Chemical Speciation Network (CSN)
Annual Quality Report
Samples Collected January 1, 2021 through December 31, 2021
Prepared for:
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
EPA Contract No. EP-D-15-020
Prepared by:
Air Quality Research Center
University of California, Davis
One Shields Avenue
Davis, CA 95616
January 31, 2023
UCPAVIS
AIR QUALITY RESEARCH CENTER
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TABLE OF CONTENTS
1. Executive Summary 6
1.1 Introduction 6
1.2 Data Quality Overview and Issues 6
2. Summary of Laboratory Operation Issues 7
2.1 RTI Ion Analysis Laboratory 7
2.2 UC Davis X-ray Fluorescence Laboratory 7
2.2.1 Instrument Repair Delays 7
2.2.2 Purchase of New Bruker S2-Puma EDXRF Instruments 7
2.3 UC Davis Thermal Optical Analysis Laboratory 7
2.3.1 OC4 Fraction Update 7
3. Quality Issues and Corrective Actions 7
3.1 Data Quality 7
3.1.1 Completeness 7
3.1.2 Comparability and Analytical Precision 10
3.1.3 Blanks 15
3.2 Corrective Actions 33
3.2.1 Elemental Analysis 33
3.2.2 Ion Analysis 35
3.2.3 Carbon Analysis 35
3.2.4 Data Processing 36
3.2.5 Technical System Audit 36
3.2.6 System Audits 36
4. Laboratory Quality Control Summaries 36
4.1 RTI Ion Chromatography Laboratory 36
4.1.1 Summary of QC Checks and Statistics 37
4.1.2 Summary of QC Results 38
4.1.3 Determination of Uncertainties and Method Detection Limits 70
4.1.3 Audits, Performance Evaluations, Training, and Accreditations 70
4.1.4 Summary of Filter Blanks 70
4.2 UC Davis X-ray Fluorescence Laboratory 72
4.2.1 Summary of QC Checks and Statistics 73
4.2.2 Summary of QC Results 75
4.2.3 Determination of Uncertainties and Method Detection Limits 91
4.2.4 4Audits, Performance Evaluations, Training, and Accreditations 91
4.2.5 Summary of Filter Blanks 91
4.3 UC Davis Thermal Optical Analysis Laboratory 94
4.3.1 Summary of QC Checks and Statistics 94
4.3.2 Summary of QC Results 95
4.3.3 Determination of Uncertainties and Method Detection Limits 110
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4.3.4 Audits, Performance Evaluations, Training, and Accreditations 110
4.3.5 Summary of Filter Blanks 110
5. Data Management and Reporting 112
5.1 Number of Events Posted to AQS 112
6. Quality Assurance and Data Validation 113
6.1 QAPP Revisions 113
6.2 SOP Revisions 113
6.3 Summary of Internal QA Activities 113
6.4 Data Validation and Review 114
6.4.1 Summary of Monthly Data Validation Review Results 114
6.5 Uncertainty Estimates and Collocated Precision Summary Statistics 127
7. References 136
LIST OF FIGURES
Figure 3.1-1: Ion repeat analysis 11
Figure 3.1-2: Carbon repeat analysis 12
Figure 3.1-3: Preliminary Replicate Analysis Results by Element and Instrument 14
Figure 3.1-4: Time series of ammonium measured on nylon filter field blanks 16
Figure 3.1-5: Time series of chloride measured on nylon filter field blanks 17
Figure 3.1-6: Time series of nitrate measured on nylon filter field blanks 18
Figure 3.1-7: Time series of potassium ion measured on nylon filter field blanks 19
Figure 3.1-8: Time series of sodium ion measured on nylon filter field blanks 20
Figure 3.1-9: Time series of sulfate measured on nylon filter field blanks 21
Figure 3.1-10: Time series of organic carbon by reflectance on quartz filter field blanks 23
Figure 3.1-11: Time series of elemental carbon by reflectance on quartz filter field blanks 24
Figure 3.1-12: Time series of silicon (Si) measured on PTFE filter field blanks 25
Figure 3.1-13: Time series of sulfur (S) measured on PTFE filter field blanks 26
Figure 3.1-14: Time series of potassium (K) measured on PTFE filter field blanks 27
Figure 3.1-15: Time series of calcium (Ca) measured on PTFE filter field blanks 28
Figure 3.1-16: Time series of titanium (Ti) measured on PTFE filter field blanks 29
Figure 3.1-17: Time series of iron (Fe) measured on PTFE filter field blanks 30
Figure 3.1-18: Time series of zinc (Zn) measured on PTFE filter field blanks 31
Figure 4.1-1: Control charts for anion CCV check standards 40
Figure 4.1-2: Control charts for cation CCV check standards 44
Figure 4.1-3: Control charts for anion CCV check standards 48
Figure 4.1-4: Control charts for cation CCV check standards 53
Figure 4.1-5: Ion duplicate analysis results 57
Figure 4.1-6: Time series of recovery (%) for anion and cation of matrix spikes 58
Figure 4.1-7: Concentrations of anions and cations in DI water blanks 59
Figure 4.1-8: Concentrations of anions and cations in method blanks 60
Figure 4.1-9: Control charts for anion LCS analyses 61
Figure 4.1-10: Control charts for cation LCS analyses 65
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Figure 4.1-11: Ion reanalysis results for the analysis period 69
Figure 4.2-1: Analysis results from daily PTFE blanks 77
Figure 4.2-2: Analysis results from daily PTFE blanks 78
Figure 4.2-3: Instrumental comparison using the weekly UC Davis ME-RM 87
Figure 4.2-4: Inter-instrument comparison by z-score of monthly reanalysis sample set 89
Figure 4.2-5: Error of each EDXRF instrument from the NIST SRM 2783 90
Figure 4.3-1: Results of daily instrument blanks from each analyze 98
Figure 4.3-2: Results of daily single-point sucrose calibration standard check 100
Figure 4.3-3: Results of internal calibration area check 101
Figure 4.3-4: Laser initial readings 102
Figure 4.3-5: Results of CSN replicate analysis for ECR and TC 104
Figure 4.3-6: Results of the weekly performance check samples 105
Figure 6.4-1: Multi-year time series of network-wide organic carbon 115
Figure 6.4-2: Multi-year time series of network-wide OC4 fraction 116
Figure 6.4-3: Multi-year time series of network-wide sulfur (S) concentrations 117
Figure 6.4-4: Multi-year time series of network-wide iron (Fe) concentrations 118
Figure 6.4-5: Multi-year time series of network-wide copper (Cu) concentrations 119
Figure 6.4-6: 2021 Cu Field Blanks 119
Figure 6.4-7: Multi-year time series of network-wide nitrate concentrations 120
Figure 6.4-8: Multi-year time series of network-wide composite variable RCM concentrations 121
Figure 6.4-9: Multi-year time series of network-wide composite variable soil concentrations 122
Figure 6.4-10: Scatter plot of potassium versus potassium ion 124
Figure 6.4-11: Scatter plot of chlorine versus chloride ion 125
Figure 6.4-12: Scatter plot of reconstructed mass (RCM) versus AirNow Tech PM2 5 mass data 126
Figure 6.5-1: Scaled relative differences for element measurements 128
Figure 6.5-2: Scaled relative differences for ion measurements 129
Figure 6.5-3: Scaled relative differences for carbon measurements 130
LIST OF TABLES
Table 3.1-1: Network sample completeness by filter type 8
Table 3.1-2: Network sites with less than 75% sample completeness 9
Table 3.1-3: Number and type of null codes applied at the filter level to SASS and URG 10
Table 3.1-4: Average method detection limits (MDLs) 32
Table 4.1-1: Sampling dates and corresponding IC analysis dates 37
Table 4.1-2: RTI quality control measures for ion (anion and cation) analysis 38
Table 4.1-3: Target concentrations of anion CCV check standards 39
Table 4.1-4: Target concentrations of cation CCV check standards 39
Table 4.1-5: Target concentrations for anion LCS 61
Table 4.1-6: Target concentrations for cation LCS 61
Table 4.1-7: Nylon filter field blank statistics in (ig/mL 71
Table 4.1-8: Nylon filter field blank statistics in jj.g/filter 71
Table 4.1-9: Nylon filter laboratory blank statistics in (ig/mL 72
Table 4.1-10: Nylon filter laboratory blank statistics in jj.g/filter 72
Table 4.2-1: Sampling months during 2021 and corresponding EDXRF analysis dates 73
Table 4.2-2: UC Davis quality control measures for element analysis by EDXRF 74
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Table 4.2-3: Descriptive statistics of XRF-1 results (|ig/cm2) 79
Table 4.2-4: Descriptive statistics of XRF-2 results (|ig/cm2) 80
Table 4.2-5: Descriptive statistics of XRF-3 results (|ig/cm2) 80
Table 4.2-6: Descriptive statistics of XRF-4 results (|ig/cm2) 81
Table 4.2-2: Descriptive statistics of XRF-5 results (|ig/cm2) 81
Table 4.2-8: Descriptive statistics of XRF-1 results (|ig/cm2) 82
Table 4.2-9: Descriptive statistics of XRF-2 results (|ig/cm2) 83
Table 4.2-10: Descriptive statistics ofXRF-3 results (|ig/cm2) 83
Table 4.2-11: Descriptive statistics of XRF-4 results (|ig/cm2) 84
Table 4.2-12: Descriptive statistics ofXRF-5 results (|ig/cm2) 84
Table 4.2-13: Precision and bias of all EDXRF instruments 86
Table 4.2-14: Dates for calibrations performed on each EDXRF instrument 91
Table 4.2-15: PTFE filter field blank statistics 92
Table 4.2-16: PTFE filter laboratory blank statistics 93
Table 4.3-1: Sampling months in 2021 and corresponding TOA analysis dates 94
Table 4.3-2: UC Davis quality control measures for carbon analysis by TOA 95
Table 4.3-3: Statistics of daily quartz filter laboratory blank and instrument blank total carbon 96
Table 4.3-4: Sucrose solution standard concentrations in (igC/cm2 99
Table 4.3-5: Statistics of daily single-point sucrose standard total carbon analyses 99
Table 4.3-6: Statistics of internal calibration peak area check on all carbon analyzers 101
Table 4.3-7: Acceptance criteria and the summary statistics of the replicate analyses 103
Table 4.3-8: Statistics (median, mean, and standard deviation) of the relative 106
Table 4.3-9: Summary of multi-point sucrose standard checks 107
Table 4.3-10: Summary of the temperature calibrations 109
Table 4.3-11: Quartz filter field blank statistics Ill
Table 4.3-12: Quartz filter laboratory blank statistics 112
Table 5.1-1: Summary of data deliveries to AQS for samples 113
Table 6.5-1: Fractional uncertainty (/), median coefficient of variation (CV), and CFR coefficient 133
Table 6.5-2: Fractional uncertainty (/), median coefficient of variation (CV), and CFR coefficient 134
Table 6.5-3: Fractional uncertainty (/), median coefficient of variation (CV), and CFR coefficient 135
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1. Executive Summary
1.1 Introduction
The University of California, Davis (UC Davis) Air Quality Research Center summarizes quality
assurance (QA) annually in this report as a contract deliverable for the Chemical Speciation
Network (CSN) program (contract #EP-D-15-020). The primary objectives of this report are:
1. Provide the U.S. Environmental Protection Agency (EPA) and other potential data users
with graphical and tabular illustrations of quality control (QC) for species measured
within the network.
2. Identify and highlight observations of interest that may have short- or long-term impact
on data quality across the network or at particular sites.
3. Serve as a record and tool for ongoing UC Davis QA efforts.
Each standard network site includes two samplers: (1) URG 3000N carbon sampler (URG
Corporation; Chapel Hill, NC) for collection of particulate matter on quartz filters; and (2) Met
One SASS or SuperSASS (Met One Instruments, Inc.; Grants Pass, OR) for collection of
particulate matter on polytetrafluoroethylene (PTFE) filters and nylon filters. The following
analyses are performed:
PTFE filters: filters are analyzed at UC Davis using energy dispersive X-ray fluorescence
(EDXRF) for a suite of 33 elements.
Nylon filters: filters are analyzed at Research Triangle Institute International (RTI) using
ion chromatography (IC) for a suite of six ions.
Quartz filters: filters are analyzed at UC Davis for organic and elemental carbon
including carbon fractions using thermal optical analysis (TOA).
Unless otherwise noted, data and discussions included in this report cover samples collected
during the time period January 1, 2021 through December 31, 2021 (batches 75-86, where each
batch corresponds with a single calendar month).
1.2 Data Quality Overview and Issues
Section 4 of this report provides laboratory performance details for each of the analytical
measurement techniques. The laboratory performance is detailed in Section 4.1 (RTI Ion
Chromatography Laboratory), Section 4.2 (UC Davis X-ray Fluorescence Laboratory), and
Section 4.3 (UC Davis Thermal Optical Analysis Laboratory).
Across the network, completeness determined by the total number of valid samples relative to
the total number of scheduled samples was 93.5% for PTFE filters, 93.7% for nylon filters,
and 91.7%) for quartz filters. Data from sites with non-standard sampler configurations are not
included in the completeness calculations.
The EPA did not conduct a Technical Systems Audit (TSA) of the UC Davis laboratory during
the 2021 data reporting period.
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2. Summary of Laboratory Operation Issues
2.1 RTI Ion Analysis Laboratory
There were no operational issues reported during this period.
2.2 UC Davis X-ray Fluorescence Laboratory
2.2.1 Instrument Repair Delays
During this reporting period, the XRF systems experienced longer than usual delays in some
repairs requiring parts from the manufacturer. These were in-part due to global production and
shipping delays, poor quality assurance review of high voltage generator units, and waning
support for the Panalytical Epsilon 5 EDXRF instrument which is no longer in production.
Specific instruments impacted and details of the delays are discussed in section 3.2.1.
2.2.2 Purchase of New Bruker S2-Puma EDXRF Instruments
During this reporting period the AQRC purchased three new Bruker S2-Puma EDXRF
instruments to replace the aging Panalytical Epsilon 5 instruments that are nearing the end of
their service support from the manufacturer. The new instruments were purchased in November
2021 and were not delivered to AQRC in this reporting period. Once delivered they will undergo
extensive testing and qualification to ensure they are fit for use before starting any network
sample analysis.
2.3 UC Davis Thermal Optical Analysis Laboratory
2.3.1 OC4 Fraction Update
UCD Sunset analyzers measure lower OC4 fraction than DRI instruments. Two variables may
contribute to this discrepancy: 1) the baseline threshold for advancing to the next step on the
Sunset instrument is set too high, and/or 2) the oven temperature is slightly lower in the Sunset
instruments than the DRI instruments. The Sunset software does not wait for the laser reflectance
to return to zero before advancing to the next step, but to a system defined, baseline value, and
the user is not allowed to adjust the baseline value. To overcome this obstacle, the analysis
protocol was adjusted for the Sunset instruments in November 2020 to fix the OC4 fraction time
to 580 seconds. This results in longer analysis times and more comparable OC4 results between
the different analyzers. More details can be found in the Data Advisory,
https://aqrc.ucdavis.edU/sites/g/files/dgvnskl671/files/files/page/CSN_DataAdvisory_carbon.pdf
3. Quality Issues and Corrective Actions
3.1 Data Quality
3.1.1 Completeness
Completeness is evaluated network-wide by filter type and determined by the total number of
valid samples relative to the total number of collected and scheduled samples (Table 3.1-1). Data
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from sites with non-standard sampler configurations are not included in the completeness
calculations. Additionally, for completeness relative to the total number of collected samples,
calculation results shown in Table 3.1-1 and Table 3.1-2 do not include placeholder records
generated for samples that were scheduled but not collected (Section 3.2.4.5). The completeness
is comparable for PTFE and nylon filters which are both collected by the Met One SASS / Super
SASS sampler; however, the number of invalid samples is higher for quartz filters, which are
collected by the URG sampler.
Table 3.1-1: Network sample completeness by filter type, January 1, 2021 through December 31, 2021. The total
number of scheduled samples is calculated from the sampling schedule (does not include field blanks). The total
number of collected samples is the actual number of samples collected in the field.
liller
T\ pe
Tolal Nil inhor
of Scheduled
Sii ill pics
Tolal NiiiiiIk-i'
of ( ollccled
Samples
Nil in her
of Valid
Samples
Number
of ln\ alid
Samples
"i> \ alid
(relali\e (o # of
eolleeled samples)
" i. Valid
(relali\e (o # of
scheduled samples)
PTFE
13,486
13,186
12,612
574
95.6
93.5
Nylon
13,486
13,186
12,630
556
95.8
93.7
Quartz
13,486
13,077
12,369
708
94.6
91.7
Across the network there were six sites with completeness (relative to the number of collected
samples, and determined for null codes applied at the filter level) less than 75% for at least one
filter type (Table 3.1-2), considering samples collected January 1, 2021 through December 31,
2021.
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Table 3.1-2: Network sites with less than 75% sample completeness (relative to the number of collected samples,
and determined for null codes applied at the filter level) for at least one filter type, January 1, 2021 through
December 31, 2021. For each filter type, the percentage of different null codes is listed relative to the total number
of null codes per site. For null code definitions, see Table 3.1-3.
AQS ID #
Location
Completeness
Null Codes
PTFE
Nylon
Quartz
PTFE
Nylon
Quartz
28-049-0020-5
Jackson Ncore, MS
95.9%
96.7%
54.9%
AO (40%)
Other (60%)
AO (50%)
AH (25%)
AM (25%)
AH (93%)
AO (4%)
Other (3%)
32-003-0540-5
Jerome Mack Middle
School, NV
95.9%
95.1%
62.3%
BI (80%)
AB (20%)
BI (67%)
AB (17%)
BJ (16%)
AH (89%)
BI (9%)
AB (2%)
37-067-0022-5
Winston-Salem - Hattie
Ave., NC
62.3%
63.9%
57.4%
BA (65%)
AH (9%)
Other (26%)
BA (68%)
AH (9%)
Other (23%)
AH (81%)
BA (8%)
Other (11%)
39-035-0076-5
Southerly WTP, OH
98.0%
100%
66.0%
AJ (100%)
...
AH (100%)
46-099-0008-5
Sioux Falls School of
Deaf, SD
51.5%
51.5%
51.5%
BA (100%)
BA (100%)
BA (100%)
46-099-0009-5
SF-USD, SD
56.9%
56.9%
80.0%
AN (89%)
BB (11%)
AN (89%)
BB (11%)
AN (46%)
Other (54%)
Samples can be invalidated for a variety of reasons, as detailed in the UCD CSN TI801C and the
Data Validation for the Chemical Speciation Network guide. Null codes indicate the reasons for
invalidation (Table 3.1-3).
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Table 3.1-3: Number and type of null codes applied at the filter level to SASS and URG samples from January 1,
2021 through December 31, 2021. Codes are ordered by frequency of occurrence.
Null
Code
SASS
PTFE
SASS
Nvlon
URG
Quartz
Total
Null Code Description
AN
109
106
103
318
Machine Malfunction
AH
99
94
243
436
Sample Flow Rate or CV out of Limits
AV
61
61
62
184
Power Failure
AF
56
56
51
163
Scheduled but not Collected
BJ
50
50
33
133
Operator Error
BA
35
35
24
94
Maintenance/Routine Repairs
AB
30
30
30
90
Technician Unavailable
AO
27
27
28
82
Bad Weather
AQ
22
24
12
58
Collection Error
AJ
16
5
5
26
Filter Damage
BB
14
14
14
42
Unable to Reach Site
AG
12
12
30
54
Sample Time out of Limits
BI
11
11
14
36
Lost or damaged in transit
AL
10
11
14
35
Voided by Operator
AD
5
5
0
10
Shelter Storm Damage
BE
4
4
4
12
Building/Site Repair
AR
4
2
9
15
Lab Error
SV
2
3
19
24
Sample Volume Out of Limits
AM
2
2
1
5
Miscellaneous Void
AI
2
2
0
4
Insufficient Data (cannot calculate)
SA
1
1
1
3
Storm Approaching
AZ
1
1
10
12
Q C Audit
AW
1
0
0
1
Wildlife Damage
AK
0
0
1
1
Filter Leak
3.1.2 Comparability and Analytical Precision
Analytical precision is evaluated by comparing data from repeat analyses, where two analyses
are performed on the same sample extract using either the same instrument (duplicate) or
different instruments (replicate). Reliable laboratory measurements should be repeatable with
good precision. Analytical precision includes only the uncertainties associated with the
laboratory handling and analysis, whereas collocated precision (Section 6.5) also includes the
uncertainties associated with sample preparation, field handling, and sample collection.
Analytical precision is used internally as a QC tool.
Comparisons of ion mass loadings from repeat analyses (replicates and/or duplicates) on nylon
filters analyzed by IC show agreement (Figure 3.1-1). Eight different IC instruments were used
for routine and repeat analyses where both replicate and duplicate analyses are performed using
the same extract.
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Figure 3.1-1: Ion repeat analysis (replicates and/or duplicates) results; data from valid samples collected January 1,
2021 through December 31, 2021.
Ammonium
Chloride
Nitrate
100
CD
ฐ OR
O. 25
CD
if- o-
y = 0.1352 + 0.9616x ,
r2 = 0.9956
2b 1
/
20-
15-
10-
5-
0-
y = -0.0024 + 1.0016* 300"
r = 0.9999
200-
100-
0-
y = -0.0182 + 1.0007*
r = 1
c/
/
/
F
*
/
/
/
CD
Q.
O) 6
0 25 50 75 100 0 5 10 15 20 25 0 100 200 300
Potassium Ion Sodium Ion Sulfate
4-
w
(/) o
03 Z
0-
y = -0.0026 +1.0058*/
r2 = 0.9992 ^
20-
15-
10-
5-
0-
y = - 3e-04 +1.0005x ~'
r2 = 0.9999 ~ '
/
/
/
/
/
/
/
i i i
,
60-
40-
20-
0-
y = 0.0129 + 0.9986x
r2 = 0.9997
2 4 6 0 5 10 15 20 0 20 40 60
Mass Loading (^g per filter): routine filter
Comparison of carbon mass loadings from repeat analyses (replicates and/or duplicates) on valid
quartz filters analyzed by TO A generally show agreement (Figure 3.1-2), with agreement
deteriorating for carbon fractions with lower mass loadings (e.g. EC2, OC1, OC4). Repeat
analyses are performed on the same filter as the routine analyses; different punches are used for
each analysis.
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Figure 3.1-2 Carbon repeat analysis (replicates and/or duplicates) results; data from samples collected during
January 1. 2021 through December 31, 2021. Elemental carbon (EC) fractions are indicated as (1) through (3),
organic caibon (OC) fractions are indicated as (1) through (4). Organic pyrolyzed (OP), elemental carbon (EC), and
organic caibon (OC) are shown by reflectance (R) and transmittance (T). AQS parameter codes indicated in
parentheses.
EC1 (88383)
EC2 (88384)
EC3 (88385)
ECR (88380)
400
300
200
100
0
y = 0.65 + 0.99x
r2 = 0.97 y
/
/
/
20-
10-
0-
y = 1.84 + 0.6X
r2 = 0.39
m ฎ
0 100 200 300 400 0 10 20
15-
10-
5
04
y = 0.02 + 0.94x
r2 = 0.93
''
0 5 10 15~
300
200
100
0
y = 0.33 + 0.99x s
r2 = 0.99 ~
/
/
/
/
/
'
0 100 200 300
w
'
-------
Replicate EDXRF analyses of routine CSN samples were started on December 20, 2020. The
data for 2021 has been collected and criteria are being evaluated. Analytical precision will be
evaluated in the next report. Preliminary results are shown in Figure 3.1-4 below. 4.2% of
network filters were put though replicate analysis. Each color represents a different analyzer. A
minimum of 2x analytical MDL is required for replicate analysis to be plotted as valid. CI and Br
are not included since they are volatile elements that are lost under vacuum. Dashed horizontal
lines (2 standard deviations) are warnings and solid lines (3 standard deviations) are limits.
Using the statistical data for sample year 2021, we set limits for each measured element. There
was one Ca failure as shown. This was an instance where the routine and replicate were off by an
order of magnitude due to a contamination or other isolated incident. Arsenic is also not plotted
because there were no measurements above the 2x analytical MDL requirement. The method
developed using 2021 data will be applied in future samples, however, we need a large data set
to generate the statistics first. This is noted because if the analyzer equipment changes, a new
data set of replicates must be collected specific to the analyzer.
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Figure 3.1-3: Preliminaiy Replicate Analysis Results by Element and Instrument. Sample year 2021.
