Rule 410  Calculation of Emissions.

     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.