FINAL ORS Protocol June 14 , 2006

1 

### Optical Remote Sensing for Emission Characterization

from Non - point Sources 1.0 Scope and Application 1.1 Introduction . This protocol provides the user with methodolog ies for characterizing gaseous emissions fro m no n - point pollutant sources. The s e met ho dolog ies use an open - path, Pat h - In tegrated Optical Remote Sensing (PI - ORS) system in multiple beam configurations to directly identify “hot spots” and measure emission fluxes. B asic knowledge of a PI - ORS system and the abilit y t o obtain quality path - int egra ted co ncentrati

on (PIC) data is assumed. The user must be capable of using commercial sof tware to utilize the procedures and algorithms explained in this protocol . The met hodolog ies in t his protocol have been well developed, evaluated, demonstrated, validated, and peer- reviewed. 1 - 1 2 NOTE 1

— Any mention of a “PI - ORS system” in this protocol refe rs to the open - path PI - ORS instrument itself, as well as any associated components used, such as mirrors, scanners, and software. This protocol does not discuss spe cific applications (e.g., hog farms, landfills), but provides general guidelines or procedures that can be applied. Detailed protocols for specific applications may be added at a future date. 1.1.1 Scope . This protocol currently describes three met hodologies , each for a specific use. The Horizontal Radial Plume Mapping (HRPM) met hodology was designed to map pollutant concentrati ons in a horizontal plane. The Vertical Radial Plume Mapping (VRPM) met ho dology was designed to measure mass flux of pollutants th rough a vert ical plane , downwind from an emission source . The one - dimensional R adial P lu me M apping met hodology (1D - RPM) was designed to profile pollutant concentrations along a line - ofsight (e.g., along an industrial site fenceline) . In future revisions to this protocol, additional PI - ORS emission monitoring met ho dologies (other than the met ho dol ogies described in this protocol) th at address non - point sources can be added as validat io n dat a are generated. 1.1.2 Choice of Instrumentation . The choice of PI - ORS syst em to be used for the co llection of measurement data ( and subsequent calculation of PIC ) is le ft to the discretion of the user, and should be dependent on the co mpounds of int erest and the purpose of the study. The met hodologies are independent of th e particular PI - ORS syst em used to generate the PIC data . It is recommended for the HRPM, VRPM, and 1D - RPM met hodologies th at the typical expected concentration over the longer beams should be about 10 times the minimum detection limit of the instrument. W hen this is not the case, the user should replace nondetects with values of half the minimum detecti on limit (see Table A.3 in the Appendix A).FINAL ORS Protocol June 14 , 2006

2 1.1.3 Developmental Basis . Several methodologies have been developed and applied to estimate emission rates from non - point fugitive sources

— such as landfills, coal mines, and wastewater treatment plants

— using PI - ORS technologies. 3 , 1 3 - 1 8 The met hodolog ies explained in t his protocol were developed from studies that concentrated on developing, evaluating , and demo nstrat ing t he various configurati ons of the radial plume mapping ( RPM) based met hodologies . 1 , 2 ,4 - 7 , 9 - 1 1 The RPM - based met hodologies (configurati ons, procedures, and algorithms) were patented as a technology for mapping air contaminants using a PI - ORS sy ste m wit h a no n - overlapping, variable pathlength , radial beam geometry. 8 The RP M methodologies are the intellectual property of the University of Washington; if you plan to employ the RPM - based methodologies, please contact the O ffice of Intellectual Property and T echnology T ransfer at The University of Washington ( UW TechTransfer; techtran@u.washington.edu ) for potential licensing . 1.1.4 Applicability . The methodolog ies described in this protocol are appropriat e for characterizing ground level area sources and non- point fugitive emission sources such as la ndfills, lagoons, and industrial complexes. The limitations of these methodologies can be based on the instrument o r beam geometry. 1.1.4.1 Instrument - S

peci fic Limitations . The PI - ORS system chosen will determine the maximu m pathlength, the co mp o unds that can be detected, and the detection limits of these compounds and can influence accuracy and precision as well. 1.1.4.2 Beam Geometry Limitations . Pl um e emis sion s are assumed to originate near ground level (within three meters fro m t he ground). If some or all o f t he emissio ns are above the three - met er criteria, then the beam geo metries explained in this protocol may need to be modified. Co mp lex topography and obstructions may require some variat io ns fro m t he standard configurations described in this protocol. 1.2 Compound L ist . Any fugitive gaseous compound is a potential candidate for application of the se met ho dol ogies . These met hodologies are restricted only by t he limitations of the PI - ORS syst em cho sen. 1.2.1 Sensitivity . Table 1 shows some ty pical sensitivit y ranges for several PI - ORS sy stems . Prior to field deployment, the expected sensitivit y o f t he PI - ORS system should be evaluated against project goals. 1.2.2 Data Quality . The level of acceptable uncertainty is dependent on the application of the reported data

– whether for hot spot determination (HRPM), measurement of emissions flux (VRPM), or line - of - sight profile concentrations (1D - RPM). The user must tailor their choice of PI - ORS system, configurati on, and tolerance parameters to meet their end needs.FINAL ORS Protocol June 14 , 2006

3 Table 1. Typical S ensitivity R anges for S everal PI - ORS S ystems PI - ORS System* Formal dehyde 1,3 -

Butadiene Acrolein Benzene Ammo nia Total VOC Scannin g OP - FTIR (for > 100 m pathlength) 2

– 10 ppb 2

– 10 ppb 8

– 30 ppb 15

– 50

ppb 0.5

– 4 ppb 1

– 5 ppb UV - DOAS (for > 250 m pathlength) 0.5 ppb NA NA 0. 1 ppb 1 ppb NA TDLAS (for > 250 m pathlength) NA NA NA NA 20

– 50 ppb NA PI - DIAL (1000 m pathlength) **   10 μg/ m3 **  **

* See Section 6 for full instrument names. NA This compound cannot currently be measured with this instrument. ** Ty pically a custom - built instrument. Sensitivity ranges are instrument - specific. 2.0 Summary of Methodologies 2.1 Principle . This protocol describes the application of the HRPM, VRPM, and 1D - RPM met hodologies designed specifically for the use of PI - ORS syst ems . The HRPM met hodology ut ilizes multiple non - int ersecting beam paths in a horizontal plane and optimizing algorithms to give a time - averaged surface co ncentration field across plumes of co nt aminants. This met hodology is used to l ocate hot spots clo se to the ground. The VRPM met hodology ut ilizes multiple non - int ersecting beam paths in a vertical plane downwind from the emissio n source to obtain a mass - equivalent plume map. This map, in conjunction wit h wind speed and direction, is used to obtain the flux of pollutants th rough th e vertical plane . The measured flux is t hen used to estimate th e emission rate of th

e upwind source b eing characterized . The 1D - RPM met hodology ut ilizes multiple beam paths along a line of - sight to obtain concentration profiles downwind of a source (e.g., along an industrial sit e fe nceline). The peak concentrati on position along the line - of - sight can be incorporated with wind direction to estimate the location of an upwind fugitive emission source. 2.1.1 The user- selected PI - ORS syst em co llects spectral data ; th ere are no true “samples” that require preservation, storage, transport, extraction, digestion , or co ncentrati

on. The chemical concentration of each gas species of interest along each beam path is obtained following the measurement and analysis procedures for the instruments being used. 2.1.2 The physical range and sensitivit y o f t he met hodologies ar e determined by the limitations of the PI - ORS syst em selected to acquire the PIC data. The accuracy of the results from the met ho dol og ies depends on the instrument accuracy as well as : 1) the quality control (QC) crit eria defined for the met ho dology- specif ic algorithms, and 2) the accuracy and representative ness of the wind data (for VRPM and 1D - RPM met hodologies ) .FINAL ORS Protocol June 14 , 2006

4 2.2 HRPM Methodology

– Hot Spot Source Location . The HRPM met ho dology is used to l ocate the source of fugitive emissions or hot spots. A rectang ular area (which may be a square) is defined around the ground location where the suspected gaseous emission s are o riginating . Ideally, the HRPM configuration will cover the entire suspected source area ; ho wever, this ma y be prevented by equipment limitations or site conditions. Larger areas may need to be divided into smaller sections and studied separately . 2.2.1 Once the HRPM configurati on area has been defined, it is divided into smaller rectangular areas called pixels. The total number of pixels requi red is less than or equal to the total number of beam paths. Each pixel will have at least one optical beam path that terminates within its boundaries by a pathlength - defining component (PDC) . NOTE 2

— The methodolog ies her e are not instrument specific. F or ease of presentation, pathlength - defining component (PDC) is used to denote the component on the other end of the optical path from the PI - ORS instrument. Depending on the instrument selected, this could be a source, detector, mirror, or other reflectin g object. 2.2.2 The scanning PI - ORS instrument is ty pically placed on a corner of the rectangular sampling area. The reconstructi on algorithm for obtaining concentrati on co nt our maps consists of two stage s (detailed in Section 12.2). NOTE 3

— Alt hough the PI - ORS instrument is typically placed on a corner of the rectangular sampling area, in some cases it may be necessary to place the PI - ORS instrument along a boundary of the survey area. This protocol does not address alternate placement of the PI ORS instrument. 2.2.2.1 An it erative inversion algorithm is used to determine averag e co ncentrati ons in each pixel. 2.2.2.2 An int erpolation procedure is then applied to these concentrati on values to calculate concentration s in higher spatial resolution. 2.2.3 HRP M calculations are performed and the locati ons of concentrati

on maxima qualitatively indicate the locations of gaseous emission hot spots. Wind speed and direction measurements may be recorded while collecting HRPM met ho dology data to aid in int erpreting t he co ncentrati on contour maps produced. 2.3 VRPM Methodology - Estimation of Emission Rate . The VRPM met hodology is used to estimate the rate of gaseous emissions from an area fugitive source. A vertical scanning plane, downwind of the source, is used to dir ectly measure the gaseous flu x (detailed in Section 12 . 3 ). 2.3.1 The total length of the measurement area required depends on the size of the emission source, as well as the limit at io ns of the selected PI - ORS syst em . 2.3.2 The height of the scanning area is dependent on the PI - ORS syst em limit ations , the distance to the upwind boundary of the source, and the limit ations of the infrastructureFINAL ORS Protocol June 14 , 2006

5 used for mo unt ing t he PI - ORS syst em co mponents (e.g., mirrors and/or meteorol ogical station). 2.3.3 Wind speed and direction measurements must be recorded f or flux calculations and preferably should be monitored in at least two heights (usually at 2 and 10 meters) for a mo re accurate int erpolation and extrapolation th rough the height of the vertical plane. In special c ases when two wind monitors are not available, one wind monitor can be used at mid - height (3 - 5 m) to represent the average wind of the ent ir e vertical plane . The VRPM met hod was validated with two wind monitors 11 ; however, because a linear interpolation i s applied between the two wind monitor heights, one wind monitor at mid - height should provide similar results. 2.3.4 The PIC measurements along the elevated beam paths (achieved by elevated PDC) provide vertical conce ntr a tion gradient informat io n of the emit ted plume. The beam paths on the ground (ground level PDC) indicate the approximate ground level concentration profile along the length of the VRPM setup . Ground - le vel refer s to the area as close to horizontal as possible, relat ive to the surface of the measurement area. 2.3.5 A bivariate Gaussian fu nction (or superposit io n of two) is assumed for the pl ume mass across the VRPM plane , and the parameters of the mass - equivalent bivariate Gaussian fu nction(s) are reconstructed from the measured PIC. The se rec onstructed param eters are then used to calculate the concentration values across the VRPM plane at high reso lut io n. 2.3.6 The concentration values (in ppm) are converted to mass concentrations using the mo lecular weight of the monitored gas species . The products of the ma ss concentration and the wind speed normal to the measurement plane are int egrated across the plane to calculate the ma ss flux th rough the plane . Because the estimat io n of the emissio n rate is dependent on the wind data , stable and measurab le wind condit io ns are desi red so th at the source remains upwind of the VRPM plane . 2.4 1 D - RPM Methodology