Na
3
-2-
-3-
Mg
A1
>: ซ
0.00 0.25 0.50 0.75 l.OO.O 0.1 0.2 0.0.0 0.5 1.0 1.5 0 1 2 3 4 0.0000.0050.0100.015
K
3
2
V
-2
-3
ป| ! t
Ca
i*
>ป *
Ti
S < t
:
0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 0.000.250.500.751.001.05)000.0250.0500.075 0.000 0.001 0.002 0.003
3-
2
t OH
1:2
: t
Fe
ki.v. v
Co
% ?
Ni
ฆ ฆ ฆ
R. . . .
0.00 0.02 0.04 0.0G.000 0.025 0.050 0.075 0.0 0.5 1.0 1.5 0.000 0.002 0.004 0.0060.00 0.01 0.02 0.03
Cu
3 2
1/5 i J
o 1"
& o-
-i4
-2
-3
i ป
Zn
~ t
Se
Rb
i 1 r
Sr
0.02 0.04 0.06 0.08) 0 0.1 0.2 0.3 0.4 0.5 0.0020.004 0.006 0.002 0.004 0.0060.000.010.020.030.04
Zr
Ag
Cd
111
Sn
sell*
0.01 0.02 0.03 0.010.0lfrO2@.O20i.O3O 0.01 0.02 0.03 0.01 0.02 0.03 0.04 0.02 0.03 0.04 0.05
0
-1
-2
-3-
Sb
Cs
Ba
Ce
Pb
ฆm
?
0.02 0.04 0.06 0.030.040.050.060.070.04 0.08 0.12 0.16 0.06 0.08 0.10 0.120.01 0.02 0.030.04 0.05
Mean Areal Density of Routine and Replicate Measurement, fig cm-
Page 14 of 136
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XRF replicates were previously not performed by EDXRF on routine CSN samples due to time
limitations, as analyses take approximately 65 minutes per sample, and to preserve volatile
elements like chlorine and bromine, and to a lesser extent sulfur, which are lost when the sample
is analyzed under vacuum on the EDXRF. For this reporting period, EDXRF precision was
evaluated by analyzing the same set of samples, which are UCD-made multi-element reference
materials (see Table 4.2.2), on a monthly basis to assess both the short- and long-term stability of
the EDXRF measurements as described in UCD CSN SOP #302; see Section 4.2.2.4.
3.1.3 Blanks
Field blanks are an integral part of the QA process and field blank analysis results are used to
artifact correct the sampled filters as part of the concentration calculation (see Section 3.1.3.1).
Artifacts can result from initial contamination in the filter material, contamination during
handling and analysis, and adsorption of gases during sampling and handling. Additionally, field
blanks are used to calculate method detection limits (MDLs; see Section 3.1.3.2).
Beginning in May 2017, field blanks are collected once per month for each filter type per site;
prior to May 2017 field blanks were collected less frequently.
There is some variability in field blank mass loadings by species. The 10th percentile of network
sample mass loadings, before artifact correction, is indicated in Figure 3.1-4 through Figure 3.1-
18 to facilitate understanding of field blank mass loadings in context of network sample mass
loadings; 90% of network sample mass loadings fall above the indicated 10th percentile. As part
of the validation process (see Section 6), field blank outliers are investigated but are only
invalidated if there is cause to do so. Artifact correction (Section 3.1.3.1) and MDL (Section
3.1.3.2) calculation methods are robust against influence from occasional outliers.
Field blank mass loadings for the ion species (Figure 3.1-5 through 3.1-10) are examined in an
effort to identify changes that may be associated with the October 1, 2018 laboratory transition
from DRI to RTI (see Section 2.1.1 of the CSN 2019 Annual Quality Report) or changes that
may be occurring independently from the laboratory transition. The monthly 10th percentile
ammonium mass loading of network samples increased in November 2017 and has become
increasingly elevated relative to earlier years. Additionally, the monthly median ammonium
mass loading of field blanks increased corresponding with the laboratory transition. This trend
has continued through 2020. For potassium ion, the monthlyl0th percentile mass loading of
network samples - as well as the monthly field blank median mass loading and variability -
increased corresponding with the laboratory transition. Both of these are also observed to be
gradually increasing since the laboratory transition. Conversely, monthly median mass loadings
of field blanks were generally lower for nitrate specifically April through August 2019 and
sulfate following the laboratory transition. Median nitrate mass loadings of field blanks from
June 2020 through December 2020 are more comparable to those measured prior to the
laboratory transition.
Page 15 of 136
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Figure 3.1-4: Time series of ammonium measured on nylon filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no nylon filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
-------
Figure 3.1-5: Time series of chloride measured on nylon filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no nylon filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
-------
Figure 3.1-6: Time series of nitrate measured on nylon filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no nylon filter field blanks were
collected. The horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th and 25th
percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
-------
Figure 3.1-7: Time series of potassium ion measured on nylon filter field blanks (FB), for valid field blanks
collected January 1, 2016 through December 31, 2021. Gaps in time series are present when no nylon filter field
blanks were collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes
represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more
than 1.5xIQR (where IQR is the interquartile range, or the distance between the 25th and the 75th percentiles). Dots
indicate individual data points beyond 1.5 xIQR. Outlier points that are off scale are plotted at the 0.5 ng/filter
boundary shown by the horizontal dotted line. Black vertical dotted line indicates laboratory transition from DRI to
RTI. The black horizontal dashes indicate the 10th percentile of network samples.
Field blanks
(year)
$ 2016
$ 2017
$ 2018
$ 2019
$ 2020
$ 2021
10th %-ile of
network samples
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Page 19 of 136
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Figure 3.1-8: Time series of sodium ion measured on nylon filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 202. Gaps in time series are present when no nylon filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
O)
3
(year)
$ 2016
$ 2017
$ 2018
$ 2019
$ 2020
$ 2021
10th %-ile of
network samples
o.o
0.5
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Page 20 of 136
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Figure 3.1-9: Time series of sulfate measured on nylon filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no nylon filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
o>
c
(year)
$ 2016
0 2017
$ 2018
0 2019
$ 2020
^ 2021
10th %-ile of
network samples
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Page 21 of 136
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Field blank mass loadings for organic carbon (Figure 3.1-10) and elemental carbon (Figure 3.1-
11) are examined in an effort to identify changes that may be associated with the October 1, 2018
laboratory transition from DRI to UC Davis (see Section 2.3.1 of the CSN 2019 Annual Quality
Report and the Carbon Analyzer Change Data Advisory available at
https://www.epa.gov/amtic/chemical-speciation-network-data-reporting-and-validation) or
changes that may be occurring independently from the laboratory transition.
Both the monthly 10th percentile organic carbon mass loading of network samples and the
monthly median organic carbon mass loading of field blanks show some variability and increases
during the time series, January 1, 2016 through December 31, 2021. As discussed in the CSN
2019 Annual Quality Report, corresponding with the October 1, 2018 laboratory transition, there
is an increase in the monthly median organic carbon mass loading of field blanks, which is likely
caused by the change in the signal integration threshold and other small differences between
instrumentation and laboratory methods associated with the transition. Conversely, the monthly
median elemental carbon field blank mass loadings decreased with the laboratory transition.
Changes in the monthly median elemental carbon mass loading of field blanks are likely caused
by differences in the organic and elemental carbon split point associated with the transition.
Page 22 of 136
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Figure 3.1-10: Time series of organic carbon by reflectance (OCR) measured on quartz filter field blanks (FB), for
valid field blanks collected January 1, 2016 through December 31, 2021. Gaps in time series are present when no
quartz filter field blanks were collected. The colored horizontal lines indicate median, and the upper and lower limits
of the boxes represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data point that
is no more than 1.5>
-------
Figure 3.1-11: Time series of elemental carbon by reflectance (ECR) measured on quartz filter field blanks (FB),
for valid field blanks collected January 1,2016 through December 31, 2021. Gaps in time series are present when no
quartz filter field blanks were collected. The colored horizontal lines indicate median, and the upper and lower limits
of the boxes represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data point that
is no more than 1.5>
-------
Figure 3.1-12: Time series of silicon (Si) measured on PTFE filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
-------
Figure 3.1-13: Time series of sulfur (S) measured on PTFE filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
c
as
o
-I
c/>
t/>
ro
1.0
0.5
0.0
-
- -
-
_
- _ _
_
1
~
_A x *
i-liij lA L i_
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Field blanks
(year)
$ 2016
2017
2018
2019
2020
2021
$
$
&
$ ;
& ฆ
10th %,-ile of
network samples
Page 26 of 136
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Figure 3.1-14: Time series of potassium (K) measured on PTFE filter field blanks (FB), for valid field blanks
collected January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field
blanks were collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes
represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more
than 1.5xIQR (where IQR is the interquartile range, or the distance between the 25th and the 75lh percentiles). Dots
indicate individual data points beyond 1.5xIQR. Outlier points that are off scale are plotted at the 2.5 ng/filter
boundary shown by the horizontal dotted line. Black vertical dotted line indicates XRF application change. The
black horizontal dashes indicate the 10th percentile of network samples.
10th %-ile of
network samples
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Page 27 of 136
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Figure 3.1-15: Time series of calcium (Ca) measured on PTFE filter field blanks (FB), for valid field blanks
collected January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field
blanks were collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes
represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more
than 1.5xIQR (where IQR is the interquartile range, or the distance between the 25th and the 75th percentiles). Dots
indicate individual data points beyond 1.5xIQR. Outlier points that are off scale are plotted at the 2.5 ng/filter
boundary shown by the horizontal dotted line. Black vertical dotted line indicates XRF application change. The
black horizontal dashes indicate the 10th percentile of network samples.
2.5
I * *
I *
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Field blanks
(year)
$ 2016
$ 2017
$ 2018
$ 2019
$ 2020
Eja 2021
10th %-ile of
network samples
i ฆ; j. -!; j i
Page 28 of 136
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Figure 3.1-16: Time series of titanium (Ti) measured on PTFE filter field blanks (FB), for valid field blanks
collected January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field
blanks were collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes
represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more
than 1.5xIQR (where IQR is the interquartile range, or the distance between the 25th and the 75th percentiles). Dots
indicate individual data points beyond 1.5xIQR. Outlier points that are off scale are plotted at the 0.15 ng/filter
boundary shown by the horizontal dotted line. Black vertical dotted line indicates XRF application change. The
black horizontal dashes indicate the 10th percentile of network samples.
1/2016 7/2016 1/2017 7/2017 1/2018 7/2018 1/2019 7/2019 1/2020 7/2020 1/2021 7/2021
Time (Month/Year)
Field blanks
(year)
$
E5
$
$
$
E5
2016
2017
2018
2019
2020
2021
10th %-ile of
network samples
Page 29 of 136
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Figure 3.1-17: Time series of iron (Fe) measured on PTFE filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
-------
Figure 3.1-18: Time series of zinc (Zn) measured on PTFE filter field blanks (FB), for valid field blanks collected
January 1, 2016 through December 31, 2021. Gaps in time series are present when no PTFE filter field blanks were
collected. The colored horizontal lines indicate median, and the upper and lower limits of the boxes represent 75th
and 25th percentile, respectively. The whiskers extend to the most extreme data point that is no more than 1.5>
-------
determined from field blanks is lower than the analytical MDL (calculated by the laboratories
using laboratory blanks, daily blank QC filters, or the lowest standard or spiked solution), the
analytical MDL is assigned as a floor value.
The average MDLs calculated for this reporting period (samples collected January 1, 2021
through December 31, 2021) are compared to those calculated using the same method from the
previous reporting period (samples collected January 1, 2020 through December 31, 2020)
(Table 3.1-4). MDLs calculated during this reporting period were within the range of 50% to
200% of values from the previous reporting period for all species except elemental carbon
species (ECR) MDLs are lower relative to their 2020 MDLs.
Table 3.1-4: Average method detection limits (MDLs) and percentage of reported data above the MDLs for all
species, calculated for data from samples collected January 1, 2020 through December 31, 2020 (previous reporting
period) and January 1,2021 through December 31, 2021 (current reporting period). Elemental carbon (EC) fractions
are indicated as (1) through (3), organic carbon (OC) fractions are indicated as (1) through (4). Organic pyrolyzed
(OP), elemental carbon (EC), and organic carbon (OC) are shown by reflectance (R) and transmittance (T). Species
shown in bold have differences > 50% between those reported for the previous reporting period (2020) and the
current reporting period (2021). Typical MDLs are from the CSN laboratory analysis contract's statement of work.
Spocics
r.PA
Attachment 1)
2020
(prc\ions reporting period)
2021
(cuiTcnl reporting period)
1 Apical
MDL. ng/nr'
A\craiic
MDL. iisi/m-'
V-'ii Allow
MDL
A\craiic
MDL.
V-'ii AllO\l*
MDL
Ag
38
13
9.3
13
5.3
A1
25
23
48
24
58
As
2.7
0.10
6.5
0.10
3.3
Ba
59
28
13
33
8.9
Br
2.3
0.13
31
0.10
31
Ca
7.6
9.9
88
8.3
93
Cd
23
14
7.8
14
5.1
Ce
88
36
8.2
38
6.1
CI
11
4.0
45
3.8
45
Co
2.0
1.6
6.8
1.7
3.9
Cr
2.6
2.3
25
2.2
22
Cs
46
27
9.4
29
4.0
Cu
2.5
4.3
23
4.6
21
Fe
3.3
8.5
97
7.6
97
In
33
15
11
16
5.2
K
11
5.4
99
5.1
99
Mg
19
45
17
45
16
Mn
2.9
3.0
28
3.1
25
Na
55
81
31
91
28
Ni
1.9
1.2
23
1.3
18
P
16
1.9
9.0
1.5
12
Pb
6.4
6.7
23
7.1
15
Rb
2.6
3.2
00
00
3.2
5.5
S
9.9
1.1
100
0.79
100
Page 32 of 136
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Spocics
r.PA
Alliichmonl 1)
2020
(|)io\ions reporting period)
2021
(ciinvnl reporting period)
T\pic;il
Ml)l.. ng/nr'
A\cr;iiie
Ml)l.. ng/nr'
V-'ii Allow
MM.
A\er;iiie
Ml)l.. iiii/m'
"/ป Allow
MM.
Sb
52
16
8.6
17
7.4
Se
2.6
2.5
11
2.6
7.7
Si
19
14
79
13
90
Sn
36
16
9.4
17
7.1
Sr
3.5
2.9
14
3.1
12
Ti
5.3
2.9
51
2.5
61
V
3.9
0.72
9.2
0.7
8.6
Zn
3.5
1.7
93
2.2
89
Zr
23
14
7.8
15
5.8
Ammonium
25
13
95
13
93
Chloride
27
25
76
30
77
Nitrate
22
39
99
38
99
Potassium Ion
24
13
79
13
80
Sodium Ion
30
14
65
14
61
Sulfate
35
29
100
33
100
Elemental Carbon (EC1)
95
34
100
23
100
Elemental Carbon (EC2)
63
31
99
19
99
Elemental Carbon (EC3)
63
5.7
72
4.8
82
Elemental Carbon (ECR)
63
2.8
100
0.039
100
Elemental Carbon (ECT)
63
0.32
100
0.52
100
Organic Carbon (OC1)
63
15
69
11
73
Organic Carbon (OC2)
63
38
100
34
99
Organic Carbon (OC3)
95
490
56
300
76
Organic Carbon (OC4)
95
96
87
79
98
Organic Carbon (OCR)
63
640
90
410
97
Organic Carbon (OCT)
63
640
91
410
97
Organic Pyrolyzed (OPR)
95
66
90
44
88
Organic Pyrolyzed (OPT)
63
66
95
43
94
3.2 Corrective Actions
To ensure ongoing quality work, UC Davis reacts as quickly and decisively as possible to
unacceptable changes in data quality. These reactions are usually in the form of investigations,
and, if necessary, corrective actions. The following subsections describe significant corrective
actions undertaken for data from samples collected during 2021.
3.2.1 Elemental Analysis
3.2.1.1 XRF-5 X-ray Intensity Loss
On 2/4/2021 a drop in X-ray intensity on XRF-5 was noticed and all sample analysis was
stopped. The manufacturer's investigation linked this to the high voltage generator. This was
reported in last year's Annual Quality Report. However, it is being reported again here because
Page 33 of 136
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due to a quality issue with the supplier of the generators, multiple replacements also failed and
XRF-5 remained unusable well into this report's analysis period. XRF-5 was operational again
on June 17, 2021 and began analyzing CSN samples again on August 6, 2021. No CSN sample
analyses from this reporting period were affected by the intensity drop on XRF-5 as it occurred
prior to this analysis period.
3.2.1.2 XRF-3 X-ray Intensity Loss
XRF-3 showed decreased X-ray intensity and a resulting drop in QC concentrations after the
weekly detector calibration performed on 3/31/2021. All analysis was stopped on the instrument
and no samples were analyzed after the intensity drop. A manufacturer technician came out on
4/7/2021 and determined the detector sleeve had shifted and broken. The sleeve was replaced,
but low intensity continued, so the detector was moved closer to the sample. This repair
necessitated a new calibration which was done, QC tests passed and XRF-3 started analyzing
samples again on 4/23/2021.
Another drop in intensity occurred on 5/20/2021 and sample analysis was stopped on 5/21/2021.
This did not affect CSN samples as the instrument was analyzing IMPROVE network samples at
the time. All IMPROVE samples analyzed since the last QC before the intensity drop were
reanalyzed on another instrument and the reanalysis results were reported. After prolonged
troubleshooting by the manufacturer, it was determined a new X-ray tube and high voltage
generator were required. Out of stock parts delayed the repair which finished on 7/12/2021. A
new calibration was completed, all QC tests passed, and the instrument resumed IMPROVE
sample analysis on 7/23/2021 with CSN sample analysis resuming on 11/17/2021.
3.2.1.3 XRF-5 Contamination Issue
This incident is being reported for completeness, but no CSN samples were analyzed on XRF-5
during the period of observed contamination. On June 22, 2021 and July 9, 2021 zinc levels on
the daily QC blank increased over the acceptance limit. Additionally, the daily QC multi-element
(QC-ME) sample showed higher than usual zinc and copper. However, during this time period
the server that stores the XRF data was moved and the QC tools were not available. These high
values were not discovered until July 15, 2021 when manganese failed acceptance on the daily
blank QC. All analysis was then stopped and an investigation determined that powder coating
was rubbing off of a cover piece when the sample chamber cap opened and closed when loading
samples for analysis. This was due to bad placement of the cover piece when the manufacturer
reinstalled it during a repair completed in June. The cover was repositioned so it did not interfere
with the cap opening and closing and the analysis chamber was cleaned to remove any powder
coating debris.
The investigation also determined that no samples analyzed since the manufacturers repair had
any indication of contamination. Only the daily QC samples showed any sign of contamination
due to their multiple analyses. The QC samples were cleaned which returned them to acceptable
levels for the contaminant elements. So, there was no contamination of the instrument itself only
of the daily QC samples. No network samples were reanalyzed and as stated previously, no CSN
samples were analyzed on this instrument during the period when contaminants were observed
on the QC samples.
Page 34 of 136
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3.2.1.4 Failed Quality Control for Silicon Issue
UCD reanalyzed 348 CSN samples from October 2019 originally run on an XRF instrument that
failed QC for silicon. A Corrective Actions Report (CAR) was accepted by the EPA on August
16, 2021. UCD updated the data in AQS on September 9, 2021; a total of 331 silicon
measurements, 331 Soil results, and 331 Reconstructed Mass results were updated. No updates
were made for 17 filters as these were reported as invalid throughout the CSN data pathway.
Data were updated having taken into consideration SLT edits on impacted filters during review
in DART as well as any changes made in AQS since UCD originally submitted the data.
3.2.2 Ion Analysis
During this reporting period there were no issues with Ion Analysis.
UCD identified the incorrect analytical MDL had been applied to data between 10/01/2018 and
12/31/2019; the analytical MDL originally applied during this time was from DRI instead of
from RTI, who began performing IC analysis on CSN samples beginning October 2018. As
described in Section 3.1.3.2, the MDL is the higher of the analytical MDL and field blank-based
MDL. Potassium ion is the primary ion where the analytical MDL is the overall MDL. Though
impacts are primarily on potassium ion MDLs, UCD suggested the MDLs, uncertainties, and
'MD' qualifier flag in AQS be updated for all ions for the time period 10/01/2018 to 12/31/2019.
Per instruction from the EPA, UCD updated and redelivered the ions data for October 2018
through December 2019 on March 16, 2022. UCD detailed these changes in MDLs over time in
a document emailed to the EPA on May 4, 2022. In addition, UCD updated the Contract
Transition Data Advisory to include details on analytical MDLs and delivered to the EPA for
review on May 4, 2022.
3.2.3 Carbon Analysis
The TOA protocol was updated for samples analyzed during this report period. UCD Sunset
analyzers measure lower OC4 than DRI carbon analyzers. In an attempt to minimize the
differences between the analyzers, the OC4 step duration was fixed at 580s to allow more time
for the organic carbon to evolve. Five of the UCD analyzers implemented the fixed OC4 duration
on Nov 6, 2020, during analysis of August 2020 samples. The sixth instrument was installed
after this date and was mistakenly setup with a non-fixed OC4 duration. Its protocol was updated
to a fixed 580 seconds on February 3, 2021. The SOP will be revised with the fixed OC4 time
and detailed explanations at the next revision. The correct time is posted on a deviation in the lab
and staff have been re-trained.
A total of 3,220 filters were analyzed by the sixth instrument, including both sample and field
blank filters, covering Intended Use Dates between 10/30/2020 and 11/9/2021, from the analysis
time period 1/19/2021 and 2/3/2022. The OC4, OP, EC1, EC, and OC parameters, including both
transmittance and reflectance parameters and corrected and raw data, have been flagged with the
'2 - Operational Deviation' and '4 - Lab Issue' qualifiers for the impacted filters. Relevant
Reconstructed Mass parameters have also been updated where parent species were flagged. Data
for filters through October 2021, a total of 2,855 filters, were updated in AQS accordingly on
April 22, 2022. The impacted filters from November 2021 were flagged and delivered to AQS on
May 18, 2022.
Page 35 of 136
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3.2.4 Data Processing
3.2.4.1 Data Flagging Modifications
Data are flagged as part of the CSN data validation process as detailed in the UCD CSN TI801C
and the Data Validation for the Chemical Speciation Network guide. Flags are applied
throughout the sampling, filter handling, analysis, and validation processes, using automated
checks and on a case-by-case basis. The use and application of flags evolves as problems are
identified and remedied, and also in response to process improvements that are implemented to
improve the quality and consistency of data for the end user.
3.2.4.2 Bromine and Chlorine Reanalysis
Beginning with filters from September 2021, the bromine (Br) and chlorine (CI) are marked
invalid with the 'AL - Voided by Operator' null code for any filters reanalyzed at XRF. Please
see Section 7.1 of the UC Davis QAPP for Analysis of Samples (available at
https://www.epa.gov/amtic/quality-assurance-project-plan-qapp-analysis-chemical-speciation-
network-csn-samples) for further details on the reason for invalidation.
3.2.5 Technical System Audit
The EPA did not conduct an audit during the time when 2021 samples were analyzed.
The EPA last conducted a Technical Systems Audit (TSA) of UC Davis laboratory and data
handling operations on August 18 & 19, 2019; on-site audit activities were performed by Battelle
(Columbus, OH) as an EPA contractor. Audit findings were detailed in a report from the EPA
delivered to UC Davis on January 16, 2020. Discussion and resolution of the corrective action
findings are documented in a corrective action report (CAR) prepared by UC Davis and
delivered to the EPA (initially on February 13, 2020, and with revisions on March 31, 2020). The
EPA sent a close-out letter to UC Davis on May 7, 2021.
3.2.6 System Audits
UCD performed an internal audit on December 17, 2020. A third-party auditor, T&B Systems,
was contracted to perform the audit. The auditors were provided with a tour of the data
processing and validation tools. No issues were noted for correction. The next internal audit will
take place in late 2022 or early 2023.
4. Laboratory Quality Control Summaries
4.1 RTI Ion Chromatography Laboratory
The RTI Ion Chromatography Laboratory, as a subcontractor to UC Davis, received and
analyzed extracts from nylon filters for batches 75 through 86, covering the sampling period
January 1, 2021 through December 31, 2021. Routine analysis of these samples was performed
March 16, 2021 through March 7, 2022. Both routine analysis and reanalysis was performed
May 18, 2021 through April 11, 2022. Using ion chromatography, RTI analyzed for both anions
(chloride [CI"], nitrate [NO3"], and sulfate [SO42"]) and cations (sodium [Na ], ammonium
[NH4+], and potassium[K+]) using five Thermo Dionex ICS systems and four Thermo Dionex
Aquion systems (five anion systems: All, A12, A9, A10, and A8; three cation systems: C9,
Page 36 of 136
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CIO, and C3) and reported the results of those analyses to UC Davis. Table 4.1-1 details the
analysis dates for each batch of data, including both routine analysis and reanalysis.
