Polymers, including natural proteins (such as DNA) and artificial materials (such as nylon and polyester), are examples of macromolecules. materials scientist Someone who studies the ways in which the atomic and molecular structure of a material relates to its overall properties.
Emission standards for engines and vehicles, including emission standards for greenhouse gas (GHG) emissions, are established by the US Environmental Protection Agency (EPA).The EPA authority to regulate engine emissionsâand the air quality in generalâis based on the Clean Air Act (CAA), most recently amended in 1990.ther states have a choice to either implement the federal emission standards, or else to adopt California requirements (CAA section 177).
As the acting federal authority, the EPA lays down the law, literally, on any type of emissions standards in the U.S. The Clean Air Act has provisions that allow California to implement its own automotive emissions standards and other states to adopt California's standards at their own discretion.ou've probably heard the expression California emissions.. This is simply shorthand for the state standards defined by California's Air Resources Board (CARB). Today, CARB's level of enforcement, known as LEV (Low-Emission Vehicle) 2, makes the EPA's standard look like an easy Sunday drive.