Section 203.208  Net Emission Determination

A net emissions increase is the amount by which the sum of any increase in actual emissions from a particular physical change or change in method of operation at a source, and any other increases and decreases in actual emissions at the source that are contemporaneous with the particular change and are otherwise creditable, exceeds zero.  The following steps determine whether the increase or decrease in emissions is available.

a)         Except for increases or decreases in volatile organic material and nitrogen oxide emissions in serious and severe ozone nonattainment areas which are addressed in Section 203.209(b), an increase or decrease in actual emissions is contemporaneous only if it occurs between the date that an increase from a particular change occurs and the date five years before a timely and complete application is submitted for the particular change.  It must also occur after either April 24, 1979, or the date the area is designated by the United States Environmental Protection Agency as a nonattainment area for the pollutant, whichever is more recent.

b)         An increase or decrease in actual emissions is creditable:

1)         Only if there is not in effect for the source at the time the particular change occurs a permit which relied on the same increase or decrease in actual emissions; and

2)         Only to the extent the new and old levels differ.

c)         A decrease in actual emissions is creditable to the extent that:

1)         It is federally enforceable at and after the time that actual construction on the particular change begins;

2)         It has approximately the same qualitative significance for public health and welfare as that attributed to the increase from the particular change;

3)         The old level of actual emissions or the old level of allowable emissions, whichever is lower, exceeds the new level of actual emissions; and

4)         It is demonstrated by the Agency not to have been previously relied on in issuing any permit pursuant to this Part or 35 Ill. Adm. Code 201.142 or 201.143 or for demonstrating attainment or reasonable further progress in the nonattainment area which the particular change will impact.

d)         An increase that results from a physical change at a source occurs when the emissions unit on which construction occurred becomes operational and begins to emit a particular pollutant.  Any replacement unit that requires shakedown becomes operational only after a shakedown period not to exceed 180 days.

(Source:  Amended at 17 Ill. Reg. 6973, effective April 30, 1993)