RALEIGH — North Carolina environmental officials say the state’s air has become clean enough that only 22 of its 100 counties still have to conduct vehicle emissions testing.

Legislation signed by Gov. Roy Cooper earlier this month slashed the number of counties required to conduct vehicle emissions testing, but some environmental advocates argue that doing so will result in air pollution going back up.

The move will allow roughly 2 million North Carolinians to discontinue testing the emissions from their cars, saving them $16.40 per inspection. All drivers still have to pay for the statewide annual safety inspection of $13.60 per vehicle.

Terry Lansdell, program director of Clean Air Carolina, a nonprofit advocacy organization that works to protect air quality in North Carolina, said the money saved isn’t worth the future damage that may be done to the quality of the air.

“We have vehicle inspections to ensure vehicles are as clean as possible,” Lansdell said. “If we stop inspecting vehicles, our air quality will continue to degrade because we won’t have the regulations to make sure we have clean vehicles on the road.”

Prior to the law, 48 of North Carolina’s 100 counties required emissions testing. The new law, which knocks 26 counties off that list, takes effect Oct. 1, 2017, or 60 days after EPA approval, whichever comes later.

Largely urban centers, such as Mecklenburg, Wake, Guilford and Forsyth, as well as some of their surrounding suburban counties, will still require emissions inspections.

“Air knows no boundaries,” Lansdell said. “The air we breathe may have been in South Carolina yesterday or Atlanta two days ago … we have to be concerned with every county in North Carolina.”

The emissions’ testing requirements were implemented as part of the state’s plan to reduce air pollution under the federal Clean Air Act.

Jamie Kritzer, with the North Carolina Department of Environmental Quality, said the state’s air quality has improved significantly since emissions testing requirements were expanded for motor vehicles in the early 2000s.

“We studied the air quality improvements for this report and concluded that we could eliminate emissions testing for motor vehicles in numerous counties without harming air quality or violating federal standards,” Kritzer said.

The provision, which is part of a larger regulatory reform statue, also contains language that exempts some older vehicles and those with low mileage from emissions testing.