Presentation to the Moffett Restoration Advisory Board on November 29, 2012.

1. J. Brian Leen
Los Gatos Research
67 East Evelyn Avenue, Suite 3
Mountain View, CA 94041
b.leen@lgrinc.com
650-965-7772
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2. Outline
 About Los Gatos Research
 Motivation
 Incoherent Cavity Ring-Down Spectroscopy
(iCRDS)
 Measurement of TCE and PCE
 MEW and NAS Moffett Field Superfund Site
 Conclusion
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3. About LGR
VOCs Aerosols
O3 NH3
OCS
NO2
CO2 H2O H2O HF CO2
CH4
CO
N2O NO HCl C2H4 C2H2 NH3
HONO H2S Isotopes
• Use optical spectroscopy to make trace gas measurements (ppm, ppb, ppt)
• Operate from the visible to the mid-infrared
• Precise and accurate; also portable, robust and low power
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4. Research Deployments
UAV
Manned Airborne
Deep Sea
Portable Field Station

5. Why Detect VOCs?
Bacterial Chemical Weapons
Industrial Pollution Detection/Typing Detection
USEPA Superfund sites
Active (red), Proposed (yellow), Deleted (green)
Benzene Formaldehyde Tetrachloroethylene Acetaldehyde Sarin
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6. MIR Spectra: Molecular “Fingerprint”
Single Laser Scanning Range
C=C C-O Out-of-plane
C-H
stretch stretch bending
O-H
stretch CH2
bend
External Cavity-QCL (EC-QCL):
• Broadly tunable (~2.5 µm)
• ~1 cm-1 spectral width
• Good for large molecules
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7. Incoherent Cavity Ring Down
Spectroscopy (iCRDS)
• High reflectivity mirrors → multiple reflections
• Multiple reflections → very long path
• Long path → high sensitivity
• Light ‘leaks’ out of cavity at measurable rate
• Changes in ‘leak’ rate quantify gas absorption
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8. TCE and PCE Absorption Spectra
(a) 97.5 ppb PCE (b) 88.7 ppb TCE
Freon-134a
• PCE and TCE are measurable at ppb concentrations
• Use linear fit to PNNL Spectroscopic Database
• Amplitude ↔ Concentration
• Spectra add linearly
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9. Measurement Linearity
(a) PCE (b) TCE
• Measurement is linear (R2 = 0.9971)
• Accurate to a few ppb
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10. Summary of Performance
• Field portable
• 50-100’ Teflon sniffing tube
• Robust to H2O, CO2 and other common interferences
• Measurement period: 20 min average
• Precision (1σ):
• PCE – 2.32 ppb (15.9 µg/m3)
• TCE – 1.96 ppb (10.6 µg/m3)
• Limit of Detection:
• PCE < 8 ppb (55 µg/m3)
• TCE < 4 ppb (22 µg/m3)
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11. MEW and Moffett Field
• Middlefield-Ellis-Whisman
(MEW)
• Moffett Field
• Primary contamination:
PCE and TCE
o Dry cleaning
o Engine degreasing
o Semiconductor
manufacture
Building 10
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12. Previous Measurements
Previous TO-15 measured values (Feb, 2012)
TCE PCE cis-1,2-DCE 1,1-DCA 1,1-DCE
Sample Location Sample Type (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3)
manhole Pathway – Grab 400 300 80J 9 6J
manhole-concrete Pathway – Grab 1,000 900 200 20 10
In B10 near electrical panel Pathway 700 200 100 10 9
In B10 near offices Pathway 1,100 800 200 20 20
In B10 beneath floor Pathway 30 20 6J ND ND
on table in center of B10 Indoor - 24 hr 50 30 8 ND ND
Mediation Depressurization
BZ Steam Tunnel
Route
Steam Gen
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13. Field Setup
Measurement Protocol:
• Continuous monitoring: Aug. 6-13
• Automatic switching between:
o Tunnel air
o Breathing zone air
o Zero air
o PCE standard
• Remediation fans off Aug 10-13
(weekend!)
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14. Building 10 Sample Locations
Sample Locations:
• Breathing Zone
• 3 Tunnel Locations:
 I: Aug 6 – 8
 II: Aug 8 – 10
 III: Aug 10 –13
Mediation Depressurization
BZ Steam Tunnel
Route
Steam Gen
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15. PCE Standard Repeatability
• Calculated from first principles
→ No calibration!
• Measured value closely matches
actual value (97.5 ppb)
• Dropouts from liquid nitrogen
refilling
• 1σ precision = 2.9 ppb (19.81
µg/m3)
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16. Breathing Zone:
Measured Spectra
• Recorded sample spectrum every 20 min avg. (each line is a measurement)
• Narrow vertical lines are H2O
• iCRDS accommodates unexpected species
• E.g., characteristic absorption from Freon-152a
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17. Steam Tunnel:
Measured Spectra
• PCE, TCE and cis-1,2-DCE increase visibly when remediation is turned off (8/10)
• TCE & PCE decrease when remediation turned on
• Buildup time constant is about 14 hrs
• Can immediately evaluate remediation efficacy!
ON
OFF
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18. Quantitative PCE and TCE
(a) PCE (b) TCE
• Levels are low with remediation on
• Tunnel air shows consistently higher concentrations
• Huge increase in tunnel concentration with remediation off
• Results match TO-15 measured values (esp. for TCE)
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19. Practical Implications
• High resolution site mapping
• Data immediately available
• On site decision making – rapid in, rapid out
• Mobile monitoring
• Minimizes sample handling artifacts
• Potential for measuring reactive species
(e.g., acrolein)
• Reduced cost of sampling
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20. Next Steps
ே
௞
௞ୀଵ
Improved sensitivity
Non-cryogenic detector
• Optical configuration
• Stirling cooled
• Data processing
• Thermo-electrically cooled
• Thermal stability
• Preconcentration
Spectral acquisition
Reduced instrument size • Rapid laser scanning
• Improved cavity mirrors • Improved laser stability
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21. Conclusions
 MIR spectra uniquely identify pollutants in
ambient air
 iCRDS provides sensitivity at the low ppb level
 Successfully measured TCE & PCE at Moffett
Field
 Continuous and autonomous for 1 week
 iCRDS results agree with TO-15
 Observed site remediation dynamics
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22. Acknowledgments
Alana Lee
Joe Lukas
Doug Baer Daniel Mendolla Heather Henry
Manish Gupta Greg Nagle
Robert Provencal
Feng Dong
Elena Berman
Russell Dickerson
Tom Owano
Jeffrey W. Stehr
Jim Liem
Patricia Castellanos
Winston T. Luke Paul
Marc Fisher
Kelley
Ken Reichl
Sheryl H. Ehrman
Lacey Brent
Joe Hsu
Cristina Vasquez-Guillamet
Xiao-Ying Yu
Celine Kluzek
John Hubbe
Funding Agencies: DOE, DOD, EPA, NASA, CARB, NIH 22

