California Air Resources Board

CARB’s diesel engine regulations and programs cover a wide range of equipment operating in California and are designed to reduce air pollution caused by diesel-powered and other non-gas fossil-fuel powered equipment. Mobile sources including cars, trucks, ships, and off-road equipment continue to contribute a majority of smog-forming NOx and the largest portion of GHG emissions in California. They are also a significant source of toxic air contaminants such as diesel particulate matter (PM) and formaldehyde that directly impact community health. Enforcement of these regulations helps move California closer to our clean-air goals, promotes a level-playing field for compliant businesses and individuals, and supports the health of communities, especially disadvantaged communities most impacted by pollution.
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