oEPA
United States Environmental Protection Agency
Office of Enforcement and Compliance Assurance
Office of Criminal Enforcement, Forensics and Training
NEICVP1456E04
Replacement Report
NEIC CIVIL INVESTIGATION REPORT
GMAP Region 6 Pollution Accountability Team FY2022
Calcasieu Parish, Louisiana
St. Charles Parish, Louisiana
St. James Parish, Louisiana
St. John the Baptist Parish, Louisiana
Investigation Dates:
April 11-23, 2022
NEIC Project Team:
Project Manager
BRADLEY
VENNER
Digitally signed by BRADLEY
VENNER
Date: 2023.02.17 14:55:17
-07'00'
Bradley Venner
Analytical Project Manager
Wolmrrh Digitally signed by
Cllllll.ll, Helmich, Richard
Date: 2023.02.17
15:00:33 -07'00'
Richard Helmich
Richard
Authorized for Release by:
Digitally signed by MARTHA
MARTHA HAMRE STL3.02.17is***
-07'00'
Martha Hamre, Acting Field Branch Manager, NEIC
Report Prepared for:
Steve Thompson
EPA Region 6
1201 Elm Street, Suite 500
Dallas, Texas 75270
1 ale
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
P.O. Box 25227
Building 25, Denver Federal Center
Denver, Colorado 80225
-------
CONTENTS
INVESTIGATION OVERVIEW 3
METHODOLOGY 4
INSTRUMENTATION 4
CALIBRATION 4
DATA MANAGEMENT 5
QUALITY ASSURANCE 5
RESULTS 9
DISCUSSION 9
TABLES
Table 1. SUMMARY OF DAILY CALIBRATION VERIFICATION RESULTS 4
Table 2. COMPARISON OF ETO RESULTS FROM CRDS AND CANISTER ANALYSIS 7
FIGURE
Figure 1. EtO and VOC response, with overlay of VOC response on EtO response delayed by 12.5
seconds. Mapping ID: 220413_MA26 6
APPENDICES (NEIC-created*)
Appendix A KML Files (51 files)*
Appendix B Graphs of Calibration Results (4 pages)*
Appendix C EtO Quality Assurance Screening Results (3 pages)*
This Contents page shows all the sections contained in this report
and provides a clear indication of the end of this report.
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GMAP R6 PAT FY22, Louisiana
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INVESTIGATION OVERVIEW
This report (NEICVP1456E04) replaces the following U.S. Environmental Protection Agency (EPA)
National Enforcement Investigations Center (NEIC) report in its entirety: NEICVP1456E02 (July
2022). This replacement was necessary to correct the following: the reference to the NEIC report
NEICVP1456E01 has been updated to reference the NEIC replacement report NEICVP1456E03.
This report supplements U.S. Environmental Protection Agency (EPA) National Enforcement
Investigations Center (NEIC) report NEICVP1456E03 with additional data provided by the
Picarro G2920 cavity ring-down spectrometer (CRDS) instrument, which measured ethylene
oxide (EtO) and methane (CH4) concentrations, and maps developed from these measurements.
The CRDS was installed in NEIC's Geospatial Measurement of Air Pollution (GMAP) vehicle for
this investigation. These measurements were not provided in report NEICVP1456E03 because
results of laboratory analysis performed by Eastern Research Group (ERG) of canisters collected
during the GMAP survey were not yet available at the time of the preparation of the original
report. These analytical results were necessary to confirm EtO responses as measured by the
CRDS. This report also describes additional steps taken to validate these results. Report
NEICVP1456E03 provides detailed information on the events of the survey, which are not
repeated in this report. Field measurements from the CRDS were processed into files in Keyhole
Markup Language (KML) format and are provided in Appendix A.
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METHODOLOGY
INSTRUMENTATION
The Picarro G2920 instrument can measure EtO, CH4, carbon dioxide, and water vapor. The
instrument was integrated into the other on-board GMAP instruments for the purposes of this
project by Richard Helmich and Ali Gitipour.
