Prepared for: U.S. Environmental Protection Agency (EPA), Clean Air Markets Division
EPA Contract No.: 68HERH21D0006, CASTNET Base Program (1003)
Prepared by: WSP USA Environment & Infrastructure Inc. (WSP), Gainesville, Florida
WSP Project No.: 6064226103
Submitted: March 31, 2023
Introduction
This quarterly report summarizes the Clean Air Status and Trends Network (CASTNET) data
collected during fourth quarter 2022. Trends in pollutants measured at eastern and western
reference sites are shown. Results from the quality assurance/quality control (QA/QC) program are
presented for fourth quarter data and include completeness and precision of filter concentrations
and hourly 03 concentrations. This report also analyzes data for continuous, trace-level NOy from
the six of eight sites that were operational during fourth quarter and continuous S02 concentrations
from three sites. Other QC statistics are given in the CASTNET Fourth Quarter 2022 Quality
Assurance Report with 2022 Annual Summary (Wood, 2023).
Figure 1. Fourth Highest Daily Maximum 8-hour Average 03 Concentrations (ppb) through Fourth
Quarter 2022
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Figure 1 shows fourth highest daily maximum 8-hour average (DM8A) 03 concentrations measured
through fourth quarter 2022. Four western sites and one eastern site exceeded the 0.070 parts per
million (ppm) National Ambient Air Quality Standard for 03_. The concentration of 83 ppb measured
at CAV436 in southeastern New Mexico was produced by emissions from oil and gas exploration,
drilling, processing, and storage in the Permian Basin. Vehicular emissions from truck traffic on
U.S. Route 285 also contributed (Sive, 2023).
Trends
Trend analyses were performed based on filter pack pollutant concentrations measured in
micrograms per cubic meter (|jg/m3) of air at the 34 eastern and 16 western reference sites during
fourth quarter. Trends in quarterly mean filter pack and 03 concentrations are shown using box
plots in Figures 2 through 13.
Fourth Quarter Concentrations
Quarterly mean S024, HN03, and K+ concentrations decreased at eastern sites in 2022, and NO~3,
NH4, total NO"3, S02, CI", Ca2+, Mg2+, and Na+ concentrations increased. Quarterly mean HN03, total
NO"3, CI", Ca2+, K+, Mg2+, and Na+ concentrations decreased at western sites in 2022 while S02,
SO4", N03, and NH4, increased.
Quarterly 03 concentrations were analyzed using box plots constructed by averaging all valid
hourly 03 concentrations within fourth quarter 2022 by site and then averaging those averages for
all eastern and western reference sites (Figure 13). The figure shows a slight overall increase in
quarterly mean 03 concentrations at eastern sites. Mean 03 concentrations at western sites
decreased in fourth quarter 2022. Quarterly mean concentrations were higher at the western
reference sites than at the eastern sites.
Figure 2. Trends in Fourth Quarter Mean HN03 Concentrations
Western Reference Sites Eastern Reference Sites
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 3. Trends in Fourth Quarter Mean N03 Concentrations
Western Reference Sites
Eastern Reference Sites
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Figure 4. Trends in Fourth Quarter Mean l\ll-f4 Concentrations
Western Reference Sites
Eastern Reference Sites
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Figure 5. Trends in Fourth Quarter Mean Total N03 Concentrations
Western Reference Sites
Eastern Reference Sites
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 6. Trends in Fourth Quarter Mean S02 Concentrations
Western Reference Sites
Eastern Reference Sites
1.4-
1.2-
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Figure 7. Trends in Fourth Quarter Mean SO - Concentrations
Western Reference Sites
Eastern Reference Sites
10
08
0.6
0.4
0.2
0.0
1 1 1 1 1 1 1 1 1 1 1 1
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Figure 8. Trends in Fourth Quarter Mean CI" Concentrations
Western Reference Sites
Eastern Reference Sites
0.20-
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 9. Trends in Fourth Quarter Mean Ca Concentrations
Western Reference Sites
Eastern Reference Sites
0.5-
0 4
E
0.3-
0.2-
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Figure 10. Trends in Fourth Quarter Mean K° Concentrations
Western Reference Sites
Eastern Reference Sites
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- 0.08-
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 12. Trends in Fourth Quarter Mean Na' Concentrations
Western Reference Sites
Eastern Reference Sites
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Figure 13. Trends in Fourth Quarter Mean 03 Concentrations
Western Reference Sites
Eastern Reference Sites
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_ 50
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rs
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Changes in 3-year Average Fourth Quarter Concentrations
As shown in Table 1 and Table 2, three-year averages of quarterly mean concentrations of total
NO,, NH4, S02, and S024" were reduced over the period 1990-1992 through 2020-2022 for eastern
reference sites and from 1996-1998 through 2020-2022 for western reference sites. Potassium
levels declined at eastern sites from 2004-2006 through 2020-2022 while Ca \ Mg2+, Na', and CI"
values increased. At western sites, Na+ levels decreased while CI" and base cation concentrations
increased. Ozone concentrations increased at eastern sites and showed no change at western
reference sites.
