California Air Resources Board (ARB)

In 1967, California's Legislature passed the Mulford-Carrell Act, which combined two Department of Health bureaus--the Bureau of Air Sanitation and the Motor Vehicle Pollution Control Board--to establish the Air Resources Board (ARB). On February 8, 1968, the first meeting of the ARB was held in Sacramento. Since its formation, the ARB has worked with the public, the business sector and local governments to find solutions to California's air pollution problem. The resulting state air quality standards set by the ARB continue to outpace the rest of the nation and have prompted the development of new antismog technology for industrial facilities and motor vehicles.

ARB's mission is to promote and protect public health, welfare and ecological resources through the effective and efficient reduction of air pollutants, while recognizing and considering the effects on the state's economy.

In-Use Off-Road Diesel Vehicle Regulation

On July 26, 2007, the Air Resources Board (ARB) adopted a regulation to reduce diesel particulate matter (PM) and oxides of nitrogen (NOx) emissions from in-use (existing) off-road heavy-duty diesel vehicles in California. Such vehicles are used in construction, mining, and industrial operations.

Stationary Diesel Engine ATCM (Airborne Toxic Control Measure)

This webpage provides information regarding the State of California's Airborne Toxic Control Measure (ATCM) for Stationary Compression Ignition Engines.  This ATCM, which applies to stationary diesel engines used in both non-agricultural and agricultural operations is resulting in a reduction in the emissions of and exposure to diesel PM from stationary diesel engines throughout California.

On-Road Heavy-Duty Vehicle Program

Emissions from on-road heavy-duty vehicles are major contributors to poor air quality in California. In particular, diesel vehicles produce emissions in amounts highly disproportionate to the total population of these vehicles. The problem is complicated by the large number of heavy-duty vehicles, like line haul trucks, registered in other states that travel on California's highways and roads, while bringing goods and commerce into and out of our state. The Air Resources Board is working closely with the U.S. Environmental Protection Agency, engine and vehicle manufacturers, and other interested parties to address this issue and reduce heavy-duty vehicle emissions in California.

Cargo Handling Equipment (Diesel) at Ports

This area of the Off-Road Mobile Sources website pertains to regulatory activities to reduce diesel particulate matter (PM) and oxides of nitrogen (NOx) emissions from diesel-fueled cargo handling equipment at California's ports and intermodal rail yards. Cargo handling equipment is used to transfer goods or perform maintenance and repair activities and includes equipment such as yard trucks (hostlers), rubber-tired gantry cranes, top handlers, side handlers, forklifts, and loaders, just to name a few. 

Commercial Harbor Craft Regulatory Activities

This area of the Commercial Marine Vessels website pertains to regulatory activities to reduce diesel particulate matter (PM), oxides of nitrogen (NOx), and reactive organic gases (ROG) from commercial harbor craft. There are several types of harbor craft in use in California, including crew and supply boats, charter fishing vessels, commercial fishing vessels, ferry/excursion vessels, pilot vessels, towboats or push boats, tug boats, and work boats. 


This page contains information on the ARB's currently locomotives activities. These include: Statewide Agreement, South Coast MOU, Intrastate Locomotive Fuel Requirements, Federal Activities, and Recent Activities and Meetings.

LSI - Large Spark-Ignition Engines

This area of the Off-Road Mobile Sources website pertains to off-road large spark-ignition (LSI) equipment greater than 25 horsepower, including farm, construction, and industrial equipment, powered by gasoline and liquefied petroleum gas (LPG), and other alternate fuels. Typical applications that use LSI engines include forklifts, specialty vehicles, airport service vehicles, large turf care equipment, portable generators, and a wide array of other agricultural, construction, and general industrial equipment. 

SSI - Small Spark-Ignition Engines

The small off-road engine (SORE) category consists of off-road spark-ignition engines below 25 horsepower, including small utility equipment, lawn mowers and weed trimmers.

On-Road Heavy-Duty Diesel Vehicles (In-Use) Regulation

The regulation requires diesel trucks and buses that operate in California to be upgraded to reduce emissions. Heavier trucks must be retrofitted with PM filters beginning January 1, 2012, and older trucks must be replaced starting January 1, 2015. By January 1, 2023, nearly all trucks and buses will need to have 2010 model year engines or equivalent.

Ground Support Equipment (GSE)

This category includes new and in-use ground support equipment (GSE) used in airport operations. GSE perform a variety of functions, including: starting aircraft, aircraft maintenance, aircraft fueling, transporting cargo to and from aircraft, loading cargo, transporting passengers to and from aircraft, baggage handling, lavatory service, and food service. As a group, GSE largely comprise off-road types of equipment fueled by either gasoline or diesel.

Commercial Marine Vessels

This area of the Off-Road Mobile Sources website pertains to regulatory activities to reduce diesel particulate matter (PM), oxides of nitrogen (NOx), and sulfur oxide (SOx) emissions from commercial marine vessels, which includes both ocean-going ships and commercial harbor craft.


Recreational Marine

ARB's recreational marine engine program is an important new element in ARB's efforts to improve air quality through reductions of hydrocarbon (HC) and oxides of nitrogen (NOx) emissions. Regulations have been adopted for certain marine vessels and regulations have been proposed for other spark-ignition engines used in boats for propulsion.


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