CALIBRATION
Calibration verifications for the CRDS were performed at the beginning and the end of each
working day. The gas cylinders used for calibration verification of EtO and CH4 were maintained
in a separate trailer. Corresponding calibration gases were metered from the cylinders through
a valved manifold. The calibration gases used for the CRDS were single-component calibration
mixtures of EtO and CH4. Detailed descriptions and certificates of analysis of the calibration
gases are in the project file. Calibration verifications also included analysis of a "ultra zero air"
that contains, at most, only very small quantities of any analyte.
Time periods during the calibration process when relatively constant zero gas and calibration
gas responses were obtained were visually identified by Bradley Venner. A summary of the daily
quantitative calibration results is shown in Table 1.
Table 1. SUMMARY OF DAILY CALIBRATION VERIFICATION RESULTS
Calibration
Level
(Span or
Zero)
Analyte
Unit
Calibration
Standard
Concentration
Average
Measured
Concentration
of Calibration
Events
Standard
Deviation
Between
Calibration
Events
Pooled Standard
Deviation Within
Calibration
Events
Span
EtO
parts per
billion (ppb)
105.4
65.2
0.7
0.4
Span
CH4
parts per
million
(ppm)
20.4
20.3
0.01
0.06
Zero
EtO
ppb
0
-0.1
0.1
0.3
Zero
CH4
ppm
0
0.0
0.0
0.0
The average calibration response of EtO was 65.2 ppb, and the stated value of the calibration
response was 105.4 ppb, so the average recovery of the calibration standard was 62%. This
response was stable; the variation in the average calibration response during the run was 0.7
ppb, a 1% relative standard deviation. This may imply that measurement results could be as
much as 162% higher than observed. Given the high precision of the instrument, this should be
considered an upper uncertainty bound on the measured results. Plots of the calibration results
used to calculate these values are shown in Appendix B.
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During the calibration process, introducing or turning off the CH4 gas often resulted in an
intermittent EtO response. This response could be positive, negative, or oscillating. The CH4
concentration in the calibration gas was 20 ppm, and the Picarro G2920 instrument is stated to
be compatible with CH4 concentrations between 0 and 10 ppm, so this response may be an
artifact of the scale switching routine in the software. As shown by the calibration results after
the instrument completed the electronic scale adjustment, the concentration measured was
congruent with the certificated concentration. As discussed below, similar behavior was seen
when high CH4 concentrations were encountered in the field.
DATA MANAGEMENT
Following the completion of field activities, data files were processed by the custom application
software Google Earth Map Plotter, version 1.7. This software produces KML files that can be
opened using geographic information systems such as Google Earth Pro (GEP).
Fixed mapping scales were used for ChUand EtO. The minimum mapping scale (green) was set
at 2 ppm and 2 ppb for CH4 and EtO, respectively. The maximum mapping scale (red) was set at
4 ppm and 5 ppb for ChUand EtO, respectively. Values greater than maximum mapping scale
appear on the maps as proportionally taller red bars.
QUALITY ASSURANCE
All sampling and measurements, including GMAP measurements and the canister analysis
performed by ERG, that are described in this report are not within the scope of NEIC's ISO/I EC
17025 accreditation issued by the ANSI National Accreditation Board (certificate No. FT-0303).
During the data analysis process, a delay was observed in the response of the CRDS when
compared to the volatile organic compound (VOC) measurements. This delay could be detected
during the collection of some VOC measurements, where a very similar response could be
observed in the EtO measurements. The magnitude of the delay was roughly 13 seconds,
although there was some day-to-day variation of a second or two. The reason for the delay has
not been identified. The delay is unlikely to be due to the photo-ionization detector (PID)
instrument since it is located on the main sample trunk and an immediate response of the PID
instrument to calibration gases is observed.
An example of the delay is shown in Figure 1. This figure shows the measured EtO
concentrations by the CRDS and the measured VOC concentrations by the PID. It also shows
both responses on the same graph, normalized to their maximum values, but with the VOC
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GMAP R6 PAT FY22, Louisiana
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response delayed by 12.5 seconds.1 The maximum concentration for VOCs on this mapping run
was 5,793 ppb, and the maximum concentration for EtO was 18.7 ppb. The qualitative
resemblance between the two responses is visually apparent, with multiple peaks matching
exactly and parallel behavior on several other peaks.
