sentence1: (2) By the later of January 1, 2009 or the date on which the unit commences operation, theowner or operator of each affected unit under subpart 2 of part B shall install and operate CEMS, quality assure the data, and keep records and reports in accordance with the regulations issued under paragraph (a)(2) with regard to sulfur dioxide, opacity, and volumetric flow.
sentence2: The owner of each unit should install and operate CEMS to affect sulfur dioxide.