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).
An emission test is a procedure in which a vehicle is subjected to a series of test that will determine if the smog released by a vehicle meets the city standards. This is necessary to make insure that the air does not get polluted. You will have to undergo this procedure or else you will not be able to have your vehicle registered for use. 2  Remember, not all states in the United States require this testing. 3  On average, the cost to have an emission test done is going to vary anywhere from $10 to $30.