Table 4.1-1: Sampling dates and corresponding IC analysis dates covered in this reporting period. Analysis dates
include reanalysis - as requested during QA level 0 and level 1 validation - of any samples within the sampling year
and month.
Sampling Month
(2021)
Analysis Batch #
IC Analysis Dates
January
75
3/16/2021- 5/18/2021
February
76
4/13/2021- 6/08/2021
March
77
5/10/2021 - 7/09/2021
April
78
6/14/2021- 8/21/2021
May
79
7/19/2021 - 9/16/2021
June
80
8/13/2021 - 09/16/2021
July
81
9/13/2021 -11/08/2021
August
82
10/12/2021 - 12/15/2021
September
83
11/12/2021 - 1/13/2022
October
84
12/17/2021 - 2/21/2022
November
85
1/18/2022 - 3/24/2022
December
86
2/17/2022-4/11/2022
4.1.1 Summary of QC Checks and Statistics
Samples are received by the RTI Ion Chromatography Laboratory following the chain-of-
custody procedures specified in RTI SOP #Ionsl. Samples are analyzed using Thermo Dionex
ICS-2000, ICS-3000, and Aquion systems following RTI SOP #Ionsl. Extraction procedures are
documented on worksheets which are maintained with the associated analysis files. The QC
measures for the RTI ion analysis are summarized in Table 4.1-2. The table details the frequency
and standards required for the specified checks, along with the acceptance criteria and corrective
actions. Stated acceptance criteria are verified and documented on review worksheets, and
reviewers document acceptance criteria not met, corrective actions, samples flagged for
reanalysis, and subsequent reanalysis dates.
Page 37 of 136
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Table 4.1-2: RTI quality control measures for ion (anion and cation) analysis by ion chromatography.
Ac(i\ i(\
l'lV(|IK'IU\\
Accoplancc ( rileria
( orroc(i\o
Action
Calibration regression
Daily
R2 >0.999
Investigate;
repeat
calibration
Continuing calibration
verification (CCV)
check standard; RTI
dilution of a
commercially
prepared, NIST-
traceable QC sample
Daily, immediately after
calibration and at every 10
samples
Measured concentrations < 0.050 ppm:
within 35% of known values.
Measured concentrations >0.050 ppm:
within 10% of known values.
Investigate;
reanalyze
samples
Duplicate sample
3 per set of 50 samples
Relative % Difference = 10% at lOx MDL
Relative % Difference = 200% at MDL
Investigate;
reanalyze
Spiked sample extract
2 per set of 50 samples
Recoveries within 90 to 110% of target
values
Investigate;
reanalyze
Reagent blanks
One reagent blank per reagent
used (DIH20 and/or eluent);
at least one per day
No limit set; the data is compiled for
comparability studies; <10 times MDL
Investigate;
reanalyze
Round Robin
(External QA by
USGS)
4 per month
Not applicable; data reported and
compared annually
Investigate
Reanalysis
5% per of all samples,
reanalyzed on different day
and as requested
MDL to 10 times MDL: RPD up to 200%,
10 to 100 times MDL: RPD < 20%,
>100 times MDL: differences within 10%
Investigate and
reanalyze
samples if
needed
4.1.2 Summary of QC Results
RTI followed the acceptance criteria stated in Table 4.1-2. Instruments were recalibrated when
calibration failed to meet the criteria. For cases where CCV failures occurred during analyses,
samples bracketed by the CCV failure were reanalyzed. When duplicate precision or spiked
sample recoveries failed to meet the criteria, the duplicated samples or matrix spike sample plus
additional samples (5% of all samples) were reanalyzed. The original data were only replaced
with reanalysis data in cases where precision between the reanalysis and original result failed to
meet the criteria. For cases where check samples failed to meet the reanalysis criteria, the
remaining samples not already reanalyzed from the set of 50 samples were reanalyzed.
4.1.2.1 Calibration Regression
Ion chromatographs are calibrated daily with calibration standards prepared as serial dilutions of
a NIST-traceable stock standard. Anion instruments are calibrated from 10 to 2,000 parts per
billion (ppb) for chloride and from 50 to 10,000 ppb for nitrate and sulfate. A high calibration
standard at 5,000 ppb for chloride and 25,000 ppb for sulfate and nitrate are used in the
calibration curve only for samples exceeding 2,000 and 10,000 ppb, respectively. Cation
instruments are calibrated from 10 to 1,000 ppb for sodium, ammonium, and potassium. A high
calibration standard at 3,000 ppb is used only for samples whose concentrations exceed 1,000
ppb. The correlation coefficients for the daily calibration must be at least 0.999. If the criterion is
not met, the curve is investigated. A calibration standard or standards that are suspect are
removed from the curve and not used for calculations. If the calibration still fails to meet the
Page 38 of 136
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stated acceptance criteria, the situation is further investigated until it has been confirmed that the
instrument is performing correctly.
After calibration, an analytical sequence is assigned to an instrument and includes 50 samples,
extraction QC checks, three sets of replicate samples, two matrix spikes, and continuing
calibration verification (CCV) standards analyzed at a frequency of every 10 samples.
4.1.2.2 Continuing Calibration Verification (CCV) Check Standard
Instrument QC samples are used to verify the initial and continuing calibration of the ion
chromatography system. These solutions are prepared at the low, medium, medium-high and
high end of the calibration curve. Table 4.1-3 and 4.1-4 lists the concentrations.
Table 4.1-3: Target concentrations of anion CCV check standards for the analysis period 3/16/2021 through
3/7/2022 (samples collected 1/1/2021 through 12/31/2021).
QC Sample
CI (ppb)
NOj (ppb)
SO/ (ppb)
Inslrumenl low QC
200
600
1200
liisli'iiinenl Medium QC
500
1500
3000
1 list I'M meiit Mcdiiini-lliiih QC
1000
3000
6000
Ills! i ll nu n ( lliiill QC
2000
6000
12000
Table 4.1-4: Target concentrations of cation CCV check standards for the analysis period 3/16/2021 through
3/7/2022 (samples collected 1/1/2021 through 12/31/2021).
QC Sample
Na+ (ppb)
NH4+ (ppb)
K+ (ppb)
liislriniieiil Low QC
20
20
20
liislriniieiil Medium QC
250
250
250
Insli'iimeiil Medium-lliiji QC
750
750
750
liislriniieiil Nigh QC
2000
2000
2000
At least two CCV check standards are analyzed immediately after the calibration standards and a
single CCV check standard is analyzed after every ten samples. When an instrument CCV check
standard fails the acceptance criteria by falling outside of the control limits, impacted samples
are reanalyzed. If a CCV check standard fails, and there is a second CCV check standard
measured immediately following the failure which passes, samples are not reanalyzed. The failed
CCV check standard, samples flagged for reanalysis, and date of reanalysis are documented on
the review worksheet and maintained with the analysis records for each set of 50 samples
analyzed. Control charts were prepared for anion (Figure 4.1-1) and cation (Figure 4.1-2) CCV
check standards. Failures occurred at a rate less than 1% for all check standards and data
obtained during failures were not reported. Only data with check standards within limits were
reported.
Page 39 of 136
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Figure 4.1-1: Control charts for anion CCV check standards at low, medium, medium-high, and high concentrations
measured in units of |ig/L (see Table 4.1-3) forthe analysis period 3/16/2021 through 3/7/2022 (samples collected
1/1/2021 through 12/31/2021). Red lines show upper and lower control limits set at ฑ10% of the nominal
concentrations for the low, medium, medium-high, and high standards. Blue lines show upper and lower warning
limits.
Instrument Low Q.C - CI
I
2/23/21 4/14/21 b/3/21 7/23/21 'J/ll/21 10/31/21 12/20/21 2/B/22 3/30/22
Analysis Date
Instrument Low Q.C - N03
520 I i i i i i
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
istrument Low Q.C - S04
i
f.
1070
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
Page 40 of 136
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Instrument Medium Q.C - CI
%
*JTซ* '
425
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
Instrument Medium QC - N03
O 1425
*
*?-
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Instrument Medium QC - S04
3275 -J
3175
Concentration ug/L
3075
2975 -J
2875 J
1 ^
2775 j
-
2675 1
2/23/21
4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 41 of 136
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Instrument Medium-High Q.C - CI
>%r^' - -tt ' *. ^
r
890
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
Instrument Medium-High Q.C - N03
TO 2990
<_> 2S90
ฃi- *
I* . J ,
* 4/
. ... '* ;;
^ -
ri
* ^
f *r%
2690
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
Instrument Medium-High QC - S04
** v<ซf : * *
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 42 of 136
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Instrument High Q.C - CI
2190
2140
1940 '
1890
1840
1790
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
Instrument High Q.C - N03
ii*/"
. W
Iff
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
1 nstrur
nent High Q.C -
S04
13290 -i
12790
-
ฃ=
o
-------
Figure 4.1-2: Control charts for cation CCV check standards at low, medium, medium-high, and high
concentrations measured in units of |ig/L (see Table 4.1-4) forthe analysis period 3/16/2021 through 3/7/2022
(samples collected 1/1/2021 through 12/31/2021). Red lines show upper and lower control limits set at ฑ35% of the
nominal concentrations for the low standards and ฑ10% of the nominal concentrations for the medium, medium-
high. and high standards. Blue lines show upper and lower warning limits.
istrument Low Q.C - Na
4*'-- ฆ
*** pM'..
9/11/21 10/31/21 12/20/21
Analysis Date
Instrument Low Q.C - NH4
3ฐ -i
28
26
24
12
lO
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
30
28
26
24
^ 22
OX>
~ 20
o
M 18
c.
CD
8 15
14
12
Instrument Low Q.C - K
*
Va
* A *
i * A A *
A 1 *
\ ^ _ *
t * ป i ^ * A * *
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 44 of 136
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Instrument Medium QC - Na
; tj* t
hKf: *
220
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
Instrument Medium Q.C - NH4
2SO -1
270
260
i 250
ro
a.)
^ 240
230
220
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/S/22 3/30/22
Analysis Date
2SO
270
Instrument Medium Q.C - K
Concentration (ng/L)
J N IsJ N NJ
J W ฃ U1 cn
) 0 0 0 0
: -? -
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 45 of 136
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Instrument Medium-High Q.C - Na
S50
S30
810
790
730
710
690
670
650 I
2/23/21
4/1-4/21 6/3/21
7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
2/8/22 3/30/22
Instrument Medium High - NH4
830
810 -
790
770
750 -
730
7 lO -
690
670
i A
^ .
-*ฆ a?
f
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
850
S30
Instrument Medium
n High Q.C - K
SIO -
790
hM:*:->
-jf-.
ClO
o
ra
770
750 -
730
O
C_J
690
670 -
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 46 of 136
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2250
2200
2150
2100
Instrument High Q.C - Na
1950
2050 V-C" .~ -
2000 -I - *.***ฃ V A -
1750 I
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
Instrument High Q.C - NH4
2250
2200
2150
2100
2050
2000
1950
19 OO
1850
1800
1750
*
A *ซ ป a" A
v-'-.
ป1 7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
Instrument High Q.C - K
2 2 50
2200
2150
2100
2050 -
2000
1950 -
1900
1S50
ISOO -
1750
2/23/21
- - - * * *
i \
tol-4'
4/14/21 6/3/21 7/23/21 9/11/21
Analysis Date
For the purpose of demonstrating instrument-to-instrument performance, control charts for the
lowest CCV check standards were generated, where instruments A11, A12, A9, A10, and A8 are
compared for anions (Figure 4.1-3) and instruments C9, CIO, and C3 are compared for cations
(Figure 4.1-4). The control charts illustrate consistent performance between instruments.
Page 47 of 136
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Figure 4.1-3: Control charts for anion CCV check standards showing comparability between instruments (A11 and
A12, Thermo Dionex Aquion systems; A9, A10, and A8 Thermo Dionex ICS-3000 systems) at low concentrations
(see Table 4.1-3) forthe analysis period 3/16/2021 through 3/7/2022 (samples collected 1/1/2021 through
12/31/2021). Red lines show upper and lower control limits set at ฑ 10% of the nominal concentrations. Blue lines
show upper and lower warning limits.
Instrument Low Q.C - CI All
<> 1 90
4^
7/73/7 1 'I/I A/~? 1 6/3/71 7/73/7 1 9/1 1/7 1 10/31/7 1 1 7/70/71 7/R/77 3/30/77
Analysis Date
Instrument Low Q.C - CI A12
<> 1 90
f- -
ฃ
* ?
170
7/73/7 1 1/1-1/7 1 (5/3/71 7/73/7 1 9/1 1/7 1 10/31/71 1 7/7Q/7 1 7/S/77 3/3Q/7 7
Analysis Date
Instrument Low Q.C - CI A9
<> 1 90
6/3/71 7/73/7 1 9/11/7 1
Analysis Date
Page 48 of 136
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istrument Low QC - CI AlO
170
L>/24/21 G/13/21 7/3/21 7/23/21 8/12/21 9/1/21 9/21/21 lQ/ll/21 10/31/21 11/2Q/21 12/10/21
Analysis Date
Instrument Low Q.C - CI A8
ro 200
* i*.
^ Si
170
4/14/21
7/23/21 9/11/21 10/31/21 12/2Q/21
Analysis Date
Instrument Low Q.C - N03 All
660
640
DO
o
ro
dJ
620
600
5SO
4A 1-
vซซ j ^1
< * # > *
O
560
540
520 1
2/23/21 4/14/21
6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 49 of 136
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Instrument Low Q.C - N03 A12
*
A
i -
* * * J
^ t
a * f *
t *?: *
**;.
520
2/23/21 4/14/21
7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
2/8/22 3/30/22
Instrument Low Q.C - N03 A9
520 I
4/14/21
6/3/21 7/23/21 9/11/21
Analysis Date
Instrument Low QC - N03 AlO
520 l.i.i.,,.
5/24/21 6/13/21 7/3/21 7/23/21 8/12/21 9/1/21 9/21/21 10/11/21 10/31/21 11/20/21 12/10/21
Analysis Date
Page 50 of 136
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Instrument Low Q.C - N03 A8
V
520
4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
Instrument Low Q.C - S04 All
1320 -
1270
i
Concentration ug/l
1220 -
1170
1120
1070
,
2/23/21 4/14/21
6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Instrument Low QC - S04 A12
> *
*. *' w* *4. . V ~
*ป i *.* si I
1170
^,4,* '<4" ฆ"
%
1070 I
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 51 of 136
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Instrument Low Q.C - S04 A9
1070 I
4/14/21
6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22
Analysis Date
Instrument Low Q.C - S04 AlO
1070 I ,,,,,,,,,
5/24/21 6/13/21 7/3/21 7/23/21 8/12/21 9/1/21 9/21/21 lO/H/2110/31/21 11/20/2112/10/21
Analysis Date
Instrument Low Q.C - S04 A8
1070 I
4/14/21
6/3/21 7/23/21
9/11/21 10/31/21 12/20/21
Analysis Date
2/S/22 3/30/22
Page 52 of 136
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Figure 4.1-4: Control charts for cation CCV check standards showing comparability between instruments (C9 and
CIO, Thermo Dionex Aquion systems; C3 Thermo Dionex ICS-2000 systems) at low concentrations (see Table 4.1-
4) for the analysis period 3/9/2020 through 3/9/2021 (samples collected 1/1/2020 through 12/31/2021). Red lines
show upper and lower control limits set at ฑ 35% of the nominal concentrations. Blue lines show upper and lower
warning limits.
30
28
26 -
24
22
20
15
16
14
Instrument Low Q.C - NH4 CIO
A? ป***
ft**
^ 3
*#*
* 5.
-
10
2/23/21
7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
30
28
Instrument Low Q.C - NH4 C9
20
18
16 -
14
%
. v V * * A * *.
*. r-- -*
i <
a* A
7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
Instrument Low Q.C - NH4 C9
30
28
26 -
24
22
20
18
16
14
; J * ฃ
i A f
*
i? ฃ-: %
6/3/21 7/23/21 9/11/21 10/31/21
Analysis Date
Page 53 of 136
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Instrun
Tent Low Q.C - Na CIO
30
28
26
QJO
o
CO
{=
a
i 4*: * * 14 K* i '
Analysis Date
Instrument Low QC - Na C3
'it
7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
Page 54 of 136
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28
26
24
22
20
IS
Instrument Low QC - K CIO
k i * aAj
^ i i* **A* . *.*
^4^' * :
* >i ;
'ฆK
~ ^ iA
^ *a
2/23/21 4/14/21
7/23/21 9/11/21 10/31/21 12/20/21 2/8/22
Analysis Date
Instrument Low Q.C - K C9
lฃ
28
26
24
22
20
18
fi1 t^ , =>'^*f=^: ;ifs' M
4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Instrument Low Q.C - K C3
24
22
20
18
A i
* *
i; C" * *
io I
2/23/21
4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21
Analysis Date
4.1.2.3 Duplicate Samples
Duplicate analysis results are obtained from two different aliquots of the same filter sample
extract run on the same instrument sequentially; there are three sets of duplicate samples for
every 50 samples analyzed. The relative percent difference (RPD) for duplicate samples must be
within ฑ 10% when sample concentrations are greater than ten times the analytical MDL and
Page 55 of 136
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within ฑ 100% when sample concentrations are at or up to ten times the analytical MDL. During
the analysis period when samples collected during 2021 were analyzed (March 16, 2021 through
March 7, 2022), there were a total of 886 duplicate samples analyzed for anions (Figure 4.1-5),
there were no cases where the RPD did not meet the acceptance criteria. Additionally during this
analysis period, there were a total of 883 duplicate samples analyzed for cations (Figure 4.1-5),
with one case each where the RPD did not meet the acceptance criteria for potassium. In all cases
when duplicate precision failed to meet the acceptance criteria, five samples were reanalyzed
(one duplicate aliquot plus four randomly selected network samples) were performed from the
analysis set. If any of the reanalyses failed to meet the acceptance criteria, the entire set of 50
samples was reanalyzed.
Page 56 of 136
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Figure 4.1-5: Ion duplicate analysis results for the analysis period 3/162021 through 3/7/2022 (samples collected
1/1/2021 111 rough 12/31/2022). Cases that did not meet the acceptance criteria, as described in Section 4.1.2.3, are
included in these figures.
1000
=i
c
o
800
ฃ
-------
recovery criteria of 90-100% for either sodium, ammonium, or potassium spiked samples (Figure
4.1-6); samples were reanalyzed for all cases.
Figure 4.1-6: Time series of recovery (%) for anion and cation of matrix spikes for the analysis period 3/16/2021
through 3/7/2022 (samples collected 1/1/2021 through 12/31/2021). The red lines are drawn to indicate the
acceptable recovery limits of 90% to 110%.
125
120
115
110
1 105
ซj 100
^ 95
90
85
80
/
Chloride Spike Recovery
Nitrate Spike Recovery
120
115
ฃฆ 110
>
.
{ ; t, .
*: i : .
'$' A ,js v
g 100
* 95
90
85
ซ '
$ .<ฃ" jp $
N ^ v-
Date Analyzed
125
120
115
110
a)
Sulfate Spike Recovery
Sodium Spike Recovery
115
110
ฃ 105
t
I ' 'ป.{: . j
| 100
^ 95
90
85
80
/
S ioo
0)
en
* 95
90
85
i
/ / / / / / / /
>x
-------
extraction vial is included as a method blank at a rate of 1 for every 50 samples. Empty
extraction vials are also spiked with exact volumes of concentrated solutions for both anions and
cations a rate of 1 for every 25 samples for LCS analysis. The same volume of water (25.0 mL)
is added to the method blank and LCS vials as is added to the vials with the filter samples to be
extracted.
Figure 4.1-7: Concentrations of anions and cations in DI water blanks for the analysis period 3/16/2021 through
3/7/2022 (samples collected 1/1/2021 through 12/31/2021). Black line indicates the analytical method detection
limit.
6
Chloride Measured in DI Blanks
ฃ 8
3 7
Nitrate Measured in DI Blanks
ง5 '
f4
C c
o
ฆB 5
.
s 3
c 2
c ^
O) *ฆ
* rv"
^ ^ ^
Analysis Date
A?
ฃy sy ฃy
\V \V v"
^
\V o\ vv
Analysis Date
Sulfate Measured in
DI Blanks
Sodium Measured in
DI Blanks
1 ->
10
o I
1
9
{J
g
7
ฆ' 8
c
C
ft
o
'H A I
o
5 I
- " *. T *
2
ro
.. .
I 4
*
c
1 '
c
0)
u
3
2
8 2
o
u
1
1
/
/ /
o>
,V
\V v>
V V ^
Analysis Date
/
V
/
/ /
/ /
/ /
Analysis Date
/
V
/
/
Page 59 of 136
-------
Figure 4.1-8: Concentrations of anions and cations in method blanks for the analysis period 3/9/2020 through
3/9/2021 (samples collected 1/1/2020 through 12/31/2021). Black line indicates the analytical method detection
limit.
Chloride Measured in Method Blanks
Nitrate Measured in Method Blanks
18
16
"a 14
3 12
c
-S 10
2 8
C ฃ
C 4
O 4
u 2
0
ง
v"
/
/
/
Analysis Date
*
<0
35
g 15
f. '
J? &
& ^ &
Analysis Date
jr
Sulfate Measured in Method Blanks
Sodium Measured in Method Blanks
12
| 10
: 8
6
4
2
0
Analysis Date
**
.5/ .U. i ...
*
*4
i
I* ป m
It . .
* .
*#
/ /
~ $
/ /
Analysis Date
~
/
i
f %
%
/
V
Ammonium Measured in Method Blanks
Potassium Measured in Method Blanks
a
1 6
c S
o
2 ^
c 3
5 . m ; * -
' /: .ซ 4
1 V . * . ' W
*? *. : ; 'f t* *
*. ~ I J
% . ,
, *
S 3'
2 ->
#
0 2
1
0 J
*
J? J* J? # & J
*?' tS ^ rS"
^ <ฃ & & ^
#
$ <$
Analysis Date
-------
Table 4.1-5: Target concentrations for anion LCS for the analysis period 03/16/2021 through 03/7/2022 (samples
collected 1/1/2021 through 12/31/2021).
QC Sample
CI (ppb)
NOs (ppb)
SO/ (ppb)
LCS Low
196
588
1180
LCS Medium
476
1430
2860
LCS High
2000
6000
12000
Table 4.1-6: Target concentrations for cation LCS for the analysis period 3/16/2021 through 03/7/2021 (samples
collected 1/1/2021 through 12/31/2021).
QC Sample
Na+ (ppb)
NH4+ (ppb)
K+ (ppb)
LCS Low
20
20
20
LCS Medium
276
276
276
LCS High
769
769
769
Figure 4.1-9: Control charts for anion LCS analyses relative to the CCV check standard acceptance criteria for the
analysis period 3/16/2021 through 3/7/2022 (samples collected 1/1/2021 through 12/31/2022). Red lines show upper
and lower control limits per the CCV check standard acceptance criteria. Blue lines show upper and lower warning
limits.
Laboratory Control Spike Low QC - CI
* 4 ^
170
2/23/21
Page 61 of 136
-------
Laboratory Control Spike Low QC - N03
660
640
540
520 ,,,,,,,,
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike Low QC- S04
*iA ^aAa
* 4. AA>^ 4 4 " V V*
A* ^ A A 4 Aa ^
1030 I
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike Medium Q.C - CI
.2 480
A i
- aA aVaa'^a,
A A 4
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 62 of 136
-------
Laboratory Control Spike Medium Q.C - N03
1650 -i
1600
1550
1500 ฑI
1450 A A* ***"* a
14oo %r- \ I'. .
- * - *
1350 -j "A 1 A
1300
1250 -j
1200
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike Medium QC - S04
/V* " A * A* 4 1 * * a ^
2525
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike High Q.C - CI
r* *a .
'j' *.A A a*a a
aa^4 **
*
2*
> ป*** *
t3 1940
1790 I
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 63 of 136
-------
Laboratory Control Spike High QC - N03
6590
v A A
^ . > - ?.
