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Vehicle Emissions Inspection and Maintenance

Photo of emissions from automobile tailpipe.

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Cars, trucks, and buses are a main cause of air pollutants in the District. Even though newer vehicles are equipped with pollution control systems, they need to be monitored and maintained to continue functioning properly. It can be difficult for the average driver to identify problems without modern emissions testing.

Vehicle emission I/M programs require regularly scheduled testing of the amount of evaporative gasses that are emitted into the atmosphere. The District conformed to the updated enhanced I/M program in 1997 set forth by the applicable State Implementation Plan for the District of Columbia under section 110 of the Clean Air Act (42 U.S.C. 7401) and 40 CFR part 51 to meet National Ambient Air Quality Standards (NAAQS). The implementation of this program continues to be an integral part of the District’s plan to attain and maintain compliance with the health-based NAAQS for ozone. Reducing the emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) (precursors to ozone formation), will help the District in its efforts to improve its air quality and protect the health and welfare of its citizens.

DOEE oversees the District's Vehicle Emissions Inspection and Maintenance Program ("I/M Program"). Actual emissions inspections are conducted by the DC Department of Motor Vehicles at a single eight-lane test station, located at 10001 Half Street in the District's Southwest quadrant. They ensure that all gasoline-fueled vehicles manufactured in or since 1968 and up to 26,000 pounds gross vehicle weight pass an emission test as a requirement for vehicle registration.

If a vehicle does not pass the emissions test, vehicle registration is denied. Emission testing helps identify and remove motor vehicles ("mobile sources") that are out of compliance with current vehicle emission standards. Inspection frequency is dependent on vehicle type and use. Approximately 170,000 emissions inspections take place each year to guarantee that dirty vehicles stay off the streets.

DOEE checks the I/M Program to make sure it is operating efficiently and effectively by conducting both overt and covert performance audits. Audits involve reviewing data collection procedures, calibrating instruments, reviewing the training certification for emissions inspectors, and conducting station performance reviews. Data is then reported to the EPA.

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