– Line - of - Sight Profile Concentrations and Upwind Source Location Estimation . The 1D - RPM met hodology is used to profile pollutant concentrations along a line - of - sight downwind of a fugit ive emissio n source. Thi s pollutant concentration profile can be combined with wind data to estimate the location of an upwind source, when applicable. The scanning PI - ORS instrument and th ree or mo re PDC are placed in a cr osswind direction alo ng a line, such as an industrial site fenceline. 2.4.1 A Gaussian fu nct io n (or superposit io n of tw o) is assumed for the plume concentration profile along the line - of - sight of the instrument and the parameters of the Gaussian function(s) are reconstructed from the measured PIC. 2.4.2 Mul

ti ple peak locat io ns are reconstructed over time along the 1D - RPM line of - sight . These peak positions are incorporated with corresponding wind direct io ns toFINAL ORS Protocol June 14 , 2006

6 create back - projected vectors for each measurement period. When t he back - proj ected vectors converge in an area, thi s indicat es the probable locat io n of an upwind hot spot. 3.0 Definitions 1D - RPM: One - dimensional Radial Plume Mapping . The 1D - RPM met ho dology is o ne o f the t hr ee met hodologies described in this proto co l, and is used for reconstructing line - ofsight profile concentrations. CCF : Concordance Correlat io n Factor . CCF is used to represent the qualit y of fit fo r the reconstruction in the path - int egrated domain. CCF is similar to the Pearson correlation coeff icient, but is adjusted to account for shifts in location and scale. Cycle : Cycle is defined as one complete sequent ia l data collection through all PDCs in the setup . Gaussian f

unction : A no rmal distribut io n curve with a specifi ed m ean and standard deviation. HRPM : Ho rizontal Radial Plume Mapping. The HRPM met hodology is one of the three methodologies described in this protocol, and is used for locat ing “hot spot” sources. Kernel matrix: A matrix detailing the length of each beam path in each pixel of the HRPM plane . NNLS : Non - negat ive least square s . NNLS is simila r to a classical least square optimizat io n algorithm, but is constrained to provide the best fit of non - negat ive concentration values used in the HRPM met hodology . PDC : Pathlength - defining co mp onents . PDC is used to denote the component on the other end of the optical path fro m t he PI - ORS instrument. Depending on the instrument selected, thi s could be a source, detector, mirror, or other reflect ing object. PIC : Path Integrated Concentration. Given in the units of parts per millio n - meter (ppmm), PIC is the int egrated co ncentration of a gaseous pollutant measured along the beam path le ngth. PI- ORS : Path - Integrated Optical Remote Sensing. An instrument system used to acquire gaseous PIC data along a n open optical beam path. ppm : Parts per millio n. Ty pical uni ts of gas concentration fo r PI - ORS instruments, ratioed by vo lu me. SBFM : Sm

ooth Basi s Funct io ns Minimizat io n. An algorithm u sed in t he VRPM and 1D - RPM met hodologies to fit the parameters of the Gaussian basis funct io n(s) to the measured PIC data.FINAL ORS Protocol June 14 , 2006

7 SSE : Sum of Squared Errors. The SSE is the sum of the squared differences between the measured and predicted PIC at each step of the iterative algorithm used in the VRPM and 1D - RPM met hodologies . Toleran ce parameter : A t hresho ld value used to terminate iterative search alg orithms o f the methodologies described in this protocol . VRPM : Vertical Radial Plume Mapping. The VRPM met hodology is one of the three methodologies described in this protocol, and is us ed for estimat io n of the emissio n rate fro m a n area source . 4.0 Interferences 4.1 General Interferenc es 4.1.1 Field - based interferences may result in the need to deviate from the setup s specified for the PI - ORS syst em (see Section 11). Some examples of po tential field - based int erferences are vehicular or pedestrian traffic through the beam path and physical site obstructions (e.g., buildings, trees, and co mple x topography) . 4.1.2 The met ho dologies described in this protocol are based on concentration analy sis of the chosen PI - ORS system, and different instrument s ma y have unique int erferences. For example, co ncentration determination may be affected by the presence of water vapor and carbon dioxide in the infrared, or oxygen and ozone in the UV . D etecti on level s fo r several co mpounds ma y increase with the presence of the interfering species . 4.2 Weather Interferences 4.2.1 General . Certain weather conditions such as rain, fog, or snow can obscure the light beam and affect the abilit y o f t he PI - ORS instrument to continuously measure gaseous co ncentrati

ons. Transient, but significant, obscuration can occur during heavy precipitation events, particularly with longer path measurements. This could limit the sensitivit y o f t he PIC measurements or the abilit y t o collect data . All met eorological co ndit io ns are recorded in t he field log so that the data co llect ed during adverse conditions can be reviewed . The data collected during these events may be filtered out before inclusion in the met hodologies calculations. 4.2. 2 Winds . Wind conditions can greatly affect the results of field measurements and should be taken into account when interpreting data collected using the met ho dol ogies described in this protocol . 4.2.2.1 Calm wind conditions do not affect the HRPM methodol ogy algorithm for hot spot source locatio n. Ho wever, very lo w wind speeds are not ideal for the VRPM met hodology for emission rate estimation, as the source plume may not be carried through the vert ical p lane in t he absence of measurable wind .FINAL ORS Protocol June 14 , 2006

8 4.2.2.2 Very hig h wind speed conditions are not ideal for th e HRPM , VRPM , or 1D - RPM met hodologies . High winds may displace or vibrate the optical alignment of the co mponents of the PI - ORS syst em used in the setup , and affect the quality of the PIC values acquired in mu lt ip le beam paths. They may also cause displacement of the hot spot in HRPM. High winds are also not ideal for obvious safety reasons, as scissors jacks and oth er vert ical towers can become unstable. 4.2.2.3 Based on controlled studies perf orm ed in the p ast, the following wind speed ranges are recommended f or optimal results: HRPM met hodology : Near 0 to 5 m/s VRPM met hodology : 1 to 8 m/s 1D - RPM met hodology : 1 to 8 m/s 4.2.2.4 For wind speeds between 8 and 11 m/s, data acquisition for VRPM and 1D RPM ma y t ake place, but should be carefully checked for reliabilit y. When sustained winds are observed above 11 m/s, field measurements are not recommended, as data quality will mo st likely be compromised. General field safety protocols should be followed for the well- being of field personnel and for the safe operation of the PI - ORS syst em . 5.0 Safety The hazards of performing the methodologies described in this protocol are those associated with any field event . S afet y procedures should be established and imple mented before using this protocol. Many o f t he potential target compounds are hazardous air pollutants ( HAP ) , which may be suspected carcinogens or present other serious healt h ri sks. Exposure to these compounds should be avo ided. PI - ORS system- specific sa fet y protocol s (e.g., eye exposure to lasers) should be followed. 6.0 Equipment and Supplies 6.1 Instrumentation . Any scanning PI - ORS system th at can provide PIC data may be co nsidered for the purposes of the met hodologies described in this protocol, and may include the following: Open - Path Fourier Transform Infrared (OP - FTIR) Spectroscopy Ul tra - Vio let Different ia l Optical Absorption Spectroscopy (UV - DOAS) Open - Path Tunable Diode Laser Absorption Spectroscopy (TDLAS) Path - Integrated Different ia l Absorption LIDAR* (PI - DIAL) * LIDAR

– Light Detection and RangingFINAL ORS Protocol June 14 , 2006

9 6.1.1 The choice of instrument must be made based on its perf ormance relative to the data quality objectives of the study. 6.1.2 The OP - FT IR and UV - DOAS technolog ies are widely used, due to their cap abilit y o f simu lt aneous chemical detection f or a large number of gas species of environmental interest. However, when only a few gas species are of interest, it may be mo re beneficial to employ other PI - ORS instrumentation, such as the TDLAS or PI - DIAL. N OTE 4

— A U.S. Envir onmental Protection Agency ( EPA) com pendium method (TO 16) for making q

uality PIC measurements is available for OP - FTIR 1 9 , and a set of companion methodologies to this protocol are anticipated for develop ment . 6.2 Vertical Structure . A stable, vertical structure is necessary for the VRPM co nfiguration, and may include scissor jacks, towers, and buildings. The particular elevation device is unimportant, as long as the required, stable elevation is achieved. The criterion f or stabilit y o f the vertical structure is reliable PIC data . 6.3 Computer Softw

are . Specific computer software may be required by particular PI - ORS syst ems for obtaining PIC data . Various versions of c om mercial software are available for post - analysis of the acquired PIC and wind data for all three met hodologies in this protocol. 6.4 Meteorological Measurements . There are a number of commercially available met eorological stations that can be used. The QC checks described in Section 9.3.1 can be used t o assess the accuracy and precision of your instruments . 6.5 Survey Measurements. There are a number of commercially available survey instruments (e.g., rangefinder or theodolite) to measure pathlength, azimuth, and elevation angle . The QC checks described in Section 9.2 can b e used to assess the accuracy and precision of your instruments. 7.0 Reagents and Standards Use verificat io n gases as a QC check for the met hodologies described in this protocol (refer to Section 10). NOTE 5

— Suggested verification gases for OP - FTIR QC purposes are acetylene, ethylene, propane, propylene , and sulfur hexafluoride . 8.0 Sample Collection, Preservation and Storage. The user will have no actual samples collected by the PI - ORS sy stem or by the applicat io n of the met hodologies described in thi s protocol . T herefore, a discussio n of sample collect io n, preservation, and storage procedures is not necessary. Section 11 describes the procedures the user will emplo y t o acqui re data by this protocol.FINAL ORS Protocol June 14 , 2006

10 9.0 Quality Control It i s assumed that the user of this protocol can acqui re qualit y PIC data for use in the methodologies described in Sect io n 12. Refer to the appropriate PI - ORS system manuals and EPA methods for instrument - specific QC checks. 9.1 Internal QC. Traditional QC samples are not applicable to PI - ORS experiments. The QC procedures detailed in the appropriate instrument manual should be followed and must be in agreement with EPA m ethods, when available. For OP - FTIR measurements, currently available documents are Co mpendium Method TO - 16 (1999) 1 9 ; American Societ y fo r Testing and Materials (ASTM) Standard Practices E1982 - 98 (1999) 20 and ASTM User Guide E1865 - 97 (Reapproved 2002) ( 1997 ) 21 ; and the German standard for OP - FTIR. 22 It should be noted that calibration cells are not required in TO - 16 or in t he ASTM documents. For TDLAS, internal calibration cells are used. 9. 2 Data Quality Indicator Goals for Critical Measurements. Data quality indicator (DQI) goals are established to assess the quality of critical measurements and are presented in Table 2. For the PI - ORS systems, they will be dependent on the specific components selected for use. Example DQIs for the OP - FTIR instrument are provided in Appendix A. Regardless of the PI - ORS system selected, the following QC checks will assess the accuracy and precision of the met eorological station and survey instrument , as well as the quality of the plume reconstructi on for the chosen met hodology . NOTE 6

— Care should be taken when collecting met eorological and survey data , as the quality of this data will ha ve a dir ect impact on the quality of the calculations. 9.2.1 Meteorological Measurements . The quality of the wind speed data can be assessed by placing the two wind monitors side - by- side and collecting data f or 10 minutes. The average wind speed for both heads during this time should be at least 1 m/s. The difference of the average wind speed measurements between the two heads should be wit hin 20% of the highest average value. The quality of the wind direction measurements can be assessed by manually setting the vane on the meteorological heads to magnetic north using a hand - held compass. For wind monitors with no vane, an artificial wind source can be used to establish a northerly wind. The measured wind direction during this check should be within 10o as compared to 360o/0o. In addition to the DQI tests detailed above, there is an additional reasonableness check th at can be conducted periodically to assess the performance of meteorol ogical instrum

ents in t he field. Specifically, the measured wind direction should compare closely to the observed wind direction.FINAL ORS Protocol June 14 , 2006

