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Air Mobile Sources Program

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The air mobile sources program includes emissions standards for all motor vehicles and mobile engines, and the fuels that are used in vehicles and engines. The mobile source standards apply to vehicles and engines of all sizes, ranging from engines that power large marine vessels and locomotives, to engines used in hand-held lawn and garden equipment. The fuels standards apply to all gasoline and diesel fuel used nationwide, including fuel that is produced at domestic refineries and fuel that is imported.

Compliance with the vehicle and engine emissions standards is the responsibility of the vehicle or engine manufacturer. Vehicles and engines used in the United States must be manufactured under the terms of an emissions certificate of conformity issued by EPA. Imported vehicles and engines must be EPA-certified, with certain very limited exceptions. The removal or disabling of vehicle or engine emission controls by any person is prohibited.

Compliance with the motor vehicle fuels standards primarily is the responsibility of the refiners and fuel importers. In addition, parties in the fuel distribution system are responsible for ensuring that motor vehicle fuel is not contaminated and is used in the proper locations and times. For example, more stringent gasoline standards apply during the summer high ozone season and to reformulated gasoline used in certain ozone nonattainment areas.

Compliance Monitoring

EPA reviews applications for emissions certificates from vehicle and engine manufacturers, and conducts emissions testing of vehicles and engines on the production line and in-use following introduction into commerce. EPA works in conjunction with the United States Customs and Border ProtectionExit EPA Disclaimer to ensure that imported vehicles and engines are certified. In addition, light-duty vehicle emissions are checked periodically through state-implemented “inspection and maintenance” programs in most ozone nonattainment areas. EPA conducts inspections of vehicle and engine manufacturing facilities, emission laboratories, dealers of vehicles and mobile engines and suppliers and installers of vehicle and engine parts.

EPA conducts fuels inspections primarily at:

Refiners and importers are required to test all their gasoline and submit reports to EPA. In addition, refiners and importers are required to use independent laboratories to conduct quality assurance testing of reformulated gasoline when it is produced and quality surveys of reformulated gasoline when it is sold at retail outlets, and to submit reports to EPA of this testing and surveys.

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Compliance Assistance | Compliance Monitoring | Compliance Incentives


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