(Matthew Du, NewsUSA Reporter) - As part of California’s Smog Check Program, Los Angeles requires a smog test for vehicles driven in the area. Vehicles manufactured in 1976 or later undergo inspection biennially to combat air pollution. Electric-powered and gasoline vehicles are exempted from the program if they are less than eight years old. However, if it’s a hybrid vehicle, smog checks are still required. Smog certifications can also be done within California only, as the state does not accept smog checks from other states as they are considered invalid, per California law. 

Smog or smoke fog is air polluted with nitrous oxide, which is caused by burning coal and engine combustion.