11 Table 2. Recommended DQIs for the M ethodologies D escribed in this P rotocol Measurement Parameter Analysis Method DQI PI - ORS Instrument Instrument specific a Wind speed Side- by- side comparison of two wind monitors Within 20% Wind direction Comparison to magnetic north Within 1 0o Optical path - length Measure and compare to known path Within 2 % Beam angle Measure and compare known angle Within 2o HRPM, VRPM, and 1D - RPM CCF •0. 8 b VRPM Flux Measurement Wind Direction - 10o to + 25 o fr om perpendicularc 1D - RPM Peak Location Variability Reconstructed peak locations d a Each PI - ORS instrument will have its own specific DQI goals. For instance, if an OP - FTIR is used, measured nitrous oxide and methane concentrations are compared to ambient levels to assess the quality of the data collected (when measurement occurs away from sources of these compounds) . 1 9 b There are no true accuracy and precision parameters associated with the CCF. The calculated CCF value ass ociated with the RPM algorithm must be •0. 8 for the reconstruction to be considered valid. See Sections 12.2.3.2 (and following Note 1 0 ) and 12.3. 3 .2. c This DQI is for each reconstruction/flux determination. Emission rate estimates

— based on the Duke Forest validation study 11 are typically considered valid when the wind direction is - 10 ° to + 25 o from perpendicular (to the optical plane) (refer to Section 11.3 .4 ). d Reconstructed peak locations should appear in at least two different segments to determine the source location using the 1D - RPM methodology (refer to Section 12 .4.4) . [A segment is defined as the distance between two consecutive PDCs or the closest PDC and the PI - ORS instrument location.] 9. 2 .2 Survey Measurements . Perform a range calibration test b y co mparing a measured distance to a set distance . The measured distance should be within 2% of the set distance . A possible angle measurement calibration test can be performed by placing the survey instrument between and in - line wit h t wo observab le targets. Measure t he horizontal angle, first fro m o ne obj ect , then the other. The difference of the two measurements should be with in 2o of 1 80°. 9. 2. 3 Plume Reconstruction . The plume reconstructions in t he met ho dologies described in this protocol are assessed for quality using a statistical parameter, Concordance Correlation Factor (CCF), that indicates the goodness of fit between measured and predicted PIC. A CCF value of >0. 8 ind icates a valid reconstruction. See Secti on 12. 2 .3. 2 (and f

ollowing Note 1 0 ) and Section 12.3. 3 .2 for a discussion of CCF. Fo r emission rate estimations using the VRPM met ho dolo gy , maximal pl um e capture is desired . Therefore, emission flux measurements are typically considered valid when theFINAL ORS Protocol June 14 , 2006

12 wind direction is clo se to perpendic ular to th e vertical plane ( - 10 ° to +25 ° fo r the Duke Forest validation study). Source locations using the 1D - RPM met hodology are typically co nsidered valid when the wind direction is within ±45o from perpendicular (to the line - ofsight ). Reconstructed peak lo cati ons should appear in at least two different segments to determine the source locati on using the 1D - RPM met ho dology (refer to Section 12.4.4). A segment is defined as the distance between two consecutive PDCs or the closest PDC and the PI - ORS instru ment location. 10.0 Calibration and Standardization 10.1 Instrument Calibration . The met hodologies described in this protocol rely on accurate PIC data provided by a PI - ORS instrument. Calibration of these instruments is instrument - specific and the user should refer to the instrument manual and EPA procedures fo r proper instrument calibration procedures. 10.2 Methodology Verification . The verification of the methodologies described in this protocol is a procedure to test the abilit y o f each met hodology to m eet its objectives as described in Secti

on 2. 10.2.1 Conduct a verification procedure involving a controlled gas release prior to using any new instrument/ setup co mbination, and repeat the procedure when a significant change is made to any part of the PI - O RS instrum ent o r setup . If only the met ho dol ogy sof tware is changed, a previously verified data set can be used for verification purposes . Detailed explanations of these peer- reviewed procedures using verification gases have been published fo r the HRPM, 6 V RPM, 7, 9 ,1 1 and 1D - RPM 2,1 0 met ho dologies . 10.2.2 T he verification procedure can be performed while data is collected in the field as long as the following three criteria are met: 1) the PI - ORS system is able to monitor mo re than one gas simultaneously; 2) the verification gas is one of th ese monitored gases; and 3) the verification gas is not emitted by the source under study. If these criteria are not met , this verification procedure must be performed in a separate locati on using the same setup geometry . T able 3 presents the DQI goals for the verification procedures. 10.3 HRPM Methodology

– Verification Procedure. The verification procedure involves releasing gas from a defined area, simulating a hot spot. 10.3.1 A suggestion f

or simulating a hot spot is to release the verification gas through a soaker hose arranged in a star- shaped pattern. This simulated source should be situated in an arbitrary location within the measurement area and comparable in size to the dimensions of one pixel. 10.3.2 A set of twelve (12) cycles can be considered a complete verification procedure. A cycle is defined as one complete sequential data collection through all PDCs in the setup. Data acquisition (see Section 11.2.9) and analysis parameters f or the verification procedure should be similar to those used for field measurements.FINAL ORS Protocol June 14 , 2006

13 Table 3 . DQIs for V erification Procedures Measurement Parameter Analysis Method Accuracy Precision % Complete a HRPM hot spot location Verification gas release 10% b NA 100% VRPM emission rate estimation Verification gas release 25% c NA 100% 1D - RPM upwind source location Verification gas release 20% d NA 100% a % Complete is the number of “valid” measurements (those that meet DQI goals for accuracy and precision) compared to the total number of measu

rements taken. b The distance between the reconstructed peak concentration and the center of the simulated hot spot should be within 10 percent of the diagonal distance of the HRPM measurement area (see Section 10.2.3.3). c The estimated release rate should be within ±25 percent of the measured (known) release rate to demonstrate an acceptable verification (see Section 10.2.4.5). d The distance between the determined upwind source and the center of the simulated hot spot should be within 20 percent of t he length of the 1D -RPM line - of - sight (see Section 10.2.5.3). 10.3.3 The sof

tw are will reconstruct a surface concentration contour map for the HRPM configurati

on. The maximum concentration value of this map is considered the reconstructed peak concentratio n. The distance between the reconstructed peak co ncentrati

on and the center of the simulated hot spot sho uld be within 10 percent of the diagonal distance of the HRPM measurement area . This 10 percent criterion applies when 8 to 16 beams are used in t he setup . NOTE 7 - Fewer than 8 beams can be used in the HRPM configuration; however, a verification procedure is not needed due to the qualitative (low resolution) nature of the results. 10. 4 VRPM Methodology - Verification Procedure . The verification procedure involves releasing gas from a defined a rea, simulating an area source. 10.4.1 A suggestion f

or simulating an area source is to release the verification gas th rough a soaker hose arranged in an “H” - shaped pattern. This simulated source should be situ at ed alm

ost immediately upwind from the VRPM plane . The distance between the VRPM plane and the nearest boundary of the simulated area source should be approximately five times the average height of the ground - level beam( s ) (refer to Secti on 11. 3 ). The dimensio ns of the simu lat ed area source should be approximately one - thir d to one - half the length of the VRPM set up , and the “H” pattern should be ce nt ered with respect to the measurement plane .FINAL ORS Protocol June 14 , 2006

14 10. 4 .2 For the VRPM met hodology verification procedure, the quant it y o f verification gas released over time should be measured . The preci se starting and ending time of the release should be recorded . 10.4.3 The mass of the gas released can be determined in several ways. Two approaches are given below. a) Weigh the gas cylind er prior to and after the release of the gas . Calculate the average actual emission rate of the gas. For example, if one kilogram (kg) of gas [1,000 grams (g)] is released over one hour [3,600 seconds (s)], the flux is calculated to be 1,000 g/3,600 s = 0. 28 g/s. b) Use a calibrated mass flo wmeter to ma int ain a constant emissio n rate. The output emissio n rate from the mass flowmeter should be converte d to units of g/s if necessary. 10.4.4 The software will calculate the flux of the verificatio n gas through the VRPM plane . Fluxes should be averaged for all time period s when the measured wind direct io n is wit hin - 1 0° to + 25 ° fro m perpendicular to the vertical plane . These averaged values are considered valid as est imated emissio n rates for the verificat io n pr ocedure. A set of 12 cycles can be considered a complete verification procedure , as lo ng as at least half o f these cycles sat is fy the - 1 0° to + 25 ° from perpendicular wind criteria . Data acquisit io n (see Section 11. 3.5 ) and analys is parameters for the verificat io n procedure should be similar to those used for field measurements. It i s recommended that at least 1 kg be released to minimize errors in weighing the cylinders. 10. 4 . 5 Com

pare the me asured emissio n rate value (Section 10.4.3) wit h t he estimated em

issio n rate from the VRPM met hodology (Section 10.4.4) . The calculated release should be ± 25 percent of the measured release rate (known) to demonstrate an acceptable verificat io n . 10. 5 1D - RPM Methodology - Verification Procedure . The verificat io n procedure invo lves releasing gas fro m a defined area, simulating a hot spot. 10. 5 .1 A suggestion for simulat ing a hot spot is to release the verification gas th rough a soaker hose arranged in a star - shaped pattern. This simulated source should be situated upwind fro m t he 1D - RPM line - of - sight at a di stance approximately equal to one quarter of the length of the setup . This source should be centered with respect to the fu ll length of the line - of

- sight . 10. 5 .2 The sof

tw are will determine the location of the upwind simu lated source. The lo cation sho uld be det ermined using data collected during time periods when the measured wind direction is within ±45 ° fro m perpendicular to the 1D - RPM line - of - sight . A set of 12 cycles can be considered a complete verification procedure, as lo ng as at least half of these cycles satisfy the ±45 ° fro m perpendicular wind criteria. Data acquisition (see Secti onFINAL ORS Protocol June 14 , 2006

15 11. 4.4 ) and analysis parameters for the verification procedure should be similar to those used for field measurements. 10.5.3 The dist ance between the determined upwind source and the center of the simulated hot spot should be within 2 0 percent of the length of the 1D - RPM line - of - sight . 11.0 Procedure for Setup and Data Acquisition 11.1 Overview . High - quality PIC data are needed for input to the met ho dol ogies described in this protocol . A pre - study geographical sit e assessment sho uld be conducted and an appropriate PI - ORS system must be selected. In addition, the user must choose the appropriate met ho dol

ogy – HRPM, VRPM, or 1 D - RPM

– depending on the purpose of the study. 11.1.1 The site assessment should co llect information on the size , layo ut , and topography of the site, any physical barriers that may affect data collection , and the lo cation of any possible off - site emission sources . This could include photographs and a detailed geographical site survey , which may be performed using a rangefinder, a theodolite, Geo graphical Positioning System (GPS), or similar instrument. 11.1.2 During the planning process , the seasonal prevailing wind direction expected during the time of the fie ld campaign should be researched . This wind data, in conjunction wit h t he suspected source locati on and site specific details, is used to design possible measurement setup s. 11.2 HRPM C

onfiguration . The HRPM co nfigurati on works best in an area without ma ny topographical features, so that the PI - ORS beam paths are close to the ground. This enhances the abilit y t o detect minor constituents emitted from the ground, since the emitted plumes may dilute significantly a s they rise above ground level. Also, if the beam paths are elevated from the ground, the plume may drift underneath the nearest beam and be detected by a beam further away. This would result in a misrepresentation of the actual source lo cation. 11.2.1 The PI - ORS instrument is typically placed at the origin (in the first quadrant of the Cartesian convention) of the rectangular area to be measure d (see Figure 1). Special cases do arise when the scanner and the PI - ORS instruments are placed on the x - axis away from the origin (see Note 3 ). For co nvenience, irregularly sized areas may be assumed to be rectangular. The maximum dimensions of the setup are limit ed only by the instrument specific capabilit ies ( i. e., maximum path length) and the user- required peak lo cation resolution . 11.2.2 A survey instrument should be used to determine the length and width of the study area and the angle of the x - axis from magnetic north. The size of the sampling area and desired peak locati

on resolution can be used to determine the optimal number of PDCs and their positions inside the area to be scanned.FINAL ORS Protocol June 14 , 2006

16 11.2.3 Once the HRPM measurement area and the number of PDCs have been determined, the area is divided into smaller rectangular areas called pixels. The total number of pixels requ ir ed is smaller or equal to the total number of beam paths. The pixels are ty pically numbered in the order sho wn in Figure 1.