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Table 1. Eastern Reference Sites: 3-Year Mean Values (ppb or jjg/m3)
Parameter
o3
(PPb)
Total
no3
nh;
so2
so*
Ca2+
K+
¦ a 2+
Mg
Na+
CI"
1990-1992
24
2.9
1.4
10.6
3.6
2004-2006
0.23
0.07
0.04
0.10
0.07
2020-2022
25
1.3
0.4
0.5
0.8
0.27
0.06
0.04
0.10
0.09
Percent
Change
7
-55
-72
-96
-78
14
-3
11
3
39
Note: Ozone concentrations are given as ppb. Concentrations for all other parameters are in |jg/m3.
Table 2. Western Reference Sites: 3-Year Mean Values (ppb or jjg/m3)
Parameter
o3
(PPb)
Total
no3
nh;
so2
so*
Ca2+
K+
• a 2+
Mg
Na+
CI"
1990-1992
38
0.8
0.2
0.7
0.6
2004-2006
0.10
0.03
0.02
0.06
0.03
2020-2022
38
0.5
0.1
0.2
0.3
0.18
0.03
0.02
0.06
0.04
Percent
Change
0
-39
-41
-70
-45
81
28
30
-9
22
Note: Ozone concentrations are given as ppb. Concentrations for all other parameters are in |jg/m3.
Time Series of Laboratory Analysis Parameters for All Sites
Figures 14 through 23 give time series of laboratory-analyzed concentrations of field samples and
field blanks in milligrams per liter (mg/L) of 11 parameters from first quarter 2020 through fourth
quarter 2022. These figures provide indications of potential issues with concentration
measurements relative to detection and reporting limits.
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 14. Concentrations of N03 (as N) from Nylon Filters
Note: Nominal reporting limit is 0.008 mg/L.
Figure 15. Concentrations of N03 (as N) from Teflon Filters
<§'&•$'•? •&<£' <§*<§* \^
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EPA Contract No. 68HERH21D0006
CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 16. Concentrations of Nhf4 (as N) from Teflon Filters
• All Samples • Median • Field Blanks
Note: Nominal reporting limit is 0.020 mg/L.
Figure 17. Concentrations of S02 from K2C03-impregnated Cellulose Filters
• All Samples • Median * Field Blanks
Note: Nominal reporting limit is 0.040 mg/L.
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 18. Concentrations of SOt from Nylon Filters
• All Samples • Median * Field Blanks
0.5-
0.4-
O)
E
c
o
0.3-
c 0 2-
s vf ' Cs' o' v Q> <3°Cr Q> Qr <5° V5 V N^Qj CT
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EPA Contract No. 68HERH21D0006
CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 20. Concentrations of CI" from Teflon Filters
Note: Nominal reporting limit is 0.020 mg/L.
0\^CS3CN^CV,oPc\v oP CV> to3 O n. ^C\ C\^CN3C>rCV,C>P
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EPA Contract No. 68HERH21D0006
CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 22. Concentrations of K+ from Teflon Filters
0.20-
J 0.15"
O)
E,
c
o
03 °-10"
fa
C
<1)
o
c
o 0.05-
o.oo-
Note: Nominal reporting limit is 0.006 mg/L.
Figure 23. Concentrations of Mg from Teflon Filters
® All Samples ~ Median Field Blanks
• All Samples • Median * Field Blanks
Note: Nominal reporting limit is 0.003 mg/L.
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CASTNET Quarterly Data Summary- Fourth Quarter 2022
Figure 24. Concentrations of Na+ from Teflon Filters
Note: Nominal reporting limit is 0.005 mg/L.
Time Series of Concentration Differences from Co-located Sites
Figures 25 and 26 show times series of concentration differences between the two sets of co-
located sites.
