1. A&WMA Southern Section Annual Meeting Biloxi, MS September 12, 2012 Carla Brown, P.E. MS Dept. of Environmental Quality 601-961-5235 cbrown@deq.ms.gov

2. PollutantAveraging Period CurrentPreviousDate of Final Rule* PM-10Annual---50 ug/m 3 July 1, 1987 24-hr150 ug/m 3 July 1, 1987 PM-2.5---July 18, 1997 65 ug/m 3 October 17, 2006 NO 2 Annual53 ppb April 30, 1971 ---February 9, 2010 SO 2 Annual---30 ppbApril 30, 1971 24-hr---140 ppbApril 30, 1971 3-hr500 ppb April 30, 1971 ---August 23, 2010 *Final Rule that established the most current standard, excluding those rules revoking previous standards.

4.  The background concentrations must be added to modeled concentrations to determine compliance with NAAQS.  MS Ambient Air Data:  Annual PM-2.5 (2009-2011): 9.5-11.8 ug/m 3  24-hr PM-2.5 (2009-2011): 18-23 ug/m 3  1-hr NO 2 (2011, only one site): 32 ppb  1-hr SO 2 (2011, only one site): 29 ppb  Problem – very limited monitor data and background can result in double-counting emissions from stationary sources that are also being included as nearby sources in the model.

5.  Roxul, a proposed mineral wool facility, was MDEQ’s first PSD processed under these significant NAAQS changes.  Proposed emissions from Roxul:  PM-10/PM-2.5 = 562/510 TPY  SO 2 = 1035 TPY  NO x = 403 TPY  Modeling initially predicted…  35 violations of 1-hr SO 2  One violation of 24-hr SO 2  61,446 violations of 1-hr NO 2

7.  Significant NOx contributions from natural gas compressor station engines:  Trunkline Compressor Station – 5,500 TPY PTE  ANR Sardis Compressor Station – 2,900 TPY PTE  Tennessee Gas, New Albany Compressor Station – 1,900 TPY PTE  For those receptors showing violations after applying the 0.8 NO 2 :NOx default ratio (still 34,475 instances), the highest contribution from Roxul was determined to be less than 30% of SIL.  Per 40 CFR 51.165(b), if less than the SIL, source/project does not cause or contribute to the violation.

8.  For PSD projects, months added to application preparation.  MDEQ has suggested submitting applications piece-meal so as not to delay the permitting process.  Time and $$$ due to refining modeling runs to meet the standards or to show no culpability should there be modeled violations.

9.  How does the State address modeled violations due to existing sources?  Based on decisions from the Sixth Circuit Court (1978-80), modeled violations are considered just as valid as measured violations.  Require those significant sources to perform air quality analysis?  Include limitations in SIP or enforceable operating permit?  Install monitor(s) in area of highest predicted impacts (at whose expense?)

10.  Based upon current modeling protocols, modeled concentrations will generally be much greater than monitored.  EPA acknowledged this in March 1, 2011, guidance memo regarding the 1-hr NO 2 standard.  Yet EPA had planned to require state-wide modeling to demonstrate compliance with the 1-hr SO 2 standard (generally due to lack of monitors for SO 2 ).