Figure 1. EtO and VOC response, with overlay of VOC response on EtO response delayed by 12.5 seconds.
Mapping ID: 220413_MA26
EtO
1.00-
0.00-
Time
variable
EtO
VOC
o
f 0.50-
E
t3
c
O
o
variable
EtO
VOC
15-
10-
5-
§ °-
CL
c 6000-
^ 5000-
4000-
3000-
2000-
1000-
14:20
14:26
VOC
14:22 14:24
Time
The delay introduces some uncertainty as to the wind conditions that prevailed at the time of a
recorded CRDS reading. This report presents maps that correlate the wind speed and direction
recorded at time t, with the CRDS reading recorded at time t + d, where d is the duration of the
delay. To create these maps, modified data files were prepared by projecting the CRDS readings
and a row identifier into a separate data table, subtracting 13 from the row identifier, and then
1 VOC data for the GMAP survey are available in report NEICVP1456E03.
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GMAP R6 PAT FY22, Louisiana
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merging the separate data table into the original file using the row identifier. Since instrumental
responses are recorded roughly every second, this approach corresponds to a 13-second delay
but avoids the complexity of the approximate merge that would be required by using the
recorded time value. Although this procedure means that the exact value of the delay can vary
from map to map, this variation should be less than 1 second. Maps prepared using this
method should be interpreted with some caution, particularly when wind directions are highly
variable, and the exact value of the delay can impact the attributed wind speed and direction.
Another data quality concern is the potential that the observed EtO response was not specific
to EtO but could be the result of an interferent. This survey involved some near-field
measurements of relatively high VOC concentrations (e.g., at the parts per million level) while
measuring EtO at low concentrations (e.g., at the parts per billion level). An example of this
type of situation is illustrated in Figure 1, where the observed VOC concentrations were much
higher than the observed EtO concentrations. Although the observed correlation does not
prove that there was an interference, this potential must be recognized.
An important measure of the specificity of the CRDS measurement can be obtained by
comparing the EtO concentration measured in the canister to the average EtO concentration
measured by the CRDS during the canister sampling time. The average EtO concentration was
calculated both with and without the delay. The results of this comparison are shown in Table
2.
Table 2. COMPARISON OF ETO RESULTS FROM CRDS AND CANISTER ANALYSIS
CanisterJD
MapJD
EtO, ppb
(CRDS, no delay)
EtO, ppb
(CRDS, with delay)
EtO, ppb
(Canister)
3071
220411_MA10
<2
<2
0.09
10027
220411_MA14
<2
<2
0.08
3101
220411_MA28
<2
<2
0.04
3068
220411_MA35
<2
<2
0.04
4612
220412_MA01
<2
<2
0.15
521
220412_MA24
<2
<2
0.05
3116
220412_MA41
<2
<2
0.04
9497
220412_MA47
<2
<2
0.11
4621
220413_MA12
<2
<2
0.57
4609
220413_MA16
3.6
3.3
5.39
4605
220414_MA36
<2
<2
0.07
10007
220414_MA42
<2
<2
0.06
10009
220415_MA03
<2
<2
0.07
9490
220415_MA07
<2
<2
0.06
3066
220416_MA24
5.5
5.3
5.13
4606
220418_MA13
3.3
<2
1.59
527
220418_MA54
<2
<2
0.06
NEICVP1456E04
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Table 2. COMPARISON OF ETO RESULTS FROM CRDS AND CANISTER ANALYSIS
CanisterJD
MapJD
EtO, ppb
(CRDS, no delay)
EtO, ppb
(CRDS, with delay)
EtO, ppb
(Canister)
535
220418_MA56
<2
<2
0.06
278
220419_MA17
12.5
13.1
19
10018
220419_MA23
5.9
5.2
10.4
118
220419_MA35
7
6.4
8.62
4602
220420_MA08
<2
<2
0.22
3073
220421_MA32
<2
<2
0.14
4618
220421_MA37
<2
<2
0.33
279
220421_MA39
<2
<2
ND
4601
220421_MA54
<2
<2
0.25
10008
220422_MA11
<2
<2
0.08
519
220422_MA18
<2
<2
ND
The EtO response also depends upon the CH4 response of the instrument. The Picarro G2920
instrument is only stated to be consistent with CH4 concentrations between 0 and 10 ppm. On
several occasions during field measurements, CH4 concentrations higher than 10 ppm were
observed, and these resulted in an EtO response, which could be positive, negative, or
oscillating. A similar phenomenon was observed during instrument calibration, when negative
EtO values were sometimes observed at the same time as a change in the CH4 calibration gas
flow (on or off).
