Diesel’s Free Ride Is Ending

Today the state Air Resources Board could begin to make some real headway against diesel emissions, a major remaining cause of air pollution. The agency is poised to adopt rules that may work a hardship on many, particularly diesel-dependent truckers, but in the long run are necessary to clear the air.

Two years ago, after much study, the air board declared the microscopic particles spewed from the exhaust pipes of diesel engines to be a toxic air contaminant, one capable of causing cancer. The ARB’s 1998 declaration obligated the agency to craft a plan to reduce the health risk. That plan, before the board today, requires the use of low-sulfur diesel fuel statewide by 2006. The board is also slated to mandate that all diesel engines, whether new or already in service, include particulate traps to reduce emissions, devices analogous to catalytic converters. If adopted, the rules would apply to both cars and trucks and, according to agency estimates, reduce emissions from California’s 1.25 million diesel engines by up to 90%.

Many within the industry, including the California Trucking Assn., acknowledge the need to clean up diesel engines but would have preferred incentives for compliance over blanket regulations.

The pace of change is quickening. In June the South Coast Air Quality Management District adopted sweeping new rules that will force buses and trash trucks to use cleaner-burning alternative fuels. Later this year, the U.S. Environmental Protection Agency will consider new nationwide standards for diesel trucks. The ARB’s expected action this week should pave the way for that landmark federal step.