| Philadelphia | Atlanta | Houston | Washington DC SO 2 Data Requirements Rule – A Proactive Compliance Approach Mark Wenclawiak, CCM | | August 19, 2015 Presented to A&WMA Southern Section Annual Meeting

2 Your environmental compliance is clearly our business. Agenda  SO 2 Data Requirements Rule (DRR) Overview  Process to Characterize Ambient Air Quality Air Dispersion Modeling Ambient Air Monitoring Technical Assistance Documents (TADs)  Implications of Upcoming Modeling and Regulatory Policies Proposed Appendix W changes  Case Study  Questions and Open Discussions

SO 2 DRR Overview: Who and When?

4 Your environmental compliance is clearly our business.  Final rule issued August 11, 2015 (40 CFR Part 51, Subpart BB)  Applies to facilities that: 1.Emitted 2,000 tons per year (tpy) of actual emissions during most recent calendar year 2.Not located in a nonattainment area 3.Discretion to include additional sources  Affected facilities will model or conduct monitoring to characterize ambient air Who is Subject?

5 Your environmental compliance is clearly our business.  Agencies notify U.S. EPA regional offices on list of SO 2 sources by January 15, 2016  Agencies specify whether each source will use monitoring or modeling by July 1, 2016  Air dispersion modeling protocols due by July 1, 2016; analysis due January 13, 2017  Ambient monitoring plans are due by July 1, 2016; monitors operational by January 1, 2017  NOW is the time to react! When is This Happening?

SO 2 DRR How: Air Dispersion Modeling

7 Your environmental compliance is clearly our business. SO 2 Modeling TAD  Representative meteorological data for most recent 3 years  Receptors placed only where an ambient monitor could actually be located Comparison to Regulatory Modeling Regulatory Modeling  Representative meteorological data for 5 years  Receptors placed anywhere deemed as ambient air Rule of Thumb: Maximum ground-level concentration at a distance approximately 10 times stack height in flat terrain

8 Your environmental compliance is clearly our business. Traditional PSD Receptor Grid

9 Your environmental compliance is clearly our business. DRR Receptor Grid

10 Your environmental compliance is clearly our business. SO 2 Modeling TAD  Actual emission rates from past 3 years  Characteristics can be varied on an hourly basis  Use of actual (i.e., current) stack heights only Comparison to Regulatory Modeling Regulatory Modeling  Potential to emit  Can vary emissions rates – but typically not varied hourly (and could result in permit limits)  Use of GEP, not current stack height

11 Your environmental compliance is clearly our business.  Varying emissions data is intensive and time consuming  Intermittent sources (i.e., emergency generators) only evaluated if operated enough to contribute to 99 th percentile  Actual emissions can be an improvement over allowable emissions  June – December 2013: 246 monitors across the U.S. did not collect 1-minute meteorological data due to a lack of funding. Considerations for DRR Modeled Emission Rates

12 Your environmental compliance is clearly our business.  Pros: Less costly Can be less time consuming  Cons: Determining actual emissions can be challenging Ongoing compliance demonstrations built into the rule Facility may not be able to demonstrate compliance with the NAAQS Pros and Cons of Modeling

Ambient Monitoring for SO 2 DRR

14 Your environmental compliance is clearly our business.  A facility may use a combination of the following: 1.Perform dispersion modeling to identify location(s) of maximum SO 2 concentrations Normalized emissions rate Rank each receptor for concentration and number of days when that receptor is the highest for the day for all receptors 2.Install temporary ambient monitors at several locations to identify the location(s) of maximum SO 2 concentrations Steps to Determining Ambient Monitoring Locations

15 Your environmental compliance is clearly our business.  Pros: More realistic view of ambient SO 2 emissions Future compliance requirements may diminish  Cons: Capital costs (installation and upkeep) Time consuming Noncompliance could mean ongoing monitoring obligations and more stringent future air permitting obligations Pros and Cons of Monitoring

Implications of Upcoming Policies

17 Your environmental compliance is clearly our business.  Constant maximum emission rate overly conservative Compounded by combining with observed monitoring concentrations as background  Higher concentrations during periods of SSM May 22, 2015 SIP call rule  Emission Variability Processor (EMVAP) Incorporate varying emissions with Monte Carlo statistical technique; 50 th percentile monitored concentration as background  Appendix W proposed changes Importance of Variable Emissions

18 Your environmental compliance is clearly our business.  What 1-hour background concentration do you add to modeled concentration? Highest hourly modeled concentration paired with highest hourly monitored concentration 3-year average of 99 th percentile of maximum daily (p=0.0001; 1 exceedance every 10,000 days!) EMVAP and 50 th percentile background concentration  Probability of exceedance 0.005; equivalent to 99.5 th percentile, compared to 99 th percentile form of the standard Selection of Ambient Air

Case Study

20 Your environmental compliance is clearly our business.  Chemical plant in the southeast  Modeling not previously conducted  CEMS data for largest SO 2 emitting source, limited emissions data for other sources  Relatively flat terrain in rural setting  Next door neighbor is utility power plant Background

21 Your environmental compliance is clearly our business.  2 tasks Modeling-based evaluation  Cumulative concentration of plant’s sources relative to the NAAQS Monitoring-based evaluation  Rank normalized modeling results Project

22 Your environmental compliance is clearly our business.  Recommendations for mitigating elevated concentrations Balance with future expansion plans with facility, particularly PSD projects  If not possible, recommend ambient monitoring locations  Outcome Modeling shows concentrations below NAAQS* Expanded scope to include other criteria pollutants and PTE rates in anticipation of future modeling needs such as a PSD project Compliance Approach

| Philadelphia | Atlanta | Houston | Washington DC Questions & Open Discussions Mark Wenclawiak, CCM | | August 19, 2015