PI - ORS Instrument Flags PDCs

PI - ORS Instrument Flags PDCs

Figure 1. Example of an HRPM Configuration Setup 11.2.4 In Figure 1, the survey area is divided into nine pixels of equal size. It should be noted that the survey area may be irregular in size, so that the resulting pixel grid is asymmetric (e.g., 2 by 4 pixels, 3 by 5 pixels, etc.). The total length of each axis should be divided by the number of pixels on that axis. This calculates the length of each pixel along each axis . Flags should be placed on each axis where each pixel boundary intersects (the lo cation of the flags are indicated by the circles in Figure 1 ) . These flags will be used as reference points for PDC placement. NO TE 8

– Due to cost considerations associated with the PDCs, this protocol addresses HRPM setup s utilizing a maximum of 16 PDCs. However, the use of a larger number of PDCs will increase the resolution of the peak location. 11.2. 5 Figure 1 shows an example HRPM configuration setup . Each pixel will have at least one optical beam path that terminates within its boundaries at a PDC. This geometry ma ximizes the spread of the optical beams inside the area of emissions by passing one optical beam through the cente r of each pixel. The approximate location (in polar coordinates) of each PDC within each pixel is determined using trigonometric calculations. 11.2.6 Each PDC should be placed as close as possible to its calculated distance and angle fro m no rth. After all PDCs had been placed, a visual inspect io n should be made to ensure a clean line - of

- sight to each PDC, and that each PDC is located wit hin the appropriate pixel.FINAL ORS Protocol June 14 , 2006

17 11.2.6.1 A clean line - of

- sight is ensured by looking at each PDC fro m t he PI - ORS instrument. T he PDC may need to be moved (within the appropriate pixel) to obtain a clear optical path. 11.2.6.2 The flags ment io ned in Sect io n 11.2.4 and illustrated in Figure 1 can be used as reference points for ensuring that each PDC is located within the boundarie s of the appropriate pixel. 11.2. 7 T he optical beam is defined by the instrument and each PDC. Measure t he actual pathlength and angle from magnetic north of each optical beam using a survey instrument. 11.2. 8 It is recommended that a meteorol ogical stati

o n is set up as part of the HRPM co nfiguration. Although this data is not required f or reconstructing the hot spot source lo cation , wind speed and directi on data may be helpf

ul in int erpreting the results. 11.2.9 Data A cquisition Parameters . Data acquisit io n param eters include total t ime of data collect io n and dwelling time per PDC. Data should be collected for a minimum of one hour during t ime s when the wind meets the criteria defined in Sect io n 4.2.2.3. Dwelling time per PDC is determined by 1) the specific proj ect goal s, and 2) the PI - ORS instrum ent - specific detection limits of the expected target gases . A recommended range fo r dwelling time per PDC is 10 to 60 seconds. 11. 3 VRPM Configuration . T he VRPM plane should be placed immediately downwind fro m t he suspected emission source. T he prevailing wind di rect io n should be as perpendicular as possible to the vert ical plane of measurement. The dimensio ns of the VRPM plane (length and height) should be ma ximize d to capture as much of the pl ume as possible . 11.3 .1 The primary purpose of the VRPM met hodology is to calculate the flux th rough the vertical plane. A minimum of two PDCs are necessary fo r this measurement

– one of which should be on the ground defining the full length of the setup , and one on the vert ical structure . The recommended setup fo r flux calculat io n is th ree PDCs, with one on the ground defining the full length of the setup , one at the top of the vertical structure, and one at approximately half o f t he height of the vert ical structure . NOTE 9 - Ground- level PDCs refer to those defining optical beams as close to horizontal as possible, given the topography of the site and the particular PI - ORS system characteristics. 11.3.2 In addit io n to measuring the flux, spatial informat ion pertaining to the source ho mo geneit y of the emitted plume can be obtained through the use of addit io nal PDCs placed at intermediate lengths alo ng the ground. This spat ia l informat io n can be used to assess source ho mo geneit y, and similar to the 1D - RPM met hodology , can be use d to determine the lo cation of the upwind source (see Section 2.4.2) . A minimum of four PDCs are necessary for the measurement of flux and plume spatial informat io n , with th ree placed at ground level ( o ne defining the full length of the setup ) and one on t heFINAL ORS Protocol June 14 , 2006

18 vert ical structure . The recommended setup utilizes five to seven PDCs , with th ree to five PDCs along the ground , one at the top of the vertical structure, and one at approximately half the height of the vert ical structure. Figure 2 illustrates a typical VRPM setup using six PDCs, placed as fo llo ws: a. At 1/4 of the distance of the length of the VRPM setup . b. At 1/2 of the distance of the length of the VRPM setup . c. At 3/4 of the distance of the length of the VRPM setup. d. At the full length of the VRPM setup. e. Positioned on the vertical structure at half height. f . Positioned at the top of the vertical structure.

X Y Z PI - ORS Instrument Fugitive Source/ Area of Interest Mean Wind Direction PDCs

a b c d

e

f

X Y Z PI - ORS Instrument Fugitive Source/ Area of Interest Mean Wind Direction PDCs

a b c d

e

f

Figure 2. Example of a VRPM Configuration SetupFINAL ORS Protocol June 14 , 2006

19 11.3.3 The vert ical structure should be located between the midpo int and far end of the VRPM setup, as referenced fro m t he PI - ORS instrument (see Figure 2). Instrument specific limit ations and topography will dictate the specific placement of the vert ical structure. For example, when co llect ing data under moderate to high wind condit ions, it may be necessary to locate the vertical structure near the midpo int of the VRPM setup to optimize the PI - ORS instrument signal qualit y. 11.3.4 Prevailing Wind Direction Criteria . Ideally, the prevailing wind direction should be as close as possible to perpendicular to the VRPM measurement plane. This needs to be determined for each field study measurement configuration. For the Duke Forest validation study , 11 the prevailing wind direction criteria was determined to be - 10o to + 25 o, where 0o is perpendicular to the vertical plane. The procedure for determining the prevailing wind direction criteria is described in Appendix A (see Section A.2.3.2.4) . 11.3.5 Data Acquisition Parameters . Dat a acquisition parameters include total time of data collection and dwelling time per PDC. Data collection should proceed regardless of the wind conditions (if safety permits) until a minimum of one hour of total data is co llected during times when the wind meets the criteria defined in Sections 4.2.2.3 and 11.3.4. Dwelling time per PDC is determined by 1) the specific project goals, and 2) the PI - ORS instrument - specific detection limits of the expected target gases. A recommended range for dwelling time per PDC is 10 to 60 seconds. 11.3.6 Wind Measurements . The wind data should preferably be measured at two heights

— near th

e base and near the top of the vertical plane (e.g., at 2 and 10 meters). Tem poral resolution of the wind data should not be longer than the dwelling time on each PDC. The dual- height measurement of wind condit io ns allo ws for interpolation and extrapolation of this data through the vertical plane and is important in determining if the wind criteria have been met. In special cases when two wind monitors are not available, one wind monitor can be used at mid - he ig ht (3 - 5 m) to represent the average wind of the entire vertical plane. 11.3.7 When Data Acquisition and Wind Criteria Are Not Met . Data collect io n may proceed even when the one - hour data acquisit io n criterion is not met. Prior knowledge on source locatio n and size, and actual wind direct io n, should be used to assess how much of the plume is captured by the setup. If the assessment of plume capture is valid ( see Appendix A fo r a suggested method for plume capture assessment), the data can be used to estimate the emissio n rate. Without prior knowledge of source location and size, the data may be insufficient to estimate the emissio n rate. 11. 4 1D - RPM Configuration . The 1D - RPM configuration is used to profile pollutant co ncentrati

ons along a line - of

- sight dow nwind of a fugitive emission source. This pollutant co ncentrati

on profile can be combined with wind data to estimate the location of an upwind source, when applicable. The scanning PI - ORS instrum ent and three or more PDCs are placed along a cro sswind direction and PIC measurements are made.FINAL ORS Protocol June 14 , 2006

20 11.4.1 The 1D - RPM configuration setup is shown in Figure 3 . It is necessary to deploy PDCs slight ly of

f o f a di rect line - of

- sight orientation to avo id overlap of the beam paths , as depicted in the figure . A minimum o f t h ree PDCs are needed, but four to six are recommended fo r this configurat io n . The additional PDCs provide a more detailed concentration profile. PDCs should be placed on the line - of - sight, with an equal distance between each subsequent PDC, if possible (see Figure 3). 11.4.2 Extending the 1D - RPM configuration. To extend the range of the 1D - RPM configuration, the PI - ORS instrument may be placed at an intermediate location in the setup. The PDCs should be placed in a line - of - sight extending in two opposite directions. For thi s special setup, the same recommendat io n and criteria detailed in Sect io n 11.4.1 should be fo llo wed. If there is an even number of PDCs, the PI - ORS instrument should be placed at approximately the center of the setup, with an equal number o f PDCs on ei ther side. If there is an odd number of PDCs, the PI - ORS instrument should be as close to the center of the setup as possible, while maintaining an equal distance between each PDC.

Concentration Profile

PI- ORS Instrument PI- ORS Instrument 100 m 200 m 300 m 400 m 500 m Y Conc. Concentration Profile

PI- ORS Instrument PI- ORS Instrument 100 m 200 m 300 m 400 m 500 m Y Conc. Figure 3. Example of a 1D - RPM Configuration Setup 11.4.3 Da ta Collection Criteria . Ideally, the prevailing wind direct io n should be within 45 o f

rom perpendicular to the 1D - RPM setup , where 0o is perpendicular to the line - of - sight . 11.4.4 Data Acquisition Parameters . Data acquisit io n param eters include total t ime o f data collect io n and dwelling time per PDC. Data collect io n should proceed regardless of the wind condit io ns unt il a minimum of one hour of total data is collected during timesFINAL ORS Protocol June 14 , 2006

21 when the wind meets the criteria defined in Section 4.2.2.3 and 11. 4 . 3 . Dwelling time per PDC is determined by 1) the specific pro ject goals, and 2) the PI - ORS instrument specific detection limit s of the expected target gases. A recommended range for dwelling time per PDC is 10 to 60 seconds. 11. 4 . 5 Wind Measurements . The wind data sho uld be measured in at least one locati on alo ng the line - of

- sight , wi th additional locations providing a better representati on of the overall site wind field . Tem poral resolution of the wind data should not be longer than the dwelling time on each PDC. 1 1.4.6 When Data Acquisition and Wind Criteria Are Not Met . Data collect io n may proceed even when the one - hour data acquisit io n criterion ( within 45 o f rom perpendicular ) is no t met. In this case, data should be co llect ed fo r a total of two hours when the pr evailing wind direct io n is within 70 o f rom perpendicular to the 1D - RPM line of - sight before reassessing the setup . 12.0 Data Analysis and Calculations 12.1 Overview

. Prior to analysis , determine the moving averaging scheme for generati on of the plume map s fo r any met hodologies used in t his protocol . Because dat a is acquired sequentially, a mo ving average is required to reduce errors th at originate from temporal variabilit y (see Appendix A , Secti on A2.3.2.2) . Ty

pically, a moving average with a grouping of th

ree cycles is sufficient to provide stable results with a CCF larger than 0. 8 . 12 . 2 HRPM Methodology 12. 2 .1 HRPM Theory . Once the PIC for all beam paths are averaged with the predetermined grouping of cycles fo r the gas species of interest, the HRPM calcu lat io ns make use of the information to reconstruct a plume map over the area of int erest . An example emissio n source location map is shown in Figure 4. The cross shows the lo cat io n of the plume center from a study where propane gas was released at the lo c at io n shown by the open circle. 12.2.2 HRPM Algorithm . Average concentrations f or each pixel are obtained by applying an iterative algebraic deconvolution algorithm. The measured PIC, as a function of the fie ld of concentrati

on, is given by: 

