A.     The maximum design capacity of a new facility or modification shall be used to determine the emissions from the new facility or modification unless the applicant, as a condition to receiving Authorities to Construct and Permits to Operate for such new facility or modification, agrees to a limitation on the operation of the new facility or modification. Such limitation shall be used to establish the maximum emissions from the new facility or modification and shall be attached as a condition to the Permits to Operate. Allowable emissions shall be calculated on the basis of the emissions limitation contained in these Rules and Regulations as of the date the Air Pollution Control Officer deems the application for Authority to Construct complete.

B.     The maximum emissions for an existing facility shall be based on the actual operating conditions averaged over the two year period preceding the date of application, or such other averaging period as determined by the Air Pollution Control Officer if the source did not operate, or operated irregularly, during the preceding two year period. If violation of laws, rules, regulations, permit conditions or orders of the District, the Air Resources Board or the Environmental Protection Agency occurred during the period used to determine the actual operating conditions, then adjustments to the operating conditions shall be made to determine the emissions the existing facility would have caused without such violations.

C.     When computing the net increases in emissions for modifications, the Air Pollution Control Officer shall take into account the cumulative net emissions changes which are represented by Authorities to Construct associated with the existing facility, and issued after January 1, 1981, excluding any emissions reductions required to comply with federal, state, or District laws, rules or regulations.