Councilman John A. Olszewski Sr. was elected chairman of the Baltimore County Council this year by a unanimous vote Monday night. In accepting the role, Olszewski said he knew he would be facing a year during which he will usher in a new council and county executive. He succeeds chairman Joseph Bartenfelder, who said that "Olszewski has the aptitude, knowledge and experience to do the job." The seven-member panel traditionally chooses its chairman during the first meeting of the new year. Olszewski, a Democrat who represents District 7, the Dundalk and Essex areas, plans to seek a fourth council term this year. He will receive $6,000 in addition to his annual $54,000 salary for the leadership role for what will be his third stint as chairman since he was elected in 1998.