Figure 25. Time Series of Filter Concentration Differences between MCK131 and MCK231, KY
0.3
0.2
Teflon SO
"eflon Ca2
Nylon SO2,
Teflon NO,
""eflon Mg'~
Nylon HNO
Teflon NHI
-•-Teflon Na+
-•-Cellulose S02
Teflon CI"
Teflon K+
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Figure 26. Time Series of Filter Concentration Differences between ROM406 and ROM206, CO
0.3
0)
o
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CO
E
0.2
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CD
CD
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CM
CN
CN
CD
CM
CM
O
CM
CM
CM
CM
CO
CM
CM
iB
CM
c3
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EPA Contract No. 68HERH21D0006
CASTNET Quarterly Data Summary - Fourth Quarter 2022
Precision of Filter Pack Concentrations
Table 3 shows mean absolute relative percent differences (MARPD) for concentrations measured
at MCK131/231 and ROM406/206 during fourth quarter 2022. The MARPD values met the
20 percent criterion.
Table 3. Precision (MARPD) for Co-located Filter Pack Data during Fourth Quarter 2022
Total
no3
hno3
no3
NH+4
so2
SO4
Ca2+
n
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EPA Contract No. 68HERH21D0006
CASTNET Quarterly Data Summary - Fourth Quarter 2022
Completeness for Filter Pack Concentrations
Table 4 shows CASTNET sites with less than 90 percent completeness for weekly filter pack concentrations. Comments are included to
provide information on why these sites experienced low data completeness.
Table 4. Sites with less than 90 Percent Data Completeness for Filter Concentrations for Fourth Quarter 2022 (1 of 2)
Site ID
Teflon
so*
Teflon
no3
Teflon
nh;
Teflon
Minor
Cations
Teflon
cr
Nylon
hno3
Nylon
so*
Cellulose
so2
Comment
ALH157, IL
69.2
69.2
69.2
69.2
69.2
69.2
69.2
69.2
Site was decommissioned 12/6/22.
ANA115, Ml
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
ASH135, ME
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
BWR139, MD
76.9
76.9
76.9
76.9
76.9
76.9
76.9
76.9
There were two 2-week samples during
the quarter. Another sample was
invalidated because of a hole in the
Teflon filter.
CDR119, WV
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
CDZ171, KY
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
DCP114, OH
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
EGB181, ON
61.5
61.5
61.5
61.5
61.5
61.5
61.5
61.5
Communication issues occurred. Data
were missing from 11/6/22 to 12/5/22.
HWF187, NY
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
LAV410, CA
84.6
84.6
84.6
84.6
84.6
84.6
84.6
84.6
A power failure affected two samples.
MKG113, PA
53.8
53.8
53.8
53.8
53.8
53.8
53.8
53.8
The mass flow controller malfunctioned in
mid-October, and its replacement
malfunctioned in late November. Six
samples were affected.
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Table 4. Sites with less than 90 Percent Data Completeness for Filter Concentrations for Fourth Quarter 2022 (2 of 2)
Site ID
Teflon
so*
Teflon
no3
Teflon
nh;
Teflon
Minor
Cations
Teflon
CI"
Nylon
hno3
Nylon
so*
Cellulose
so2
Comment
PED108, VA
84.6
84.6
84.6
84.6
84.6
84.6
84.6
84.6
One sample was invalidated for
insufficient flow volume. Another was
affected by power outage.
PNF126, NC
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
PSU106, PA
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
UND002, VT
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
UVL124, Ml
69.2
69.2
69.2
69.2
69.2
69.2
69.2
69.2
The mass flow controller malfunctioned in
early October and was replaced on
11/1/2022. Four samples were
invalidated.
VOY413, MN
84.6
84.6
84.6
84.6
84.6
84.6
84.6
84.6
A flow system leak affected two samples.
VPI120, VA
84.6
84.6
84.6
84.6
84.6
84.6
84.6
84.6
There was one 2-week sample. Another
was invalidated due to power failure.
WST109, NH
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Site was moth balled due to EPA's
FY2022 budget.
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Precision of Ozone Concentrations
Time series of co-located hourly 03 concentration differences for fourth quarter 2022 are provided
in Figures 27 and 28 for MCK131/231 and ROM406/206, respectively. The figures indicate no
consistent bias between the co-located analyzers at these site locations.
