This change to the proposed rule clarifies specific engine requirements that will allow sources to better understand the intent of the proposed engine requirements. The changes do not substantially change the proposed requirements. (EDITOR'S NOTE: The original proposed new rule upon which this change in proposed rule (CPR) was based was published in the October 1, 2017, issue of the Utah State Bulletin, on page 81. Underlining in the rule below indicates text that has been added since the publication of the proposed new rule mentioned above; strike-out indicates text that has been deleted. You must view the CPR and the proposed new rule together to understand all of the changes that will be enforceable should the agency make this rule effective.)