Therefore, a quality assurance screen was conducted on each mapping ID for which the average
EtO response was greater than 3 ppb. Maps were excluded from this report when CH4
concentrations were outside the recommended range or had strong correlations with VOCs and
for which there were no known EtO sources.
KML files were included for each mapping run that passed the quality assurance screening
process. The resulting KML files are provided electronically as Appendix A. The results of the
quality screen are provided in Appendix C.
The GMAP AirMar instrument (wind speed and direction sensor) failed to provide wind speed
and direction data on several occasions. The most severe outages occurred on April 11, 2022,
and April 22, 2022, when approximately 50% and 0%, respectively, of the wind speed and
direction data were recorded. However, most survey days had at least one partial outage.
During malfunction events, source attribution can be more challenging. Wind speed and
direction data from the National Weather Service at nearby locations can be examined in the
absence of data from the AirMar.2
2 https://www.weather.gov/help-past-weather, accessed May 16, 2022.
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RESULTS
GMAP field measurement activities were conducted on 12 days during the investigation period.
Detailed information of GMAP activities, indexed by mapping run, are provided in report
NEICVP1456E03.
DISCUSSION
GMAP data are best used to screen for areas where further investigation using more traditional
inspection and leak detection instruments can help to determine if emissions meet regulatory
requirements.
Wind direction provides an important, but not infallible, source of information on the direction
of potential emissions sources. For example, when the wind direction is changing frequently, a
measured concentration may also be from an emitted plume that has been blown back to the
source. Large obstructions such as tanks also have wakes that can generate local winds
opposite of the prevailing wind direction. Additionally, the AirMar is located on top of the
moving vehicle and can be affected by the vehicle slipstream at higher speeds. To avoid issues
with vehicle slipstream causing erroneous wind data, the data is only recorded when the
vehicle's speed is less than 25 miles per hour. The wind direction is determined with an internal
magnetic compass that also may be affected by local magnetic fields and large, nearby metallic
objects.
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Appendix A
KML Files
VP1456E04
GMAP Region 6 Pollution Accountability Team FY2022
Calcasieu Parish, Louisiana
St. Charles Parish, Louisiana
St. James Parish, Louisiana
St. John the Baptist Parish, Louisiana
Please see folder sent with project report for digital KML files.
