1. Agricultural and Biological Engineering
Open Path Methods
Albert J. Heber, Professor
Building Environment
Research & Education
AgAirQuality.com
Agricultural and Biological Engineering
Purdue University
Slides: Title: Heber only under title

2. Biocurtain at Laying House
Biocurtain over 3 fans
Lab

3. Inside Biocurtain at Layer House

4. NRC Report on Air Emissions
Global/Nat.
Local
Concern
NH3
Major
Minor
N-Dep/PM2.5
N2O
Significant
Insignificant
Climate
NOx
Haze/Health
CH4
VOCs
Quality
H2S
PM10
Haze
PM2.5
Health/Haze
Odor

5. Comparing Open Path Sensors
Type of Sensor
FTIR UV
OPL
Detector cooling
Cryocooler -
Path Length, m
400
2000
Mode
Monostatic
Bistatic
Compounds
NH3, VOC*, CH4
NH3, H2S, Nox
H2S or NH3
Scan frequency, Hz 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
1.5 2
2-50
3-20
1-40
903
Models
BLS, TOM
BLS

6. Repump cooler, replace retros
Type of Sensor
FTIR UV
OPL
Scanning
Yes ?
Reflectors -
200 m
30 cube
Small retro
400 m
60 cube
1000 m
90 cube
Real-time quantification
yes
yes, w/ BLS
Capital cost
140K
$20K-$45K
$30K
Short term costs
none
Annual costs
Repump cooler, replace retros
New source
None
Recalibration needs
Annually
$7K laser/7 yr.

7. FTIR with 48-m Closed Cell
Advantages
Measures greenhouse gases
Measures ammonia: MDL=<6 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
Slides – FTIR Nexus 670: Advantages and Disadvantages

8. Scanning FTIR - Tomography
Layer house
Horizontal scanning
Vertical scanning

9. Source: Bruce Harris, U.S. EPA, 2004

10. Source: Bruce Harris, U.S. EPA, 2004

11. Field Measurement of Air Pollutants Near Swine Confined Animal Feeding Operations using UV DOAS and FTIR C. 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.

12. Area sources -> diffuse plumes Open-path -> entire plume length
An array paths maps the plume
Source: Bruce Harris, U.S. EPA, 2004

13. OP-FTIR Measurement Paths for Path-Integrated Optical Remote Sensing (Tomography)
wind
Source: Bruce Harris, U.S. EPA, 2004

14. Controlled release simulation of an area source under unstable air conditions – worst case40 80
120
160
200
240 2 6 10 14
Crosswind Distance [meters]
Height [meters]
Oxford 10/15/99: average flux g/s
0.2
0.4
0.6
0.7
concentrations are in mg/m 3 40 80
120
160
200
240 2 6 10 14
Crosswind Distance [meters]
Height [meters]
Oxford 10/15/99: Run #1 flux g/s
0.1
0.3
0.4
0.5
concentrations are in mg/m 3
Reconstructed plumes
Actual release rate = 1.7 g/s
Calculated flux = 1.2 g/s
Measured σθ = 50.7°
Pasquill-Gifford Stability A - Unstable 40 80
120
160
200
240 2 6 10 14
Crosswind Distance [meters]
Height [meters]
Oxford 10/15/99: Run #2 flux g/s
0.2
0.3
0.5
0.6
concentrations are in mg/m 3
Height [meters] 40 80
120
160
200
240 2 6 10 14
Crosswind Distance [meters]
Height [meters]
Oxford 10/15/99: Run #3 flux g/s
0.2
0.3
0.5
0.7
concentrations are in mg/m 3
Source: Bruce Harris, U.S. EPA, 2004

