The U.S. Environmental Protection Agency implemented new, more stringent limits on smog-producing emissions from heavy-duty trucks Tuesday.
It is the first time tailpipe standards have been tightened for the heaviest class of vehicles -- such as tractor-trailers or garbage trucks -- in more than 20 years and are more than 80% stronger than current standards.
The new standards, which will go into effect for model year 2027 vehicles, are expected to reduce nitrogen oxide output by 48% by 2045. They are also expected to reduce carbon monoxide by 18%, particulate matter by 8% and volatile organic compounds by 23% in the same time frame.
Heavy-duty vehicles are one of the largest contributors of transportation-related nitrogen oxide emissions in the U.S. Without the new rules, the EPA estimated the vehicles would produce up to 90% of on-road nitrogen oxide emissions by 2045.
Nitrogen oxide is a pollutant that can cause heart disease, asthma and other lung diseases. People who live close to highways are most affected by nitrogen oxide pollution, including an estimated 72 million people who are disproportionately low-income or people of color, said EPA administrator Michael Regan.
"This rule will result in widespread air quality improvements across the U.S., especially in communities near major roadways that are overburdened by air pollution," Regan said.
However, the new rule doesn't go as far as one the agency proposed in March that would have reduced nitrogen oxide emissions by up to 60% by 2045, frustrating some environmental groups.
"These standards fall short, and the agency missed a critical opportunity to slash soot and smog, and accelerate the shift to the cleanest vehicles," said Britt Carmon, federal clean vehicles advocate at the Natural Resources Defense Council, urging the EPA to put the next round of standards in place as quickly as possible.
But the standards were welcomed by other groups, including Moms Clean Air Force, the Environmental Defense Fund and the American Lung Association.
"The plan announced today includes long-awaited final emissions standards for nitrogen oxides pollution that will significantly reduce this deadly pollutant and ultimately save thousands of lives and prevent numerous serious illnesses every year," said Vickie Patton, general counsel for the Environmental Defense Fund.
Regan said the smog- and soot-forming pollutant rules are the first step in the agency's Clean Trucks Plan, which intends to propose new carbon emissions rules in March 2023.
Transportation is the largest source of greenhouse gas emissions in the U.S., accounting for 29% of all emissions. Light duty vehicles make up 58% of transportation-related greenhouse gas emissions, while medium- and heavy-duty trucks make up 23%.