(51 files)
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Appendix B
Graphs of Calibration Results
VP1456E04
GMAP R6 Pollution Accountability Team FY2022
Calcasieu Parish, Louisiana
St. Charles Parish, Louisiana
St. James Parish, Louisiana
St. John the Baptist Parish, Louisiana
4 pages
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Figure 1: Ultra-zero gas data and mapping scales, EtO
X
w
w
0)
o
o
dI
+
Cone °
ProcessMin °
Quant °
ProcessMax 0
0 10203040 5060
0 102030405060
0 102030 405060
3-
2'
1"
o-
-1"
3
2
1"
0"
-1-
220421 CA01
220421 CA02
220422 CA01
220422 CA02
220423 CA01
220423 CA02
Aa
220418 CA01
220418 CA02
220419 CA01
220419 CA02
220420 CA01
220420 CA02
-'^vaA^'W
220414 CA01
220414 CA02
220415 CA01
220415 CA03
220416 CA01
220416 CA02
W/V
220411 CA01
220411 CA02
220412 CA01
220412 CA02
220413 CA01
220413 CA02
vWW
3
2
" 1
- 0
- -1
" 3
2
1
" 0
- -1
0 1 020 3040 50 60
0 10 2030405060
Row.lndex
0 102030405060
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Appendix B
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GMAP R6 PAT FY22, Louisiana
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Figure 2: Ultra-zero gas data and mapping scales, CH4
X
w
w
O)
o
o
dI
+
220421 CAP 1220421 CA02 220422 CAP 1220422 CA02 220423 CAP 1220423 CA02
220418 CA01
CHi:
cm
0:11
CMH
0i):
0:
0:
0i)i
Cone °
ProcessMin °
Quant °
ProcessMax 0
0 102030405060 0 102030405060 0 102030405060
220418 CA02220419 CA01
220414 CA01
220411 CA01
i\2-
<11-
I I I I I I I
i i i i i i i
220419 CA02
220414 CA02220415 CA01
220411 CA02220412 CA01
m—i i i i i
^"WVWvvWV^/v
220420 CA01
220415 CA03
220412 CA02
i i i i i i i
220420 CA02
220416 CA01
220413 CA01
i i i i i i i
220416 CA02
220413 CA02
I I I I I I I
0 102030405060
0 102030405060
Row.lndex
0 102030405060
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Appendix B
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GMAP R6 PAT FY22, Louisiana
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Figure 3: Calibration gas data and mapping scales, EtO
X
w
w
0)
o
o
dI
+
74
72
70
68
66
64
74
72
76
68
66
6 A
0 102030405060
220421 CA01
220418 CA01
220414 CA01
220411 CA01
i i i i i i i
220421 CA02
220422 CA01
220418 CA02
220419 CA01
220414 CA02
220411 CA02
I I I I I I I
Cone °
ProcessMin °
Quant °
ProcessMax 0
0 102030405060
220415 CA01
220412 CA01
i i i i i i i
220422 CA02
220419 CA02
220415 CA03
220412 CA02
i i i i i i—r
0 102030405060
I'll.
220423 CA01
220423 CA02
220420 CA01
220420 CA02
220416 CA01
220413 CA01
l—i i i i i i
220416 CA02
220413 CA02
i i i i i i i
0 102030405060
0 102030405060
Row.lndex
0 102030405060
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Appendix B
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GMAP R6 PAT FY22, Louisiana
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Figure 4: Calibration gas data and mapping scales, CH4
X
CO
W
w
0)
o
o
dI
+
Cone 0
ProcessMin 0
Quant 0
ProcessMax 0
0 102030405060
0 102030405060
0 102030405060
2+
2t
20
20
2t
21-
20
20
220421 CA01
220421 CA02
220422 CA01
220422 CA02
220423 CA01
220423 CA02
220418 CA01
220418 CA02
220419 CA01
220419 CA02
220420 CA01
220420 CA02
5
n
-A/\\r>A-V^rt/>AuyA_A^
220414 CA01
220414 CA02
220415 CA01
220415 CA03
220416 CA01
220416 CA02
A.
