U.S. Environmental Protection Agency Administrator Lisa Jackson announced in a statement today that she is leaving the agency after President Barack Obama’s 2013 State of the Union address, ending her four-year tenure.

“As the president said earlier this year when he addressed EPA’s employees, ‘You help make sure the air we breathe, the water we drink, the food we eat are safe,”’ Jackson said. “‘You help protect the environment not just for our children but their children. And you keep us moving toward energy independence. …We have made historic progress on all these fronts.’”

During Jackson’s tenure, the agency created new emissions standards for vehicles and, in 2011, established the first U.S. standards for mercury and other pollutants in coal- and oil-fired power plants. Earlier this month, the agency issued a rule intended to strengthen clean air protections against fine particulate matter, or soot.

“I will leave the EPA confident the ship is sailing in the right direction,” Jackson said.