15. Controlled release simulation of an area source under stable air conditions – best case40 80
120
160
200
240 2 6 10 14
Crosswind Distance [meters]
Height [meters]
Oxford 10/19/99: average flux g/s
0.9
1.8
2.6
3.5
concentrations are in mg/m 3
Oxford 10/19/99: Run #1 flux g/s
1.9
2.8
3.8
Oxford 10/19/99: Run #2 flux - 1.6g/s
1.1
2.1
3.2
4.2
Oxford 10/19/99: Run #3 flux g/s 7
10.5
Oxford 10/19/99: Run #4 flux g/s 1
2.9
3.9
Reconstructed plumes
Actual release rate = 1.7 g/s
Calculated flux = 1.5 g/s
Measured σθ = 12.7°
Pasquill-Gifford Stability C-D - Neutral
Source: Bruce Harris, U.S. EPA, 2004

16. FTIR References
Harris, D. B., and E.L. Thompson, Jr Evaluation of ammonia emission from swine operations in North Carolina. Proc. Emission Inventory-Living in a Global Environment, VIP-88, pp AWMA, Pittsburgh, PA.
Harris, D. B., E.L. Thompson, Jr., D.A. Kirchgessner, J.W. Childers, M. Clayton, D.F. Natschke, W.J. Phillips 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
Childers, J. W., E.L. Thompson, Jr., D.B. Harris, D.A. Kirchgessner, M. Clayton, D.A. Natschke, W.J. Phillips Multi-pollutant measurements around a concentrated swine production facility using open-path spectrometry. Atm. Env. 35:
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. 35:
Source: Bruce Harris, U.S. EPA, 2004

17. FTIR References
Childers, J. W., E.L. Thompson, Jr., D.B. Harris, D.A. Kirchgessner, M. Clayton, D.A. Natschke, W.J. Phillips 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. 56:
Hashmonay, R. A., D.A. Natschke, K. Wagoner, D.B. Harris, E.L. Thompson, Jr., M.G. Yost Field evaluation of a method for estimating gaseous fluxes from area sources using open-path fourier transform infrared. Env. Sci. Tech. 35:
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 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.”
Source: Bruce Harris, U.S. EPA, 2004

18. Neutral Stability ponds sheds ponds sheds Source: Lowry Harper
Notice that a complete flux measurement (flux sampling of plume to large height) overestimates the flux by ~ 10% (this is because of the neglect of turbulent flux)
15 m
5 m
25 m
C plume in neutral conditions along measurement plane
Flux measurement plane
Neutral Stability
Wind
ponds
sheds
Source: Lowry Harper
USDA-ARS, 2004
ponds
sheds

19. Unstable (daytime) Smeared plume Source: Lowry Harper USDA-ARS, 2004
C plume in unstable conditions along measurement plane
Flux measurement plane
Notice that even if you go to z=50 m you don’t capture all the flux
Unstable (daytime)
Wind
Source: Lowry Harper
USDA-ARS, 2004
Smeared
plume

20. Stable (nighttime) Source: Lowry Harper USDA-ARS, 2004 Wind
C plume in stable conditions along measurement plane
Flux measurement plane
Stable (nighttime)
Wind
Source: Lowry Harper
USDA-ARS, 2004

21. Backward Lagrangian Stochastic (BLS) Dispersion Models
Backward Lagrangian Stochastic Modeling
Introduced by Flesch, T.K., and J.D. Wilson Backward-time Lagrangian stochastic dispersion models and their application to estimate gaseous emissions. J. Applied Meteorology 34:
Utilizes point or line measurement
Ultrasonic or cup anemometers
Flexible and easy to use.
Surface layer model. Locate < 1 km.
Commercial software available

22. UV-DOAS Ultraviolet Differential Optical Absorption Spectroscopy
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 ETV Technology Evaluation Report. Opsis, Inc. AR-500 Ultraviolet Open-Path Monitor. ETV Advanced Monitoring Systems Center, Battelle.

23. EPA Lab for Ambient Measurements
TEOM
UV-DOAS
UV-DOAS
TEOM
UV-DOAS
1-min averaging and
recording intervals
MET
tower

24. Collocated UV’s

25. Micromet Setup at Lagoons
FTIR & Tomography
UV & BLS
FTIR & BLS
Source: Bruce Harris, U.S. EPA, 2004

26. 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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Thank you!
Slides – Thank you: Haven Acres
Check out AgAirQuality.com