220411 CA01
220411 CA02
220412 CA01
220412 CA02
220413 CA01
220413 CA02
5
o
I
n
11111n11111n11111n11111n11111n11111r
0 102030405060 0 102030405060 0 102030405060
Row.lndex
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Appendix B
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GMAP R6 PAT FY22, Louisiana
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Appendix C
EtO Quality Assurance Screening Results
VP1456E04
GMAP Region 6 Pollution Accountability Team FY2022
Calcasieu Parish, Louisiana
St. Charles Parish, Louisiana
St. James Parish, Louisiana
St. John the Baptist Parish, Louisiana
3 pages
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Mt°p ID
L'iO {j'ipi:) jC'h!4 (pptii)
IVU;P iNoi Ci
220411_MA09
8.3
11.5
No
Single large EtO negative spike at -7500 ppb
220411_MA13
3.5
2.7
Yes
No clear relation with VOC or CH4
220411_MA14
5.3
4.1
No
Parallel with VOC
220411_MA15
3.3
2.7
No
Below quant; no clear relation with VOC or CH4
220411_MA24
4.5
5.6
No
CH4 greater than 5 ppm; EtO spikes correspond with
CH4 peaks
220411_MA35
14.1
2.1
No
Strong correlation with VOC
220412_MA01
8575.3
2.0
No
Peaked VOC plus CH4 goes to zero
220412_MA02
10.5
2.6
No
Strong correlation with VOC but only a single peak
220412_MA08
3.2
2.0
No
Below quant; no clear relation with VOC or CH4
220413_MA04
5.8
2.1
Yes
No clear relation with VOC or CH4
220413_MA08
3.5
2.0
No
Below quant; no clear relation with VOC or CH4
220413_MA09
4.1
2.0
No
Averaged 1 meter bin below quant; ORD canister; No
clear relationship with VOC or CH4
220413_MA13
5.0
1.9
Yes
No clear relation with VOC or CH4
220413_MA16
25.0
2.7
Yes
Confirmed by ERG canister
220413_MA24
3.9
5.5
No
Large negative EtO value
220413_MA26
18.7
2.0
No
Parallel with large VOC value
220413_MA27
15.8
1.9
No
Parallel with large VOC value
220413_MA28
13.5
1.9
No
Parallel with large VOC value
220413_MA29
14.5
1.9
No
Parallel with large VOC value
220413_MA30
12.8
2.0
No
Parallel with large VOC value
220413_MA31
15.5
1.9
No
Parallel with large VOC value
220413_MA37
15.7
2.2
No
Parallel with large VOC value
220413_MA38
12.4
2.1
No
Parallel with large VOC value
220413_MA41
11.1
6.6
No
Methane-related spike
220413_MA42
24843.4
No
Methane-related spike
220413_MA43
824.0
7.9
No
Methane-related spike
220413_MA45
13.3
2.3
Possible
No clear relation with VOC or CH4
220413_MA46
4.7
2.0
No
Parallel with large VOC value
220413_MA47
11.2
8.0
Possible
Early hit on EtO followed by methane-related spike
220413_MA48
65.5
2.3
No
Methane-related spike
220413_MA49
13.3
1.9
No
Parallel with VOC value
220413_MA50
22.4
2.0
No
Parallel with VOC value
220413_MA51
16.8
481.8
No
Methane-related spike
220414_MA06
3.0
440.6
No
Methane-related spike
220415_MA35
4.0
2.0
Possible
Brief peak but unrelated to CH4 or VOC
220416_MA23
3.5
2.3
Possible
Brief peak but unrelated to CH4 or VOC
220416_MA24
10.4
2.0
Yes
Confirmed by ERG canister
220416_MA25
7.2
1.9
Yes
Unrelated to CH4 & VOC, vicinity of previous canister
220416_MA27
7.2
1.9
Possible
Peak occurs near peak VOC value but not exact parallel
220416 MA28
3.2
1.9
Possible
Barely over background but unrelated
220418_MA04
5.0
2.1
Possible
Unrelated to CH4 & VOC
220418_MA05
53.4
2.0
No
Parallel to VOC
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Appendix C
Page 1 of 3
GMAP R6 Louisiana, FY2022
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[•.¦¦'idp ID