Figure 27. Time Series of the Differences in Co-located 03 Concentrations for MCK131/231, KY
4
-4
OJ
OJ
OJ
OJ
OJ
OJ
CM
OJ
OJ
OJ
I
OJ
OJ
OJ
OJ
OJ
OJ
OJ
OJ
OJ
T—
T—
T—
T—
o
o
o
o
o
o
o
T—
OJ
CO
T—
OJ
CO
T—
OJ
CO
o
o
o
T—
OJ
OJ
OJ
T—
T—
T—
T—
T—
T—
T—
T—
T—
Figure 28. Time Series of the Differences in Co-located 03 Concentrations for ROM406/206, CO
6
CM
CM
CM
CM
CM
CM
CM
o
CM
OJ
CO
O
CM
OJ
O
OJ
OJ
O
OJ
OJ
OJ
O
CO
OJ
OJ
o
OJ
OJ
OJ
o
OJ
OJ
OJ
OJ
o
CO
OJ
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Table 5 gives MARPD data for 03 data measured at the two co-located sites.
Table 5. Quarterly Precision (MARPD) for Co-located 03 Concentrations
Site Pair
Quarter
Start Date
MARPD
Records
MCK131/231, KY
4
1/1/22
1.1
2046
1
4/1/22
0.6
2066
2
7/1/22
0.8
2058
3
10/1/22
0.6
2098
ROM406/206, CO
4
1/1/22
2.0
1970
1
4/1/22
1.5
1932
2
7/1/22
1.8
1638
3
10/1/22
1.5
1531
Completeness for 03 Concentrations
Calculation of an annual 03 value requires 75 percent completeness. However, calculation of the
3-year design value used for regulatory purposes requires 90 percent completeness. Table 6
shows CASTNET sites with less than 90 percent completeness for DM8A 03 concentrations.
Comments are provided for these sites.
Table 6. Sites with less than 90 Percent Data Completeness for DM8A Concentrations during
Fourth Quarter 2022
Site ID
Percent
Completeness
Comments
ASH135, ME
0
Site was mothballed due to EPA's FY2022 budget.
HWF187, NY
0
Site was mothballed due to EPA's FY2022 budget.
WST109, NH
0
Site was mothballed due to EPA's FY2022 budget.
PNF126, NC
0
Site was mothballed due to EPA's FY2022 budget.
CDZ171, KY
0
Site was mothballed due to EPA's FY2022 budget.
DCP114, OH
0
Site was mothballed due to EPA's FY2022 budget.
CDR119, WV
0
Site was mothballed due to EPA's FY2022 budget.
DEN417, AK
71
Ozone data were invalid from 10/20/22 through 11/14/22 due to a
failed pump and an issue with the solenoid.
ALH157, IL
72
Site was decommissioned 12/6/22.
ROM206, CO
74
QC failures resulted from malfunctioning analyzer solenoid.
Associated data were invalidated. Analyzer was replaced 12/16/22.
ALC188, TX
74
Several sampling system issues had to be addressed following
maintenance and replacement of the analyzer in late October.
Associated data were invalidated.
LAV410, CA
82
Ozone data were invalid intermittently throughout December due to
poor QC checks and noise in the minute data trace.
NPT006, ID
88
QC failures resulted from sampling system issues in late October.
Associated data were invalidated.
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CASTNET Quarterly Data Summary - Fourth Quarter 2022
Table 7 shows CASTNET sites with less than 90 percent completeness for hourly 03
concentrations. Comments are provided for these sites. The annual average for each of these sites
is included for reference.
Table 7. Sites with less than 90 Percent Data Completeness for 03 Concentrations
Site ID
Q4 2022
Q1 2022-
Q4 2022
Comments
ALC188, TX
75
90
Several sampling system issues had to be addressed following
maintenance and replacement of the analyzer in late October.
Associated data were invalidated.
ASH135, ME
0
56
Site was mothballed due to EPA's FY2022 budget.
CDR119, WV
0
56
Site was mothballed due to EPA's FY2022 budget.
CDZ171, KY
0
60
Site was mothballed due to EPA's FY2022 budget.
DCP114, OH
0
60
Site was mothballed due to EPA's FY2022 budget.
DEN417, AK
71
89
Ozone data were invalid from 10/20/22 through 11/14/22 due
to a failed pump and an issue with the solenoid.
HWF187, NY
0
59
Site was mothballed due to EPA's FY2022 budget.
LAV410, CA
86
94
Ozone data were invalid intermittently throughout December
due to poor QC checks and noise in the minute data trace.
PNF126, NC
0
60
Site was mothballed due to EPA's FY2022 budget.