# ∑ = m m

km k c K PIC (12 - 1)FINAL ORS Protocol June 14 , 2006

22 Figure 4. An Example Emission Source Location Map Where: K = a kernel matrix that incorporates the specific beam geometry wit h t he

pixel dimensio ns; k = the number index for the beam paths; m = the number index for the pixels; and c = the average concentration in the m th pixel. 12. 2 .2.1 Each value in the kernel matrix K is t he length of the k th beam wit hin t he m th pixel; therefore , the matrix is specific to the beam geometry. The HRPM procedure so lves fo r the average concentrations (one f or each pixel) by applying non - negative least squares ( NNLS ) . 23 12. 2 .2.2 The HRPM procedure m ult ip lies the resulting vertical vector of averaged co ncentrati

on by the matrix K to yie ld t he end vector of predicted PIC data. 12. 2 .2.3 The second stage of the plume reconstruction involves interpolation among the reconstructed pixel’s aver age concentration, providing a peak concentrati on not limited to the center of the pixels. A triangle - based cubic interpolation procedure (in Cartesian coordinates) i s currently used in the HRPM procedure . 24 12. 2 .3 Check for Reasonableness of Surface Concentration Plot Results . Evaluate the data f or reasonableness with the following qualitative (12. 2 .3. 1 ) and quantitative (12. 2 .3. 2 ) checks.FINAL ORS Protocol June 14 , 2006

23 12. 2 .3. 1 If the order in whi ch the beam paths were scanned ( and the corresponding pixel numbering convent io n inside the HRPM program ) are different than the order of PIC data input, the reconstructed plume center could fall in an incorrect pixel. Verify that the generated result is reasonable based on the raw PIC data. 12. 2 .3. 2 To determine the qualit y o f t he reconstructed plume maps against the measured PIC data, t he Concordance Correlat io n Factor (CCF) is used to represent the level of fit between measured PIC and predicted PIC . A CCF greater than 0. 8 verifies that the surface concentration plot is a reasonable fit with the raw data (Table 2, Section 9. 2 ). 2 5 If the CCF is less than 0.8 , the Check for Reasonableness procedures should be perform ed a second time to confirm the input da ta. The analysis may repeated with a lo nger average scheme , which t yp ically increases the CCF value . NOTE 1 0

— The CCF is similar to the Pearson correlation coefficient, but is adjusted to account for shifts in location and scale. Like the Pearson correlation (correlation coefficient, ‘R’), CCF values are bounded between - 1 and 1, yet the CCF can never exceed the absolute value of the Pearson correlation factor. For example, the CCF will be equal to the Pearson correlation when the linear regression line intercepts the ordinate at 0, its slope equals 1. Its value will be lower than the Pearson correlation when the above conditions are not met. 1 4 , 2 6 A detailed description of the procedure for calculating the CCF is included in Section 12.3.3.3. 12. 2 .4 Ho t spot location determination The HRPM procedure provides a plume map and calculates the location of the peak concentrations. It is for the user to interpret this informat io n and site constraints , such as obstructions or terrain complexit ies , fo r the determinat io n of the actual locat io n of the hot spot. 12. 3 VRPM Methodology 12.3.1 VRPM Theory and Algorithms . Once the PIC for all beam paths are averaged wit h t he predetermined grouping of cycles for the gas species of interest, the VRPM calculations make use of the information to reconstruct a plume map in the vertical downwind plane. Two different beam configurations of the VRPM methodology are recommended : the five - beam (or more) and the three - beam VRPM configuration. Figure 2 illustrates the setup for t hese two VRPM beam configuration s . In the five - beam (or more) co nfiguration , the ORS instrument sequentially scans over five PDCs. T hree PDCs are alo ng the ground- level crosswind direction (beams a , b , and c in Figure 2 ) , and the other two are elevated on a vertical structure (beams e and f in Figure 2 ). The additional beam (d) in Figure 2 is for 6 - beam configuration, which provides better spatial definition of the plume in the crosswind direction. In the three - beam configurati on , the ORS instrument sequen tially scans over th

ree PDCs. O nly o ne beam is along the ground level (beam c or d in Figure 2 ) and the other two are elevated on a vertical structure (beams e and f in Figure 2 ). PIC data are collected over time , co mplet ing many cycles through the defined beams of each configurati

on. 12. 3 .1. 1 A t wo - phase smooth basis function minimization (SBFM) approach is applied where there are three or more beams along the ground level (5 - beam or moreFINAL ORS Protocol June 14 , 2006

24 co nfiguration). In the two - phase SBFM approach, a one - dimensional SB FM reconstructi on procedure is first applied in order to reconstruct the smoothed ground level and crosswind co ncentrati

on profile. The reconstructed parameters are then substituted into the bivariate Gaussian function when applying a two - dimensional SBFM procedure. 12.3.1.1.1 A o ne - dimensio nal SBFM reconstruction is applied to the ground level segmented beam paths ( Figure 2 ) of the same beam geometry to find the cross wind concentration profile. A univariate Gaussian funct ion is fitted to measured PIC grou nd level values. 12.3.1.1.2 The error function for the minimizat io n procedure is the Sum of Squared Errors (SSE) funct io n and is defined in the one - dimensional SBFM approach as fo llo ws: 2
0 2 2 1 exp 2 ) , , ( 

## ∑ ∑ ∫                     

      

−

− − = i j r j y j y j y j i j y j y j i dr r m B PIC m B SSE σ σ π σ ( 12 - 2 ) Where: B = equal to the area under the one - dimensional Gaussian distribut io n

(int egrated concentration); ri = the pathlength of the i th beam; my = the mean (peak location); σ y = the standard deviation o f t he j th Gaussian funct io n; and PICi = the measured PIC value of the i th path . 12. 3 .1. 1.3 The SSE function is minimized using the Simplex minimizat io n procedure to solve for the unknown parameters ( i. e. , B , my, σ y ) . 2 7 12. 3 .1. 1.4 When there are more than three beams at the ground level, two Gaussian functions are fitted to retrieve skew ed and sometimes bi- mo dal concentrati on profiles. Thi s is the reason f

or th e index j in Equation 12 - 2. 12.3.1.1 .5 Once the one - dime nsional phase is completed, the two - dimensional phase of the two - phase process is applied. To derive the bivariate Gaussian f unction used in the second phase, it is co nvenient to express the generic bivariate function G in polar coordinates r and θ

: 

## ( ) 

## ( ) ( ) ( ) G r A r m r m r m r m

y z y y y z y z z z ( , ) exp ( cos ) cos sin sin θ πσ σ ρ ρ θ σ ρ θ θ

σ σ θ

σ =

− −

− ⋅ −

− ⋅ − ⋅ − + ⋅ −                   2 1 1

2 1 2 12 2 12

2 2

2 12 2 2 (12 - 3 )FINAL ORS Protocol June 14 , 2006

25 12.3.1. 1.6 The bivar iat e Gaussian has six unknown independent parameters: A = normaliz ing coefficient which adjusts for the peak value of the

bivariate surface; ρ 12 = correlat io n coefficient which defines the direct io n of the

di stribut io n - independent variat io ns in relat io n to th e Cartesian di rect io ns y and z ( ρ 12 =0 means that the distribut io n variat io ns overlap the Cartesian coordinates); my and mz = peak locations in Cartesian coordinates; and σ y and σ

z = standard deviat io ns in Cartesian coordinates. 12.3.1. 1.7 Six independent beam paths are sufficient to determine one bivariate Gaussian that has six independent unknown parameters. 12.3.1. 1.8 Some reasonable assumptions are made when applying the VRPM met hodology to this problem, to reduce the number of unknown parameters. The first is setting the correlation parameter ρ 12 equal to zero. This assumes that the reconstructed bivariate Gaussian is limited only to changes in the vertical and crosswind directions. Secondly, when ground level emissions are known to exist, the ground level PIC is expected to be the largest of t he vertical beams. Therefore, the peak location in the vertical direction can be fixed to the ground level. In the above ground - level scenario, Equation 12 - 3 reduces into Equati on 12 - 4: 

## ( ) 

                

⋅

+ − ⋅

− = 2 2 2 2 sin ) cos ( 2 1 exp 2 ) , ( z y y z y r m r A r G σ θ σ θ σ πσ θ (12 - 4) 12.3.1. 1.9 The standard deviat io n and peak location retrieved in the one - dimensio nal SBFM procedure are substituted in Equation 12 - 4 to yield: 

## ( )                  
⋅

+ − ⋅

− =

− −

− 2 2 2 1 2

1 1 sin ) cos ( 2 1 exp 2 ) , ( z D y D y z D y z r m r A A G σ θ σ θ σ πσ σ (12 - 5 ) Where: σ

y - 1D = standard deviat io n along the crosswind direction (found in the one dimensio nal SBFM procedure); my - 1D = peak location along the crosswind direction (found in the one dimensio nal SBFM procedure);FINAL ORS Protocol June 14 , 2006

26 12.3.1. 1.10 A and σ z are unknown parameters to be retrieved in the second phase of the fit ting procedure. 12.3.1. 1.11 A n error funct io n (SSE) fo r minimizat io n is defined for this phase in a similar manner . The SSE funct io n fo r the second phase is defined as: 

## ( ) 

## ∑ ∫        

− = i r z i i i z i dr A r G PIC A SSE 2 0 )

, , , ( , σ

θ σ ( 12 - 6 ) Where: PICi = the measured path - int egrated concentration value of the i th path. 12. 3.1. 1.12 T he SSE function is minimized using the Simplex method to s olve fo r the two unknown parameters. 12.3.1. 2 When the VRPM configurat io n consists only of three beam paths

— one at the ground level and the other two elevated

—the one - dimensio nal phase can be skipped, assuming that the plume is very wide. In this scenario, peak location can be arbitrarily assigned to be in the middle o f t he configurat io n. Therefore, the three - beam VRPM c onfiguration is most suitable for area sources (where no localized hot spot is expected) or for so urces with a series of po int and fugit ive sources that are known to be distributed across the upwind area. In this case, the bivariate Gaussian has the same t wo unknown param eters as in the second phase ( Equation s 12 - 5 and 12 - 6 ), but information about the pl ume width or location is not known. The standard deviat io n in t he crosswind direct io n is t yp ically assumed to be about 10 times that of the ground level bea m path (length of vert ical plane) . If r1 represents the length o f t he vertical plane, the bivariate Gaussian would be as fo llo ws: 

## ( ) ( )                 ⋅

+ − ⋅

− = 2 2 2 1 2 1 2 1 1 sin

10 ) cos ( 2 1 exp ) 10 ( 2 ) , ( z z z r r r r r A A G σ θ θ σ π σ ( 12 - 7 ) This process is for determining the vert ical gradient in concentration. It allows an accurate int egration of concentrations across the vertical plane as the long - beam ground level PIC provides a direct integration of concentration at the lowest level. 12.3 .2 Once the parameters of the function are found f or a specific run, the VRPM procedure calcu lat es the concentrati on values for every square elementary unit in a vertical plane . Then, th

e VRPM procedure integrates the values, incorporating wind speed data at each height level to compute the flux. The concentration values are converted from parts p er million by volume (ppmv) to grams per cubic meter (g/m 3 ), taking into consideration the mo lecular weight of the target gas. This enables the direct calculation of the flux in grams per second (g/s), using wind speed data in meters per second (m/s).FINAL ORS Protocol June 14 , 2006

27 12. 3 . 3 Check for Reasonableness of the Calculated Flux . Evaluate the data for reasonableness with the following qualitative (12. 3 .2. 1 ) and quanti ta tive (12. 3 .2. 2 ) checks. 12. 3 . 3 . 1 Verify that the generated result is reasonable based on the raw PIC data. 12. 3 . 3 . 2 To determine the qualit y o f t he reconstructed plume maps against the measured PIC data, the CCF is used to represent the level o f fit between measured PIC and predicted PIC (see Note 1 0 ) . 12.3. 3 .3 As described in earlier studies , 7 the Concordance Correlat io n Factor (CCF) was used to represent the level of fit for the reconstruction in the path - int egrated domain (predicted versus me asured PIC). CCF is defined as the product of two components: rA CCF = ( 12 - 8 ) Where : r = the Pearson co rrelat io n coefficient; A = a correction factor for the shift in populat io n and location. 12.3. 3 .4 This shift is a funct io n of the relat io nship between the averages and standard deviat io ns o f t he measured and predicted PIC vectors: 1 2 2 1 −                            

− + + = M P P M M P PIC PIC M P PIC PIC PIC PIC PIC

PIC A σ σ σ σ σ σ ( 12 - 9 ) Where:

