CASTNET 2020 Annual Network Plan
Response to Comments
Clean Air Markets Division
Office of Atmospheric Programs
US Environmental Protection Agency
June 30, 2020
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Table of Contents
1. US EPA Region 1 3
2. GADNR 5
3. US EPA Region 2 7
Page 2 of 8
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1. Comment received in regard to the level of the 1-point QC checks for CASTNET ozone
analyzers.
Commenter: Robert Judge, EPA Region 1.
Date received: April 30, 2020
Comment 1.
Tim- I'm not going to give this as detailed review as I would for a State ANP, which we in the Regions
actually "approve." But as a Region who reviews your CASTNET data quarterly, you guys do a good job. I
will observe, just like we do with our States that are collecting data for regulatory purposes- and in
compliance with 40 CFR Part 58, Appendix A, I would consider all CASTNET ozone monitors to be more
analogous to research based sites/ NCORE, and would therefore be asking the State to run p-checks at
values close to the mean/ median. These CASTNET sites are not primarily NAAQS compliance monitors.
(I know I've said this before) Be safe...
Table 1 Quality
Table 1 Quality 03 (ppb) S02 (ppb) CO(ppm)
Control
Checks Frequency
Zero
Daily
0
0
0
Precision
Daily
60
25
250
Span
Daily
225*
90
1800
Additional
Weekly
30**
5**
80**
point #1
Additional
Weekly
QQ* *
40**
300**
point #2
Additional
Weekly
150**
60**
800**
point #3
3. Measurement Quality Check Requirements
3.1. Gaseous Monitors of SOI, N02, 03, and CO.
3.1.1 One-Point Quality Control (QC) Check for S02, N02, 03, and CO. (a) A one-point QC check
must be performed at least once every 2 weeks on each automated monitor used to measure S02, N02,
03 and CO. With the advent of automated calibration systems, more frequent checking is strongly
encouraged. See Reference 10 of this appendix for guidance on the review procedure. The QC check is
made by challenging the monitor with a QC check gas of known concentration (effective concentration
for open path monitors) between the prescribed range of 0.005 and 0.08 parts per million (ppm) for
S02, N02, and 03, and between the prescribed range of 0.5 and 5 ppm for CO monitors. The QC check
gas concentration selected within the prescribed range should be related to the monitoring objectives
for the monitor. If monitoring at an NCore site or for trace level monitoring, the QC check concentration
hould be selected to represent the mean or median concentrations at the site. If the mean or median
concentrations at trace gas sites are below the MDL of the instrument the agency can select the lowest
concentration in the prescribed range that can be practically achieved. If the mean or median
concentrations at trace gas sites are above the prescribed range the agency can select the highest
concentration in the prescribed range. An additional QC check point is encouraged for those
Page 3 of 8
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organizations that may have occasional high values or would like to confirm the monitors' linearity at
the higher end of the operational range or around NAAQS concentrations. If monitoring for NAAQS
decisions, the QC concentration can be selected at a higher concentration within the prescribed range
but should also consider precision points around mean or median monitor concentrations.
(b) Point analyzers must operate in their normal sampling mode during the QC check and the test
atmosphere must pass through all filters, scrubbers, conditioners and other components used during
normal ambient sampling and as much of the ambient air inlet system as is practicable. The QC check
must be conducted before any calibration or adjustment to the monitor.
Response 1.
The CASTNET ozone monitoring program is designed to provide ozone monitoring data that fulfill the
requirements for ozone NAAQS attainment designations. CASTNET site locations span the continental
U.S. and Alaska. As a national program, CASTNET utilizes the same quality assurance and quality control
(QA/QC) protocols across very different geographic regions. A review of the 2019 ozone design value
report1 shows that seven CASTNET ozone analyzers reported ozone design values above the 2015
NAAQS. Over the last five years, CASTNET sites averaged 199 ozone exceedances (i.e., eight hour daily
maximum ozone concentrations above 70 ppb) per year.
The 2019 ozone design value report also illustrates the unique role that CASTNET ozone analyzers fulfill
where they are oftentimes the only regulatory ozone analyzer within a county or community based
statistical area (CBSA). For example, out of 80 valid CASTNET ozone design values, 79 sites were in the
top five of their respective county and 45 were in the top five of their respective CBSA. Sixty-three
CASTNET sites had the leading design value for their respective county and 32 CASTNET sites had the
leading ozone design value for their respective CBSA. Lastly, in 49 counties and 17 CBSAs CASTNET sites
provided the only regulatory ozone concentrations for citizens of those communities.
Appendix A to 40 CFR Part 58 states, "If monitoring for NAAQS decisions, the QC concentration can be
selected at a higher concentration within the prescribed range but should also consider precision points
around mean or median monitor concentrations." Given the importance of national consistency across
the CASTNET monitoring program, paucity of ozone monitoring where CASTNET sites are located, and
the episodic ozone exceedances, our program finds that setting the daily 1-point QC check level at 60
ppb meets both the requirements spelled out in Appendix A to 40 CFR Part 58 and the objectives of the
CASTNET program. To evaluate ozone measurements near the mean or median (approximately 35 ppb
for the CASTNET network) a precision check is also performed weekly at 30 ppb and results for EPA-
sponsored sites are reported on the CASTNET website.
12019 Design Value Reports. Accessed on June 10, 2020. https://www.epa.gov/air-trends/air-quality-design-values
Page 4 of 8
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2. Comment received in regard to missing URL website links and grammar suggestions.
