The Mobile Source Emissions Regulatory Compliance Data Inventory data asset contains measured summary compliance information on light-duty, heavy-duty, and non-road engine manufacturers by model, as well as fee payment data required by Title II of the 1990 Amendments to the Clean Air Act, to certify engines for sale in the U.S. and collect compliance certification fees. Data submitted by manufacturers falls into 12 industries: Heavy Duty Compression Ignition, Marine Spark Ignition, Heavy Duty Spark Ignition, Marine Compression Ignition, Snowmobile, Motorcycle & ATV, Non-Road Compression Ignition, Non-Road Small Spark Ignition, Light-Duty, Evaporative Components, Non-Road Large Spark Ignition, and Locomotive. Title II also requires the collection of fees from manufacturers submitting for compliance certification. Manufacturers submit data on an annual basis, to document engine model changes for certification. Manufacturers also submit compliance information on already certified in-use vehicles randomly selected by the EPA (1) year into their life and (4) years into their life to ensure that emissions systems continue to function appropriately over time.The EPA performs targeted confirmatory tests on approximately 15% of vehicles submitted for certification. Confirmatory data on engines is associated with its corresponding submission data to verify the accuracy of manufacturer submission beyond standard business rules.Section 209 of the 1990 Amendments to the Clean Air Act grants the State of California the authority to set its own standards and perform its own compliance certification through the California Air Resources Board (CARB). Currently manufacturers submit compliance information separately to both the EPA and CARB. Currently, data harmonization occurs between EPA data and CARB data only for Motorcycle & ATV submissions.Submitted data comes in XML format or as documents, with the majority of submissions being sent in XML. Data includes descriptive information on the engine itself, as well as on manufacturer testing methods and results. Submissions may include information (CBI) such as information on estimated sales, new technologies, catalysts and calibration, or other data elements indicated by the submitter as confidential. CBI data is not publically available, but it is available within EPA under the restrictions of the Office of Transportation and Air Quality (OTAQ) CBI policy [RCS Link]. Pollution emission data covers a range of Criteria Air Pollutants (CAPs) including carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter. Datasets are segmented by vehicle/engine model and year, with corresponding emission, test, and certification data. Data assets are primarily stored in EPA's Verify system. Data collected from the Heavy Duty Compression Ignition, Marine Spark Ignition, Heavy Duty Spark Ignition, Marine Compression Ignition, and Snowmobile industries, however, are currently stored in legacy systems the will be migrated to Verify in the future.Coverage began in 1979, with early records being primarily paper documents that did not go through the same level of validation as the digital submissions that began in 2005.Mobile Source Emissions Compliance documents with metadata, certificate and summary decision information is made available to the public through EPA.gov via the OTAQ Document Index System (http://iaspub.epa.gov/otaqpub).