L'iO ijipi:) iOi4 i|;p:n)
IVU;P iNoi Ci
220418_MA07
11.9
2.1
Possible
Unrelated to CH4 & VOC
220418_MA13
29.1
2.0
No
Parallel to VOC
220418 MA63
3.5
2.1
Possible
Brief peak but unrelated to CH4 or VOC
220418 MA68
30.4
2.2
Possible
Somewhat related to VOC but not exact
220418 MA69
8.6
2.1
Possible
Unrelated to CH4 & VOC
220418_MA70
13.5
2.0
Possible
Continued from previous result, unrelated to CH4 and
VOC
220418_MA71
10.4
2.0
Possible
Unrelated to CH4 & VOC
220418_MA72
17.0
2.1
Possible
Somewhat related to VOC but not exact
220418_MA73
10.6
2.1
Possible
Somewhat related to VOC but not exact
220419_MA04
9.8
10.6
No
Large negative EtO value
220419_MA09
10.2
2.0
Possible
Unrelated to CH4 & VOC
220419_MA17
23.3
2.1
Possible
Somewhat related to VOC but not exact
220419_MA18
20.4
2.0
Yes
Unrelated to CH4 & VOC
220419_MA19
20.2
2.0
Yes
Unrelated to CH4 & VOC
220419_MA20
12.5
2.1
Possible
Somewhat related to VOC but not exact
220419 MA22
12.0
2.2
Possible
Somewhat related to CH4 but not exact, unrelated to
VOC
220419_MA23
16.1
2.2
Yes
Confirmed by ERG canister
220419_MA24
7.2
2.1
Possible
Unrelated to CH4 & VOC
220419_MA26
11.5
2.0
Possible
Unrelated to CH4 & VOC
220419_MA31
4.7
2.4
Possible
Unrelated to CH4 & VOC
220419_MA33
21.9
2.1
No
Parallel to VOC
220419_MA34
12.1
2.1
Possible
Somewhat related to VOC but not exact
220419_MA35
16.4
2.1
Yes
Confirmed by ERG canister
220419_MA36
15.2
2.1
Possible
Somewhat related to VOC but not exact
220419_MA44
5.0
2.4
Possible
Unrelated to CH4 & VOC
220420_MA03
10.0
4.1
Possible
Somewhat related to VOC but not exact
220420_MA04
5.9
2.5
Possible
Somewhat related to CH4 but not exact, unrelated to
VOC
220420_MA10
3.6
2.8
Possible
Somewhat related to CH4 but not exact, unrelated to
VOC
220420_MA12
3.2
2.9
Possible
Barely over background but unrelated
220420_MA15
9.9
2.3
Possible
Unrelated to CH4 & VOC
220420_MA16
13.6
2.0
Possible
Parallel with VOC but may be co-generated
220420_MA17
13.4
2.1
Possible
Late rise in value prior to end of mapping run
220420_MA18
66.6
6.0
Possible
Somewhat related to VOC but not exact
220420_MA19
7.4
3.3
Possible
Somewhat related to VOC but not exact
220420_MA20
18.2
5.3
Possible
Closely related to VOC but not exact
220420_MA24
6.6
2.4
Possible
Unrelated to CH4 & VOC
220420 MA26
5.6
2.4
Possible
Unrelated to CH4 & VOC
220420_MA27
4.4
2.3
Possible
Looks like drift
220420 MA28
11.0
2.0
Possible
Unrelated to VOC, related to CH4 but at very low levels
of CH4
220420_MA29
7.4
2.0
No
Map duration is too short
220420_MA30
9.6
2.5
Possible
Unrelated to CH4 & VOC
NEICVP1456E04
(Replacement)
Appendix C
Page 2 of 3
GMAP R6 Louisiana, FY2022
-------
Map_ID
EtO (ppb)
CH4 (ppm)
Map
Notes
220420_MA31
10.1
2.4
Possible
Closely related to CH4 but not exact
220421_MA32
7.6
356.9
No
Sharp spike in CH4
220421_MA42
3169.2
25.2
No
CH4 greater than 25 ppm
220421_MA43
11940.7
596.9
No
CH4 greater than 400 ppm; EtO spikes at the same time
220421_MA44
643.9
531.8
No
CH4 greater than 400 ppm; EtO spikes at the same time
220421_MA45
3442.5
14.0
No
CH4 greater than 10 ppm
220421_MA47
3903.5
661.4
No
CH4 greater than 600 ppm; EtO spikes correspond with
CH4 peaks
220422 MA25
136.8
16.5
No
CH4 greater than 15 ppm; EtO spikes correspond with
CH4 peaks
NEICVP1456E04
(Replacement)
Appendix C
Page 3 of 3
GMAP R6 Louisiana, FY2022
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