: : a
- *
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike High QC - S04
13290
^ *ป
1 " * . ^ * i" :
ฆ"t -*ฆ ' "* . . ./ A .ป J* * VA
* * --- f'. v ,
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 64 of 136
-------
Figure 4.1-10: Control charts for cation LCS analyses relative to the CCV check standard acceptance criteria for the
analysis period 3/16/2021 through 3/7/2022 (samples collected 1/1/2021 through 12/31/2021). Red lines show upper
and lower control limits per the CCV check standard acceptance criteria. Blue lines show upper and lower warning
limits.
Laboratory Control Spike Low QC - Na
<
* * *
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21
Analysis Date
10/31/21 12/20/21
Laboratory Control Spike Low QC - NH4
>vo: f:i c- > v
4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Page 65 of 136
-------
Laboratory Control Spike Low QC - K
30
28
26
24
<
1
22
- . -
<ง
20
18
15
\ a A ^ A
-- -"= * - -v 'ฆ - -
A* A " Aa a ^ ^
* \ ป A
^A aaa
14
A
12
10
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21
2/8/22 3/30/22
Analysis Date
Laboratory Control Spike Medium Q.C - Na
310
-
300
Concentration ng/L
280
270
- A *
ฑ A * - 4 A
A v * ~A
* i >a V ^ ' A * A'
aA V . i -
A *A A*
260
250
240
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21
2/8/22 3/30/22
Analysis Date
Page 66 of 136
-------
Laboratory Control Spike Medium QC - NH4
310 -i
//I A
* A ^ t*
. ; v
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike Medium QC - K
> * /."I- ^
- vv5 * - V: . -V
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
Laboratory Control Spike High Q.C - Na
820
800
760
740
1
A ' * 1
2/23/21 4/14/21 6/3/21
7/23/21 9/11/21 10/31/21 12/20/21 2/8/22
Analysis Date
Page
67
of 136
-------
Laboratory Control Spike High QC - NH4
* A A ป J* *
/aV * At A
: *
r4
730 *
Laboratory Control Spike HighQ.C-K
\ a a
* ->ป* s * - **" _ ป ซKf* **
2/23/21 4/14/21 6/3/21 7/23/21 9/11/21 10/31/21 12/20/21 2/8/22 3/30/22
Analysis Date
4.1.2.5 Round Robin (USGS)
The RTI Ions Chromatography Laboratory participated in the National Atmospheric Deposition
Program/Mercury Deposition Network Interlaboratory Comparison Program. The program is
administered by the United States Geological Survey (USGS) Branch of Quality Systems. Four
samples per month were sent to participating laboratories for analysis.
Results as well as previous years' data may be viewed using this URL:
https://bqs.usgs. gov/PCQA/Interlaboratory_Comparison/graphOutput.php?page=start.
4.1.2.6 Reanalysis
Replicate analyses are reanalyses where two analyses are performed on the same sample extract
using different instruments. Five percent of all samples are randomly selected for reanalysis and
are reanalyzed using different instruments and different calibration curves (these reanalyses are
specific to the analytical acceptance criteria described in Table 4.1-2, distinct from additional
reanalyses that may be requested later during the UC Davis Level 0 or Level 1 validation process
described in Section 6). Sample will also be reanalyzed that are flagged during analyst review of
analytical results, and reasons include poorly integrated peaks and cases where one peak is
significantly higher than the other peaks in the chromatograph (particularly for cations peaks,
which elute very close together). In these cases, the sample may be diluted for reanalysis.
Page 68 of 136
-------
Samples are also flagged if the acceptance criteria for reanalysis samples are not met. When
more than one analysis within an analysis set fails to meet the acceptance criteria as outlined in
Table 4.1-2, the whole set of samples is reanalyzed. Most reviewed-flagged reanalyzed samples
are from acceptance criteria failure for background contamination from sodium, chloride, and/or
potassium detected in either the original or reanalysis result. In cases where the entire set of
samples were reanalyzed, background contamination did not propagate through the whole set.
During this reporting period, there were 2,168 samples reanalyzed for anions and 2,150 samples
reanalyzed for cations (Figure 4.1-11). Less than 0.6% and 1.6% of samples reanalyzed for
anions and cations, respectively, failed to meet the acceptance criteria for precision between the
original and reanalysis result. For cases that failed, a third analysis was performed. The
reanalysis result was reported only for the impacted ion species. Typically, a sample only fails
the acceptance criteria for one ion species, and these failures are usually caused by
contamination introduced during the analysis.
Figure 4.1-11: Ion reanalysis results for the analysis period 3/16/2021 through 3/7/2022 (samples collected
1/1/202 lthrough 12/31/2021).
Chloride Reanalysis Precision
y = 0.9993x + 0.3939
R2 = 0.9994
400 600 800 1000 1200
Concentration ng/L (first analysis)
y = 0.9955x +0.1169
R2 = 0.9995
Nitrate Reanalysis Precision
2000 4000 6000 8000 10000 12000 14000
Concentration ng/L (first analysis)
Sulfate Reanalysis Precision
Sodium Reanalysis Precision
6000
5000
4000
3000
2000
1000
0
y = 1.0028x-1.0249
R2 =0.9983
2000 3000 4000
Concentration [ig/L (first analysis)
v = 0.9965x + 0.5261
R2 = 0.9979
200 300 400 500 600 700
Concentration ng/L (first analysis)
Page 69 of 136
-------
Ammonium Reanalysis Precision
y = 1.031Sx-3.8288
R! =0.9921
V
1000 1500 2000 2500 3000
Concentration ng/L (first analysis)
ro 5000
"5 4500
ง 4000
$ 3500
^ 3000
=s- 2500
.2 2000
2 1500
ง 1000
ง 500
u
0 '
Potassium Reanalysis Precision
y = 1.0299x-1.0779
R7= 0.9966
1000 1500 2000 2500 3000 3500 4000 4500
Concentration ng/L (first analysis)
4.1.3 Determination of Uncertainties and Method Detection Limits
For discussion of Method Detection Limits (MDLs) see Section 3.1.3.2.
For discussion of analytical uncertainty and total uncertainty see Section 3.1.2 and Section 6.5,
respectively.
4.1.3 Audits, Performance Evaluations, Training, and Accreditations
4.1.3.1 System A udits
The prime contractor (UC Davis) did not conduct any audit of the RTI Ion Chromatography
Laboratory during this reporting period.
4.1.3.2 Performance Evaluations
No performance evaluations were conducted during this reporting period.
4.1.3.3 Training
All new laboratory staff receive training for performing tasks described in the SOPs relevant to
their assigned work.
4.1.3.4 Accreditations
There are no accreditations for analysis of ions on aerosol filters by Ion Chromatography.
4.1.4 Summary of Filter Blanks
4.1.4.1 Field Blanks
Over the sampling period (January 1, 2021 through December 31, 2021) there were 1,658 valid
nylon filter field blanks. Table 4. l-7a and Table 4.1 -7b summarize the field blank statistics.
Page 70 of 136
-------
Table 4.1-7: Nylon filter field blank statistics in ng/mL for the analysis period 3/24/2021 through 2/25/2022
(samples collected 1/1/2021 through 12/31/2021).
Ions
( Oil II1
Median
Ulii/llll.)
A\era tie
Uiii/ml.)
Min
(uii/nil.)
Max
Ulli/llll.)
S(. I)e\.
(uii/nil.)
CI
1,658
0.003
0.005
0.000
0.159
0.009
no3
1,658
0.009
0.011
0.000
0.549
0.022
scv-
1,658
0.000
0.003
0.000
0.772
0.027
Na+
1,658
0.005
0.006
0.000
0.097
0.004
nh4+
1,658
0.005
0.005
0.000
0.273
0.009
K+
1,658
0.006
0.005
0.000
0.122
0.004
Table 4.1-8: Nylon filter field blank statistics in |ig/filter (extraction volume 25 mL) for the analysis period
3/24/2021 through 2/25/2022 (samples collected 1/1/2021 through 12/31/2021).
Ions
('on III
Median
(.ii li/fillert
A\era tie
(fiii/lillen
Min
(fi "/filler)
Max
(fiii/lillen
Si. I)e\.
(fiii/lillen
CI
1,658
0.082
0.121
0.000
3.974
0.216
no3
1,658
0.222
0.280
0.000
13.714
0.555
scv-
1,658
0.000
0.071
0.000
19.294
0.669
Na+
1,658
0.134
0.140
0.000
2.416
0.106
nh4+
1,658
0.123
0.135
0.000
6.828
0.231
K+
1,658
0.141
0.136
0.000
3.047
0.091
4.1.4.2 Laboratory Blanks
As described in Section 3.1.3, beginning with filters from the sampling period July 1, 2020, five
nylon laboratory blanks are shipped with each batch of routine filters to the analysis laboratory
and analyzed. A total of 60 nylon laboratory blanks were analyzed during the current reporting
period, where each set of laboratory blanks were analyzed either before or straight after the
routine analysis of the associated batch. Table 4.1-8a and Table 4.1-8b summarize the laboratory
blank statistics.
Page 71 of 136
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Table 4.1-9: Nylon filter laboratory blank statistics in ng/mL for the analysis period 4/7/2021 through 2/27/2022
(samples collected 1/1/2021 through 12/31/2021).
Ions
Count
Median
(jijj/mL)
Average
(jijj/mL)
Min
(jig/mL)
Max
WmL)
St. Dev.
(Htf/niL)
CI
60
0.001
0.002
0.000
0.014
0.003
no3
60
0.011
0.014
0.000
0.049
0.011
scv-
60
0.000
0.000
0.000
0.005
0.001
Na+
60
0.005
0.005
0.000
0.011
0.002
nh4+
60
0.006
0.006
0.000
0.016
0.003
K+
60
0.006
0.006
0.000
0.016
0.003
Table 4.1-10: Nylon filter laboratory blank statistics in |ig/filter (extraction volume 25 mL) for the analysis period
4/7/2021 through 2/27/2021 (samples collected 1/1/2021 through 12/31/2021).
Ions
(on III
Median
(fiii/liller)
A\c ratio
(fig/filler)
Min
(fiji/liller)
Max
(fiii/l'illen
Si. I)e\.
(HSi/filler)
CI
60
0.032
0.060
0.000
0.356
0.083
no3
60
0.266
0.343
0.000
1.217
0.283
scv-
60
0.000
0.007
0.000
0.136
0.025
Na+
60
0.131
0.128
0.000
0.265
0.041
nh4+
60
0.113
0.114
0.000
0.179
0.046
K+
60
0.148
0.149
0.000
0.410
0.065
4.2 UC Davis X-ray Fluorescence Laboratory
The UC Davis X-ray Fluorescence Laboratory received and analyzed PTFE filters from samples
collected January 1, 2021 through December 31, 2021. UC Davis performed analysis for 33
elements using energy dispersive X-ray fluorescence (EDXRF) instruments. These analyses were
performed during an analysis period from February 19, 2021 through April, 22, 2022, including
both routine analysis and reanalysis. Five EDXRF instruments XRF-1, XRF-2, XRF-3, XRF-
4, and XRF-5 performed all of the analyses during this period; see Table 4.2-1 for details.
Page 72 of 136
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Table 4.2-1: Sampling months during 2021 and corresponding EDXRF analysis dates during this reporting period.
Analysis dates include reanalysis as requested during QA Level 1 validation of any samples within the
sampling year and month.
Sampling
Moil I h
Analysis
lialeli #
XUI-'-l Analysis
Dales
XRI-2 AiiiiKsis
Dales
XUI-'-J Analysis
Dales
XRI-4 Analysis
Dales
XRI--5 Analysis
Dales
January
75
2021-02-19 -
2021-05-19
2021-03-23 -
2021-04-12
2021-03-19 -
2021-03-31
2021-03-20 -
2021-04-12
NA
February
76
2021-04-21 -
2021-05-27
2021-04-21 -
2021-05-14
2021-04-23 -
2021-05-08
2021-04-21 -
2021-05-07
NA
March
77
2021-05-14 -
2021-07-08
2021-05-15 -
2021-07-24
NA
2021-05-14 -
2021-06-08
NA
April
78
2021-06-19 -
2021-08-13
2021-06-19 -
2021-07-12
NA
2021-06-19 -
2021-07-12
NA
May
79
2021-07-23 -
2021-09-21
2021-07-23 -
2021-08-19
NA
2021-07-23 -
2021-08-05
2021-08-06 -
2021-08-14
June
80
2021-08-20 -
2021-10-13
2021-08-19 -
2021-09-14
NA
2021-08-28 -
2021-09-13
NA
July
81
2021-09-17 -
2021-10-10
2021-09-19 -
2021-10-09
2021-11-17 -
2021-11-17
2021-09-21 -
2021-11-15
NA
August
82
2021-10-19-
2021-12-17
2021-10-22 -
2021-11-07
NA
2021-10-18 -
2021-11-07
2021-10-22 -
2021-11-05
September
83
2021-11-24-
2022-01-18
2021-11-27-
2021-12-14
2021-12-03 -
2021-12-15
2021-11-25 -
2021-12-15
NA
October
84
2022-01-01 -
2022-01-20
2021-12-31 -
2022-02-17
2021-12-31 -
2022-01-20
2022-01-01 -
2022-01-20
NA
November
85
2022-01-20 -
2022-03-22
2022-01-21 -
2022-03-23
2022-01-20 -
2022-02-05
2022-01-20 -
2022-02-07
NA
December
86
2022-02-22 -
2022-04-22
2022-03-23 -
2022-03-24
NA
2022-02-23 -
2022-03-26
NA
All Months
75-86
2021-02-19 -
2022-04-22
2021-03-23 -
2022-03-24
2021-03-19 -
2022-02-05
2021-03-20 -
2022-03-26
2021-08-06 -
2021-11-05
4.2.1 Summary of QC Checks and Statistics
Samples are received by the UC Davis XRF Laboratory following the chain-of-custody
procedures detailed in the UCD CSN TI302B. Samples are analyzed using Malvern-Panalytical
Epsilon 5 EDXRF instruments following UCD CSN SOP #302. Calibration of the EDXRF
instruments is performed annually and as needed to address maintenance or performance issues
(e.g. an X-ray tube or detector is replaced). Quality control procedures are described in UCD
CSN TI 302D and are summarized in Table 4.2-2.
Page 73 of 136
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Table 4.2-2: UC Davis quality control measures for element analysis by EDXRF.
Analysis
l"m|iK'iio
( rik'rinn
( orivc(i\o Action
Detector
Calibration
Weekly
None (An automated process done
by XRF software)
XRF software automatically adjusts
the energy channels
Laboratory Blank
Daily
< acceptance limits with
exceedance of any elements not to
occur in more than two
consecutive days
Change/clean blank if
contaminated/damaged
Clean the diaphragm, if necessary
Further cross-instrumental testing
Reanalyze network samples since last
pass QC as needed.
UCD Multi-
element sample
Daily
Larger of ฑ 10% or 3 standard
deviations of reference mass
loadings for Al, Si, S, K, Ca, Cr,
Fe, Zn, As, Se, Rb, Sr, Cd, Sn,
and Pb with exceedance of any
element not to occur in more than
two consecutive days
Check sample for
damage/contamination
Further cross-instrumental testing
Replace QC sample if necessary
Reanalyze network samples since last
passing QC as needed.
Precision of UCD
Multi-element
sample
Daily
Relative standard deviation of last
5 measurements less than 10 %
for Al, Si, S, K, Ca, Cr, Fe, Zn,
As, Se, Rb, Sr, Cd, Sn and less
than 20% for Pb
UCD Multi-
element sample
Weekly
Larger of ฑ 10% or 3 standard
deviations of reference mass
loadings for Al, Si, S, K, Ca, Cr,
Fe, Zn, As, Se, Rb, Sr, Cd, Sn,
and Pb with exceedance of any
element not to occur in two
consecutive measurements
Sample Replicate
Measures
Weekly
For elements with mass loadings
between 5*MDL and
3 Uncertainty the relative percent
difference (RPD) must be, -50% <
RPD < 50%, and for mass
loadings greater than
3 Uncertainty, -20% < RPD <
20%. Elements checked = Al, Si,
S, K, Ca, Cr, Fe, and Pb
Reanalysis samples
Monthly
z-score between ฑ 1 for Al, Si, S,
K, Ca, Cr, Fe, Zn, As, Se, Rb, Sr,
Cd, Sn, and Pb
SRM 2783
Monthly
Bias within acceptance for Al, Si,
S, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu,
Zn and Pb
Daily QC checks include a laboratory blank (PTFE blank) and a multi-elemental reference
material (ME-RM) to monitor contamination and stability/performance of the instruments. A UC
Davis-made ME-RM is also analyzed weekly to check the instrument performance as well as
replicate sample measurements. Inter-instrumental comparability is monitored by analyzing the
bias and precision between instruments of the weekly UC Davis ME-RM. Long-term inter-
instrumental comparability is monitored using a set of reanalysis filters which are reanalyzed
monthly on each instrument. Long-term reproducibility is monitored using the reanalysis filters
Page 74 of 136
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and by analyzing a NIST SRM 2783 standard monthly and comparing the EDXRF error from the
certified/reference mass loadings to acceptance limits.
4.2.2 Summary of QC Results
QC tests conducted over the course of the analysis period showed good overall control of the
instruments and process. There were occasional acceptance criteria failures, which were
investigated promptly and corrected with no impact on sample results. The following
summarizes the QC issues which occurred during the analysis period reported here.
Random occasional zinc contamination was observed on daily PTFE blank filters for all XRF
analyzers. This intermittent contamination appears to be related to the design of the instrument
and is unavoidable. Samples analyzed during this period were monitored closely for any
contamination and were reanalyzed if there was any question of contamination. The reported
data were not impacted.
QC failures and issues and the corrective actions taken are reported in section 3.2.1. All QC
issues during this reporting period were found and acted upon quickly. In all cases sample results
were not impacted because the samples were either reanalyzed or no CSN samples were being
analyzed during the observed QC issue. A summary of the QC performance of the instruments is
presented below.
4.2.2.1 Results of Daily QC Checks
Possible contamination and instability issues are monitored by analyzing a daily PTFE blank.
The EDXRF results are compared to acceptance criteria, which are calculated as three times the
standard deviation plus the mean of a set of the PTFE blanks. Figure 4.2-la and Figure 4.2-lb
show the results of daily analyses of PTFE blanks for each instrument. If the mass loading
exceeds the acceptance criteria for more than two consecutive days, the blank is replaced to
distinguish between contamination on the blank and instrument contamination. Some occasional
exceedances of the acceptance criteria are expected but not continuous or repeated exceedances.
In all cases of exceedance, the other QC filters are checked to determine if the problem is
instrumental or strictly contamination of the PTFE blank. Sample analysis results are reviewed
and elements associated with occasional contamination (e.g. zinc, copper) are monitored closely.
When contamination is suspected, filters are reanalyzed and the reanalysis result is reported if
contamination was present in the original analysis. A total of nineteen samples from 2021 were
reanalyzed for suspected zinc contamination. Of those, thirteen were found to have zinc
contamination and the reanalysis result was reported. For the rest the original valid result was
reported.
All XRF instruments had intermittent elevated measurements of zinc on the daily PTFE blank
throughout the analysis period. These elevated levels were not measured over consecutive days
thus did not fail the acceptance criteria; however, these occurrences are monitored closely. Zinc
contamination likely comes from wear on the sample changer; zinc is a common contaminant in
elemental analysis systems.
XRF-2 had single elevated values for sulfur and calcium on 6/15/2021. This was the first
measure of a new QC blank after replacing the old blank. The levels returned to baseline values
for both elements at the next day's measurement, so this was not a QC failure. The elevated
signals were confined to the specific blank sample and no network samples were affected by this
spike.
Page 75 of 136
-------
XRF-5 had failures for Cu and Zn from late June 2021 through mid-July 2021. These are related
to contamination from the powder coating rubbing off the instrument's cap cover. No CSN
samples were analyzed during this time. More details can be found in section 3.2.1.3.
XRF-1 had an elevated iron value above the acceptance limit on 9/25/2021. The blank QC filter
was cleaned and reanalyzed the next day, 9/26/2021, but still had an elevated iron response. So,
the blank filter was replaced with a new one which measured on 9/27/2021 and had an
acceptable iron response. So, the elevated signal was confined to the specific blank filter and no
network samples were affected.
XRF-4 had a very elevated zinc signal above the acceptance limit on 1/4/2022. The blank QC
filter was cleaned and the following day's analysis showed the zinc had returned to normal
acceptable levels. This high zinc signal was confined to the specific blank QC filter and no
network samples were affected.
Page 76 of 136
-------
Figure 4.2-1: Analysis results from daily PTFE blanks for the analysis period 2/19/2021 through 4/22/2022 (see
Table 4.2-1 for corresponding sampling dates). Elements Na through Zn shown.
XRF-5
XRF-1 XRF-4
XRF-2
XRF-3
Acceptance Limit
Si
Ni
0.006
0.004
0.002
0.000
0.125
0.100
0.075
0.050
0.025
0.200-
0.100-
0.000-
0.150
0.100
0.050
0.000
0.008-
0.006
0.004
0.002-
s
~hl ~ Hr.
Fe
- "" "U
0.004
0.003-
0.002-
0.001
0.000 4
Ca
Cr
Co
Zn
i ii 'ii
ฆ11Z.TJ.-J
T
T
T
T
T
CM
CM
CM
T-
X
r
T
CM
CM
CM
T
T
T-
x
T
CM
CM
CM
CM
CM
CM
CM
CM
C\l
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
O
O
o
O
O
o
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CD
>%
Q.
>
c
CD
>%
CD
>N
Q.
>
d
CD
>
CD
>%
Q.
>
C
CD
><
CD
2
-3
CD
C0
O
CD
3
CD
CD
2
~3
<1)
O
z
CD
CD
2
CD
2
-5
CD
C/5
O
CD
~3
TO
2
XRF Analysis Date
Page 77 of 136
-------
Figure 4.2-2: Analysis results from daily PTFE blanks for the analysis period 2/19/2021 through 4/22/2022 (see
Table 4.2-1 for corresponding sampling dates). Elements As through Pb shown.
XRF-5
XRF-1 XRF-4
XRF-2
XRF-3
Acceptance Limit
Ag
Sn
0.040'
0.030'
0.020'
0.010
0.060
0.040
0.020'
0.100-
0.050
Cd
Sb
Ce
0.050'
0.040
0.030
0.020
0.010
0.100
0.075
0.050
0.025 H
Cs
T
T
T
T
y
CM
CM
CM
T
T-
y
T
T
CM
CM
CM
T
y
T
x
T
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
CN
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CM
CN
CD
>%
Q.
>
C
i
>
CD
>
Q.
>
C
CD
t
>>
CL
>
C
CD
>>
(O
CD
O
03
CD
CD
CD
0)
O
CD
CD
CO
CD
CD
O
CD
CD
(/)
2
-3
cn
2
5
if)
2
XRF Analysis Date
Daily operational performance of the instruments is monitored using UC Davis produced ME-
RM (different than the weekly ME-RM); each instrument had its own daily ME-RJVI The
acceptance criterion is the larger of +/-10% or +/- three standard deviations of the reference
values for the relevant elements, as listed in Table 4.2-2. When more than two consecutive
measurements exceed these limits, the results are marked unacceptable. Corrective actions for
Page 78 of 136
-------
unacceptable QC results include checking the sample for damage or contamination, checking the
results for the affected element on other QC samples, cross-instrumental testing if necessary to
determine if the unacceptable result is due to the instrument or the QC sample, and further
investigations as necessary. Sample analysis is halted or samples analyzed after the unacceptable
QC result are noted for possible reanalysis depending on the outcome of the investigation. When
a problem with the instrument is found the affected samples are reanalyzed on a different
instrument or the same instrument after the issue is corrected and once it has been demonstrated
to be within control again. QC samples which have been found to be damaged or contaminated
will be replaced (UCD CSN TI302D).
Tables 4.2-3 through 4.2-7 show the results of the UC Davis ME-RMs. A small number of
criteria exceedances are expected statistically, but not more than a few percent of the total
number of measurements. Investigations of other QC filters and laboratory blanks following
these exceedances did not show any contamination or instrumental issues, so no corrective
actions were taken. Also, note that the Lower Limit and Upper Limit do not represent exact QC
criteria as they are averaged over the reporting period and may include more than one QC-ME
sample which would have different reference and limit values. These values are merely
representative. The QC result is considered unacceptable if it fails the QC criteria as outlined in
Table 4.2-2.
Table 4.2-3: Descriptive statistics of XRF-1 results (|ig/cm2) of the daily UC Davis ME-RM for the analysis period
2/19/2021 through 4/22/2022 (see Table 4.2-1 for corresponding sampling dates), N = 586.