P

PIC σ = standard deviat io n of the predicted PIC vector ;

M PIC σ = standard deviat io n of the measured PIC vector;

P PIC = the mean of the predicted PIC vector; and

M PIC = the mean of the measured PIC vector. 12.3. 3 .5 The Pearson correlat io n coefficient is a good indicator of the qualit y o f fit to the Gaussian mathemat ical funct io n . In thi s procedure , ty pically an r close to 1 will be fo llo wed by an A very close to 1. Thi s means that the averages and standard deviat io ns in the two concentration vectors are very similar and the mass is conserved (good flux value). However, when a poor CCF is reported (CCF<0.80) at the end of the fitt ingFINAL ORS Protocol June 14 , 2006

28 procedure it does not direct ly me an that the mass is not conserved. It could be a case where only a poor fit to the Gaussian funct io n occurred if the correction factor A was still very close to 1 (

A >0. 9 0). However, when both r and A are low one can assume that the flux calculat io n is inac curate. 12.3. 3 .6 A CCF greater than 0. 8 0 indicates th at the surface concentration plot is a reasonable fit with the measured PIC (Table 2, Section 9.2). 2 5 If the CCF is less than 0. 8 0 , but A >0.90, this is still a reasonable indicat io n of a good mass equiva lent surface concentration plot. If the CCF is less than 0.8 0 , but A <0.90, then the Check for r easonableness procedures (Section 12.3. 3 ) should be performed a second time to confirm the input data. The analysis may be repeated wi th a lo nger average scheme , which t yp ically increases the CCF value . 12. 4 1D - RPM Methodology 12. 4 .1 1D - RPM Theory and Algorithms . Once the PIC for all beam paths are averaged wit h t he predetermined grouping of cycles fo r the gas species of interest, the 1D - RPM calculat io ns make use o f t he informat io n to reconstruct a plume concentration profile along the measurement line - of - sight. Similar to the case of VRPM (which assumes a bivariate Gaussian plume mass in two dimensio ns ), the 1D - RPM calculat io ns utilize the one - dimensio nal (1D) SBFM to reconstruct a mass - equivalent plume concentration profile along the line - of - sight m easurem ent. The plume crosswind peak lo cat io n, coupled wit h t he average wind direct io n data, can provide an idea of the emissio n source location and configurat io n. 12. 4 . 2 T he 1D - RPM procedure fit s a univariate Gaussian funct io n to measured PIC ground - le vel values. The error funct io n fo r the minimizat io n pro c edure is the SSE funct io n, and is defined in the 1D - SBFM approach as fo llo ws: 2
0 2 2 1 exp 2 ) , , ( 

## ∑ ∫

∑                   

      

−

− − = i r y y j y

j i y y j i j j j j j dr r m B PIC m B SSE σ σ π σ (12 - 10 ) 1 2. 4 . 3 The unknown independent parameters for the 1D - SPFM Gaussian are: B = the area under the Gaussian distribution; ri = the path length of the i th beam; my = the mean (peak location); σ y = standard deviat io n of the jth Gaussian funct io n; and PICi = the measured path - int egrated concentration value of the i th path.FINAL ORS Protocol June 14 , 2006

29 12.4.4 Check for Reasonableness of the Concentration Profile . Evaluate the data f or reasonableness with the following qualitative (12. 4 . 4 .1) and quanti ta tive (12. 4 . 4 .2) checks. 12. 4 . 4 .1 Verify that the generated result is reasonable based on the raw PIC data. 12. 4 . 4 .2 To determine the qualit y o f t he reconstructed plume maps against the measured PIC data, the CCF is used to represent the level o f fit between measured PIC and predicted PIC (see Note 1 0 ). A CCF greater than 0. 8 verifies that the surface concentration plot is a reasonable fit with the raw data (Table 2, Section 9.2). 2 5 If the CCF is less than 0. 8 , the Check for Reasonableness procedures should be performed a second time to co nfir m t he input data. The analysis may be repeated with a longer average scheme, which typically increases the CCF value.

NOTE 1 1 • The 1D - RPM met hodology above explains a single Gaussian mass equivalent plume. It is possible to fit mult iple Gaussian plume profiles when more than three PDC are used [e.g., a comb ination of two Gaussian profiles with four or more PDC as explained in Ha shmonay and Yost (1999) 2 ]. This mult iple Gaussian approach can provide mu ltiple mode or skewed concentration profiles. Also this can be extended for VRPM configurations where four or mor e ground - level PDC are used to fit bi - modal or skewed bivariate Gaussi an profiles. This ma y improve the accuracy of flux measurements , as it always provide s higher CCF values . 12. 4. 5 The 1D - RPM procedure r econstruct s the plum e profile along the measurement line - of - site and note s the peak location. Over time, as the wind direction fluctuates, different peak locat io ns are reconstructed from the PIC measurements as illustrated in Figure 5 . Each time a peak location is noted , a source project io n line is drawn fo r each peak location . This is done by calculat ing a line equation th rough the peak location, with the same orientation as the averaged wind direct io n fo r the same measurement time int erval . Ideally, for a stationary point source, all source project io n lines drawn over time should intersect at a point upwind of the measurement line in the vicinit y o f t he real emissio n source location. C alculat ing the densit y of lines per unit area upwind fro m t he measurement plane, the most likely locat io n of the source can be est imated as the region of the maximal line densit y. 13.0 Method ology Performance 13.1 Data Quality Objectives . A verification gas release may be conducted during a fie ld study to verify that the instrument is performing well, as long as the PI - ORS instrument is capable of detecting multiple compounds. Note the beginning and end of the release and the amount released. 13.1.1 For a verification gas release using the HRPM met hodology , a plume center lo cation error of ± 10 percent of the diagonal distance of the entire area scanned is co nsidered a good indicator of qualit y .FINAL ORS Protocol June 14 , 2006

30 13.1.2 For the weight of the verificat io n gas release retrieved using the VRPM methodology , an error of ± 25 percent of the total actual release for the duration of the experiment is considered a good indicator of qualit y. 13.1.3 For the locat io n of the verificat io n gas release using the 1D - RPM methodology , an error of ± 2 0 percent of the lo ngest beam path alo ng the line - of - sight is considered a good indicator of qualit y.

Figure 5. An Example of a 1D - RPM Fenceline Monitoring Setup 14.0 Pollution Prevention A d iscussio n of pollut io n prevention issues is not necessary, as they are instrum ent specific and not direct ly associated with applicat io n of the methodologies described in this protocol . Source Location Reflectors PI - ORS Instrument

Met Station Wind

Direction

Industrial Complex

1 2 3

PDCFINAL ORS Protocol June 14 , 2006

31 15.0 Waste Management Becaus e no actual samples are co llected with PI - ORS instrumentation, there are no waste management issues. 16.0 References 1 Hashmo nay, R. A.; Yost, M. G. Innovat ive Approach for Estimat ing Gaseous Fugit ive Fluxes Using Co mputed Tomography and Remote Optical Se nsing Techniques. J. Air & Waste Manage. Assoc. 1999, 49 , 966. 2 Hashmo nay, Ram A.; Yost, Michael G. Localizing Gaseous Fugit ive E missio n Sources by Combining Real - Time Remote Optical Sensing and Wind Data. J. Air & Waste Manage. Assoc. 1999, 49 , 1374 - 1379 . 3 Hashmo nay, R. A.; Yost, M. G.; Mamane, Y.; Benayahu, Y. Emissio n Rate Apportionment from Fugitive Sources Using Open - Path FTIR and Mathemat ical Inversio n. Atmos. Environ. 1999, 33 , 735 - 743. 4 Hashmo nay, R. A.; Yost, M. G.; Wu, C. F. Computed Tomography of Air Pollutants Using Radial Scanning Path - Integrated Optical Remote Sensing. Atmos. Environ. 1999, 33(2), 267. 5 Price, P. N. Pollutant Tomography Using Integrated Concentration Data from NonIntersecting Optical Paths. Atmos. Environ. 1999, 33(2), 275 - 280. 6 Wu, C. F. ; Yost, M. G. ; Hashmo nay, R. A.; Park, D. Y. Experimental E valuat io n of a R adial B eam G eo metry fo r M apping A ir P ollutants U sing O pt ical Rem ote S ensing and C om

puted To mo graphy . Atmos. Environ . 1999, 33(28), 4709 - 4716. 7 Hashmo nay, R.A.; Nat schke, D. F.; Wagoner, K.; Harris, D. B.; Thompson, E. L.; Yost, M. G. Field Evaluat io n of a Method for Estimat ing Gaseous Fluxes from Area Sources Using Open - Path Fourier Transform Infrared. Environ. Sci. Technol . 2001, 35, 2309 - 2313. 8 Yost, M. G.; Hashm

onay , R. Mapping Air Contaminants Using Path- Integrated Optical Remote Sensing with a Non - Overlapping Variable Path Length Beam Geom etry . U.S. Patent 6,542,242 B1, 2003. 9 Modrak, M. T.; Hashmo nay, R. A.; Keagan [Kagann], R. Measurement of Fugitive Emissio ns at a Region I Landfill; U.S. Environmental Protection Agency, Research and Development, EPA - 600/R - 04 - 001, January 2004. 1 0 Thoma, E. D.; Shores, R. C.; Thom pson, E. L.; Harris, D. B.; Thornloe, S. A.; Varma , R. M.; Hashmo nay, R. A.; Modrak, M. T.; Natsc hke , D. F.; Gamble , H.A. OpenFINAL ORS Protocol June 14 , 2006

32 P ath T unable D io de Laser Absorption Spectroscopy for Acquisit io n of Fugitive E missio n F lux D ata. J. Air & Waste Manage. Assoc. 2005, 55 , 658 - 668. 1 1 Hashmo nay, Ram A.; Varma, Ravi M.; Modrak, Mark T.; Kagann, Robert H.; Egler, Kim; Sullivan, Patrick D.; Segall, Robin R. Validation of Vertical Radial Plume Mapping Methodology for Estimating Gaseous Emissio n Rates fro m Area Sources. J. A ir & Waste Manage . Assoc . Submitted in 2006. 1 2 Huang, Zhonghua ; Wang, Junde ; Li, Yan . Mappin g Spacial Tracer Gases Concentration Profiles on a Two - Dimensio nal Plane by OP - FTIR Remote Sensing . Instrumentation Sci. & Technol . 2003 , 31 (1) , 23 - 32 . 1 3 Scotto, R. L.; Minnich, T. R.; Leo, M.R. A Method for Estimat ing VOC Emissio n Rates fro m Area Sources Using Remote Optical Sensing. In Proceedings of the EPA/A& WMA International Symposium on the Measurement of Toxic and Related Air Pollution , Raleigh, NC, 1991, 698. 1 4 Piccot, S. D.; Masemore, S. S.; Lewis - Bevan, W.; Ringler, E. S.; Harris, D. B. Field As sessment of a New Method for Estimat ing E mission Rates fro m Volume Sources Using Open - Path FTIR. J. Air & Waste Management Assoc. 1996, 46, 159. 1 5 Simpson, O. A.; Kagann, R. H. Measurements of Emissio ns at a Chemical Waste Water Site with an Open Path Rem ote Fourier Transform Interfero met er. In Proceedings of the EPA/ A& WMA International Symposium on the Measurement of Toxic and Related Air Pollution , Raleigh, NC, 1990, 937. 16 Weber, Konradin ; Lamp , Torsten ; Schulte, Klaus ;Weidemann, Johannes ; van Haren, Günther ; Gärtner , Andrea ; Bröker , Günter . Open - Path FTIR - Measurements of Methane as a Tracer Gas for Waste Site Emissio ns at a Waste Site in Germany . Proceedings of the A& WMA 89th Annual Meeting & Exhibition , Pittsburgh, PA, 1996, 11p . 17 Heise,Michael ; Mü ller, Uwe; Gärtner , Andrea ; Hölscher ; Norbert . Im proved Chem om etric Strategies for Quantitative FTIR Spectral Analysis and Applications in At mo spheric Open - Path Monitoring . Field Anal. Chem. & Technol. 2001 , 5(1 - 2) , 1 3 - 28 . 18 Schäfer, Klaus ; Steinecke, In a; Em eis, Stef an ; Stockhause, Martina ; Sussmann, Ralf; Trickl, Tho mas ; Reitebuch, Oliver ; Hoechstetter, Karsten ; Sedlmaier, Achim ; Depta, Georg ; Gronauer, Andreas ; Seedorf, Jens ; Hartung, Jö rg . Inverse M odelling on the B asis of Rem ote S ensing to D et er min e E missio n R ates . Meteorol. Zeitschrift

