem at the source, at the tire, before the pollution ever reaches the road. The device is completely passive. It has no motor, no fan, no electrical draw, and no spray. It mounts in the wheel well behind the tire and uses the physics already at work: as a tire rolls, it flings wear particles backward off the contact patch along a predictable path. TireCapture places a collection surface directly in that path, so the particles' own momentum carries them in and traps them. Inside is a sealed, removable cartridge that captures the material in stages. A coarse stage catches the heavy grit, finer layers trap the smaller particles, and a sorptive layer adsorbs the dissolved tire chemicals, including the 6PPD before it can transform into its deadly quinone.

Because capture happens at the tire, the contaminant is intercepted before it can wash away. When the cartridge fills, it is removed cleanly, and the captured material can be analyzed, recycled, or disposed of properly instead of poisoning a watershed. The device is simple, rugged, and retrofittable to nearly any vehicle, with no modification to the electrical system, which makes it practical for cars, trucks, fleets, and buses alike.

What makes it novel is the combination. It is a passive, source-capture device that works with the tire's own ejection of particles rather than against it, and it captures both the solid microplastic and the dissolved chemical fraction in a single sealed unit. That is a fundamentally earlier and more effective intervention than treating stormwater after the fact.

It can be produced from durable molded housings and standard filter and sorbent media, manufacturable in the United States at low cost. Regulators, municipalities, fleets, and automakers all face mounting pressure to reduce tire pollution, and watershed and fisheries programs urgently need a solution. TireCapture turns the tire from the source of the problem into the point of the cure.