I'llcmcnl A\oraiic l ower l imit I ppcr limit ฆ!ฆป r.\m'(lance "<> I naccopl a hie KM)'!-<>
A1
2.020
1.709
2.438
0
0
1.9
Si
0.895
0.751
1.159
0
0
2.1
S
17.253
15.746
19.245
0
0
0.6
K
2.415
2.204
2.694
0
0
0.7
Ca
2.399
2.143
2.619
0
0
0.7
Cr
0.996
0.895
1.094
0
0
0.7
Fe
2.829
2.501
3.057
0
0
1.0
Zn
0.348
0.305
0.373
0
0
1.2
As
0.681
0.609
0.745
0
0
0.9
Se
0.472
0.439
0.536
0
0
1.5
Rb
0.234
0.210
0.256
0
0
1.5
Sr
0.226
0.203
0.248
0
0
1.6
Cd
0.300
0.271
0.331
0.5
0
3.7
Sn
0.351
0.315
0.396
0
0
3.7
Pb
0.088
0.063
0.105
0
0
7.6
Page 79 of 136
-------
Table 4.2-4: Descriptive statistics of XRF-2 results (|ig/cm2) of the daily UC Davis ME-RM for the analysis period
2/20/2021 through 4/22/2022 (see Table 4.2-1 for corresponding sampling dates), N = 634.
Element
\l
Average
1.784
Lower Limit
1.469
Upper Limit
2.047
%
Exeeedanee
0
% Unacceptable
u
RSD %
1.8
Si
0.832
0.637
1.017
0
0
2.4
S
15.010
13.349
16.315
0
0
0.6
K
2.100
1.900
2.322
0
0
0.7
Ca
2.044
1.830
2.237
0
0
1.0
Cr
0.850
0.764
0.934
0
0
0.8
Fe
2.391
2.142
2.618
0
0
0.8
Zn
0.260
0.223
0.273
0.7
0
2.1
As
0.584
0.529
0.647
0
0
1.2
Se
0.420
0.378
0.462
0
0
1.2
Rb
0.203
0.182
0.223
0
0
1.9
Sr
0.199
0.177
0.216
0
0
1.9
Cd
0.265
0.220
0.3 11
0
0
4.8
Sn
0.314
0.263
0.349
0.9
0
4.6
Pb
0.095
0.076
0.115
1.3
0
8.2
Table 4.2-5: Descriptive statistics of XRF-3 results (|ig/cm2) of the daily UC Davis ME-RM for the analysis period
2/20/2021 through 4/22/2022 (see Table 4.2-1 for corresponding sampling dates), N = 576.
Elemenl A\eratie Lower l.imil I pper l.imil " ".. I n;iccenl ;i ble RSI)"..
Lxceedance
A1
1.816
1.381
2.012
0
0
2.2
Si
0.797
0.602
0.946
0
0
1.5
S
14.676
13.089
15.998
0
0
1.0
K
2.130
1.871
2.286
0
0
1.0
Ca
1.995
1.795
2.193
0
0
1.5
Cr
0.854
0.761
0.930
0
0
1.1
Fe
2.386
2.122
2.594
0.781
0
2.8
Zn
0.277
0.242
0.296
1.563
0
3.8
As
0.585
0.522
0.638
0.781
0
4.1
Se
0.417
0.376
0.459
0.781
0
4.1
Rb
0.199
0.180
0.220
0
0
1.8
Sr
0.194
0.175
0.214
0
0
1.6
Cd
0.260
0.228
0.295
1.563
0
3.9
Sn
0.303
0.260
0.355
0
0
4.2
Pb
0.090
0.063
0.110
0.781
0
8.1
Page 80 of 136
-------
Table 4.2-6: Descriptive statistics of XRF-4 results (|ig/cm2) of the daily UC Davis ME-RM for the analysis period
2/20/2021 through 4/22/2022 (see Table 4.2-1 for corresponding sampling dates), N = 635.
Element
U
Average
1.844
Lower Limit
1.656
Upper Limit
2.393
% Exceedanee
u
% Unacceptable
0
RSD %
2.0
Si
1.018
0.672
1.137
0
0
3.5
S
16.230
14.853
18.154
0
0
0.6
K
2.337
2.146
2.623
0
0
0.6
Ca
2.458
2.190
2.677
0
0
0.8
Cr
0.996
0.897
1.096
0
0
1.1
Fe
2.758
2.478
3.029
0
0
0.6
Zn
0.386
0.340
0.416
0
0
2.1
As
0.685
0.617
0.754
0
0
1.1
Se
0.485
0.443
0.542
0
0
1.1
Rb
0.237
0.213
0.260
0
0
1.8
Sr
0.228
0.205
0.250
0
0
1.8
Cd
0.301
0.267
0.347
0.2
0
4.4
Sn
0.351
0.321
0.398
1.7
0
4.0
Pb
0.082
0.067
0.101
2.9
0
9.4
Table 4.2-7: Descriptive statistics of XRF-5 results (|ig/cm2) of the daily UC Davis ME-RM for the analysis period
3/19/2021 through 4/22/2022 (see Table 4.2-1 for corresponding sampling dates), N = 437.
Elemenl A\eraiie l.oซer limit I pper l.imil "<> I'.xceedance "<> I nacceplable RSI)",.
A1
1.897
1.438
2.083
0
0
1.3
Si
0.701
0.565
0.932
0
0
1.4
S
15.364
13.643
16.674
0
0
0.5
K
2.179
1.941
2.373
0
0
0.3
Ca
2.070
1.872
2.288
0
0
0.7
Cr
0.892
0.792
0.968
0
0
0.6
Fe
2.463
2.220
2.713
0
0
0.4
Zn
0.308
0.272
0.332
0
0
1.3
As
0.616
0.547
0.669
0
0
0.7
Se
0.449
0.397
0.485
0
0
0.8
Rb
0.211
0.187
0.228
0
0
1.6
Sr
0.204
0.182
0.223
0
0
1.6
Cd
0.278
0.231
0.309
0
0
3.5
Sn
0.326
0.273
0.370
0
0
4.2
Pb
0.079
0.061
0.103
0
0
7.6
4.2.2.2 Results of Weekly QC Checks
Weekly QC checks include analysis of a UC Davis produced ME-RM (different than the daily
ME-RM). The UC Davis weekly ME-RM was replaced in December 2018. Weekly results are
Page 81 of 136
-------
compared to acceptance criteria of +/- 10% of the reference values for the relevant elements, as
listed in Table 4.2-2. When more than two consecutive measurements exceed these limits, the
results are marked unacceptable. Corrective actions for unacceptable results are described in
section 4.2.2.1 and can be found in the UCD XRF SOP 302 and UCD CSN TI302D. A weekly
QC report is generated internally, which includes checks of the laboratory blanks and the daily
and weekly ME-RMs. Also, note that the Lower Limit and Upper Limit columns do not
represent exact acceptance limits. They are averaged over the reporting period and my include
more than one QC-ME sample which would have different reference and limit values. These
values are merely representative. The QC result is considered unacceptable if it fails the QC
criteria as outlined in Table 4.2-2.
Tables 4.2-8 through 4.2-12 show the EDXRF statistics of the weekly UC Davis ME-RM
through 4/22/2022.
Table 4.2-8: Descriptive statistics of XRF-1 results (|ig/cm2) of the weekly UC Davis ME-RM for the analysis
period 2/25/2021 through 4/13/2022 (see Table 4.2-1 for corresponding sampling dates), N = 58.
I'llcmcnl A\eraiic l ower l imit I ppcr limit r.xm'ilanco " <> I n;iccopl ;i hie RSI)"..
A1
1.088
0.862
1.360
0
0
2.6
Si
1.152
1.094
1.360
0
0
2.1
S
8.596
8.063
9.855
0
0
1.8
K
1.269
1.174
1.434
0
0
0.8
Ca
1.213
1.062
1.297
0
0
1.7
Cr
0.459
0.418
0.511
0
0
0.9
Fc
1.339
1.201
1.468
0
0
1.4
Zn
0.378
0.327
0.400
0
0
1.6
As
0.319
0.288
0.352
0
0
1.4
Se
0.229
0.208
0.254
0
0
1.3
Rb
0.112
0.100
0.123
0
0
2.7
Sr
0.115
0.103
0.126
0
0
2.4
Cd
0.157
0.127
0.184
0
0
6.8
Pb
0.235
0.210
0.256
0
0
3.1
Page 82 of 136
-------
Table 4.2-9: Descriptive statistics of XRF-2 results (|ig/cm2) of the weekly UC Davis ME-RM for the analysis
period 2/24/2021 through 4/20/2022 (see Table 4.2-1 for corresponding sampling dates), N = 63.
Element
U
Average
1.077
Lower Limit
0.862
Upper Limit
1.360
% Exceedanee
0
% Unacceptable
0
RSD %
3.0
Si
1.197
1.094
1.360
0
0
3.1
S
8.681
8.063
9.855
0
0
2.4
K
1.265
1.174
1.434
0
0
1.5
Ca
1.214
1.062
1.297
0
0
1.4
Cr
0.459
0.418
0.511
0
0
0.9
Fe
1.328
1.201
1.468
0
0
0.9
Zn
0.376
0.327
0.400
0
0
1.6
As
0.315
0.288
0.352
0
0
1.7
Se
0.230
0.208
0.254
0
0
1.9
Rb
0.111
0.100
0.123
0
0
3.2
Sr
0.116
0.103
0.126
0
0
2.8
Cd
0.157
0.127
0.184
0
0
6.7
Pb
0.233
0.210
0.256
0
0
3.8
Table 4.2-10: Descriptive statistics of XRF-3 results (|ig/cm2) of the weekly UC Davis ME-RM for the analysis
period 2/23/2021 through 4/18/2022 (see Table 4.2-1 for corresponding sampling dates), N = 50.
Elemenl A\eraiie l.oซer l imit I pper l.imil V<> r.xceedance "ป I nacccplablc USD "ฆป
A1
1.178
0.862
1.360
0
0
4.5
Si
1.232
1.094
1.360
0
0
4.0
S
8.595
8.063
9.855
0
0
2.2
K
1.298
1.174
1.434
0
0
1.9
Ca
1.216
1.062
1.297
0
0
2.1
Cr
0.463
0.418
0.511
0
0
1.4
Fe
1.327
1.201
1.468
0
0
1.3
Zn
0.379
0.327
0.400
0
0
2.4
As
0.320
0.288
0.352
0
0
2.4
Se
0.230
0.208
0.254
0
0
2.2
Rb
0.110
0.100
0.123
0
0
2.6
Sr
0.113
0.103
0.126
0
0
2.6
Cd
0.155
0.127
0.184
0
0
6.4
Pb
0.238
0.210
0.256
2.0
0
3.3
Page 83 of 136
-------
Table 4.2-11: Descriptive statistics of XRF-4 results (|ig/cm2) of the weekly UC Davis ME-RM for the analysis
period 2/24/2021 through 4/21/2022 (see Table 4.2-1 for corresponding sampling dates), N = 62.
Element
U
Average
0.965
Lower Limit
0.862
Upper Limit
1.360
% Exceedanee
0
% Unacceptable
0
RSD %
3.4
Si
1.215
1.094
1.360
1.6
0
3.4
S
8.645
8.063
9.855
1.6
0
2.0
K
1.285
1.174
1.434
0
0
1.4
Ca
1.221
1.062
1.297
0
0
1.4
Cr
0.463
0.418
0.511
0
0
1.2
Fe
1.342
1.201
1.468
0
0
0.8
Zn
0.377
0.327
0.400
0
0
1.8
As
0.320
0.288
0.352
0
0
1.7
Se
0.229
0.208
0.254
0
0
1.9
Rb
0.112
0.100
0.123
0
0
3.0
Sr
0.115
0.103
0.126
0
0
2.9
Cd
0.156
0.127
0.184
0
0
6.7
Pb
0.234
0.210
0.256
0
0
3.9
Table 4.2-12: Descriptive statistics of XRF-5 results (|ig/cm2) of the weekly UC Davis ME-RM for the analysis
period 6/17/2021 through 4/19/2022 (see Table 4.2-1 for corresponding sampling dates), N = 34.
Elemenl A\eraiie l.oซer limit I pper l.imil "ป Hxceedance "ป I nacccplablc RSI)";.
U
1 125
0.862
1.360
u
0
4.1
Si
1.147
1.094
1.360
0
0
2.5
S
8.655
8.063
9.855
0
0
2.1
K
1.279
1.174
1.434
0
0
1.4
Ca
1.203
1.062
1.297
0
0
1.1
Cr
0.464
0.418
0.511
0
0
0.9
Fe
1.325
1.201
1.468
0
0
0.9
Zn
0.378
0.327
0.400
0
0
1.1
As
0.321
0.288
0.352
0
0
2.0
Se
0.231
0.208
0.254
0
0
1.5
Rb
0.111
0.100
0.123
0
0
2.3
Sr
0.114
0.103
0.126
0
0
2.4
Cd
0.159
0.127
0.184
0
0
5.4
Pb
0.233
0.210
0.256
0
0
2.6
4.2.2.3 Reproducibility and Inter-instrument Performance Tests
The weekly ME-RM is also used as an inter-instrument comparison, with the same sample
analyzed by all EDXRF instruments. Figure 4.2-2 plots the elemental concentrations for the
weekly UC Davis ME-RM sample used during this analysis. The following approach is used to
Page 84 of 136
-------
quantify the differences observed in the plots. A reference value for the weekly ME-RM is
calculated as the mean of all the instrument results:
Reft = j; (Z XRFli + Z XRF2t + Z XRF3t + Z XRF4t + Z XRFSt),
where XRFl^ XRF2t, XRF3t, XRFA^ and XRFSi are the mass loadings of the ith element
measured by each instrument and JV is the total number of results of all instruments.
For each element, i, the bias of each instrument is estimated as the mean relative error from the
reference,
XRFij-Refi
error = a,- ,ฆ = ,
l-J Refi '
BiaSi = ^Zy=i d-i j,
where n is the number of measurements, j, made of the weekly ME-RM by the EDXRF
instrument over the analysis period.
The precision is estimated by,
n I . ; (/' - ( V; ii )'
Precision, = i ฆ'
\
n(n 1)
The results from this analysis, for the elements listed for the weekly ME-RM in Table 4.2-2,
averaged over the UC Davis ME-RM sample used during the analysis period, are presented in
Table 4.2-13. Boxplots of the mass loading results from the instruments are presented in figure
4.2-2 for each weekly ME-RM sample.
Page 85 of 136
-------
Table 4.2-13: Precision and bias of all EDXRF instalments from the weekly UC Davis ME-RM calculated for the
analysis period 2/19/2021 through 4/22/2022 (see Table 4.2-1 for corresponding sampling dates). Only elements
listed in Table 4.2-2 for the weekly UC ME-RM are evaluated.
I'llcmcnl
XUI-'-1 XUI-2 XUI -3 XUI-4 XUI-5
Kins " ISiiis 'In liia\ " ii liia\"
-------
Figure 4.2-3: Instrumental comparison using the weekly UC Davis ME-RM. Bias shown in plot labels is the
maximum bias between any two instruments. The thick horizontal lines indicate median, and the upper and lower
limits of the boxes represent 75th and 25th percentile, respectively. The whiskers extend to the most extreme data
point that is no more than 1.5 xIQR (where IQR is the interquartile range, or the distance between the 25th and the
75th percentiles). Dots indicate individual data points beyond 1.5xIQR.
XRF-5 Ej3 XRF-1 Ej3 XRF-4 Ej3 XRF-2 Ej3 XRF-3
K, Bias= 1.i
Fe, Bias= O.f
Se, Bias= 0.!
Cd, Bias= 1.2%
Si, Bias= -3.7%
XRF-1 XRF-2 XRF-3 XRF-4 XRF-5
1.280
1.240
1.200-
1.160-
0.390-
0.380-
0.370
0.360-
0.120-
0.115
0.110
0.105
0.220-
0.200
0.180H
0.160
Ca, Bias= -0.9%
Sn, Bias= 2.2%
S, Bias= 0.5%
9.200
8.800
8.400
8.000
0.480
0.470
0.460-
0.450
Cr, Bias= 0.6%
Zn, Bias= -0.4%
0.340
0.330
L i Xj
ry
rh
0.320
T
0.310
As, Bias= -1.3%
Rb, Bias= -1.3%
X ,
p r
0.125-[
0.120
0.115
0.110-
Sr, Bias= -1.3%
XRF-1 XRF-2 XRF-3 XRF-4 XRF-5
0.250
0.240 H
0.230
0.220-
Pb, Bias
ป= 1.6%
E
3E
1
1
1
1
4.2.2.4 Long-term Stability, Reproducibility, and Inter-instrument
Performance
A set of filters are reanalyzed monthly to monitor the long-term instrument performance. The set
consists of 16 UC Davis produced ME-RMs and covers a range of mass loadings simulating the
Page 87 of 136
-------
range of real CSN samples. In order to compare multiple filters with different mass loadings, the
results of reanalysis are first converted to z-scores. For a given month, the z-score for the ith
element and jth filter is
7
%-ij %ij
\u(xij)2 + U{x[j)2
where xtj is that month's result, Xiiis the reference value for element i in filter /, and U{x,ij) and
)are the uncertainty of that month's result and the reference uncertainty respectively. The
instrument-specific reference values for the samples of the reanalysis set are determined as the
mean and standard deviation of five initial measurements, while the values for SRM 2783 are the
certified or reference loadings. Monthly z-scores for each element are then summarized across
the N filters in terms of
Bias, = ztj RMS\ =
and * '
Every month, z-scores are plotted and checked to be within -1 to 1 for elements which have mass
loadings above the MDL (Al, Si, S, K, Ca, Ti, Mn, Fe, Zn, Se, and Sr). For further detail see
UCD CSN TI302D.
Figure 4.2-3 shows the mean z-score plots during the analysis period. Issues observed include
increasing mean z-scores for calcium and zinc which are most likely indicative of environmental
contamination build up on the monthly reanalysis samples. Additionally, the silicon z-score for
XRF-3 were near the upper limit through December 2021. These higher z-scores are due to a
higher bias for silicon for that calibration. When the instrument was recalibrated in December
2021 the silicon z-score dropped to near zero indicating the new calibration has far less bias for
silicon. Additionally, XRF-3 does not have a z-score result in June 2021 because the instrument
was not operational that month due to maintenance issues. See section 3.2.1.2 for further details.
Page 88 of 136
-------
Figure 4.2-4: Inter-instrument comparison by z-score of monthly reanalysis sample set. The orange dashed lines
indicate the mean z-score acceptance criteria of ฑ1.
XRF-1 XRF-2 XRF-3 XRF-4 XRF-5
1.00
0.50
0.00
-0.50
-1.00
1.00
0.50
0.00
-0.50
-1.00
1.00
0.50
0.00
-0.50 -
-1.00-
Al
1.00-
Si
1.00 -
S
~1 1
0.50-
o.oo-
-0.50
-1.00
.*.* *
0.50-
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-0.50 -
-1.00-
. * . .
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fVfTJ
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0.50
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0.50
0.00
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1.00
0.50
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-------
relative error plus three times the standard deviation for a set of monthly measurements (n=44);
see UCD CSN 71302D for further detail.
The NIST SRM 2783 results from this analysis period (2/19/2021 through 4/22/2022) are shown
in Figure 4.2-4, and Table 4.2-14 summarizes the calibrations performed during this analysis
period. All EDXRF instruments underwent routine annual calibrations in November/December
2020 and 2021. Calibrations required after maintenance repairs are listed. The results from the
monthly NIST SRM 2783 analyses indicate that calibrations for all instruments were stable over
the calibration periods.
Figure 4.2-5: Error of each EDXRF instrument from the NIST SRM 2783 standard run monthly for the analysis
period 2/19/2021 through 4/22/2022.
XRF-5 XRF-1 XRF-4 XRF-2 XRF-3 --- Acceptance Limit
10%
0%
-10%
10%
5%
0%
-5%
-10%
60%
30%
0%
-30%
-60%
30%
0%
-30%
60%
30%
0%
-30%
-60%
Al
* *t
**
s
i * ป***
:ป> M ซ r* ;i; v
10%
-10%-
Ca
* / 9 %
10%-
5% -
0%-
-5% -
-10%
Cr
* ซซซ ft)*
25% -
o%-
-25%
Mn
Fe
5% ฆ
o%-
-5% ฆ
I . t I r hi * ซ*
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Ni
. \ . t
I.
_ _
Zn
* ปv f ซ ซ t *V *> # * ป
1 1 1 1 1 1 1 11
Pb
*:ซ* i:i i
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Page 90 of 136
-------
Table 4.2-14: Dates for calibrations performed on each EDXRF instrument during this analysis period (February 19,
2021 through April, 22, 2022).
EDXRF
Instrument
XRF-1
Calibration
Date
11/25/2020
Reason for
Calibration
Annual Calibration
Range of Sample Dates Analyzed
1/1/2021-8/26/2021
XRF-3
12/22/2020
Annual Calibration
1/1/2021 - 1/25/2021
XRF-4
11/25/2020
Annual Calibration
1/4/2021-8/29/2021
XRF-2
11/04/2020
Annual Calibration
1/13/2021 -8/14/2021
XRF-3
4/22/2021
Detector moved
2/15/2021 -2/21/2021
XRF-5
6/15/2021
X-ray tube replaced
5/10/2021 - 8/26/2021
XRF-3
7/21/2021
X-ray tube replaced
7/9/2021 - 7/9/2021
XRF-1
11/24/2021
Annual Calibration
8/8/2021 - 11/30/2021
XRF-4
11/24/2021
Annual Calibration
9/4/2021 - 12/24/2021
XRF-2
11/26/2021
Annual Calibration
9/10/2021 - 12/30/2021
XRF-3
12/02/2021
Annual Calibration
9/19/2021 - 11/30/2021
XRF-1
2/17/2022
X-ray tube replaced
11/09/2021 - 12/30/2021
XRF-5
2/11/2022
Secondary X-ray
target repositioned
N/A
4.2.3 Determination of Uncertainties and Method Detection Limits
For discussion of Method Detection Limits (MDLs) see Section 3.1.3.2.
For discussion of analytical uncertainty and total uncertainty see Section 3.1.2 and Section 6.5,
respectively.
4.2.4 Audits, Performance Evaluations, Training, and Accreditations
4.2.4.1 System Audits
No system audits were performed during this analysis period.
4.2.4.2 Performance Evaluations
No performance evaluations were conducted during this reporting period.
4.2.4.3 Training
Training of all personnel who assist with or operate the EDXRF instruments is mandatory
through UC Davis. Personnel in the XRF laboratory are required to take the following UC Davis
safety trainings: UC Laboratory Safety Fundamentals, Radiation Safety for Users of Radiation
Producing Machines, and Cryogen Safety.
Only personnel listed in UC Davis CSN Quality Assurance Project Plan (QAPP), trained on the
appropriate SOPs and Technical Information materials (CSNSOP 302 and CSN TI302A-D), and
authorized by the Laboratory Manager can perform EDXRF analysis on CSN samples.
4.2.4.4 Accreditations
There are no accreditations for elemental analysis on aerosol filters by EDXRF.
4.2.5 Summary of Filter Blanks
Page 91 of 136
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4.2.5.1 Field Blanks
Over the sampling period (January 1, 2021 through December 31, 2021) there were 1,650 valid
PTFE filter field blanks. Table 4.2-15 summarizes the field blank statistics.
Table 4.2-15: PTFE filter field blank statistics for the 2021 sampling analysis period 2/19/2021 through 4/22/2022
(samples collected 1/1/2021 through 12/31/2021).
Species
Count
Median
(US/cm2)
Average
(jig/cm2)
Min
(Hjj/cm2)
Max
(HU/cm2)
St. Dev.
