WASHINGTON (Reuters) - President Barack Obama will announce on Monday his intent to nominate air quality expert Gina McCarthy to lead the Environmental Protection Agency and nuclear physicist Ernest Moniz to head the Department of Energy, a White House official said. The long-awaited announcement will come as Obama fills out his second term cabinet. At 10:15 a.m. EST (1515 GMT) the president also plans to announce his choice of Sylvia Mathews Burwell, head of the Walmart Foundation, to become director of the White House budget office. The nominations require confirmation by the Senate. ...