Open Path Methods

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Open Path Methods
Albert J. Heber, Professor heber_at_purdue.edu
AgAirQuality.com
Agricultural and Biological Engineering Purdue
University
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Biocurtain at Laying House
Biocurtain over 3 fans
Lab
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Inside Biocurtain at Layer House
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NRC Report on Air Emissions
Emissions Global/Nat. Local Concern
NH3 Major Minor N-Dep/PM2.5
N2O Significant Insignificant Climate
NOx Significant Minor Haze/Health
CH4 Significant Insignificant Climate
VOCs Insignificant Minor Quality
H2S Insignificant Significant Quality
PM10 Insignificant Significant Haze
PM2.5 Insignificant Significant Health/Haze
Odor Insignificant Major Quality
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Comparing Open Path Sensors
Type of Sensor FTIR UV OPL
Detector cooling Cryocooler - -
Path Length, m 400 150-1000 2000
Mode Monostatic Bistatic Monostatic
Compounds NH3, VOC, CH4 NH3, H2S, Nox H2S or NH3
Scan frequency, Hz 1 1 4000
Detection Limits
Hydrogen sulfide Deuterium
ppm-m 10-30 0.4-5 6-25
ppb 75-600 2.8-33 3-120
Linear upper range
Ammonia Xenon
ppm-m 1.5 2 2
ppb 2-50 3-20 1-40
Linear upper range 903
Models BLS, TOM BLS, TOM BLS
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Type of Sensor FTIR UV OPL
Scanning Yes Yes ?
Reflectors -
200 m 30 cube Small retro
400 m 60 cube
1000 m 90 cube
Real-time quantification yes yes, w/ BLS yes
Capital cost 140K 20K-45K 30K
Short term costs none none none
Annual costs Repump cooler, replace retros New source None
Recalibration needs None Annually 7K laser/7 yr.
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FTIR with 48-m Closed Cell

• Advantages
• Measures greenhouse gases
• Measures ammonia MDLlt6 ppb, NO, NO2
• Measures dozens of other gases, SO2
• Real-time measurement
• Quick response limited by cell volume
• Disadvantages
• Expensive 75,000
• Heavy, non-portable

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Scanning FTIR - Tomography

• Layer house
• Horizontal scanning
• Vertical scanning

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Source Bruce Harris, U.S. EPA, 2004
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Source Bruce Harris, U.S. EPA, 2004
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Field Measurement of Air Pollutants Near Swine
Confined Animal Feeding Operations using UV DOAS
and FTIRC. D. Secrest (paper presented in 2000)

• Ambient ammonia concentrations 0.8 km from a
  large swine facility with lagoons over a two week
  period were 0 to 900 ppb.
• An Iowa Study Group recommended that ambient
  exposure to ammonia should not exceed 150 ppb.
• The UV DOAS and FTIR were in good agreement.
• Open-path monitors combined with wind monitors
  are powerful tools for comparing daytime and
  nighttime pollutant concentrations, and for
  determining the effect of wind speed on
  concentration.

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• Area sources -gt diffuse plumes
• Open-path -gt entire plume length
• An array paths maps the plume

Source Bruce Harris, U.S. EPA, 2004
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OP-FTIR Measurement Pathsfor Path-Integrated
Optical Remote Sensing (Tomography)
Source Bruce Harris, U.S. EPA, 2004
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Controlled release simulation of an area source
under unstable air conditions worst case
Reconstructed plumes Actual release rate 1.7
g/s Calculated flux 1.2 g/s Measured s?
50.7 Pasquill-Gifford Stability A - Unstable
Height meters
Source Bruce Harris, U.S. EPA, 2004
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Controlled release simulation of an area source
under stable air conditions best case
Reconstructed plumes Actual release rate 1.7
g/s Calculated flux 1.5 g/s Measured s?
12.7 Pasquill-Gifford Stability C-D - Neutral
Source Bruce Harris, U.S. EPA, 2004
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FTIR References

• Harris, D. B., and E.L. Thompson, Jr. 1998.
  Evaluation of ammonia emission from swine
  operations in North Carolina. Proc. Emission
  Inventory-Living in a Global Environment, VIP-88,
  pp. 420-429. AWMA, Pittsburgh, PA.
• Harris, D. B., E.L. Thompson, Jr., D.A.
  Kirchgessner, J.W. Childers, M. Clayton, D.F.
  Natschke, W.J. Phillips. 1999. Multi-pollutant
  concentration mapping around a concentrated swine
  production facility using open-path FTIR
  spectrometry. Workshop on Atmospheric Nitrogen
  Compounds II Emissions, Transport,
  Transformation, Deposition and Assessment, NCSU,
  Raleigh, NC, pp. 237-246.
• Childers, J. W., E.L. Thompson, Jr., D.B. Harris,
  D.A. Kirchgessner, M. Clayton, D.A. Natschke,
  W.J. Phillips. 2001. Multi-pollutant measurements
  around a concentrated swine production facility
  using open-path spectrometry. Atm. Env. 35
  1023-1936.
• Childers, J. W., Thompson, E. L., Jr., Harris, D.
  B., Kirchgessner, D. A., Clayton, M., Natschke,
  D. A., Phillips, W. J. (2001) Application of
  standardized quality control procedures to
  open-path fourier transform infrared data
  collected at a concentrated swine production
  facility. Env. Science Tech. 351859-1866.