(HU/cm2)
Ag
1650
0.020
0.020
0.007
0.050
0.006
A1
1650
0.070
0.071
0.023
0.176
0.013
As
1650
0.000
0.000
0.000
0.000
0.000
Ba
1650
0.064
0.064
0.026
0.118
0.015
Br
1650
0.000
0.000
0.000
0.002
0.000
Ca
1650
0.002
0.004
0.000
0.378
0.011
Cd
1650
0.020
0.021
0.006
0.044
0.006
Ce
1650
0.075
0.076
0.034
0.151
0.018
CI
1650
0.002
0.003
0.000
0.181
0.006
Co
1650
0.001
0.001
0.000
0.004
0.001
Cr
1650
0.004
0.004
0.002
0.019
0.001
Cs
1650
0.046
0.047
0.013
0.105
0.013
Cu
1650
0.009
0.008
0.003
0.021
0.003
Fe
1650
0.020
0.021
0.007
0.388
0.011
In
1650
0.023
0.024
0.008
0.048
0.007
K
1650
0.012
0.012
0.001
0.720
0.018
Mg
1650
0.009
0.015
0.000
0.110
0.017
Mn
1650
0.006
0.006
0.000
0.025
0.002
Na
1650
0.000
0.017
0.000
0.156
0.027
Ni
1650
0.001
0.001
0.000
0.005
0.001
P
1650
0.000
0.000
0.000
0.027
0.001
Pb
1650
0.014
0.014
0.006
0.028
0.003
Rb
1650
0.003
0.003
0.000
0.012
0.001
S
1650
0.000
0.001
0.000
0.523
0.019
Sb
1650
0.028
0.029
0.008
0.063
0.008
Se
1650
0.002
0.002
0.000
0.007
0.001
Si
1650
0.017
0.019
0.000
0.308
0.014
Sn
1650
0.029
0.029
0.010
0.062
0.008
Sr
1650
0.004
0.004
0.002
0.011
0.001
Ti
1650
0.001
0.001
0.000
0.021
0.001
V
1650
0.000
0.000
0.000
0.002
0.000
Zn
1650
0.002
0.003
0.000
0.025
0.001
Zr
1650
0.018
0.019
0.002
0.049
0.007
Page 92 of 136
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4.2.5.2 Laboratory Blanks
Five PTFE laboratory blanks are shipped with each batch of routine filters to the analysis
laboratory and analyzed. A total of 60 PTFE laboratory blanks were analyzed during the current
reporting period. Table 4.1-16 summarizes the laboratory blank statistics.
Table 4.2-16: PTFE filter laboratory blank statistics for the 2021 sampling analysis period 2/19/2021 through
4/22/2022 (samples collected 1/1/2021 through 12/31/2021).
Species
Count
Median
(Hjj/cm2)
Average
(Hjj/cm2)
Min
(Ujj/cm2)
Max
(Ujj/cm2)
St. Dev.
(Hjj/em2)
Ag
60
0.020
0.020
0.009
0.034
0.006
A1
60
0.064
0.065
0.053
0.092
0.008
As
60
0.000
0.000
0.000
0.000
0.000
Ba
60
0.066
0.066
0.038
0.113
0.015
Br
60
0.000
0.000
0.000
0.001
0.000
Ca
60
0.002
0.002
0.000
0.005
0.001
Cd
60
0.019
0.019
0.008
0.035
0.005
Ce
60
0.078
0.078
0.048
0.113
0.017
CI
60
0.002
0.002
0.000
0.006
0.001
Co
60
0.001
0.001
0.000
0.003
0.001
Cr
60
0.004
0.004
0.002
0.006
0.001
Cs
60
0.042
0.044
0.024
0.080
0.013
Cu
60
0.010
0.009
0.004
0.014
0.003
Fe
60
0.019
0.019
0.011
0.030
0.003
In
60
0.024
0.024
0.009
0.041
0.007
K
60
0.013
0.012
0.005
0.018
0.003
Mg
60
0.007
0.011
0.000
0.061
0.014
Mn
60
0.006
0.006
0.003
0.013
0.001
Na
60
0.000
0.020
0.000
0.108
0.030
Ni
60
0.001
0.001
0.000
0.002
0.000
P
60
0.000
0.000
0.000
0.002
0.000
Pb
60
0.013
0.014
0.009
0.024
0.003
Rb
60
0.003
0.003
0.001
0.008
0.001
S
60
0.000
0.000
0.000
0.001
0.000
Sb
60
0.026
0.028
0.014
0.050
0.007
Se
60
0.003
0.003
0.001
0.005
0.001
Si
60
0.013
0.015
0.004
0.030
0.006
Sn
60
0.028
0.029
0.017
0.045
0.007
Sr
60
0.004
0.004
0.002
0.007
0.001
Ti
60
0.001
0.002
0.000
0.005
0.001
V
60
0.000
0.000
0.000
0.001
0.000
Zn
60
0.003
0.003
0.001
0.009
0.001
Zr
60
0.019
0.019
0.007
0.042
0.006
Page 93 of 136
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4.3 UC Davis Thermal Optical Analysis Laboratory
The UC Davis Thermal Optical Analysis (TOA) Laboratory received and analyzed quartz filters
from batches 75 through 86, covering the field sampling period beginning from January 1, 2021
through December 31, 2021. Analyses of these samples were performed March 11, 2021 through
April 1st, 2022. Six existing Thermal Optical Carbon Analyzers (Sunset Laboratory Model 5L;
designated as Alpha, Beta, Delta, Gamma, Zeta, and Theta were used for analysis during the
whole period using the IMPROVEA temperature protocol.
Table 4.3-1: Sampling months in 2021 and corresponding TOA analysis dates covered in this reporting period.
Analysis dates include reanalysis - as requested during QA level 0 and level 1 validation - of any samples within
the sampling year and month.
Sa in pi i nu Month
<:ฆ>': i >
Analysis lialch
TOA Analysis Dales
January
75
3/11/2021-4/7/2021
February
76
4/7/2021-4/27/2021
March
77
5/6/2021-6/10/2021
April
78
6/10/2021-8/20/2021
May
79
7/15/2021-8/13/2021
June
80
8/17/2021-9/16/2021
July
81
9/22/2021-10/22/2021
August
82
10/25/2021 -11/18/2021
September
83
11/18/2021 -12/20/2021
October
84
1/3/2022 - 2/3/2022
November
85
1/25/2022-2/28/2021
December
86
3/7/2022-4/1/2022
All month
75-86
3/11/2021-4/1/2022
4.3.1 Summary of QC Checks and Statistics
Samples are received by the UC Davis Thermal Optical Analysis Laboratory following the
chain-of-custody procedures specified in the UCD CSN TI 402A. Samples are analyzed using
Sunset Laboratory Model 5L OCEC analyzers following UCD CSN SOP #402. Daily and
weekly QC checks are implemented to ensure data quality. Calibrations of the analyzers are
performed semi-annually or as needed (e.g., when the CH4/He mixture gas cylinder is replaced
or a consistent one-side bias is observed with the daily single-point sucrose standard check,
whichever comes first). Maintenance is performed as needed by trained laboratory staff. Quality
control procedures are described in UCD CSN SOP #402 and are summarized in Table 4.3-2.
Page 94 of 136
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Table 4.3-2: UC Davis quality control measures for carbon analysis by TOA (Sunset Laboratory OCEC analyzer).
Activity
Frequency
Acceptance Criteria
Corrective Action
Laboratory Blank
Check
Beginning of
analysis day
<1.0 ng C/cm2
Repeat analysis. If same result,
check filter lot for possible
contamination and perform pre-
firing
Instrument Blank
Check
Beginning of
analysis day
Between -0.3 and 0.3 |ig C/cm2
Repeat analysis. If same result,
check instrument and gas lines for
possible contamination
Single-point
Sucrose Standard
Check
Beginning of
analysis day
Within ฑ7% of the calculated value
Repeat analysis. If same result, run
a different sucrose solution to
determine if the problem is with the
solution or instrument. If former,
make new sucrose solution. If latter,
perform multi-point calibration to
determine new calibration constant
Calibration Peak
Area Check
Every analysis
Within ฑ10% of the daily average value for a
specific instrument
Void analysis result; Repeat
analysis with second filter punch
Laser Performance
Check
Beginning of
analysis day
Laser Transmittance signal for Instrument
blank > 5000
First check laser-sample-detector
alignment and/or examine top oven
window for frosting or debris;
replace laser source when necessary
Network Sample
Replicates
Every 20th
network sample
analysis
Within ฑ10% RPD when TC >10 |ig C /cm2
within ฑ20% RPD when ECR >2.5 |ig C /cm2
or
Within ฑ1 |ig/cm2 when TC <10 |ig C /cm2
Within ฑ0.5 |ig/cm2 when ECR <2.5 ng
C/cm2.
Investigate instrument and sample
anomalies. Analyze the third punch
on a different analyzer
Within ฑ 10 % RPD* when TC > 10 |ig C/cm2
Within ฑ 20 % RPD when EC > 2.5 |ig C/cm2
Inter-instrument
Comparison Check
Weekly
or
Within ฑ 1 |ig/cm2 when TC < 10 ng C/cm2
Within ฑ0.5 |ig/cm2 when EC < 2.5 |ig
C/cm2
*RPD for each analyzer is calculated against
the average measurement from all analyzers
Analyze a second punch from the
same sample on the failed analyzer.
If same result, analyzer taken offline
and investigated for the root cause
of the failure
Multi-point
Sucrose Standard
Check
Every six months
or after major
instrument repair
or change of
calibration gas
cylinder
NAa
Calculate new calibration constant
based on calibration slope and
update in the IMPROVEA
protocol parameter file
Temperature
Calibrations
Every six months
or after major
instrument repair
NA
Change the temperature offset
values in the IMPROVE A protocol
parameter file accordingly
a NA: Not Applicable.
4.3.2 Summary of QC Results
Page 95 of 136
-------
Detailed results from the TOA QC checks are presented in the subsections below. In addition to
performing routine daily and weekly QC activities, readings of oven pressure, back oven
temperature, methanator oven temperature, FID baseline, and initial laser
transmittance/reflectance are verified to be within the acceptable range specified for each
analyzer before starting sample analysis. After analysis, each thermogram is reviewed for the
following: 1) correct peak identification and integration, 2) correct laser response, 3) system
pressure stability, and 4) FID baseline stability to ensure data quality objectives are met.
Individual samples with unusual laser response, baseline shift, low system pressure, erroneous
split point, or samples impacted by failure to meet acceptance criteria outlined in Table 4.3-2 are
reanalyzed.
4.3.2.1 Laboratory and Instrument Blanks
At the beginning of the analysis day, following the clean oven procedure, a quartz filter
laboratory blank and an instrument blank are analyzed to check for system contamination and
evaluate laser response. These blanks are purchased by UC Davis and are not necessarily the
same as the quartz filters used for sampling. The filters are pre-fired by UC Davis to remove
contaminant carbon according to SOP #402. Results are reviewed immediately upon analysis
completion and are compared against the acceptance criteria. Table 4.3-3 lists the number of
blanks analyzed during the report period and their areal density statistics.
Table 4.3-3: Statistics of daily quartz filter laboratory blank and instrument blank total carbon (TC) analyses on all
carbon analyzers for the analysis period 3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through
12/31/2021).
lilank T\|U'
( CHIII1
Median
(uii/cnr I
A\c ratio
(fiii/cnr)
Min
uiii/cnr)
Max
uiii/cnr)
S(.l)c\.
(fiii/cnr)
# r.xcoodanco
Laboratory Blank
1354
0.18
0.23
-4.23
2.44
0.34
37
Laboratory Blank - R*
40
-0.01
0.07
-0.42
0.98
0.31
1
Instrument Blank
1358
-0.09
-0.09
-1.78
1.03
0.13
42
Instrument Blank - R*
57
-0.18
-0.23
-1.76
0.29
0.33
13
*Laboratory/Instrument Blank - R: Repeated laboratory/instrument blank when original analysis fails the acceptance
criteria.
For laboratory blanks, if the TC areal density exceeds 1.0 |ig C/cm2, a second punch taken from
the same blank filter lot is analyzed (Laboratory Blank-R). Usually, the exceedances can result
from contamination on the filter blanks, on the punching device, or in the system. If the original
and repeated blank analyses on more than one instrument exceeds the acceptance criteria, or if
the Laboratory Blank-R analysis still exceeds the limit (one case during the report period), a new
lot of quartz blank filters is used to determine the source of contamination. Occasionally,
exceedances result from unstable FID baseline, which is distinguishable from contamination. On
April 28, 2020, the carbon analyzers were brought back online after being down for over a month
due to COVID-19. The laboratory blanks were repeated 5 times on each analyzer to achieve an
operable and stable baseline. Figure 4.3-1 and Figure 4.3-2 show the results of daily laboratory
and instrument blanks, respectively, analyzed by each instrument during this reporting period.
Page 96 of 136
-------
Figure 4.3-1: Total carbon results of daily quartz filter laboratory blanks from each analyzer for the analysis period
3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021). Red dashed horizontal line indicates
the acceptance criteria of 1.0 |ig C/cm2 for total carbon areal density. For cases when the acceptance criteria were
exceeded (red points), a repeat analysis (blue points) was performed.
* *
yAfw* f *. ; V.\
**
r .. * V
gamma
* ป
ป V ซ;'
+
zeta
,6, .
exceeded
normal
reanalyzed
Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022 Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022
Analysis Date
Instrument blank (IB) analysis is performed following the laboratory blank analysis by reusing
the sample punch. The instrument blank acceptance criteria is TC (total carbon) within ฑ 0.3
|ig/cm2. When the instrument blank fails to meet the QC criteria (red points in Figure 4.3-2),
analysis is repeated (blue points in Figure 4.3-2). If the Instrument Blank-R analysis still exceeds
the acceptance limit (seven cases during the report period; Table 4.3-3), the operator checks the
instrument and gas line for possible contamination and examines the stability of the FID baseline
from thermograms. The analysis results from instrument (and laboratory) blanks must be
acceptable before continuing with analysis of the sucrose standard.
Figure 4.3-2 shows the results of daily analyses of instrument blanks by each instrument. In most
cases the repeated IB analysis is satisfactory.
Page 97 of 136
-------
Figure 4.3-1: Results of daily instrument blanks from each analyzer for the analysis period 3/11/2021 through
4/1/2022 (samples collected 1/1/2021 through 12/31/2021). Horizontal dash lines in red color indicate the
acceptance criteria of ฑ 0.3 |ig C/cm2 for total carbon areal density. For cases when the acceptance criteria was
exceeded (red points), a repeated analysis was performed until the instrument pass QC criteria. The blue points show
the reanalyzed IB passed the QC criteria.
O
"ro
ฆ5 "0-2
*
* ป, #ป **> ซ * " V"
* *> .. . ;>. k
x-'.y v; ***ป.* * * .
<ซ..
ป ซ.
: w- .
. mMm
'If*V ' * *
ซ
v
*#
. *
. <
:
.
ซ
_ %
ซ
ป
* u.
' 9
t-*
*
y: :
<ฆ
v-r-s-;
# <
A
>} ''A.'
^
%
Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022 Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022
Analysis Date
4.3.2.2 Single-Point Sucrose Standard Check
Following the daily blank analyses, a single-point sucrose calibration check is performed to
evaluate FID response by injecting 10 |iL of sucrose standard solution onto a clean filter punch
and analyzing for its total carbon content. Table 4.3-4 summarizes the concentrations of all
sucrose standard solutions generated for calibrating the carbon analyzers on a semi-annual basis
(or as needed). Sucrose calibration standards cover a wide range of the TC levels from 2.11 |ig
C/cm2 through 210.5 |ig C/cm2, typically seen from the CSN network samples. Among these
standards, Sucrose #15 is chosen for daily single-point calibration check as its concentration is
most comparable to the CSN median TC value.
Page 98 of 136
-------
Table 4.3-4: Sucrose solution standard concentrations in |igC7cnr.
Sucrose ID
Concentration
(U2 C/cm2)
Sucrose 11
210.50
Sucrose|12
105.25
Sucrose 13
42.10
Sucrose 14
21.05
Sucrose|15
10.53
Sucrose 16
2.11
Sucrose|17*
36.38
*A secondary source standard acquired from the manufacturer, i.e.. Sunset laboratory Inc.
Upon completion of the sucrose analysis, the measured TC is compared against the true value
(i.e. calculated TC) provided in Table 4.3-4. The % error between the measured and calculated
TC is derived using Equation 4.3-1. If the error exceeds the ฑ 7% acceptance criteria, a second
analysis is performed before any network samples are analyzed on that instrument. If the second
analysis still exceeds the acceptance criteria, or if a consistent one-sided bias (with error within ฑ
7%) is observed on multiple instruments, a different sucrose solution is analyzed to determine if
the problem is with the solution or with the instrument. If the former, a new sucrose solution is
made and verified; if the latter, a full five-point calibration is performed to determine the new
calibration constant for that instrument. Table 4.3-5 summarizes the statistics of the daily sucrose
check. There were 60 exceedances out of the 1,416 sucrose analyses during the report period. All
repeat-analyses of the sucrose solution showed acceptable results (Figure 4.3-3).
Error
f
(%) = (ฆ
Measured TC Calculated TC>
Calculated TC
x 100%
(Eq. 4.3-1)
Table 4.3-5: Statistics of daily single-point sucrose standard total carbon analyses on all carbon analyzers for the
analysis period 3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021).
Count
Median
Error (%)
Average
Error (%)
Min
Error (%)
Max
Error (%)
St.Dev.
Error (%)
# Exceedance
1,416
1.84
1.81
-24.02
105.24
4.31
60
Page 99 of 136
-------
Figure 4.3-2: Results of daily single-point sucrose calibration standard check for the analysis period 3/11/2021
through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021) for all instruments. Red dashed lines indicate the
acceptance criteria of ฑ7% error. For cases when original measured sucrose value (red points) exceeded the
acceptance criteria, a repeated analysis was performed (blue points).
80-
SS
o 40-
1
LU
0-
exceedance
exceeded
normal
reanalyzed
Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022
AnalysisDate
4.3.2.3 Calibration Peak Area Check
At the end of each analysis, a fixed amount of methane (CH4) from a cylinder containing 5%
CH4 in helium is injected into the system as an internal gaseous standard. The CH4 peak area is
quantified and compared to the average peak area of all analyses performed on that instrument
on that day. If the error (calculated using Equation 4.3-2) exceeds ฑ 10% acceptance criteria, the
analysis result is voided; the flowrate of the calibration gas and sample oven pressure are
verified; corrective actions (if applicable) are taken immediately after the problem is identified;
and the analysis is repeated using a second filter punch analyzed on the original analyzer (or on a
different analyzer if the original analyzer is not available). Table 4.3-6 summarizes the statistics
of the calibration peak area checks. There were 12 exceedances during this reporting period. Two
of the 12 exceedances occurred because the FID ignition turned off during analysis. All repeat
analyses of the affected samples had acceptable results. One exceedance occurred because the
front oven cap was opened and the sample was removed before the analysis had finished. Two of
the 12 exceedances occurred when the clamp that connects the oven ball joint was not
sufficiently tightened, resulting in a leak and gradual pressure drop in the system. Two
exceedances occurred due to FID ignition being off during the analysis. Seven calibration peak
area exceedances due to the FID error were performed by the carbon analyzer. On 10/18/2021
the methanator oven was replaced due to a decrease in calibration area readings on Zeta. On
6/24/2021, the methanator oven was replaced on Alpha due to a decrease in calibration area
reading.
/Cal. Peak Averaqe Cal. Peak\
Error (%) = - x 100%
\ Average Cal. Peak /
Page 100 of 136
(Eq. 4.3-2)
-------
Table 4.3-6: Statistics of internal calibration peak area check on all carbon analyzers for the analysis period
3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021). '
Analyzer
Count
Median
Error
(%)
Average
Error (%)
Min
Error (%)
Max
Error (%)
St.Dev.
Error (%)
#
Exceedance
Alpha
2367
0.08
-0.01
-12.20
9.57
1.16
1
Beta
2339
-0.02
-0.04
-100.00
4.95
2.18
1
Delta
2514
0.04
-0.02
-18.35
6.65
1.77
2
Gamma
2396
-0.01
-0.06
-52.00
6.80
1.92
4
Zeta
2483
0.03
0.00
-7.58
7.50
1.54
0
Theta
3053
0.01
-0.11
-100.21
5.11
3.26
4
Figure 4.3-3: Results of internal calibration area check for the analysis period 3/11/2021 through 4/1/2022 (samples
collected 1/1/2021 through 12/31/2021). Red dashed lines indicate the acceptance criteria of ฑ10% error from the
mean value. For cases when calibration area exceeded the acceptance criteria, a repeated analysis (blue points) was
performed and the original analysis was voided (red points).
*
m
>w
alpha
7
i
omm
25-
50-
beta
8880
* ฆ
75-
00-
-1
9
delta
ฆWW *,.ซ"WW
- sป
SSfcCSs
gamma
vTwi{- $sC
t
20-
theta
40-
zeta
.... _ . _ . m n i ii
5-
i
li
ii
m
w$
-5-
10
J.
"7 1 ^
Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022 Apr 2021 Jun 2021 Aug 2021 Oct 2021 Dec 2021 Feb 2022 Apr 2022
Analysis Date
Page 101 of 136
-------
4.3.2.4 Laser Performance Check
Laser signals (both reflectance and transmittance) are monitored throughout the TOA analysis
and are examined for stability during post-analysis thermogram review. Any unusual laser
response, caused by either weak/non-functioning laser or laser-sample-detector misalignment,
results in corrective actions (if applicable) and reanalysis of the sample. In addition, before
starting the instrument blank analysis each day, the readings of clean filter reflectance and
transmittance are checked to make sure they are above the initial laser acceptance criterion (i.e.
5000 a.u.). Figure 4.3-5 shows the filter reflectance and transmittance initial readings for all
instrument blank analyses during the report period. Gamma had a laser source alignment on
7/9/2021. Alpha had back oven heating coil replaced, which resulted in laser fine-tuning and
signal optimization performed on 10/15/2021. During this report period, there were no
exceedances of laser reflectance signal.
Figure 4.3-4: Laser initial readings (top: Transmittance; bottom: Reflectance) of the instrumental blank analysis for
the analysis period 3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021). Red dashed line
indicates the acceptance criteria of 5000 a.u. of the laser signal. Other vertical lines indicate dates of related
maintenance on the instrument optical components. Different analyzers are indicated by data point color.
03 20000
$ 10000
Gamma laser alignment (7/9/2021)
alpha laser alignment
(10/15/2021)
Apr 2021
Aug 2021
Oct 2021
Analysis Date
Apr 2022
20000-
Gamma laser alignment (7/9/2021),
&ฃฃฃ tts:
alpha laser alignment
(10/15/2021)
..
7*
4>V?V:-
"
Apr 2021
Aug 2021
Oct 2021
Analysis Date
Apr 2022
Page 102 of 136
-------
4.3.2.5 Network Sample Replicates
Replicate analyses are performed on every 20th CSN filter (samples and field blanks), where
replicate analysis results are obtained from a second punch from the same filter analyzed on a
randomly selected analyzer. Table 4.3-7 lists the acceptance criteria for replicate analysis and the
summary statistics from this reporting period. A total of 708 replicate analyses were performed
out of the 15002 samples and field blanks. For cases that exceeded the acceptance criteria, a third
punch (if available) was analyzed on a different analyzer, and all three sets of results (routine,
replicate, and reanalysis) from the same filter are compared to determine analysis validity.
Instrument anomaly and/or deposit inhomogeneity are also examined. Figure 4.3-7 shows the
results of the replicate analyses. There was a total of 42 TC exceedances and 69 ECR
exceedances during this reporting period. Samples with exceedances were reanalyzed on a third
analyzer. Only the passing re-analysis result is plotted in Figure 4.3-7 and the failing test is
overwritten in the data creating the figure. This is noted in Table 4.3-7 where all reanalysis of
exceedances passed. All other reanalyses had satisfactory results.
Table 4.3-7: Acceptance criteria and the summary statistics of the replicate analyses for the analysis period
3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021).
Parameler
Aeeeplanee Criteria
#
Keplieale
#
l-'.xeeedanee
# Keanal> sis
passed
TC
*RPD < ฑ10% when TC >10 ng /cm2
or
Absolute difference <ฑ1 ng/cnr when TC <10 |ig /cm2
708
42
42
ECR
*RPD < ฑ20% when EC >2.5 ng /cm2
or
Absolute difference <ฑ0.5 |ig/cnr when EC <2.5 |ig/cm2
708
69
69
*RPD: Relative Percentage Difference = (Replicate-Routine)/Average *100%
Page 103 of 136
-------
Figure 4.3-5: Results of CSN replicate analysis for ECR (Panel a and b) and TC (Panel c and d) for the analysis
period 3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021). The red dashed lines in each
panel represents the acceptance criteria. These plots include passing retests of exceedances, the original failures are
not plotted.
. . alpha delta theta . . alpha delta theta
Analyzer # beta # gamma # zeta Analyzer # betg # gamma # zeta
1.0-
0
o
c
0
1
b
o
0
E
<
cm
u
LLJ
. 0.5-
0.0
-0.5-
-1.0-
(a)
t *
t .
ซ
% 1
!
