tire dust is one of the primary causes of mass juvinile salmon death, as it contains a biocide to prevent tires from rotting, that acumulates in roadside ditches and can be washed into rivers and streams in aerly spring whem the salmon smolts are vulnerable. Jet fuel also contains a biocide to prevent it bieng degraded by certain algae, along with, well, I'm thinking just about everything else at this point. Oh, wait, sorry, I get it, this about trying to deamonise cars in "urban" "environments" nevermind.