ROM206, CO
74
92
QC failures resulted from a malfunctioning analyzer solenoid.
Associated data were invalidated. Analyzer was replaced
12/16/22.
WST109, NH
0
60
Site was mothballed due to EPA's FY2022 budget.
Filter Pack Total Nitrate and Continuous Trace-level NOy Concentrations at CASTNET Sites
Figures 29 through 36 show a comparison of weekly average continuous NOy measurements with
weekly filter pack total NOj concentrations collected at the six of eight sites with NOy
measurements. The NOy concentrations were consistently higher than the total NO"3 levels at all
sites. The average weekly NOy levels, the weekly total NO"3 concentrations, and their ratios for the
six sites with available data are shown in Table 8. Ratios of NOy to total NO"3 varied from 4.82 at
MAC426 to 8.22 at PND165. No data are available from HWF187 and PNF126 for fourth quarter
2022. These sites were mothballed due to EPA's budget constraints.
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Table 8. Summary of Total N03 and N0y Measurements for Fourth Quarter 2022
Site ID
Elevation
Total NO~3 (ppb)
NOy (ppb)
Ratio
DUK008, NC
164*
0.71
2.89
5.87
BVL130, IL
213
0.98
4.57
5.44
MAC426, KY
243
0.57
2.55
4.82
HWF187, NY*
497
-
-
-
GRS420, TN
793
0.35
1.76
5.47
PNF126, NC *
1216
-
-
-
PND165, WY
2386
0.08
0.67
8.22
ROM206, CO
2742
0.12
0.82
7.37
Note: The inlet of the enhanced NOy monitor is located at the top of the 30-meter tower.
* The site was mothballed in second quarter 2022 due to EPA's FY2022 budget. No measurements were recorded
during fourth quarter 2022.
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Figure 30. Comparison of BVL130 Weekly Mean NOy and Total NO"3 Concentrations
T 5
-¦-Mean Continuous NOy
-~-Filter Pack Total Nitrate
Figure 31. Comparison of MAC426 Weekly Mean NOy and Total NO"3 Concentrations
-¦-Mean Continuous NOy
-~—Filter Pack Total Nitrate
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32. Comparison of HWF187 Weekly Mean NOy and Total NO"3 Concentrations
O.i
-Mean Continuous NOy
-Filter Pack Total Nitrate
0.6
0.4
Site mothballed due to EPA's FY2022 budget.
TO
0
0.2 o
c
o
O
o
ro
0.0 £
-0.2
-0.4
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Figure 34. Comparison of PNF126 Weekly Mean NOy and Total NO"3 Concentrations
1.5
-Mean Continuous NOy
-Filter Pack Total Nitrate
1.0
Site mothballed due to EPA's FY2022 budget.
0.5
0.0
1.2
1.0
O.i
0.6
0.4
0.2
0.0
Figure 35. Comparison of PND165 Weekly Mean NOy and Total NO"3 Concentrations
-•-Mean Continuous NOy
-~-Filter Pack Total Nitrate
0.05 J
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Figure 36. Comparison of ROM206 Weekly Mean NOy and Total NO"3 Concentrations
-¦-Mean Continuous NOy
-~—Filter Pack Total Nitrate
Filter Pack and Continuous Trace-level Gas Sulfur Dioxide Concentrations
Figures 37 through 39 provide diagrams that compare weekly filter pack S02 concentrations with
continuous trace-level gas data measured at BVL130, MAC426, and GRS420. The continuously
measured trace-level concentrations were higher than filter pack concentrations during the first four
weeks of fourth quarter at BVL130 and then were comparable. The filter pack concentrations were
higher than continuous concentrations at MAC426. The S02 data completeness was insufficient
at GRS420.
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Figure 37. Comparison of BVL130 Weekly Mean S02 Concentrations
Figure 38. Comparison of MAC426 Weekly Mean S02 Concentrations
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Figure 39. Comparison of GRS420 Weekly Mean S02 Concentrations
0.4
—¦— Mean Continuous S02
—Filter Pack S02
0.0
Completeness for Continuous Trace-level Gas Measurements
Table 9 shows the percent completeness for CASTNET trace-level gas measurements. Comments
are provided for sites with less than 90 percent completeness for hourly trace-level gas
concentrations during fourth quarter 2022. The average for first quarter 2022 through fourth quarter
2022 for each of the sites is included for reference.