. v* **r~
i tf
v..
ซ *
i i
0.0 0.5 1.0 1.5
Average Areal Density, |i g/cm
2.0
2
E
o
O)
CO
0
q:
O
1-
-25-
-50-
12.E
50
75
100
Average Areal Density, n g/cm
(d)
%>
1
100
200
300
Average Areal Density, n g/cm
4.3.2.6 Inter-instrument Comparison Check
Instrument inter-comparison is evaluated weekly by analyzing performance check (PC) samples
collected at UC Davis. Pre-fired quartz filters with 37 mm diameter are used to provide enough
deposit area for at least seven 0.6 cm punches. A total of 65 weekly PC samples were analyzed
during this reporting period. Six 0.6 cm punches were taken from the same PC sample, one was
Page 104 of 136
-------
analyzed by each instrument. Figure 4.3-6 shows the results of the weekly PC samples for each
analyzer.
Figure 4.3-6: Results of the weekly performance check samples by each analyzer for ECR (Panel a and b) and TC
(Panel c and d) for the analysis period 3/11/2021 through 4/1/2022 (samples collected 1/1/2021 111 rough
12/31/2021). The red dashed lines in each panel represent the acceptance criteria. Note the difference in limits and
method between figures (a) and (b). low ECR and normal ECR respectively. Note the difference in limits and
method between figures (c) and (d). low TC and normal TC respectively.
.. alpha delta theta .. alpha delta theta
Name .... , Name . , ,
beta gamma zeta beta gamma zeta
O)
zL
:
3
es
t
1
0.0
0.5
1.0
1.5
2.0
Average Areal Density, jj g/cm
ฃ
o
D)
o
c
2
b
o
o>
ฃ
2-
H -2
0.0 2.5 5.0 7.5
Average Areal Density, (.i g/cm
10.0
2
(c)
Q) 25
0
C
0)
cm
tr -25
o
LU
-50
(b)
u
&
tSm m
9m :
f.
10
Average Areal Density, n g/cm
50-
25-
0
O
c
03
0
Cฃ
O
1-
-25-
-50-
(d)
___4
f
f
1
1
9
ฆ
9
12.:
25 50 75
Average Areal Density, n g/cm
100
2
125
The measured carbon areal density from each analyzer (Ax) is compared against the average
value derived from measurements by all available analyzers on the same performance check
sample. Acceptance criteria at higher filter loadings (TC > 10 pg C/cm2 and ECR > 2.5 pg
Page 105 of 136
-------
C/cm2) are based on the relative difference (%) by dividing the difference between the measurement
of a given analyzer (/') and the average value for the same PC sample obtained from all analyzers
used in comparison by the average value using the equation as follows:
(Measuredฃ Average) x 100
Relative differenceฃ (%) =
Average
(Eq. 4.3-3)
The acceptance criteria for inter-instrument comparison at low filter loadings (TC <10 jag C/cm2
and ECR <2.5 [j,g C/cm2) are based on the arithmetic difference between the measurement from a
given analyzer and the average value for the same PC sample obtained from all analyzers used in
each comparison. The acceptance criteria for inter-instrumental check is the same as that for the
network sample replicates (See Table 4.3-2 for details). Exceeding the acceptance criteria results
in further investigation of the instrument, and reanalysis of the performance check sample. Table
4.3-8 summarizes the statistics of the instrument bias for ECR and TC. There were nine
exceedances during this reporting period.
Table 4.3-8: Statistics (median, mean, and standard deviation) of the relative (%) and arithmetic difference values
from the weekly inter-instrument comparison analysis of high and low PC filter loadings, respectively. Analysis
period covers the dates starting from 3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021).
Ki'hiliw ilil'li-mui- ("'ฆ>) fur lii^li I'ilk-r ln;i(lin^s (Aiiiplinui- limit: ฑIO"-ป fur TC ;ind
ฑ20" lor l.( K)
l-'CR > 2.5 iiป/inr
TC > 10 uป/i nr
An;il>/.i-r
Cllll 111
Mi-di;in
\k-;ui
Si. IX-*.
Ciiiini
Mi-(li;in
.Mi-;in
Si. IX*.
Alpha
39
-1.55
0.37
9.32
55
0.19
-0.04
2.52
Beta
49
5.04
6
8.27
61
0
-0.42
2.93
Delta
30
-7.59
-6.28
8.76
50
-1.05
-0.26
3.54
Gamma
38
-0.69
0.11
9.12
54
-0.3
0.5
3.14
Zeta
34
-0.54
-1.41
7.9
52
-0.79
-0.29
3.12
Theta
40
3.5
3.14
7.14
54
0.17
0.64
3.11
Arillimi-lk' ilil'li-mui- fur In" filu-r ln;i(lin^s (.Uii-phiiHi- limit: ฑ1 uป/im: lur TC ;iml
ฑ0.5 iiป/iiii: 1'nr I C R)
l!Ck: 0 - 2.5 ii<>/mii-
TC: 0 - 10 uป/ini:
An;il>/.i-r
Cmi nl
Mi'(li;in
Mi-nil
Si. IX-*.
(mini
Mi-di;in
.Mi-;in
Si. IX*.
Alpha
17
-0.14
-0.09
0.18
1
-0.22
-0.22
NA
Beta
13
0.09
0.12
0.21
1
0.14
0.14
NA
Delta
21
-0.14
-0.16
0.22
1
-0.45
-0.45
NA
Gamma
17
0
-0.01
0.13
1
0.09
0.09
NA
Zeta
19
-0.1
-0.15
0.16
1
-0.14
-0.14
NA
Theta
14
0.06
0.08
0.11
NA
NA
NA
NA
NA: Not available.
Page 106 of 136
-------
4.3.2.7 Multi-point Sucrose Standard Check
A multi-point calibration is performed every six months, when the calibration gas cylinder or
instrument main oven is replaced, or if a consistent one-sided bias is observed with the daily
single-point sucrose standard check, whichever comes first. The calibration uses sucrose
standards with at least six different concentration levels that cover a wide range of TC
concentrations typically seen on the CSN samples (See Table 4.3-4 for details). The least-square
correlation coefficient (r2) of measured versus calculated mass of carbon, force-fit through the
origin (0, 0), should be higher than 0.995. The new calibration constant for each analyzer is
calculated by taking the ratio of the current constant and the calibration slope. The calibration
constant is automatically updated in the database after the calibration is completed. Table 4.3-9
summarizes the multi-point sucrose calibrations performed during this reporting period.
Table 4.3-9: Summary of multi-point sucrose standard checks performed for the analysis period 3/11/2021 through
4/1/2022 (samples collected 1/1/2021 through 12/31/2021).
Analyzer
Calibration Date
Slope
r2
Calibration
Constant
Alpha3
3/22/2021
0.9734
1.0000
21.2923
Alpha2
3/7/2022
1.0161
0.9999
20.9787
Alpha2
7/12/2021
1.0267
1.0000
20.7386
Alpha3
1/3/2022
0.9863
1.0000
21.3165
Beta3
3/22/2021
1.0211
1.0000
20.9335
Beta2
7/12/2021
0.9897
1.0000
21.1514
Beta2
3/7/2022
1.0075
1.0000
21.1078
Beta3
1/3/2022
0.9973
1.0000
21.2661
Delta3
3/22/2021
0.9927
0.9998
21.3599
Delta2
3/7/2022
0.9951
1.0000
20.9608
Delta2
7/14/2021
1.0323
0.9997
20.6916
Delta1
8/13/2021
1.0061
0.9997
20.5661
Delta3
1/3/2022
0.9860
0.9999
20.8581
Gamma3
3/22/2021
1.0055
1.0000
20.3554
Gamma2
7/14/2021
0.9946
1.0000
20.4659
Gamma2
3/7/2022
1.0009
1.0000
20.8224
Gamma3
1/3/2022
0.9819
0.9999
20.8432
Theta3
3/22/2021
0.9807
0.9995
21.2723
Theta2
7/12/2021
1.0394
1.0000
20.4659
Theta2
3/7/2022
1.0304
1.0000
20.7275
Theta3
1/3/2022
0.9789
0.9999
21.3576
Zeta3
3/22/2021
1.0273
0.9999
20.5692
Zeta1
8/13/2021
1.0444
1.0000
20.7882
Zeta2
7/12/2021
0.9474
0.9999
21.7112
Zeta2
3/7/2022
0.9970
1.0000
22.0037
Zeta3
1/3/2022
0.9476
0.9992
21.9377
Page 107 of 136
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1 Sucrose result is high
2 Calibration gas cylinder was replaced on 7/13/2021 and 3/4/2022
3 Semi-annual sucrose calibration
4.3.2.8 Temperature Calibration
A temperature calibration is performed every six months (usually along with a multi-point
sucrose calibration) or after a major instrument repair (e.g., replacement of main oven or heating
coils). The difference (i.e. offset) between the oven temperature and sample temperature at each
IMPROVEA protocol temperature set point is determined using a manufacturer-provided
temperature calibration device, inserted into the sample oven so that the external temperature
probe sits where a sample punch would be during routine analysis. The oven temperature cycles
through the IMPROVE A protocol temperature set points (from 140 ฐC to 840 ฐC). The
differences in temperature readings by the calibration probe and oven temperature probe (i.e.
temperature offsets) are calculated and updated in the IMPROVE A protocol parameter file. The
system then goes through the IMPROVE A protocol temperature cycle again to verify that the
temperature readings from the two probes are within 10 ฐC at all temperature steps. Table 4.3-10
summarizes the temperature calibrations performed on each analyzer during this reporting
period.
Page 108 of 136
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Table 4.3-10: Summary of the temperature calibrations performed on each analyzer for the analysis period
3/11/2021 through 4/1/2022 (samples collected 1/1/2021 through 12/31/2021). Oven re-wrap refers to adjustment or
replacement of heating coils that are wrapped around the sample oven.
Annl\/er
( alihralioii Dale
()\ on Re-
NX rapped?
Temperature OITsels (ฐC)
I40ฐ(
2S0ฐC
4S0ฐ(
5S0ฐC
"MOT
S40ฐ(
Alpha
A in JMiJM
No
11
:o
:i
18
-9
Alpha2
4/28/2021
Yes
6
9
6
5
-7
-16
Alpha1
9/20/2021
No
3
4
-l
-3
-9
-19
Alpha3
10/06/2021
Yes
-23
-53
-79
-92
-52
-58
Alpha1
12/21/2021
No
-27
-52
-61
-66
-21
-31
Beta1
3/10/2021
No
14
24
14
11
-16
-32
Beta3
4/8/2021
Yes
-7
-23
-63
-84
-26
-28
Beta1
9/22/2021
No
-23
-49
-72
-88
-38
-34
Beta2
10/22/2021
Yes
2
14
28
31
7
-4
Beta1
12/21/2021
No
-8
-10
-1
4
-3
-16
Gamma1
3/10/2021
No
12
24
26
26
-4
-13
Gamma4
6/18/2021
Yes
-16
-36
-61
-82
-26
-26
Gamma5
7/09/2021
Yes
2
-12
-41
-52
-48
-45
Gamma3
7/12/2021
Yes
11
20
21
18
-9
-22
Gamma1
9/20/2021
No
-27
-48
-61
-73
-43
-43
Gamma3
12/21/2021
Yes
-48
-93
-121
-138
-64
-69
Gamma5
03/08/2022
Yes
-3
-6
5
4
4
-3
Delta1
3/10/2021
No
5
11
17
15
6
5
Delta3
7/12/2021
Yes
-25
-49
-69
-90
-27
-26
Delta1
9/21/2021
No
-3
-7
-8
-5
-7
-8
Delta3
12/22/2021
Yes
8
5
-19
-30
-23
-31
Delta6
03/04/2022
No
26
39
22
8
-8
-18
Zeta1
3/10/2021
No
-19
-32
-25
-21
6
-6
Zeta1
9/20/2021
No
-12
-21
-10
-10
8
-3
Zeta1
12/22/2021
No
-17
-27
-20
-21
11
-2
Theta1
03/10/2021
No
30
45
42
37
5
0
Theta1
9/20/2021
No
29
38
36
29
3
-1
Theta1
12/21/2021
No
29
41
40
35
3
-2
Theta3
03/03/2022
Yes
8
13
25
23
9
0
1 Semi-annual temperature calibration
2 Alpha's main oven was repositioned on 4/27/2021. Beta main oven was repositioned on 10/21/2021
3 Beta's main oven was replaced on 4/7/2021. Delta's main oven was replaced on 7/9/2021. Gamma's main oven
was replaced on 7/12/2021. Alpha's main oven was replaced on 10/4/2021. Gamma changed main oven on
12/20/2021. Delta changed main oven on 12/21/2021. Theta main oven was changed on 3/3/2022
4 Gamma's main oven heating coils was replaced on 6/18/2021
Page 109 of 136
-------
5 Gamma main oven was repositioned and rewrapped on 7/9/2021. Gamma's main oven was rewrapped on 3/8/2022
6 Pushed heating coil on delta
4.3.3 Determination of Uncertainties and Method Detection Limits
For determination of Method Detection Limits (MDLs) see Section 3.1.3.2.
For uncertainty estimates see Section 6.5.
4.3.4 Audits, Performance Evaluations, Training, and Accreditations
4.3.4.1 System Audits
The EPA did not conduct any audits or performance evaluations of the UC Davis Carbon
Laboratory during this reporting period.
4.3.4.2 Performance Evaluations
The UC Davis Thermal Optical Analysis Laboratory did not participate in an inter-laboratory
comparison study during this reporting period.
4.3.4.3 Training
All new laboratory staff and student assistants working in the UC Davis Thermal Optical
Analysis Laboratory receive mandatory UC Laboratory Safety Fundamentals training. Personnel
who operate the TOA analyzers receive additional training on the CSN SOP 402 and relevant
Technical Information materials.
4.3.4.4 Accreditations
There are no accreditations for analysis of carbon on aerosol filters by TOA.
4.3.5 Summary of Filter Blanks
4.3.5.1 Field Blanks
Over the sampling period (January 1, 2021 through December 31, 2021) there were 1678 valid
quartz filter field blanks. Table 4.3-11 summarizes the field blank statistics.
Page 110 of 136
-------
Table 4.3-11: Quartz filter field blank statistics for the analysis period 3/11/2021 through 4/1/2022 (samples
collected 1/1/2021 through 12/31/2021). Elemental carbon (EC) fractions are indicated as (1) through (3), organic
carbon (OC) fractions are indicated as (1) through (4). Organic pyrolyzed (OP), elemental carbon (EC), and organic
carbon (OC) are shown by reflectance (R) and transmittance (T).
Species
( (III 111
Median
Uiii/cnr)
A\era tie
(fiii/enr)
Mill
(fiii/enr)
Max
(HSi/enr)
Si.l)e\.
(fiii/enr)
EC1
1,678
0.04
0.07
-0.06
4.00
0.14
EC2
1,678
0.06
0.08
-0.02
0.71
0.09
EC3
1,678
0.00
0.00
-0.06
0.99
0.03
ECR
1,678
0.00
0.00
-0.03
3.09
0.08
ECT
1,678
0.00
0.00
-0.03
2.25
0.06
OC1
1,678
0.16
0.16
-0.01
0.57
0.07
OC2
1,678
0.44
0.47
0.01
4.64
0.21
OC3
1,678
0.66
1.05
0.03
12.64
1.19
OC4
1,678
0.20
0.31
-0.07
4.21
0.32
OCR
1,678
1.65
2.14
-0.03
16.37
1.57
OCT
1,678
1.65
2.14
-0.03
16.37
1.57
OPR
1,678
0.11
0.15
-0.13
1.66
0.19
OPT
1,678
0.11
0.15
-0.13
2.49
0.19
4.3.5.2 Laboratory Blanks Supplied by Wood PLC
Five quartz laboratory blanks are shipped from the Sample Handling Laboratory (Wood PLC)
with each batch of routine filters to the analysis laboratory and analyzed. These filters are
different than those used for daily QC as described in section 4.3.2.1. These filters are from the
same filter lots as the sample filters and are pre-fired by Desert Research Institute (Reno, NV)
and delivered to Wood PLC along with the quartz filters to be used for sampling. There are no
QC criteria for these laboratory blanks. A total of 60 quartz laboratory blanks were analyzed
during the current reporting period, with four runs of analysis per filter using different analyzers
for each run. Table 4.1-12 summarizes the laboratory blank statistics.
Page 111 of 136
-------
Table 4.3-12: Quartz filter laboratory blank statistics for the analysis period 3/11/2021 through 4/1/2022 (samples
collected 1/1/2021 through 12/31/2021). Elemental carbon (EC) fractions are indicated as (1) through (3), organic
carbon (OC) fractions are indicated as (1) through (4). Organic pyrolyzed (OP), elemental carbon (EC), and organic
carbon (OC) are shown by reflectance (R) and transmittance (T).
Species
Count
Median
(jig/cm2)
Average
(jig/em2)
Min
(jig/cm2)
Max
(jig/cm2)
St.Dev.
(jig/em2)
EC1
60
-0.01
-0.01
-0.08
0.25
0.04
EC2
60
0.00
0.01
-0.06
0.34
0.04
EC3
60
0.01
0.01
-0.06
0.31
0.03
ECR
60
0.00
0.00
-0.05
0.31
0.02
ECT
60
0.00
0.01
-0.05
0.54
0.04
OC1
60
0.05
0.05
0.01
0.13
0.02
OC2
60
0.05
0.05
0.00
0.30
0.03
OC3
60
0.07
0.13
0.00
1.31
0.17
OC4
60
-0.01
-0.01
-0.29
0.67
0.09
OCR
60
0.18
0.23
-0.41
2.76
0.34
OCT
60
0.17
0.23
-0.41
2.76
0.34
OPR
60
0.00
0.01
-0.20
0.54
0.09
OPT
60
0.00
0.01
-0.20
0.50
0.08
5. Data Management and Reporting
5.1 Number of Events Posted to AQS
Table 5.1-1 summarizes dates that data were delivered to AQS for samples collected January 1,
2021 through December 31, 2021. Data are expected to be delivered to AQS within 120 days of
receipt of filters by the analytical laboratories.
Page 112 of 136
-------
Table 5.1-1: Summary of data deliveries to AQS for samples collected January 1, 2021 through December 31, 2021.
Sampling Month
(2021)
Analysis lialeli #
Killer Keeeipl Dale
AQS Deli\en Dale
Da j s
January
75
March 10, 2021
July 2, 2021
114
February
76
April 7, 2021
August 5, 2021
120
March
77
May 5, 2021
September 2, 2021
120
April
78
June 9, 2021
October 7, 2021
120
May
79
July 14, 2021
November 10, 2021
119
June
80
August 11, 2021
December 9, 2021
120
July
81
September 9, 2021
January 7, 2022
120
August
82
October 6, 2021
February 2, 2022
119
September
83
November 10, 2021
March 10, 2022
120
October
84
December 15, 2021
April 13, 2022
119
November
85
January 12, 2022
May 12, 2022
120
December
86
February 9, 2022
June 9, 2022
120
6. Quality Assurance and Data Validation
6.1 QAPP Revisions
The UC Davis Quality Assurance Project Plan (QAPP) for Laboratory Analysis and Data
Processing/Validation for Chemical Speciation of PM2.5 Filter Samples is reviewed and updated
annually; The last QAPP revision (1.4) was delivered to the EPA for review on July 30, 2021,
titled the UC Davis 2021 QAPP, revised again on August 31, 2021, and accepted by the EPA on
September 15, 2021. The next draft is currently under revision.
6.2 SOP Revisions
The UC Davis Standard Operating Procedures (SOPs) and Technical Information (TI) material
for Laboratory Analysis and Data Processing/Validation for Chemical Speciation of PM2.5 Filter
Samples are reviewed and updated annually. The 2022 revisions are currently in process.
6.3 Summary of Internal QA Activities
Following laboratory analysis all analytical results are assembled by UC Davis for processing
and initial validation. Data processing involves calculating ambient concentration, uncertainty,
and MDL for each analyte using the laboratory result plus the sample volume determined from
the field data. The calculated concentrations undergo two levels of validation at UC Davis: (1)
Level 0 validation to examine the fundamental information associated with each measured
variable, such as chain of custody, shipping integrity, sample identification, and damaged
samples, and (2) Level 1 review for technical acceptability and reasonableness based on
Page 113 of 136
-------
information such as routine QC sample results, data quality indicator calculations, performance
evaluation samples, internal and external audits, statistical screening, internal consistency
checks, and value range checks. Further detail regarding the UC Davis data processing and
validation can be found in UCD CSN SOP #801: Processing and Validating Raw Data, and in
the associated Technical Information (TI) documents as follows:
1) UCD CSN TI 801 A, Data Ingest. Sample event information (including filter IDs, flow
rates, qualifier and null code flags, and comments) are received from the Sample
Handling Laboratory (Wood PLC) via email and uploaded to the UC Davis CSN
database. UC Davis EDXRF and TOA analysis results are transferred into the UC
Davis CSN database through an automated service. RTIIC analysis result files are
received via email from RTI and are ingested to the UC Davis CSN database.
Additionally, for a select subset of field blanks and special studies, Wood PLC
gravimetric mass result files are received via email from Wood PLC and are ingested
to the UC Davis CSN database.
2) UCD CSN TI 801C, Level 0 Validation: Data and metadata are reviewed through
several visualizations to identify oddities such as inconsistent dates that appear to be
data transcription and/or data entry errors. These are resolved through communication
with the Sample Handling Laboratory.
3) UCD CSN TI 80IB, Data Processing: Sample volume and analysis results are
combined to calculate concentrations. Field blank values are used to derive MDLs.
MDLs and concentrations are used to estimate uncertainty.
4) UCD CSN TI 801C, Level 1 Data Validation: Several statistical and visual checks are
applied and examined. Laboratory reanalyses are requested as needed. Data are
flagged with qualifier or null codes.
5) UCD CSN TI 80ID, Data Posting: Initially validated concentration data and metadata
are posted to DART for SLT (State, Local, and Tribal) agency review. After the
specified 30-day review period, changed or unchanged data are re-ingested to the UC
Davis CSN database.
6) UCD CSN TI 80IE, AQS Delivery. SLT initiated changes and comments are reviewed
and resolved. Data are formatted for delivery to AQS and posted.
6.4 Data Validation and Review
The validation graphics shown in this section are a small subset of the many QC evaluations that
UC Davis performs on a routine basis. They are selected to illustrate the nature and use of the
QC tools, and provide an overview of the review process.
Additional information and detail regarding analytical and validation procedures can be found in
the standard operation procedure (SOP) documents, UC Davis CSN Quality Assurance Project
Plan (QAPP), and the Data Validation for the Chemical Speciation Network guide, all available
at the UC Davis CSN site: https://aqrc.ucdavis.edu/csn-documentation.
6.4.1 Summary of Monthly Data Validation Review Results
Page 114 of 136
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6.4.1.1 Comparisons Across Years
Multi-year time series plots are used to examine large-scale trends and/or analytical problems.
Comparisons to historical network data provide context for validation and review of more recent
data.
Figure 6.4-1 shows time series for the network-wide 90th percentile, median (50th percentile), and
10th percentile concentrations of organic carbon by reflectance (OCR). This figure show
concentration data without blank correction to enable comparison across a wider timeframe. The
carbon fraction OCR is determined by thermal optical analysis (TOA) with a correction for
pyrolysis based on optical monitoring as the sample is heated. Measurements for samples
collected from 2005 through 2015 were performed at DRI using DRI Model 2001 analyzers;
samples collected from January 2016 through September 2018 were analyzed at DRI using DRI
Model 2015 analyzers; and, beginning with samples collected from October 2018 analysis was
performed at UC Davis using the Sunset Laboratory Model 5L analyzer.
Figure 6.4-1: Multi-year time series of network-wide organic carbon by reflectance concentrations (OCR; raw data
without blank correction). Symbols denote laboratory and type of analyzer: DRI Model 2001 (circle), DRI Model
2015 (triangle), andUCD Sunset Laboratory Model 5L (square).
CT>
i
a:
o
o
90th Percentile
en
o
o
Median
E 2.5-
a 2.0
1.5-1
1.0
Jan
10th Percentile
Jul Aug Sep Oct
Nov Dec
Year
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
Jul Aug Sep Oct
Nov Dec
Analyzer DRI Model 2001 A DRI Model 2015
UCD Sunset Laboratory Model 5L
Page 115 of 136
-------
The 0C4 plot in Figure 6.4-2 indicates when AQRC changed the 0C4 time setting to be 580s for
every analysis. This is seen in the 10th percentile plot as a jump in Sept 2020 when the change
was implemented. This change allowed analyzers to collect all the OC4 without cutting the
analysis short. The change was not as visible in other Carbon fractions.
