Authority: IC 13-14-8; IC 13-17-3-4

Affected: IC 13-12

Sec. 6. (a) Any demonstration under section 5 of this rule shall demonstrate that increased emissions caused by the proposed major stationary source or major modification will not exceed eighty percent (80%) of the available maximum allowable increases (MAI) over the baseline concentrations for sulfur dioxide, PM, and nitrogen dioxide indicated in subsection (b)(1). Available maximum allowable increases are determined by adjusting the MAI to include impacts from actual emissions:

1. (1) from any major stationary source or major modification on which construction commenced after the major source baseline date; and
2. (2) increases and decreases at any source occurring after the minor source baseline date.

On a case-by-case basis, a source may petition the commissioner to use in excess of this eighty percent (80%). The commissioner may authorize such use provided the source adequately demonstrates the need for the same.

(b) Increment consumption shall be in accordance with the following:

1. (1) The following allowable increments reflect the PSD increments for a Class II area (as defined in the CAA). Indiana has no Class I or Class III areas; however, should some areas of the state be classified as Class I or III, the PSD increments pursuant to 40 CFR Part 52.21* to which it must be adhered. New permits issued after January 1, 1995, shall use PM10 as the indicator for PM. The allowable increments are as follows:

   Maximum Allowable Increments
   Pollutants				Allowable Increments (Micrograms per Cubic Meter, μg/m3 Limits)
   	(A) PM:
   		(PM10):
   			Annual arithmetic mean	17
   			24-hour maximum	30
   		(PM2.5):
   			Annual arithmetic mean	4
   			24-hour maximum	9
   	(B) Sulfur dioxide:
   		Annual arithmetic mean		20
   		24- hour maximum		91
   		3- hour maximum		512
   	(C) Nitrogen dioxide:
   		Annual arithmetic mean		25

2. (2) For any period other than the annual period, the applicable maximum allowable increase may be exceeded during one (1) such period per year at any one (1) location.
3. (3) When an applicant proposes to construct a major stationary source or major modification in an area designated as attainment or unclassified and the increments listed in subdivision (1) have been consumed, the increased emissions from the source or modification may be permitted to be offset by reducing emissions in the affected areas by an equal amount of the pollutant for which the area was designated as attainment or unclassified.

4. (4) The following pollutant concentrations shall be excluded when determining compliance with a maximum allowable increase:

   1. (A) Concentrations attributable to the increase in emissions from sources that have converted from the use of petroleum products or natural gas, or both, by reason of an order in effect under Sections 2(a) and 2(b) of the Energy Supply and Environmental Coordination Act of 1974 over the emissions from the sources before the effective date of the order.
   2. (B) Concentrations attributable to the increase in emissions from sources that have converted from using natural gas by reason of a natural gas curtailment plan in effect pursuant to the Federal Power Act over the emissions from the sources before the effective date of the plan.
   3. (C) Concentrations of PM attributable to the increase in emissions from construction or other temporary emission-related activities of new or modified sources.

   4. (D) Concentrations attributable to the temporary increase in emissions of sulfur dioxide, PM, or nitrogen oxides from stationary sources that are affected by state implementation plan revisions approved by U.S. EPA are excluded provided the following criteria is met:

      1. (i) The exclusion shall not exceed two (2) years in duration unless a longer time is approved by the commissioner and the U.S. EPA.
      2. (ii) The exclusion is not renewable.
      3. (iii) The exclusion shall allow no emissions increase that would impact a Class I area or an area where an applicable increment is known to be violated, or cause or contribute to a violation of an ambient air quality standard as designated in 326 IAC 1-3.
      4. (iv) An emission limitation shall be in effect at the end of the time period specified in accordance with item (i) that will ensure that the emissions levels will not exceed those levels occurring from the source before the exclusion was granted.
5. (5) No exclusion of such a concentration under subdivision (4)(A) and (4)(B) shall apply more than five (5) years after the date the exclusion is granted under this rule. If both such order and plan are applicable, no such exclusion shall apply more than five (5) years after the latter of the effective dates.

*This document is incorporated by reference. Copies may be obtained from the Government Printing Office, 732 North Capitol Street NW, Washington, D.C. 20401 or are available for review and copying at the Indiana Department of Environmental Management, Office of Air Quality, Indiana Government Center North, Tenth Floor, 100 North Senate Avenue, Indianapolis, Indiana 46204.

(Air Pollution Control Division; 326 IAC 2-2-6; filed Mar 10, 1988, 1:20 p.m.: 11 IR 2398; filed Jun 14, 1989, 5:00 p.m.: 12 IR 2025; filed Oct 3, 1995, 3:00 p.m.: 19 IR 185; filed Mar 23, 2001, 3:03 p.m.: 24 IR 2422; filed Dec 20, 2001, 4:30 p.m.: 25 IR 1567; filed Mar 9, 2004, 3:45 p.m.: 27 IR 2222; filed Aug 10, 2004, 3:35 p.m.: 27 IR 3903; filed Jun 11, 2012, 3:15 p.m.: 20120711-IR-326110251FRA; readopted filed Oct 18, 2024, 2:09 p.m.: 20241113-IR-326230809RFA)