modeling guidance and examples for commonly asked questions (part ii)
DESCRIPTION
Modeling Guidance and Examples for Commonly Asked Questions (Part II). Reece Parker and Justin Cherry, P.E. Air Permits Division Texas Commission on Environmental Quality Advanced Air Permitting Seminar 2014. What Is Ozone?. Stratospheric Ozone. Good. sunlight. O + O. O 2. O + O 2. O 3. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/1.jpg)
Modeling Guidance and Examples for Commonly Asked Questions
(Part II)
Reece Parker and Justin Cherry, P.E.Air Permits Division
Texas Commission on Environmental QualityAdvanced Air Permitting Seminar 2014
![Page 2: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/2.jpg)
What Is Ozone?
Good• Stratospheric Ozone
O2sunlight O + O
O + O2 O3
Bad• Ground-level Ozonesunlight
VOC + NOx O3 (and other products)
![Page 3: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/3.jpg)
Ground-level Ozone Is:
• The main component of smog.
• Not emitted directly in the air but forms when emissions of precursors, including NOx and VOCs “cook” in the sun:
– Emissions from industrial facilities, electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are the major man-made sources of NOx
and VOCs.
• Mainly a summertime pollutant because sunlight and hot weather accelerate its formation.
Ozone levels can be high in both urban and rural areas, often due to transport of emissions of ozone precursors.
![Page 4: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/4.jpg)
2008 Ground-level Ozone Standards
• Primary and secondary 8-hr ozone standards:
75 ppb*
*based on the 3-yr average of the annual fourth highest daily maximum
8-hr ozone concentration
![Page 5: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/5.jpg)
Type of Application
Non-Attainment Review?
PSD Increment:• SO2
• PM10
Property Line:• SO2
• H2S
Health Effects:• Benzene
PSD Review?• SO2
• PM10
Property Line:• SO2
• H2S
Health Effects:• Benzene
![Page 6: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/6.jpg)
Non-attainment vs. Attainment
![Page 7: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/7.jpg)
Non-attainment Review
• Provide full documentation and details to reduce review time and mitigate potential issues
• Protocol document should resemble AQA without modeling results
Final product? Not exactly...
Ozone Impact Analysis not required.
Emissions offsets to improve air quality
![Page 8: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/8.jpg)
PSD Review
• If project is major by itself or a major modification, a protocol is required:– For all criteria pollutants with an increase– Must be sent to EPA Region 6 for review– May include protocol for state-only requirements
• Items to include in protocol are listed in protocol checklist
• Consider all the items in the protocol check list before you start on your protocol document
An ozone impacts analysis is required when a project emits:
100 tpy or more of VOCs
and/or
100 tpy or more of NOx
![Page 9: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/9.jpg)
Ozone Impacts Analysis
• Obtain representative monitoring data
• Determine whether the project area is VOC-limited or NOx-limited*
• Quantitative demonstration
• Qualitative demonstration
*Based on TCEQ’s own SIP photochemical modeling, most of the urban and rural areas of Texas are NOx-limited.
![Page 10: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/10.jpg)
Quantitative Demonstration
• Photochemical modeling: Comprehensive Air Quality Model with extensions
(CAMx)
• Screening approach using AERMOD: Demonstration based on comments by EPA for NOx-
limited areas
![Page 11: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/11.jpg)
Quantitative Demonstration (Cont.)
• Screening approach using AERMOD:
Conservative analysis based on NOx modeling:
– Determine if the project is NOx-limited or VOC-limited
– If VOC-limited, determine GLCmax at a distance of 10-11 km
– Assume 90% conversion of NOx to NO2
– Assume 3 ozone molecules per NOx molecule
– Add result to the representative monitored concentration
– Compare to the standard
![Page 12: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/12.jpg)
Example of Quantitative Demonstration
Determine a representative monitor concentration
Project Location
![Page 13: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/13.jpg)
Example (Cont.)
Determine a representative monitor concentration
Monitor Location
3-yr avg of 4th highest daily maximum 8-hr conc.
69 ppb
![Page 14: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/14.jpg)
Example (Cont.)
Determine GLCmax 10-11 km from project sources
![Page 15: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/15.jpg)
Example (Cont.)
Model Output
Converting model result to ppb:
2.96 µg/m3 x (100 ppb)/(188 µg/m3) = 1.57 ppb
![Page 16: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/16.jpg)
Example (Cont.)
• Assume 90% conversion of NOX to NO2:
1.57 ppb x 0.9 = 1.413 ppb
• Assume 3 molecules ozone per molecule NOX:
3 x 1.413 ppb = 4.24 ppb
• Add result to monitored concentration:
69 ppb + 4.24 ppb = 73.24 ppb
• Compare to standard:
73.24 ppb < 75 ppb
![Page 17: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/17.jpg)
Qualitative Demonstration
• Assessment of current air quality:– Ozone trends
– NOX trends
– VOC trends
• Analysis of the project’s potential ozone impact – Selection of Existing Photochemical Modeling Analyses:– Modeling simulation (Did photochemical modeling follow EPA
guidance?)