Figure 6.4-2: Multi-year time series of network-wide OC4 fraction (OC4; raw data without blank correction).
90th Percentile
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Median Year
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2020
2021
10th Percentile
0.25
E
,
O)
0.20
ฆ'
g
0.15
TO
o
0.10
o
2012
2013
2014
2015
2016
2017
2018
-~ 2019
Similar to recent years, the 2021 sulfur concentrations generally continue to be low (Figure 6.4-
4), with reduced seasonal variability.
Page 116 of 136
-------
Figure 6.4-3: Multi-year time series of network-wide sulfur (S) concentrations.
Median
Year
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
0.25-
"g 0.20-
9] 0.15-
w 0.10-
10th Percentile
The 2020 iron concentrations are similar to previous years with the median peaking in the
summer months (Figure 6.4-5). 2020 data showed lower Fe concentrations in the median and
90th percentiles, perhaps as a result of Covid-19 shutdowns. The 2021 data returned to normal
and sometimes higher levels could be from lockdowns lifted and levels rose across all 3 plots.
Page 117 of 136
-------
Figure 6.4-4: Multi-year time series of network-wide iron (Fe) concentrations.
90th Percentile
cn
=i
2020
2021
Median
0.08-
0.07-
0.06-
0.05-
0.04-
Year
2012
2013
2014
2015
2016
2017
2018
2019
Copper 10th, median, and 90th percentile values show a see-saw pattern from June through
December 2021 (Figure 6.4-5). This erratic pattern was caused by the blank correction. The
median field blank concentration is subtracted from each ambient sample concentration to
account for any background contamination inherent in the blank filters themselves or picked up
during handling. Figure 6.4-6 shows that the Cu field blank concentrations are not normally
distributed and instead show a bifurcated distribution; unfortunately, the medians fall on
alternating sides of the distribution in the latter half of 2021, resulting in significantly different
blank corrections each month. The ambient concentrations are close to zero (MDL=0.005
jjg/m3), so these changes in blank correction are obvious in the ambient concentrations. This is
an artifact in the measurements produced by the blank correction technique.
Page 118 of 136
-------
Figure 6.4-6: 2021 Cu Field Blanks.
! i
:||
1 ,
1!
; |
ii
*! .
: ii i
|: i
!|
ri
1
a
1
i!
ฆ I
tj
1
t
1
1
i :
i
_ !' "!
!
i
i
i
i ;
137
134
136
138
139
139 142
140
136
136
136
137
Jul 2021
IntendedUseDate
Figure 6.4-5: Multi-year time series of network-wide copper (Cu) concentrations.
90th Percentile
m 0.002
ฃ
D) o.ooo-
(J -0.002
Year
0.006
0.004
0.002
0.000
2012
2013
2014
2015
2016
2017
-* 2018
2019
10th Percentile
2020
2021
=J
o
0.016-
0.012-
0.008-
0.004-
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Median
The 2021 nitrate concentrations continue to show strong seasonality with elevated winter
concentrations (Figure 6.4-8).
Page 119 of 136
-------
E
U)
0.3
zL
-------
Figure 6.4-8: Multi-year time series of network-wide composite variable reconstructed mass (RCM) concentrations.
90th Percentile
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
10th Percentile
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Page 121 of 136
-------
Figure 6.4-9: Multi-year time series of network-wide composite variable soil concentrations.
90th Percentile
ฃ 2.0
cn , r
=S. 1.5
OT 10
.
^
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Median
Dec
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
10th Percentile
Dec
Feb Mar
Aug Sep
Nov Dec
Page 122 of 136
-------
6.4.1.2 Comparisons Between Modules
The following graphs compare two independent measures of aerosol properties that are expected
to correlate. These graphs are used to identify cases where the two measurements do not
correlate well, which can result from real atmospheric and anthropogenic events or analytical and
sampling issues.
6.4.1.3 Sulfur versus Sulfate
PTFE filters are analyzed for elemental sulfur using EDXRF, and nylon filters are analyzed for
sulfate (SO4) using IC. The molecular weight of SO4 (96 g/mol) is three times the atomic weight
of S (32 g/mol), so the concentration ratio (3>
-------
6.4.1.4 Potassium versus Potassium Ion
PTFE filters are analyzed for elemental potassium using EDXRF, and nylon filters are analyzed
for potassium ion using IC. Similar to the S/SO4 ratio relationship, the potassium/potassium ion
ratio can be used to identify outliers as well as atmospherically unusual events. In a scenario
where all the particulate potassium is present as water-soluble potassium ion, the
potassium/potassium ion ratio is expected to be near one (Figure 6.4-9).
Figure 6.4-10: Scatter plot of potassium versus potassium ion, samples collected January 1, 2021 through December
31, 2021. Number of observations (complete pairs) is 12,566. Dotted black horizontal and vertical lines indicate
MDLs. Solid gray line indicates 1:1. Solid red line indicates regression. Outlier points that are off scale are plotted at
the 12 |ig/m3 boundaries shown by the dashed lines.
Potassium Ion ((ig/m3)
Page 124 of 136
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6.4.1.5 Chlorine versus Chloride
PTFE filters are analyzed for elemental chlorine using EDXRF, and nylon filters are analyzed for
chloride using IC. Chloride ion is the reduced form of chlorine and chlorine in particulate matter
is typically in the form of chloride. Similarly to the potassium/potassium ion relationship, in a
scenario where all the particulate chlorine is present as water-soluble chloride ion, the
chlorine/chloride ion ratio is expected to be near one (Figure 6.4-10).
Figure 6.4-11: Scatter plot of chlorine versus chloride ion, samples collected January 1, 2021 through December 31,
2021. Number of observations (complete pairs) is 12,551. Dotted black horizontal and vertical lines indicate MDLs.
Solid gray line indicates 1:1. Solid red line indicates regression. Outlier points that are off scale are plotted at the 5
|ig/m3 boundaries shown by the dashed lines.
Chloride (|ig/m3)
Page 125 of 136
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6.4.1.6
PM2.5 versus Reconstructed Mass (RCM)
Gravimetric data are compared to composite variable reconstructed mass (RCM), where the
RCM composite variable is estimated from chemical speciation measurements, to test many
different aspects of overall data quality. The formulas used to estimate the mass contributions
from various chemical species are detailed in UCD CSN TI801B. In the simple case where valid
measurements are available for all needed variables, reconstructed mass is the following sum:
RCM = (4.125 x S) + (1.29 xN03") + (1.4 x OC) + (EC) +
(2.2 x A1 + 2.49 x Si + 1.63 x Ca + 2.42 x Fe + 1.94 x Ti) + (1.8 x chloride)
The parenthesized components represent the mass contributions from, in order, ammonium
sulfate, ammonium nitrate, organic compounds, elemental carbon, soil, and sea salt.
Gravimetric analysis is not routinely performed using CSN filters. Thus, for comparison
purposes 24-hour average gravimetric PM2.5 mass data from AirNow Tech is used as part of the
validation process in DART. The data provided by AirNow Tech is not final, so the data used
here is a snapshot, downloaded at the time the plots were generated.
If the RCM completely captures and accurately estimates the different mass components, the
RCM to AirNow Tech mass ratio is expected to be near one. The RCM and AirNow Tech mass
generally correlate (Figure 6.4-11), but RCM tends to underestimate AirNow Tech mass.
Figure 6.4-12: Scatter plot of reconstructed mass (RCM) versus AirNow Tech PM2.5 mass data (Mass), samples
collected January 1, 2021 through December 31, 2021. Number of observations (complete pairs) is 9,220. Solid gray
line indicates 1:1. Solid red line indicates regression.
Mass ((.ig/m3)
Page 126 of 136
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6.5 Uncertainty Estimates and Collocated Precision Summary Statistics
Several network sites are equipped with collocated samplers, where simultaneous samples are
collected on independent samplers and analyzed using the same analytical protocols. Differences
between the resulting data provide a measure of the total uncertainty associated with filter
substrates, sampling and handling in the field, and laboratory analysis.
Scaled relative difference between sample pairs collected at CSN collocated sites is calculated as
shown in Equation 6.5-1 and used to evaluate collocated precision (Figure 6.5.1, elements;
Figure 6.5-2, ions; Figure 6.5-3, carbon).
Scaled Relative Difference (SRD) = (Eq- 6.5-1)
The scaled relative differences are ฑV2, when one of the two measurements is zero and vary
between these limits at concentrations close to the detection limit. The scaled relative differences
generally decrease with increasing concentration, and are expected to converge to a distribution
representative of multiplicative measurement error when the concentration is well above the
detection limit. This convergence is not observed for many elements and carbon fractions that
are rarely measured above the MDL at the collocated sites.
Page 127 of 136
-------
Figure 6.5-1: Scaled relative differences for element measurements at sites with collocated samplers across the
network (January 1, 2020 through December 31, 2021). Dotted vertical lines indicate MDL.
0)
c 0
(D
aj
ฃ -1'
Q
Ag
Cd
CT3
CD
* H
"D
Q)
TO n.
O u
c/d
-1 -
0.01 1 100
Al
UJ|f
Wo
Cu
ฐ
ฐ Q,sb
o JiMcv.
ฐฐ Ji
1
Na
ฐ
o0
C
o
CCt
O&P
ฉ
Zn
0.01 1 100
As
Ce
oo
oqM
Fe
Se
ฐM
ฐฅ
Ba
In
o o
O
cPi
P
ฐ oS&g*
j ?o
c, $
-------
Figure 6.5-2: Scaled relative differences for ion measurements at sites with collocated samplers across the network
(January 1. 2020 through December 31, 2021). Dotted vertical lines indicate MDL.
Ammonium
o
o
%
o
o
D
O O
0
ฉฐ
o
o
Chloride
o o
o
oฐ 0
O ฐ%
0%
<%p
o
ฐd
SP ฐ
c
o
&-C
0ฐ
ฆ ฐ
Potassium Ion
o
0
o
oฐ
%i
ifF0
o
o
0 o
o
o
Nitrate
oฐ
OKI ฐ
O
Sodium Ion
o
o
ฐ o
ฐ ft ฐ
iปฐo 0
f" ฐ
ฐ ฉ ฐ
: ฐ
Sulfate
o
ML
gGP
o
0.01
100
0.01 1 100
Average Concentration/MDL
0.01
100
o Bakersfield - California Ave. (06-029-0014)
Site Name ฐ Deer Park (48-201-1039)
o G.T. Craig (39-035-0060)
o Riverside - Rubidoux (06-065-8001)
o Dudley Square - Roxbury (Boston) (25-025-0042) o Rutgers (34-023-0011)
Page 129 of 136
-------
Figure 6.5-3: Scaled relative differences for carbon measurements at sites with collocated samplers across the
network (January 1, 2020 through December 31, 2021). Dotted vertical lines indicate MDL. Elemental carbon (EC)
fractions are indicated as (1) through (3), organic carbon (OC) fractions are indicated as (1) through (4). Organic
pyrolized (OP), elemental carbon (EC), and organic carbon (OC) are shown by reflectance (R) and transmittance
(T).
EC1
0.1 1 10 100
EC2
l
ECT
OC1
OC4
0.1 1 10 100
EC3
o :
cJQ ~ o
jf
OCR
|Pป
0.1 1 10 100
ECR
ฆm-
pP
OC2
oฐฐ
OC3
OCT
1*
1
OPR
Dฐฐ0
|jfc
a
0.1 1 10 100
Average Concentration/MDL
o Bakersfield - California Ave. (06-029-0014) o G.T. Craig (39-035-0060)
Site ฐ Deer Park (48-201-1039) o Riverside - Rubidoux (06-065-8001)
o Dudley Square - Roxbury (Boston) (25-025-0042) o Rutgers (34-023-0011)
Collocated precision is reported for CSN data as fractional uncertainty. Fractional uncertainty is
calculated from scaled relative differences (Equation 6.5-1) between sample pairs collected at
CSN collocated sites, using the subset of observations with concentrations at least three times the
MDL. Beginning with samples collected January 1, 2019 through December 31, 2019, fractional
uncertainty is updated annually and calculated using collocated data from the previous two years.
For this reporting period (samples collected January 1, 2021 through December 31, 2021) the
Page 130 of 136
-------
fractional uncertainty is calculated from sample pairs collected at CSN collocated sites June 1,
2018 through May 31, 2020, with a minimum of 60 collocated pairs. For cases where the total
number of valid collocated pairs over the two-year period is less than 60, a value of 0.25 (25%)
is adopted as the fractional uncertainty. The calculation for fractional uncertainty is documented
in UCD CSN TI801B, and summarized in Equation 6.5-1 and Equation 6.5-2.
Fractional Uncertainty (f) = C84'h p'rc""'""ฐf 5RDMปa *"ป (Eq. 6.5-2)
Table 6.5-1 (elements), Table 6.5-2 (ions), and Table 6.5-3 (carbon) list fractional uncertainties
calculated for this reporting period. Since many species are routinely measured at or below the
MDL, there are numerous instances where a fractional uncertainty of 0.25 (25%) is assigned.
Each species concentration result delivered to AQS is accompanied by calculated method
detection limit (MDL; see Section 3.1.3.2) and additive uncertainty (Equation 6.5-3). Additive
uncertainty includes both fractional uncertainty (Equation 6.5-2) and analytical uncertainty as
reported by the laboratories. Similar to the fractional uncertainty, beginning with samples
collected January 1, 2019 through December 31, 2019 analytical uncertainties are reviewed
annually and updated per direction from the laboratories.
Additive Uncertainty = (Analytical Uncertainty)2 (f x C)2 g 5 3^
Where / is fractional uncertainty and C is ambient concentration.
The network measurement quality objectives (MQOs) are based on the coefficient of variation
(CV) between collocated measurements, and are defined as CV of 10% for ions, 20% for
elements, and 15% for total carbon.
Using the methodology as shown in Rice and Landis (2016), CV is calculated as the median
(.Psoth) relative percent difference (RPD) from sample pairs (J) collected at collocated sites, using
the subset of observations with concentrations at least three times the MDL, as shown in
Equation 6.5-4 and Equation 6.5-5.
where X and Y, are the measurements from routine and collocated sites, respectively, for the ith
pair of measurements.
Using the methodology in the Code of Federal Regulations (CFR) Appendix A to Part 58 -
Quality Assurance Requirements for Monitors used in Evaluations of National Ambient Air
Quality Standards (available at https://www.law.cornell.edu/cfr/text/40/appendix-A_to_part_58),
precision is estimated from duplicate measurements from collocated samplers. Here, only the
subset of observations with concentrations at least three times the MDL are used. For each
Relative Percent Dif ference (RPDJ =
(Eq. 6.5-4)
(Eq. 6.5-5)
Page 131 of 136
-------
collocated pair, the relative percent difference is calculated using Equation 6.5-4. The CV upper
bound is calculated using Equation 6.5-6:
\
jn.EL] RPDr - (Z'URPD,)
J 2n{n - 1)
x
ii l
(Eq. 6.5-6)
Where n is the number of valid data pairs being aggregated, and ^o.i,n-i is the 10th percentile of
a chi-squared distribution with n-1 degrees of freedom. The factor of 2 in the denominator
adjusts for the fact that each RPDt is calculated from two values with error.
Table 6.5-1 (elements), Table 6.5-2 (ions), and Table 6.5-3 (carbon) list median CV calculated
using Equations 6.5-4 and 6.5-5 from collocated samples collected during 2021 (current
reporting period) as well as 2020 (previous reporting period). The CFR CV calculated using
Equations 6.5-4 and 6.5-6 from collocated samples collected during 2021 (current reporting
period) and 2020 (previous reporting period) is also included.
Page 132 of 136
-------
Table 6.5-1: Fractional uncertainty (/), median coefficient of variation (CV), and CFR coefficient of variation (CFR CV) for
element species. For the previous reporting period, / is calculated from samples collected June 1, 2017 through May 31, 2019
and used in relevant calculations for samples between January 1, 2020 through December 31, 2020 and CV is calculated from
samples collected January 1, 2020 through December 31, 2020. For the current reporting period, / is calculated from samples
collected June 1, 2018 through May 31, 2020 and used in relevant calculations for samples between January 1, 2021 through
December 31, 2021 and CV is calculated from samples collected January 1, 2021 through December 31, 2021. For both
reporting periods, / and CV values are not calculated for species with less than 60 collocated pairs with concentrations at least
three times the MDL; the adopted value of 25% for / are shown in the table.
2020 (previous reporting period)
2021 (previous reporting period)
Species
/(%)
Pairs
CV
(%)
Pairs
CFR
CV
(%)
Pairs
/(%)
Pairs
CV
(%)
Pairs
CFR
CV
(%)
Pairs
Na
17.6
68
25
25
18.8
67
32
32
Mg
25.0
10
4
4
25.0
8
2
2
A1
15.3
91
58
58
17.4
89
12.0
95
26.8
95
Si
14.2
329
9.8
170
24.6
170
14.5
327
7.0
241
20.2
241
P
25.0
7
15
15
25.0
3
12
53.5
12
S
5.7
654
3.0
292
8.7
292
5.4
658
3.5
353
7.7
353
CI
35.1
179
25.5
85
43.3
85
32.9
173
19.8
85
39.4
85
K
8.4
567
5.0
271
10.8
271
8.2
595
5.3
340
13.2
340
Ca
13.4
263
6.9
174
23.8
174
13.6
371
7.9
247
21.2
247
Ti
15.5
98
8.0
62
16.6
62
15.5
86
10.7
101
24.1
101
V
25.0
0
1
1
25.0
0
3
3
Cr
25.0
1
0
0
25.0
0
0
0
Mn
25.0
16
19
19
25.0
19
21
21
Fe
13.2
328
6.1
237
16.6
237
11.8
386
5.9
319
16.7
319
Co
25.0
0
0
0
25.0
0
0
0
Ni
25.0
0
0
0
25.0
0
1
1
Cu
25.0
6
17
17
25.0
6
18
18
Zn
9.8
245
6.2
223
16.7
223
10.0
281
8.6
260
16.2
260
As
25.0
0
0
0
25.0
0
0
0
Se
25.0
0
0
0
25.0
0
0
0
Br
25.0
1
35.6
70
57.6
70
25.0
23
34.6
91
55.1
91
Rb
25.0
0
0
0
25.0
0
0
0
Sr
25.0
0
1
1
25.0
0
0
0
Zr
-25.0
0
0
0
25.0
0
0
0
Ag
25.0
0
0
0
25.0
0
0
0
Cd
25.0
0
0
0
25.0
0
0
0
In
25.0
0
0
0
25.0
0
0
0
Sn
25.0
0
0
0
25.0
0
0
0
Sb
25.0
0
0
0
25.0
0
2
2
Cs
25.0
0
0
0
25.0
0
0
0
Ba
25.0
0
0
0
25.0
0
0
0
Ce
25.0
0
0
0
25.0
0
0
0
Pb
25.0
0
0
0
25.0
0
1
1
Page 133 of 136
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Table 6.5-2: Fractional uncertainty (/), median coefficient of variation (CV), and CFR coefficient of variation for ion species.
For the previous reporting period, / is calculated from samples collected June 1, 2017 through May 31, 2019 and used in
relevant calculations for samples between January 1, 2020 through December 31, 2020 and CV is calculated from samples
collected January 1, 2020 through December 31, 2020. For the current reporting period, / is calculated from samples collected
June 1, 2018 through May 31, 2020 and used in relevant calculations for samples between January 1, 2021 through December
31, 2021 and CV is calculated from samples collected January 1, 2021 through December 31, 2021. For both reporting
periods, / and CV values are not calculated for species with less than 60 collocated pairs with concentrations at least three
times the MDL; the adopted value of 25% for / are shown in the table.
2020 (previous reporting period)
2021 (current reporting period)
Species
/(%)
Pairs
CV
(%)
Pairs
CFR
CV
(%)
Pairs
/(%)
Pairs
CV
(%)
Pairs
CFR
CV
(%)
Pairs
Ammonium
15.9
591
4.6
263
14.0
263
10.8
626
4.9
309
12.5
309
Chloride
11.4
403
5.4
173
17.5
173
10.1
432
4.0
219
14.9
219
Nitrate
7.9
628
3.1
284
13.4
284
5.5
636
2.9
342
8.1
342
Potassium
Ion
25.0
11
7.7
126
16.8
126
25.0
38
5.8
153
14.6
153
Sodium Ion
14.1
411
5.0
163
19.2
163
11.1
414
4.0
188
16.8
188
Sulfate
5.8
654
2.9
292
11.2
292
4.1
656
2.1
352
4.8
352
Page 134 of 136
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Table 6.5-3: Fractional uncertainty (/), median coefficient of variation (CV), and CFR coefficient of variation for carbon
species. For previous reporting period, / is calculated from samples collected June 1, 2017 - May 31, 2019 and used in
relevant calculations for samples between January 1, 2020 - December 31, 2020 and CV is calculated from samples collected
January 1, 2020 - December 31, 2020. For the current reporting period, / is calculated from samples collected June 1, 2018 -
May 31, 2020 and used in relevant calculations for samples between January 1, 2021 - December 31, 2021 and CV is
calculated from samples collected January 1, 2021 - December 31, 2021. For both reporting periods, / and CV values are not
calculated for species with less than 60 collocated pairs with concentrations at least three times the MDL; the adopted value of
25% for / are shown in the table. Elemental carbon (EC) fractions are indicated as (1) through (3), organic carbon (OC)
fractions are indicated as (1) through (4). Organic pyrolyzed (OP), elemental carbon (EC), and organic carbon (OC) are shown
by reflectance (R) and transmittance (T).
2020 (previous reporting period)
2021 (current reporting period)
Species
/(%)
Pairs
CV
(%)
Pairs
CFR
CV
(%)
Pairs
/(%)
Pairs
CV
(%)
Pairs
CFR
CV
(%)
Pairs
Elemental
Carbon
(EC1)
12.1
653
7.9
292
17.7
292
9.5
643
10.5
336
18.9
336
Elemental
Carbon
(EC2)
27.4
509
13.1
243
22.7
243
20.6
535
20.4
322
31.0
322
Elemental
Carbon
(EC 3)
25.0
18
32
32
23.9
78
40
40
Elemental
Carbon
(ECR)
13.5
650
6.5
293
14.3
293
11.0
644
7.7
336
15.2
336
Elemental
Carbon
(ECT)
15.4
649
8.0
294
15.6
294
12.5
644
9.8
336
16.3
336
Organic
Carbon
(OC1)
32.5
399
24.1
124
40.5
124
33.5
290
23.4
155
41.4
155
Organic
Carbon
(OC2)
11.6
643
7.9
286
18.5
286
12.8
620
8.1
331
12.7
331
Organic
Carbon
(OC3)
12.2
530
34
34
10.9
312
7.0
115
11.8
115
Organic
Carbon
(OC4)
19.1
461
12.7
101
27.5
101
19.2
176
13.1
246
24.4
246
Organic
Carbon
(OCR)
8.5
614
5.7
141
8.8
141
7.5
469
5.4
247
9.3
247
Organic
Carbon
(OCT)
7.4
619
4.9
154
8.1
154
6.4
484
4.7
260
8.4
260
Organic
Pyrolyzed
(OPR)
23.7
421
15.7
183
24.3
183
17.2
437
15.8
210
30.3
210
Organic
Pyrolyzed
(OPT)
20.1
597
9.6
238
21.5
238
13.2
560
13.6
291
27.7
291
Page 135 of 136
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7. References
Chow, J.C., Watson, J.G. (2017). Enhanced ion chromatographic speciation of water-soluble
PM2.5 to improve aerosol source apportionment. Aerosol Science and Engineering 1:7-24.
EPA 40 CFRPart 58. Available at
https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=91010WLJ.TXT
Rice, J. and Landis, E. (2016): Chemical Speciation Network (CSN) Summary of Precision from
Six Collocated Sites [Poster presentation], 2016 National Ambient Air Monitoring Conference,
Portland, OR, United States, https://www.epa.gov/sites/production/files/2016-
09/documents/summary _of_precision.pdf
RTI (2020): RTI Quality Assurance Reports: 2021 Ions QA Report. Available at
http://vista.cira.colostate.edu/Improve/quality-assurance/
Wetherbee, G.A., and Martin, R. (2020). External quality assurance project report for the National
Atmospheric Deposition Program's National Trends Network and Mercury Deposition Network, 2017-
18. U.S. Geological Survey Scientific Investigations Report 2020-5084.
https://doi.org/10.3133/sir20205084.
Page 136 of 136
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