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Table 9 Percent Data Completeness for Continuous Trace-level Gas Measurements (1 of 2)
Site ID
Parameter*
Q4 2022
Q1 2022 -
Q4 2022
Comments
BVL130, IL
CO
18
43
The CO system was subject to intermittent
analyzer stability issues throughout the
quarter.
NO
59
79
QC failures occurred in December. Associated
data were invalidated.
NOY
33
77
The converter and ozone generator
malfunctioned beginning in late October. Both
were replaced by early December. Associated
data were invalidated.
NOYDIF
33
73
S02_GA
86
88
Data were invalid during several multipoint
calibrations.
CHC432, NM
NO
98
98
NOX
98
98
NOXDIF
98
98
DUK008, NC
HN03
43
75
Data were invalidated 11/23/23 to 12/14/23 for
high noise levels and 12/23/23 to 12/26/23 for
high shelter temperatures. An additional week
of data was not collected due to a power
failure. HN03 and NOY Minus were invalidated
10/25/23 and 11/8/23 for suspect values.
NH3
57
61
NO
57
79
N02 TRUE
57
79
NOX TRUE
57
79
NOY
57
79
NOY MINUS
43
75
NOYDIF
57
79
TNX
57
64
GRS420, TN
CO
93
83
NO
94
88
NOY
94
88
NOYDIF
94
87
S02_GA
62
78
The lamp was failing. Associated data were
invalidated.
HWF187, NY
NO
0
33
Site mothballed due to EPA's FY2022 budget.
NOY
0
32
NOYDIF
0
32
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Table 9 Percent Data Completeness for Continuous Trace-level Gas Measurements (2 of 2)
Site ID
Parameter*
Q4 2022
Q1 2022 -
Q4 2022
Comments
MAC426, KY
CO
91
94
NO
96
97
NOY
96
97
NOYDIF
96
97
S02_GA
78
92
S02 data invalid from 11/26/22 through
12/13/22 because the instrument changed its
background and intercept frequently
throughout this period.
PND165, WY
NO
93
85
Site mothballed due to EPA's FY2022 budget.
NOY
91
83
NOYDIF
91
83
PNF126, NC
NO
0
33
Site mothballed due to EPA's FY2022 budget.
NOY
0
33
NOYDIF
0
33
ROM206, CO
NO
95
95
NOY
95
95
NOYDIF
95
95
Note: * See Table 10
The parameters listed in Table 9 are both calculated and measured. Table 10 provides information
on how the parameters listed in Table 9 are obtained.
Table 10. CASTNET Trace-level Gas Measurements
Parameter Name
How Obtained
Description of Process
CO
Measured
Gas filter correlation
HN03
Calculated
NOY minus NOY_MINUS
NH3
Calculated
TNX minus NOY
NO
Measured
Chemiluminescence reaction/no converter used
N02_TRUE
Calculated
NOX_TRUE minus NO
NOX_TRUE
Measured
Photolytic converter
NOY
Measured
Molybdenum converter at 315° Celsius
NOYDIF
Calculated
NOY minus NO
NOY_MINUS
Measured
Sodium carbonate denuder followed by molybdenum converter at
315° Celsius
NOX
Measured
Molybdenum converter at 325° Celsius
NOXDIF
Calculated
NOX minus NO
S02_GA
Measured
Ultraviolet fluorescence
TNX
Measured
Platinum/stainless steel converter at 825° Celsius followed by
molybdenum converter at 315° Celsius
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References
Sive, Barkley C., Prenni, Anthony J., Gebhart, Kristi A., Schichtel, Bret A., Stacy, Andrea, Vimont,
John, Benedict, Katherine B., Zhou, Yong, Pan, Da, Marsavin, Andrey, Naimie. Lillian,
Pollack, Nana, Fischer, Emily V., Sullivan, Amy P., Collet, Jeffrey L. Jr., George, Ingrid,
Sather, Mark Sather, Apodaca, Suzanne, Luke, Winston, Mao, Huiting. 2023. Volatile
Organic Compound and Ozone Measurements at Carlsbad Caverns National Park: Impacts
of Oil and Natural Gas Operation Emissions on Park Air Quality. Presented at the American
Meteorological Society Annual Meeting, January 8-12, Denver.
Wood Environment & Infrastructure Solutions, Inc. 2022. Clean Air Status and Trends Network
(CASTNET) Fourth Quarter 2022 Quality Assurance Report.
https://java.epa.gov/castnet/documents.do
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