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The Mobile Source Control Division and Mobile Source Operations Division are responsible for developing statewide programs and strategies to reduce the emission of smog-forming pollutants by mobile sources. These include both on and off-road sources such as passenger cars, motorcycles, trucks, busses, heavy duty construction equipment, recreational vehicles, marine vessels, lawn and garden equipment, and small utility engines.

Who we are

Information about the Haagen-Smit Laboratory, the Air Resources Board's motor vehicle testing facility.
Information about mobile source pollution control authority in California.
Directory of the Mobile Source Controls Division and Mobile Source Operations Division.


Identifying mobile source emissions

Mobile source emissions inventory information


What we are doing to reduce mobile source emissions

Low-Emissions vehicle program.
Zero-Emissions vehicle program.
Off-road mobile source emissions reduction programs.
On Board Diagnostics systems (OBD II) information.
Heavy-duty vehicle inspection programs.
Mobile source emissions credit programs.
Alternate fuel vehicle information.
Mobile source emissions standards summary.

How to buy a low pollution car in California

The buyers guide to cleaner cars

Vehicle emission control information.

Information about importing a car to California from another country.
Information about bringing a car to California from another state.
Information about the California Registration and Recall program.
Aftermarket, performance, and replacment parts information.
Information about emission control system warrantys on California vehicles.

Text of Mobile source emission regulations available to download

e program.
Zero-Emissions vehicle program.
Off-road mobile source emissions reduction programs.
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