The U.S. Environmental Protection Agency announced settlements Friday with three interstate trucking companies that use Southland freeways, imposing $417,000 in penalties for contributing to the high levels of air pollutants in Southern California.

“As trucks are one of the largest sources of air pollution in California, EPA will continue to ensure these heavy-duty vehicles have the needed pollution-control equipment and operate in compliance with the rules,” said EPA Pacific Southwest Regional Administrator John Busterud. “These companies have agreed to bring their trucks into compliance and operate more cleanly in all communities they serve.”

Transportation is a primary contributor to the high levels of air pollutants in Southern California and the Central Valley. Diesel emissions from trucks are one of the state’s largest sources of fine particle pollution, or soot, which is linked to health issues including asthma, impaired lung development in children, and cardiovascular effects in adults. Many of these trucks are older models and emit high amounts of particulate matter and nitrogen oxides.

Some communities face a higher risk from respiratory and cardiovascular illness. For example, the area around Southern California’s I-710 freeway, which passes through 15 cities and unincorporated areas with a population of over a million residents — about 70% of which are minority and low-income populations — is dense with goods-transport traffic, industrial facilities, residences, schools and day care facilities and serves the nearby ports of Long Beach and Los Angeles. These entry points account for 40% of all imports to the U.S. The San Joaquin Valley’s air quality is also affected by heavy truck traffic on I-5 and Highway 99.

The announcement highlights separate administrative settlement agreements with three companies:

— Roadrunner Transportation Systems Inc., based in Downers Grove, Illinois, operated heavy-duty diesel vehicles that lacked the diesel particulate filters required by the Truck and Bus Regulation and operated unregistered and noncompliant drayage trucks, EPA said. The company also hired carriers to transport goods in California without verifying that the vehicles complied with the Truck and Bus Regulation, and dispatched drayage trucks without required record-keeping. As part of the settlement, the company will pay a $117,000 civil penalty and has agreed to use compliant trucks.

— Ruan Transportation Management Systems Inc., of Des Moines, Iowa, operated heavy-duty diesel trucks in California lacking the required diesel particulate filters. Ruan also failed to verify that the carriers it hired to transport goods in California complied with the Truck and Bus Regulation, EPA said. Ruan is the first company cited by EPA for failing to timely meet specified PM emission reductions in transport refrigeration equipment under state requirements. As part of the settlement, the company will pay a $125,000 civil penalty and will use compliant trucks.

— And the Boise Cascade Company, of Boise, Idaho, failed to verify that the carriers it hired to transport goods in California complied with the Truck and Bus Regulation, EPA said. As part of the settlement, the company will pay a $175,000 civil penalty and has agreed to use compliant trucks.

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