E.P.A. to Tighten Tailpipe Rules for the Biggest Polluters on the Road

But in order to put the United States on a path toward a transition to all-electric trucks, the forthcoming truck rules would have to be far more stringent, experts said. Transportation is the largest single source of greenhouse gases generated by the United States, representing 29 percent of the nation’s total emissions.

“It’s great to see that the rule is driving 90 percent reduction in air pollution in heavy-duty vehicles and at the same time opening the door to reducing greenhouse gas pollution,” said Drew Kodjak, executive director of the International Council on Clean Transportation, a research organization. “But we’ve got this thing called climate change and we’ve really got to start driving electrification in the heavy-duty truck sector. My big concern is that the proposal as it is written will not do that.”

Advocates for warehouse workers, many of whom are exposed to pollution from truck exhaust, said they would like regulations that replace diesel-fueled trucks with electric or zero-emissions vehicles.

“Cutting emissions anywhere is good,” said Yana Kalmyka, an organizer with Warehouse Workers for Justice. “But if you’re thinking about a community that has tens of thousands of trucks a day passing through it, electrification is the only just solution. The rule is not addressing other industrial truck pollutants such as soot, and we know that Black and brown communities are facing cumulative burdens from these pollutants.”

“Warehouse workers are breathing in all this air — this is a workplace issue and an environmental racism issue,” she added.

The E.P.A. has said it intends to create another set of greenhouse gas rules for trucks, beginning as soon as model year 2030, that will be “significantly stronger” than the current standards, and designed to speed the transition to all-electric trucks.

“Waiting for another few years to do the next set of greenhouse gas standards for trucks is wrong. We just don’t have time,” said Margo Oge, an expert on electric vehicles who headed the E.P.A.’s Office of Transportation and Air Quality from 1994 to 2012. “My hope is that they will use this time to strengthen the standard now.”

The rule announced Monday will be open for public comment for 46 days, and the E.P.A. is expected to finalize it by the end of 2022.