, 1998 , N.F. 7, 7 - 10 (Februar) .FINAL ORS Protocol June 14 , 2006

33 1 9 Compendium Method TO - 16: Long - Path Open - Path Fourier Transform Infrared Monitoring of Atmospheric Gases; U.S. Environmental Protection Agency, Center for Environmental Research Info rmat io n - Office of Research and Development: Cincinnat i, Ohio, January 1999. 2 0 American Society for Testing and Materials (ASTM) Standard Practice E1982 - 98, Standard Practice for Open - Path Fourier Transform Infrared (OP/FT - IR) Monitoring of Gases and Vapo rs in Air; March 1999. 2 1 American Society for Testing and Materials (ASTM) Standard Guide E1865 - 97 (Reapproved 2002), Standard Guide for Open - Path Fourier Transform Infrared (OP/FT - IR) Monitoring of Gases and Vapors in Air ; July 1997. 2 2 VDI 4211, Part 1 . Rem ote Sensing, At mo spheric M easurements N ear Ground with FTIR S pectroscopy , Measurements of G aseous E missio ns and I mmissio ns . Beuth Verlag Berlin, 2000 . 2 3 Lawson, Charles L.; Janson, Richard J. Solving Least Squares Problems ; Societ y fo r Industrial and Applied Mathemat ic s: Philadelphia, 1995; Chapter 23, pp 158 - 165. 24 Barber, C. B., D.P. Dobkin, and H.T. Huhdanpaa, "The Quickhull Algorithm for Convex Hulls," ACM Transact io ns on Mathemat ic al Sof tware, Vol . 22, No. 4, Dec. 1996, p. 469 - 483. 25 Lin, L. I - K. A C oncordance C orrelat io n C oefficient to E valuate Reproducibilit y. Biometrics . 1989, 45. 255 - 68. 2 6 Byer, R. L.; Shepp, L. A. Two - Dimensio nal Remo te Ai r - Pollut io n Monitoring Via Tom ography . Opt. Lett. 1979, 4(3), 75 - 77. 2 7 Press, W. H.; Teukolsky, S. A. ; Vetterling, W. T.; Flannery, B.P. Numerical Recipes in FORTRAN

, 2nd ed.; Cambridge Universit y Press: Cambridge, MA, 1992 .FINAL DRAFT ORS Protocol June 14 , 2006

34 

### Appendix A Example Application of Methodologies Described in this Protocol using OP - FTIR The met hodologies described in this prot oc ol are independent of the particular PI - ORS instrument. This appendix has been included to illustrate the applicat io n of the methodologies described in this protocol during tw o separate experiment s using a scanning open - path FTIR (OP - FTIR). A1 - 4 The met hodologies described in this protocol have been ut ilized for several other environmental mo nit oring programs. A5 - 7 A1.0 Examples of DQI Goals and Internal QC. The Data Qualit y Indicator (DQI) goals for the OP - FTIR instrument are shown in Table A.1 The DQI g oal s were developed based on analysis o f t he historical data obtained in similar studies and available guidance documents . Table A.1 Data Quality Indicators (DQIs) for OP - FTIR Measurement Parameter Analysis Method Accuracy Precision % Complete PI C Deter mination OP -FTIR: Nitrous Oxide Conc. ±25 % /15%/10% a ± 10% 90% Mid- IR absorbance OP -FTIR: Spectra Quality Acceptable b NA 100% a The accuracy acceptance criterion is ±25 percent for pathlengths of less than 50 m, ±15 percent for pathlengths between 50 and 100 m, and ±10 percent for pathlengths greater than 100 m. b Spectral quality must meet minimal quality (refer to instrumentation manuals and EPA methods for instrument - specific spectral quality criteria). A1.1 Procedures for Evaluating OP- FTIR DQIs . The development and determination of DQIs f or open- path measurements is an ongoing process. The following section detail s the procedure for assessing the OP - FT IR DQI goals presented in Table A.1. A1.1.1 PIC Determination . The accuracy and precision of the abso rbance data may be verified by analyzing measured atm ospheric nitrous oxide concentrati ons over time. This test is valid only if the background spectrum is void of nitrous oxide, and nitrous oxide is not used in the verification gas release. For the duration of the study, t he calculated co ncentrati

on results for nitrous oxide should be comparable to the natural ambient at mo sphere level of 315 ppb ±2 5 percent f or path lengths less than 50 met ers, 315 ppb ± 15 percent for path lengths bet ween 50 and 100 meters , and 315 ppb ±10 percent for path le ngths greater than 100. A 8 Refer to Secti on 11.3.1.1 of ASTM Standard Practice E 1982 - 98 for more information on this procedure. A2 A1.1.2 Mid- IR Absorbance . The quality of the mid - IR absorbance data can be assessed by performing several qualitative and quanti ta tive checks. These checks include assessing instrument noise, detector nonlinearity, detector saturation, and instrumentFINAL DRAFT ORS Protocol June 14 , 2006

35 response. These checks were developed based on ASTM Standard Practice E 1982 - 98 . Additional details on how to perform these checks can be found in the EPA document entitled, ECPB Optical Remote Sensing Facility Manual . A9 A1.2 Internal Quality Control . Traditional quality control ( QC ) samples are not applicable to OP - FTIR experiments. Instead, the analyses of IR- active ambient gases having relatively constant values are included in the quantification process. Examples include nitrous oxide and methane, which are found at relatively constant concentrati ons of 315 ppb and 1.7 ppm as global backgrou nds, respectively. These must be used with caution, because a particular measurement area may prove to be a so urce of these gases . Methane, for example, is often emitted from hog waste lagoons and landfills. A1.2.1 Generation of a Background Spectrum . As described in EPA Compendium Method TO - 16 ( 1999), A2, A3 the generati on of a background spectrum, more precisely the I0 spectrum, is best accomplished synthetically. The best approach to this depends upon the sof tware being used for processing the data. Many commercially available sof tware sy stems are compatible with the data format used by OP - FT IR instruments. Ho wever, all of the available software opti ons require analyst input; therefore, there is some subjectivit y involved in the process. A1.2.2 Data Integ rity . Spectra are analyzed fo r peaks of commo n atmospheric constituents, such as water vapor, carbon dioxide, and methane. If these peaks are located outside o f t heir expected spectral region or exhibit any other abnormal characteristics , a spectroscopist should manually examine a select portion of the original data to determine the reason for these deviat io ns and/or the usabilit y o f t he collected data. A2.0 RPM Example using the HRPM and VRPM Methodologies A2.1 Introduction . During the Fall of 2002 and Spring of 2003, the met ho dol ogies described in this protocol was evaluated using the controlled release of verification gases and a scanning monostatic OP - FT IR instrument . The experiments were performed at the Duke Forest Facilit y o f Duke University, located in Chapel Hill, North Carolina. A nearly flat and square area of 14,400 m 2 was selected for the study. The verification gases released during the experiments inc luded et hyle ne and acetylene. This example briefly describes the preliminary results obtained f rom this controlled demonstration study using the HRPM and VRPM met ho dol

ogies . A2.2 Experimental Setup . This study was supported by the Environmental Security Technology Certification Program (ESTCP) of the Department of Defense (DoD) and audited by the Emissions Monitoring Center (EMC) of the EPA. In thi s study , an OP - FTIR mounted on a scanner and an array of mirrors (PDC) fo rm ed mult ip le , non - int ercept ing beam paths. Nine mirrors were used for the HRPM experiment, and five were used for the VRPM experime nt . The OP - FTIR was scanned sequent ia lly fro m mirror to mirror, acquiring spectra fro m each beam path. The OP - FTIRFINAL DRAFT ORS Protocol June 14 , 2006

36 dwelling time on each mirror was 30 seconds for the HRPM experiment and 60 seconds fo r the VRPM experiment. A2.3 Results and Discussion . PIC data were derived from the co llect ed spectra , and wind data were time - synchronized wit h the spectral data and averaged for the co rresponding measurement cycle. Following this, the PIC data were sorted according to mirror number, and the expanded data matrix ( see Table A.2 ) was then used as input to the sof tware developed by ARCADIS in Research Triangle Park, NC. In the case of the HRPM met hodology , the software re co nstructs the surface co ncentrati on contour map. In the case of the VRPM met hodology , the software provides spatial information on the homogeneity of the plu me, and calculates the emission flux th rough the configurati

on . A2.3.1 HRPM Results . Several verification gases were released at random locations and spectral data were co llected by sequentially scanning the OP - FTIR from mirror to mirror. Thi s spectral data were used to derive PIC data along each beam path, which were then input into the RPM sof tware to construct a surface concentrati on contour map. The hot spot location was det ermined by t he ar ea of highest concentrati ons in the contour map . This lo cation was then co mpared to the actual release location of the verification gas. For thi s example, acetylene was released and data were collected for 18 cycles. Figure A.1 shows the concentration co nt our map constructed by averaging PIC data from all 18 cycles. The open circle indicates the actual release locat io n, and the closed circle indicates the hot spot lo cation determined by the software. The dislocat io n distance (di stance between the actual a nd determined release location) i s shown wit h a double headed arrow. In this case, the dislo cation distance was 17 meters. Table A.2 presents the data matrix used to construct Figure A.1.FINAL DRAFT ORS Protocol June 14 , 2006

37 Figure A.1 Actual V ersus Determined Source Location for the Ace tylene Release
Table A.2 Data Matrix U sed to Construct Figure A.1 Pixel no. 1 2 3 4 5 6 7 8 9 Physical Beam Path Length (m) 68.4 102.6 148.9 103.1 137.2 169.6 149.1 171.2 178.5 Cycle 1 (ppm-m) 0.0 0.0 0.0 0.0 0.0 0.0 11.6 23.2 0.0 Cycle 2 (ppm-m) 0.0 1.3 0.0 0.0 0.0 0.0 0.0 32.6 0.0 Cycle 3 (ppm-m) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 5.2 0.0 Cycle 4 (ppm-m) 0.0 1.1 0.0 0.0 0.0 0.0 8.5 6.6 0.0 Cycle 5 (ppm-m) 1.0 1.0 0.0 0.0 0.0 2.3 49.6 34.3 0.0 Cycle 6 (ppm-m) 0.0 0.0 0.0 0.0 0.0 2.1 6.5 7.5 0.0 Cycle 7 (ppm-m) 0.0 0.0 0.0 0.0 1.4 0.0 8.0 11.7 0.0 Cycle 8 (ppm-m) 0.0 0.0 0.0 4.0 0.0 0.0 55.6 62.8 1.8 Cycle 9 (ppm-m) 0.0 0.0 0.0 0.0 0.0 0.0 8.2 4.2 0.0 Cycle 10 (ppm-m) 1.1 0.5 0.0 0.0 1.1 0.0 8.0 73.0 0.0 Cycle 11 (ppm-m) 0.0 0.0 0.0 0.0 0.0 0.0 28.3 0.0 0.0 Cycle 12 (ppm-m) 0.0 0.0 0.0 0.0 0.0 0.0 28.8 91.9 0.0 Cycle 13 (ppm-m) 0.0 0.0 0.0 0.0 0.0 2.4 49.1 10.1 3.2 Cycle 14 (ppm-m) 0.0 0.0 0.0 0.0 0.0 4.4 25.5 119.1 2.1 Cycle 15 (ppm-m) 0.8 0.0 1.3 0.0 0.0 1.9 63.0 192.0 2.8 Cycle 16 (ppm-m) 0.0 0.0 0.0 4.1 0.0 2.7 78.0 12.4 0.0 Cycle 17 (ppm-m) 1.1 1.0 0.0 49.6 0.0 0.0 303.0 247.2 0.0 Cycle 18 (ppm-m) 37.9 0.0 0.0 120.7 52.4 13.4 169.1 199.6 98.7 18-Cycle Average (ppm-m) 2.33 0.27 0.07 9.91 3.05 1.62 50.04 62.97 6.03FINAL DRAFT ORS Protocol June 14 , 2006

38 A2.3.2 VRPM Results . Several verification gases were released in an “H” pattern upwind of the VRPM configuration to simulate a small area source in Duke Forest (see Figure A.2 ). A9 The verification gas cylinders were weighed before and af ter each release to calculate the actual release rate (in g/s). Spectral data were co llected by sequentially scanning the OP - FTIR from mirror to mirror. This data were used to derive PIC data along each beam path, which were used as input to the VRPM algorithm to determine a plane int egrated concentration. Wind data were simu lt aneously collected at two heights (2 and 10 m) , and were inco rporated with the plane - int egrated concentrati on data to calculate the emission flux through the VRPM configurati on.

