The document presents updates and recommendations on PM2.5 modeling for compliance with National Ambient Air Quality Standards (NAAQS). It discusses recent regulatory changes, case studies, and approaches for evaluating PM2.5 emissions from industrial sources. Additionally, it emphasizes the need for accurate modeling and monitoring to ensure environmental compliance.

1. PM2.5 Modeling for PSD
Presented to Workshop on PM2.5 Measurement and
Modeling for Compliance Demonstrations by All4 Inc.
Dan Dix | ddix@all4inc.com | 610.933.5246 x118
May 7, 2013
www.all4inc.com
Kimberton, PA | 610.933.5246
Columbus, GA | 706.221.7688

2. Agenda
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Review of PM2.5 modeling updates from the last 6 months.
Case study of PM2.5 NAAQS modeling analysis from a pulp and
paper mill.
Findings & recommendations from case study.
General recommendations for PM2.5 modeling.
Your environmental compliance is clearly our business.

3. PM2.5 Modeling Updates
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December 14, 2012 – U.S. EPA announced revised annual average
PM2.5 National Ambient Air Quality Standards (NAAQS) reduced
from 15 g/m3 to 12 g/m3.
December 17, 2012 – U.S. EPA’s Office of Air Quality Planning and
Standards (OAQPS) releases regulatory modeling update to
AERMET and AERMOD (AKA Version 12345).
January 22, 2013 – DC Circuit Court vacated and remanded PM2.5
Significant Monitoring Concentrations (SMCs) and Significant
Impact Levels (SILs).
March 4, 2013 – U.S. EPA OAQPS issues draft PM2.5 modeling
guidance for regulatory applications that addresses secondary
formed PM2.5.
Your environmental compliance is clearly our business.

4. PM2.5 Modeling Updates
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12 g/m3 Annual PM2.5NAAQS leaves very little room when
included background concentrations of PM2.5 from State run
ambient monitors for NAAQS modeling demonstrations.
35 g/m3 24-hour PM2.5NAAQS determined during review to be
adequate.
New Version of AERMOD/AERMET released December 17, 2013.
• New beta options for evaluating low wind speed events.
Your environmental compliance is clearly our business.

5. PM2.5 Modeling Updates
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What does recent DC Court Decision mean for PSD modeling?
PM2.5 Significant Impact Levels (SILs) (0.3 g/m3 & 1.2 g/m3)
Vacated & Remanded.
• Permit Applicants should not rely alone on PM2.5 SILs.
• Need to also demonstrate that an increase below the SILs will
not lead to a NAAQS violation.
PM2.5 Significant Monitoring Concentration (SMC) (4 g/m3)
Vacated.
• Must rely upon representative State ambient monitoring data.
• Much more scrutiny will be placed on whether the monitor is
representative of the site.
Although court decision addressed PM2.5 other pollutants will also
be under same scrutiny for their respective SILs & SMCs.
Your environmental compliance is clearly our business.

6. PM2.5 Modeling Updates
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PSD permits must now address secondary formed PM2.5 emission
from precursors pollutants (i.e., NO2 & SO2) in NAAQS & PSD
Increment air quality modeling demonstrations.
Four (4) tiered approach for addressing secondary formed PM2.5
emissions laid out in guidance document based on which
pollutants are greater than significant emission increase levels.
Still time to comment since the comment period has been
extended 45 days from May 31, 2013 to July 15, 2013.
Your environmental compliance is clearly our business.

7. PM2.5 Case Study
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Pulp & Paper Mill
AERMOD
Fugitive Emissions Included
• Roadways
• Chip Piles
• Chip Drops
Emergency Generators Included
NWS Meteorological Data (w/AERMINUTE)
24-Hour and annual PM2.5 concentrations evaluated
Large property boundary (No onsite receptors included)
Building Downwash Included
Rolling Terrain
Your environmental compliance is clearly our business.