Source Bruce Harris, U.S. EPA, 2004
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FTIR References

• Childers, J. W., E.L. Thompson, Jr., D.B. Harris,
  D.A. Kirchgessner, M. Clayton, D.A. Natschke,
  W.J. Phillips. 2000. Comparison of an innovative
  algorithm to classical least squares for
  analyzing open-path fourier transform infrared
  spectra collected at a concentrated swine
  production facility. Appl.Spect. 56325-336.
• Hashmonay, R. A., D.A. Natschke, K. Wagoner, D.B.
  Harris, E.L. Thompson, Jr., M.G. Yost. 2001.
  Field evaluation of a method for estimating
  gaseous fluxes from area sources using open-path
  fourier transform infrared. Env. Sci. Tech.
  352309-2313.
• Harris, D. B., E.L. Thompson, Jr., Vogel, C. A.,
  Hashmonay, R. A., Natschke, D. A., Wagoner, K.
  Yost, M.G. Innovative approach for measuring
  ammonia and methane fluxes from a hog farm using
  open-path fourier transform infrared
  spectroscopy. 94th Annual Conf. of the AWMA,
  VIP-102-CD, AWMA, Pittsburgh, PA 2001.
• Hashmonay, R.A. and D.B. Harris. 2001.
  Particulate matter measurements using open-path
  Fourier transform infrared spectroscopy. 94th
  Annual Conference of the Air Waste Management
  Association, VIP-102-CD, AWMA, Pittsburgh, PA.
• Harris, D.B., R.C. Shores, L.G. Jones. Ammonia
  Emission Factors from Swine Finishing Operations.
  Int. Emissions Inventory Conference, One
  Atmosphere, One Inventory, Many Challenges.
  www.epa.gov/ttn/chief/conferences/ei10/index.html.

Source Bruce Harris, U.S. EPA, 2004
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Wind
ponds
sheds
ponds
sheds
Source Lowry Harper USDA-ARS, 2004
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Wind
Source Lowry Harper USDA-ARS, 2004
Smeared plume
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Wind
Source Lowry Harper USDA-ARS, 2004
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Backward Lagrangian Stochastic (BLS) Dispersion
Models

• Backward Lagrangian Stochastic Modeling
• Introduced by Flesch, T.K., and J.D. Wilson.
  1995. Backward-time Lagrangian stochastic
  dispersion models and their application to
  estimate gaseous emissions. J. Applied
  Meteorology 341320-1332.
• Utilizes point or line measurement
• Ultrasonic or cup anemometers
• Flexible and easy to use.
• Surface layer model. Locate lt 1 km.
• Commercial software available www.thunderbeachscie
  ntific.com

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UV-DOAS

• Ultraviolet Differential Optical Absorption
  Spectroscopy
• 1-1000 ppb path length
• Fast scanning, compact, tunable
• EPA Equivalent Method for SO2, O3 and NO2.
• Also measures ammonia, benzene, toluene, xylenes,
  styrene, Hg, HF, HNO2, HCHO
• Continuous operation
• MDL for ammonia 2.8 to 5.8 ppb

Source Myers, J., T. Kelly, C. Lawrie, and K.
Riggs. 2000. ETV Technology Evaluation Report.
Opsis, Inc. AR-500 Ultraviolet Open-Path Monitor.
ETV Advanced Monitoring Systems Center, Battelle.
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EPA Lab for Ambient Measurements
TEOM
UV-DOAS
UV-DOAS
TEOM
UV-DOAS
1-min averaging and recording intervals
MET tower
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Collocated UVs
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Micromet Setup at Lagoons
FTIR Tomography
UV BLS
FTIR BLS
Source Bruce Harris, U.S. EPA, 2004
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Equipment Required per Team

• Two FTIR scanning systems with 20 retros
• Two UV systems
• Four computers for optical remote sensors
• One computer for data QAQC and analysis
• Two 3D ultrasonic anemometers (2 and 12 m)
• Complete weather station
• Two, 12-m towers for FTIR/UV systems
• One, 2 m tower for ultrasonic anemometer
• Software for computed tomography method
• Software for BLS method
• Van and trailer

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