SAN FRANCISCO — San Joaquin Valley air regulators voted Monday to approve a plan asking the government for an 11-year extension to bring the region’s smog-laden air in line with federal standards.

The San Joaquin Valley Air Pollution Control District proposed extending the clean-up until 2023 to avoid federal sanctions that could cut off more than $2 billion in federal transportation funds to the region.

The district’s governing board approved the plan in a 9-2 vote Monday evening, after hearing eight hours of testimony from dozens of air quality experts, business leaders and clean air activists.

“There is no silver bullet out there,” said Seyed Sadredin, the air district’s executive director. “If money were no object, there is no other plan that could get us to clean air faster.”

The California Air Resources Board must approve the proposal before forwarding it to the U.S. Environmental Protection Agency by June 15.

The valley, stretching 240 miles from Stockton to Bakersfield, is one of the dirtiest air basins in the nation for emissions that create ozone, the main ingredient of smog.