8. PM2.5 Case Study
Emission Unit
Peak 98th Percentile of Modeled 24Hour Concentrations ( g/m3)
Natural Gas Fired Power Boiler
1.63
Recovery Furnace
1.69
Smelt Dissolving Tank
7.98
Lime Kiln
15.93
Slaker
1.16
Combination Boiler
1.70
Chip Drops (Fugitive)
Negligible
Starch Silos
16.90
Chip Piles (Fugitive)
1.92
Paper Machine Dryers
0.29
Pulp Dryers
42.15
Emergency Generators
7.72
Roadways (Fugitive)
8
115.80
Your environmental compliance is clearly our business.

9. PM2.5 Case Study
Emission Unit
Peak Annual Modeled Concentrations
( g/m3)
Natural Gas Fired Power Boiler
0.31
Recovery Furnace
0.31
Smelt Dissolving Tank
1.59
Lime Kiln
2.77
Slaker
0.16
Combination Boiler
0.31
Chip Drops (Fugitive)
Negligible
Starch Silos
Chip Piles (Fugitive)
0.23
Paper Machine Dryers
0.07
Pulp Dryers
6.74
Emergency Generators
0.82
Roadways (Fugitive)
9
2.85
16.90
Your environmental compliance is clearly our business.

10. PM2.5 Case Study
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Facility wide peak 98th percentile modeled 24-Hour and annual
Concentration 129 g/m3 and 20.9 g/m3, respectively.
WI DNR Regional Background Level for rural areas is 25.6 g/m3
for 24-hour PM2.5 and 8.7 g/m3 for annual PM2.5.
24-Hour PM2.5 NAAQS 35 g/m3 & annual PM2.5 NAAQS 12 g/m3.
Not much room for facility contribution.
Your environmental compliance is clearly our business.

11. PM2.5 Case Study
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Peak facility wide concentration being driven by roadway & low
stack height sources (Lime Kiln-90ft/Pulp Dryers-46ft).
Elevated concentrations from emergency generators due to
horizontal release (no vertical dispersion accounted for in
AERMOD from horizontal or rain capped sources).
PM2.5 concentration driven by dispersion characteristics more than
emission rates.
Your environmental compliance is clearly our business.

12. PM2.5 Case Study
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So what’s the facility doing to refine the PM2.5 NAAQS modeling
analysis?
• Conducting surface/bulk dust loading sampling to develop site
specific silt loading for roadway fugitive emission calculations
(currently using default AP-42 silt loading levels).
• Turning emergency generators stacks from horizontal to
vertical.
• Undertaking a meteorological monitoring program to develop a
site specific dataset. Includes collecting data not collected by
NWS (i.e., vertical winds speed/solar radiation) to enable
AERMOD to more accurately predict PM2.5 concentrations.
Your environmental compliance is clearly our business.

13. PM2.5 Modeling Recommendations
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What other things can facilities do to demonstrate compliance
with the PM2.5 NAAQS?
• Avoid tripping PSD PM2.5 significant emission increase (i.e., 10
TPY) through over-control or emission reductions.
• PAL
• Evaluate your PM2.5 emission limits. Determine if a lower limit
can be taken. NAAQS modeling demonstrations based on
potential-to-emit (PTE) emission rates.
• PM2.5 ambient monitoring could be beneficial because
representative site-specific background levels can be developed
and not double-counted.
• Variability in how fugitive (especially roadway) emissions are
characterized in AERMOD from state to state. Refer the “Haul
Road Workgroup Final Report to EPA-OAQPS” for different
Your environmental compliance is clearly our business.

14. Final Comments on PM2.5 Modeling
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Even though the results aren’t always favorable it’s always good to
know where your facility stands with regard to all the NAAQS to
help in long range planning at your facility.
Allows your facility to identify issues that aren’t always obvious
(e.g., smaller fugitive sources).
Allows your facility to plan for activities that could substantially
affect timing of projects (i.e., ambient pollutant or meteorological
monitoring require a year of data).
Consider input from counsel before undertaking air quality
modeling/monitoring evaluations.
Your environmental compliance is clearly our business.

15. PM2.5 Modeling for PSD
Dan Dix| ddix@all4inc.com | 610.933.52.46 x118
www.all4inc.com
Kimberton, PA | 610.933.5246
Columbus, GA | 706.221.7688