23. Supplemental Material
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24. Simulated Sensitivity Analysis:
VOCs in Office Air
LOD (3s) Measured Office Levels†
Compound
[ppb] [ppb]
Acetone 0.60 21.8
Benzene 3 0.3 – 18.9
Formaldehyde 4 25.8 – 52.5
Methanol 0.3 ND
Toluene 7 2.6 – 76.9
Acrolein 0.5 ND
Styrene 0.75 0.4 – 18.4
Trimethyl Benzene 5 0.4 – 8.51
m-Xylene 3 3.2 – 75
o-Xylene 3.6 0.7 – 15.5
Trichloroethylene 0.14 0.02 – 23.7
Tetrachloroethylene 0.11 0.1 – 67.8
†L.
C. Holcomb, et al., "Review : Indoor Concentrations of Volatile Organic Compounds: Implications for Comfort, Health and
Regulation," Indoor and Built Environment 4, 7-26 (1995). 24

25. Lab Precision
PCE Repeated Measurements TCE Repeated Measurements
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26. Minimum Detectable
Concentration
PCE MDC TCE MDC
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27. Previous Measurements (ppb)
Previous TO-15 measured values (Feb, 2012)
TCE PCE cis-1,2-DCE
Sample Location Sample Type (ppb) (ppb) (ppb) 1,1-DCA (ppb) 1,1-DCE (ppb)
manhole Pathway - Grab 74 44 20 2.2 1.5
manhole-concrete Pathway - Grab 185 132 50 5 2.5
In B10 near electrical panel Pathway 129 29 25 2.5 2.2
In B10 near offices Pathway 203 117 50 5 5
In B10 beneath floor Pathway 6 3 1.5 ND ND
on table in center of B10 Indoor - 24 hr 9 4 2 ND ND
Remediation suction
BZ Steam Tunnel
Route
Steam Gen
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28. Cost Estimates
Cost Category Portable GC/MS iCRDS
Purchase $75,000 – 175,3751, 2 $45,000 – 110,000
Daily Operation $200 – 2502,3 $4 – 10*
Personnel (per day) $380 – 540† $0‡ – 230
Per Sample Cost - -
Total 1st Year $214,200 – 364,975 $45,960 – 165,210
* Includes pump rebuild, electricity, periodic calibration gas, and drying agents ($1-2k/year)
† Loaded labor for skilled technician (e.g., BS in Chemistry)
‡ Assumes a one in 10 day visitation for data transfer. This may be performed remotely by researches.
(1) C. M. Harris, "Product Review: GC To Go," Analytical Chemistry 74, 585 A-589 A (2002).
(2) USEPA, “ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM: FIELD-PORTABLE GC/MS” (Washington, D.C., 1998).
(3) USEPA, “Innovations in Site Characterization: Technology Evaluation: Real-Time VOC Analysis Using a Field Portable GC/MS”, Aug 2001.
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