– Source characterization
– Meteorological parameters and regional transport
![Page 18: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/18.jpg)
Example Qualitative DemonstrationOzone Trends BPA Area
BPA Area Ozone Design Values for all Monitoring Sites (1992-2013)0.105
0.100
0.095
0.090
0.085
0.080
0.075
0.070
0.065
0.060
Site ID: 482450009Site ID: 482450101Site ID: 4824510351997 8-hr Ozone NAAQS
2008 NAAQS Threshold
2008 8-hr Ozone NAAQS 1997 NAAQS Threshold
Site ID: 482450011Site ID: 482450102Site ID: 483611001
Site ID: 482450022Site ID: 482450628Site ID: 483611100
8-hr
Ozo
ne D
esig
n Va
lue
(ppm
)
![Page 19: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/19.jpg)
Example (Cont.)
NOx Trends (BPA Area)
Summary of NOx Emissions Data in BPA Area (tons per day)
0
50
100
150
200
250
NO
x Em
issi
ons
(ton
s pe
r day
)
Nonroad
NonroadNonroad
Onroad
Area
PointPoint Point
Point
AreaArea
Area
OnroadOnroad
Onroad Nonroad
2005 NEI 2008 NEI 2011 NEI
![Page 20: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/20.jpg)
Example (Cont.)NOx Trends (BPA Area)
Maximum BPA Area Annual Average NOX Concentration (1998-2013)
14.0
16.0
Annu
al N
Ox C
once
ntra
tion
(ppb
)
12.0
10.0
8.0
6.0
4.0
2.0
0.0
![Page 21: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/21.jpg)
Example (Cont.)VOC Trends (BPA Area)
Summary of VOC Point and Area Emissions Data in BPA Area (tons per day)
![Page 22: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/22.jpg)
Example (Cont.)VOC Trends (BPA Area)
Annual Average Level of Ethylene Measured in the BPA Area (1997-2013)
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Annu
al A
vera
ge M
easu
rem
ents
(ppb
)
Ethylene Emissions
Range of Measured Annual Averages
Median of Measured Annual Averages
Year
![Page 23: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/23.jpg)
Example (Cont.)VOC Trends (BPA Area)
Annual Average Level of Propylene Measured in the BPA Area (1996-2013)An
nual
Ave
rage
Mea
sure
men
ts (p
pb)
3.0
1.0
10.0
8.0
6.0
4.0
2.0
0.0
Propylene Emissions
Range of Measured Annual Averages
Median of Measured Annual Averages9.0
7.0
5.0
Year
![Page 24: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/24.jpg)
Example (Cont.)Source Characterization
• Photochemical Modeling Project:– 24 Natural Gas-fired
Refrigeration Compressor Turbines
– 4 Acid Gas Vents– 1 Marine Flare– 2 Wet Gas Flares– 2 Dry Gas Flares– 2 Natural Gas-fired
Generator Turbines– 2 Emergency
Generators
• Proposed Project:– 6 Natural Gas-fired
Refrigeration Compressor Turbines
– 1 LNG Storage LP Flare– 1 Wet/Dry Gas Ground
Flare– 1 Auxiliary Boiler– 4 Thermal Oxidizers– 7 Diesel Generators– 1 Natural Gas-fired
Essential Generator– 1 Blowdown Vent
![Page 25: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/25.jpg)
Example (Cont.)
Source Characterization
Photochemical ModelingPTE NOx Emissions
2,665.29 tpyPSD Increment:• SO2
• PM10
Property Line:• SO2
• H2S
Health Effects:• Benzene
Proposed ProjectPTE NOx Emissions
681.46 tpyPSD Increment:• SO2
• PM10
Property Line:• SO2
• H2S
Health Effects:• Benzene
Photochemical modeling approx. 4X more NOx than proposed project.
![Page 26: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/26.jpg)
Example (Cont.)Meteorological Parameters and Regional Transport
BPA Area
Surface Pressure (HPA) Relative Humidity (%)
![Page 27: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/27.jpg)
Example (Cont.)Meteorological Parameters and Regional Transport
BPA Area
Surface Roughness (m) Temperature (oC)
![Page 28: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/28.jpg)
Example (Cont.)Meteorological Parameters and Regional Transport
BPA Area
Wind Vectors (knts) Wind Velocity (knts)
![Page 29: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/29.jpg)
Example (Cont.)
Model Results
Photochemical modeling results in the BPA Area based on 4X as much NOx is between 0.1-0.5 ppb.
![Page 30: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/30.jpg)
Questions?
![Page 31: Modeling Guidance and Examples for Commonly Asked Questions (Part II)](https://reader030.vdocuments.us/reader030/viewer/2022032414/56813409550346895d9afbf5/html5/thumbnails/31.jpg)
Contact Information
• Justin Cherry, P.E.– Air Dispersion Modeling Team
– (512) 239-0955
• Reece Parker– Air Dispersion Modeling Team
– (512) 239-1348
Air Permits Division
(512) [email protected]
Justin Cherry
Air Permits Division
Reece Parker
(512) 239-1348