Figure A.2 Schematic of the VRPM Configuration U sed for the Ethylene Release For this example, ethylene was released and data were collected f or 12 cycles. Figure A.3 show s th

e reconstructed mass - equivalent plume map constructed by averaging PIC data from all 12 cycles. A total of 1 .0 lb o f et hyle ne was released over a period of 68 minutes, which resulted in an average release rate of 0.11 g/s. The average calculated emission flux was 0.10 g/s. Table A.3 presents the data matrix used to construct Figure A.3. X Y Z 15 m 30 m 30 m 90 m

40 m

50 m 90 m 140 m 7 m 13 m

Scanning OP - FTIR Mean Wind Direction RetroreflectorsFINAL DRAFT ORS Protocol June 14 , 2006

39 Figure A.3 Flux Measurement for Ethylene
Table A.3 Data Matrix U sed to Construct Figure A.3 Beam Path no. 1 2 3 4 5 Physical Bea m Path Length (m) 52.1 90.1 137 141.5 141.9 WS (m/s) WD from

Normal (deg) Cycle 1 (ppm - m) 2.7 13.4 17.8 3.8 5.1 2.7 5 Cycle 2 (ppm - m) 6.4 28.0 19.4 9.0 5.4 2.6 1 Cycle 3 (ppm - m) 4.5 23.4 23.1 8.8 7.9 2.1 0 Cycle 4 (ppm - m) 2.8 28.3 20.4 10.0 7.3 2.1 14 Cycle 5 (ppm - m) 5.0 1 9.8 34.7 4.2 5.3 2.9 13 Cycle 6 (ppm - m) 2.9 27.9 14.4 11.1 7.8 2.9 3 Cycle 7 (ppm - m) 10.8 14.1 28.5 4.7 7.9 3.0 - 11 Cycle 8 (ppm - m) 2.7 10.3 49.1 4.9 5.8 2.3 18 Cycle 9 (ppm - m) 2.7 23.1 25.8 23.3 7.1 1.8 - 2 Cycle 10 (ppm - m) 6.7 11.6 18.7 4.5 11.1 1.7 - 15 Cycle 11 (ppm - m) 14.4 20.2 36.0 15.7 7.0 2.0 - 8 Cycle 12 (ppm - m) 2.6 3.3 30.9 8.3 6.7 2.2 14 12 - Cycle Average (ppm - m) 5.4 18. 6 26.6 9.0 7.0 2.35 3 BOLD v alues represent one - half the minimum detection limit.FINAL DRAFT ORS Protocol June 14 , 2006

40 A2.3.2.1 Average wind speed and di rect io n data for each measurement cycle is shown in Table A.3. Wind measurements were interpolated every 2 meters between the 2 - and 10 - meter heights. The average wind data for each cycle at 4 met ers above the ground are shown. The wind direct io n is meas ured clockwi se fro m a n axis perpendicular to the VRPM configuration . In this convention, 0o is perpendicular to the vertical plane . A2.3.2.2 A mo ving average is used in the calculat io n of average values to show tem poral variabilit y in t he measurements. A m oving average invo lves averaging values fro m several different consecutive cycles. For example, a data set may be reported using a mo ving average with a group size of 4, where values from cycles 1 to 4, and 2 to 5 are averaged together to show any variabil it y in t he values. The exam ple in t his appendix explore s the dependence of the results on the group size of the mo ving average , and is illustrated in Figure A.4 . To assess the accuracy of the reconstruction for each moving average group, the CCF is co mpute d. It is apparent in F igure A.4 th at as the group size of the moving averages increase, the standard deviation decreases (smaller error bar). The CCF value increases for larger group sizes of moving averages (indicat ing a better fit for the measured data), but levels off at a group size of th ree . A mo ving average group of th ree is recommended fo r the VRPM methodology . In some condit io ns, it may not be advisable to use a larger group size fo r the moving average . CCF vs grouping size for moving averages

0.86 0.88 0.9 0.92 0.94 0.96 0.98 1

0 2 4 6 Group siz eCCF

Figure A.4 Dependence of CCF vs. Moving Average Group Size A2.3.2.3 A t ime plot of the flux calculat io n fo r the ethylene verification release, using a mo ving average wit h a group size of th ree , is shown in Figure A.5. The dashed horizontal line corresponds to the actual mass released ; the dashed p lo t indicates the measured wind direct io n fro m perpendicular to the VRPM configurat io n ; and the solidFINAL DRAFT ORS Protocol June 14 , 2006

41 plot indicates the calculated emissio n flux values . The corresponding data are listed in Table A.4 .

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

1 2 3 4 5 6 7 8 9 10 Cy cle Num be rFlux [g/s]

-80.0 -60.0 -40.0 -20.0 0.0 20.0 40.0 60.0 80.0Wind Direction from Normal [degrees] Flux WD

Figure A.5 Time Series of Ethylene Emission Flux Estimation

( • • • Indicates the actual release rate) Table A.4 Moving Average of Three Ethylene Emission Data Points for Figure A.5

Group CCF Flux(g/s) WS(m/s) WD(deg.) 1 0.95 0.08 2.2 2 2 0.96 0.1 2.1 3 3 0.96 0.09 2.2 8 4 0.96 0.11 2.4 8 5 0.96 0.11 2.7 2 6 0.97 0.13 2.5 3 7 0.98 0.16 2.2 2 8 0.96 0.12 1.8 2 9 0.98 0.11 1.7 - 7 10 0.94 0.12 1.8 - 3 Average 0.96 0.11 Std. Dev. 0. 012 0. 022FINAL DRAFT ORS Protocol June 14 , 2006

42 A2.3.2.4 The example below of flux data fro m t he Duke Forest study provides guidance for determining the range o f w ind direct ions that will ensure co mp lete capture of the pl ume (in the horizontal direct io n) by the VRPM configuration. The VRPM flux resul ts are representative of the source emissio n rate only during periods that the prevailing wind directio ns meet the established criterion. The determinat io n of the acceptable wind criterion is done by analyzing a data set of calculated flux values, with the corresponding wind direct io n, at the time of the flux calculat io n. The data set should consist of dat a collected over a wide range of wind di rect io ns on both sides o f t he perpendicular directio n to the VRPM configurat io n. A plot is create of the calculated flux values as a funct io n of the angle of the prevailing wind di rect io n (fro m perpendicular to the V RPM configuration) of all runs made when the wind direct io n angles were close to the perpendicular direct io n of the VRPM configuration. Because these runs were collected over a period of six mo nt hs, the flux values were normalized to the maximum flux value in each run. Figure A.6 presents a plot of this data set. The figure shows the calculated normalized flux values and the corresponding wind direct io n (fro m t he normal to the VRPM configuration during the time of the measurements). The figure shows that the raw flux values steadily increase, up to a certain po int , as the prevailing wind direct io n beco mes closer to perpendicular to the configuration. However, over a certain range of wind direct io ns, there appears to be no relat io nship between calculated flux values and prevailing wind direct io n. This range is approximately between - 10 ° and +25 ° fo r the Duke Forest validat io n study . This is the approximate range of acceptable wind direct io ns, as the variat io ns in flux values in this range are due to variat io ns in the source strength, and not due to changes in wind di rect io n. It is recommended that these flux plots be smoothed out with a moving average approach to retrieve a more definite and accurate cutoff of the wind criterion. The lined curves in the fi gure show examples of such mo ving averages, one with a grouping of 10 data values (thin line) and the other with a grouping of 20 data values (thicker line). These examples of mo ving averages clearly define the range of wind di rect io ns where flux values are independent fro m t he wind direct io n values.FINAL DRAFT ORS Protocol June 14 , 2006

43 Horiz ontal Plume Capture

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

-20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 Wind Dire ction [de gree s]Normalized Flux Raw Data Mov ing Av erage of 10 Mov ing Av erage of 20

Figure A.6 Plot of Calculated Flux Values and Corresponding Wind Direction

During the Time of Measurements A 3 .0 RPM Example using the 1D - RPM Methodology An example of a 1D - RPM met hodology controlled release can be found in Hashmonay and Yost (1999). A 1 0 A 4 .0 Refere nces A1 Varma, R. M.; Hashmo nay, R.A.; Kagann, R.H.; Modrak, M. T.; Sullivan, P.D.; Segall, R. R. Optical Remote Sensing Method for Flux Measurement fro m Non Point Sources. In Proceedings of the 96th Air & Waste Management Association Conference , San Diego , CA, June 22 - 26, 2003. A2 American Society for Testing and Materials (ASTM) Standard Practice E1982 - 98, Standard Practice for Open - Path Fourier Transform Infrared (OP/FT - IR) Monitoring of Gases and Vapors in Air; March 1999. A3 American Society for Testin g and Materials (ASTM)Standard Guide E1865 - 97 (Reapproved 2002), Standard Guide for Open - Path Fourier Transform Infrared (OP/FT - IR) Monitoring of Gases and Vapors in Air ; July 1997. A4 Russwurm, G. M.; Childers, J. W. FT - IR O pen - Path M

onitoring G uidance D o cument , 3 rd ed.; Submitted by ManTech Environmental Techno lo gy , Inc.,FINAL DRAFT ORS Protocol June 14 , 2006

44 under contract 68 - D5 - 0049 to the U.S. Environmental Protection Agency, Human Exposure and At mo spheric Sciences Divisio n, Natio nal E xposure Research Laboratory : Research Triangle Park, NC , 1999. A5 Modrak, M. T.; Hashmo nay, R. A.; Keagan [Kagann], R. Measurement of F ugitive E missions at a Region I Landfill; U.S. Environmental Protection Agency, Research and Development, EPA - 600/R - 04 - 001, January 2004. A 6 Hashmo nay, R.A.; Natschke, D. F.; Wagoner, K.; Harris, D. B.; Thompson, E. L., Yost, M. G. Field Evaluat io n of a Method for Estimat ing Gaseous Fluxes from Area Sources Using Open - Path Fourier Transform Infrared. Environ. Sci. Technol. 2001, 35, 2309 - 2313. A7 Modrak, M. T.; Varma, R. M.; Has hmonay, R. A.; Kagann, R. H.; Bolch, M. A. Dem onstration of Opt ical Remote Sensing Method for Flux Measurement from Non - Point Sources. In Proceedings of the 97th Air & Waste Management Association Conference , Indianapo lis, IN, June 22 - 25, 2004. A 8 ARCADIS G&M, Inc. ECPB Optical Remote Sensing Facility Manual; U.S. Envi ronmental Protection Agency, Emissio ns Characterizat io n and Prevent io n Branch, Research Triangle Park, NC; Contract No. EP - C - 04 - 023, Work Assignment No. 0 - 33, expected publicat io n 2006. A9 Has hmo nay, Ram A.; Varma, Ravi M.; Modrak, Mark T.; Kagann, Robert H.; Egler, Kim; Sullivan, Patrick D.; Segall, Robin R. Validation of Vertical Radial Plume Mapping Methodology for Estimating Gaseous Emissio n Rates fro m Area Sources. J. A ir & Waste Manage . Assoc . Submitted in 2006. A1 0 Hashmo nay, Ram A.; Yost, Michael G. Localizing Gaseous Fugit ive E missio n Sources by Combining Real - Time Remote Optical Sensing and Wind Data. J. Air & Waste Manage. Assoc. 1999, 49 , 1374 - 1379.