Commenter: James W. Boylan, Ph.D., Georgia Department of Natural Resources
GA EPD - Air Protection Branch
Date received: May 7, 2020
Comment 2.
Submitted by electronic email to: Sharac.Timothygepa.gov
Mr. Timothy Sharac
Office of Air & Radiation - Clean Air Markets Division
U. S. EPA Headquarters
1200 Pennsylvania Avenue, N.W.
MC-6204M
Washington, DC 20460
Dear Mr. Timothy Sharac:
The Georgia Environmental Protection Division (Georgia EPD) appreciates the opportunity to provide the
following comments on the draft "2020 CASTNET Annual Network Plan" document (hereafter "Draft
CASTNET Plan") dated April 30, 2020.
Overall, EPA's Draft CASTNET Plan document provides a clear and comprehensive plan for the CASTNET
network. Below, we provide some general and specific comments for EPA to consider as they finalize the
planning document.
General Comments
Georgia EPD recommends that EPA use "a" before words that start with a consonant sound and "an"
before words that start with a vowel sound. When an acronym starts with a consonant that when
pronounced sound like a vowel (e.g., the letters "F" pronounced "eff" or "S" pronounced "ess"), then
the acronym should be preceded by "an" not "a" (e.g., "an FSA" instead of "a FSA" or "an S/L/T" instead
of "a S/L/T").
Specific Comments
The attached Table 1 contains Georgia EPD's comments on specific items in EPA's Draft CASTNET Plan.
We attempted to include the original text of the Draft CASTNET Plan in Table 1 so that EPA staff can
easily locate our discussion items. For editorial changes, we used red font.
If you have any questions about our comments, please contact Gil Grodzinsky at
Gil.Grodzinsky@dnr.ga.gov.
Page 5 of 8
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T.ible I, Georgia EPD's specific comments on EPA's draft 2020 CASTNET Annual Network Plan.
P.ige
Original Ten
Coimn«H
(top)
"A summary of the entire
CASTNET monitoring program is
era liable online J"
The link associated '.vitli footnote 1 a;
tlx bottom of page 3, which is
TNET-Factsheet-2019.od£ does not
exist or isn't at this location.
3
(under Figure 1 i
" "Ninety-three CASTNET sites
measure weekly concentrations of
sulfur dioxide (SOi), sulfate
(SOis"), nitrate (NOj), nitric acid
(HNO3), ammonium (NHi4),
chloride (CT) and base cations
using a 3-stage liter pact (see
Firmc 2)."
Nitrate is an anion with a charge of -L
so should read NQf. Change to
"Ninety-three CASTNET sites measure
weekly concentrations of sulfur dioxide
(SOaX sulfate (SGr"), nitrate QtOi%
nitric acid (HNO3), ammonium (NBs"*),
chloride (CI") and base cations using a
3-stage filter pack (see Figure 2)."
4
"The QA program routinely
assesses compliance with the
CASTNET Quality Assurance
Project Han (QAPWf through
internal monitoring, including
audits slid oii-sife system clieclcs.
Xhe litilf sssocisted. wiUi footnote 2- st
lie bottom of page 4, which is
https:/,%ww3.epa.gov/castnet/docs/CA§
TNET OAPP v9-3 Main bodv.odf
does not exist or isn't at this location.
8
(Table 2 caption)
'Table 2 Note: 40 CFR Part 58
Appendix A - Quality Assurance
Requirements for Monitors used in.
Evaluations of National Ambient
Air' Quality Standards.11"
The Ink associated with footnote 11 at
the bottom of page 8, which is
hflps;//mw,ecfr.eo„/cgi-l»ii''text-
idx?SID=43aS2c5 c9a954280524a 1 atoflSa
332ica&iiic=lme&n
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3. Comment received in regard to 1-point QC checks and NPAP audit levels for CASTNET trace-
level gas analyzers.
Commenter: Mustafa Mustafa, EPA Region 2.
Date received: May 14, 2020
Comment 3.
Hi Tim,
I reviewed the 2020 CASTNE Annual Network Plan, and I have the following couple of QA comments:
1. Table 1 Quality Control Checks, page 8: the levels for CO need to be corrected, either by
changing the CO units to (PPb) instead of (ppm), or the numbers into ppm to match. Also, the 1-
Point Precision check range in the QA Handbook, Appendix D is .5 - 5.00 ppm. The point should
be within the range, and CASTNET could do extra point at a lower level if they choose to.
2. Recommend that the additional check points level to be lowered. Attached is the levels and
acceptance criteria we follow for the NPAP audits.
3. Table 2 Audit Levels for Performance Evaluations, pg 8: Just correct the absolute difference
allowed for Levels 1&2 for CO to .031 ppm.
4. I understand that you don't have as many CO and SO2 monitors as 03 in the Network: are the
NPAP audits are done just for 03?
Thank you,
Mustafa A. Mustafa
USEPA Region 2
(732)906-6881
The NPAP Acceptance Criteria Excel attachment is shown below.
Page 7 of 8
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TTP NPAP Audits Acceptance Criteria
Citation
Pollutant
Audit
Frequency
Acceptance Criteria
03 :
FiitrsHndilf (STAPi
if tfiw miM in (Mw
Audi! levels 142 ¦ *1.5 ppb difference all
other Itwb percent difference <+10,111
1 ad
3)NP
2> -«0 CTR Pan SS App A Sec. 3.1.3
VQAPWS0P
CO 1
J>
FtienlAxtin iST.iPi
M 0/ sAs muM in s ctlmihr
Aiil Irak 142
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