Automaker Daimler AG and its subsidiary, Mercedes-Benz, have agreed to pay $1.5 billion to the U.S. government and California state regulators to resolve emissions cheating allegations.

A European research and data firm suggested in a study that particulates coming from tire wear may be 1,000 times worse than exhaust emissions.

A new study suggests that direct-injection engines might produce harmful carbon aerosols.

After four companies aligned with California in its plan to curb auto emissions, others have positioned themselves with the Trump administration in opposing the state.

Those involved in the deal are at odds with the Trump administration's plans.