326 IAC 6.8-11-3 Exceedances

Sec. 3. (a) If the department's review of ambient monitoring data from Lake County by the department reveals an exceedance of the twenty-four (24) hour ambient air quality standard for PM10, the department shall undertake a culpability study to determine the source or sources causing or contributing to the exceedance. An exceedance means a daily value that is above the level of the twenty-four (24) hour standard after rounding to the nearest ten (10) micrograms per cubic meter. In determining whether a source has caused or contributed to an exceedance of the twenty-four (24) hour ambient air quality standard for PM10, the department shall take whatever steps as are necessary to determine which source or sources are culpable for the exceedance, including, but not limited to, the following: (1) Evaluating whether the exceedance should be classified as an exceptional event under "Guideline on the Identification and Use of Air Quality Data Affected by Exceptional Events, EPA 450/4-88-007*". (2) Reviewing operating records of the source or sources identified under subdivisions (3) and (4) to determine whether any source or sources so identified experienced a malfunction or breakdown or violated any term or condition of its operating permit or applicable rule that contributed to the exceedance. (3) Evaluating the monitoring equipment filter evidencing the exceedance to determine the type of source or sources that contributed to the exceedance. (4) Evaluating meteorological data and conducting dispersion analyses under the "Guideline on Air Quality Models, Appendix W of 40 CFR Part 51", EPA 450/2-78-027R* to determine which source or sources caused or contributed to the exceedance, as needed. (b) If the department determines that an exceedance can be classified as an exceptional event, the department shall make no request upon any source for voluntary controls. (c) If the department determines that an exceedance would not have occurred except for a malfunction or violation of: (1) any term or condition of a source's operating permit; or (2) a rule adopted by the board; the department shall pursue enforcement or other appropriate action and shall make no request upon any source under the provisions of this article. (d) Following any exceedance of the twenty-four (24) hour ambient air quality standard for PM10 and upon completion of the culpability study described in section 3 of this rule, the department shall notify the source or sources that the department has identified as likely to have caused or contributed to the exceedance and request that the source or sources voluntarily implement controls that will reduce the source's PM10 emissions by fifteen percent (15%). The department's notification shall include the results of the culpability study. The department shall request a reduction less than fifteen percent (15%) if the culpability study demonstrates that a lesser percent reduction would ensure that no further exceedance will occur under the same circumstances. If the department determines that a single facility at a source caused or significantly contributed to the exceedance, then the department will request that voluntary reductions be implemented only at the specific facility. *These documents are incorporated by reference and are available from U.S. EPA, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711 or are available for review and copying at the Department of Environmental Management, Office of Air Quality, Indiana Government Center-North, Tenth Floor, 100 North Senate Avenue, Indianapolis, Indiana 46204.