THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
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TECHNOLOGY TYPE: FIELD PORTABLE ION CHROMATOGRAPH
APPLICATION:
MONITORING OF SOLUBLE GASES AND AEROSOL
SPECIES IN AMBIENT AIR
TECHNOLOGY NAME: Monitor for Aerosols and Gases in Ambient Air (MARGA)
ADI 2080
COMPANY:
ADDRESS:
WEB SITE:
E-MAIL:
Applikon Analytical BV
P.O Box 149
3100 AC Schiedam
The Netherlands
PHONE: +31 10 2983500
http://www.metrohm-applikon.com/
Dr. Timoer Frelink (TFr@Applikon.com)
ETV Joint Verification Statement
The U.S. Environmental Protection Agency (EPA) has established the Environmental Technology Verification
(ETV) Program to facilitate the deployment of innovative or improved environmental technologies through
performance verification and dissemination of information. The goal of the ETV Program is to further
environmental protection by accelerating the acceptance and use of improved and cost-effective technologies.
ETV seeks to achieve this goal by providing high-quality, peer-reviewed data on technology performance to
those involved in the design, distribution, financing, permitting, purchase, and use of environmental
technologies. Information and ETV documents are available at www.epa.gov/etv.
ETV works in partnership with recognized standards and testing organizations, with stakeholder groups
(consisting of buyers, vendor organizations, and permitters), and with individual technology developers. The
program evaluates the performance of innovative technologies by developing test plans that are responsive to
the needs of stakeholders, conducting field and laboratory tests (as appropriate), collecting and analyzing data,
and preparing peer-reviewed reports. All evaluations are conducted in accordance with rigorous quality
assurance (QA) protocols to ensure that data of known and adequate quality are generated and that the results
are defensible.
The Advanced Monitoring Systems (AMS) Center, one of six verification centers under ETV, is operated by
Battelle in cooperation with EPA's National Risk Management Research Laboratory. The AMS Center
evaluated the performance of a field portable ion chromatograph for determining the concentrations of water-
soluble gases and aerosol species in ambient air. This verification statement provides a summary of the test
results for the Applikon Analytical B.V. Monitor for Aerosols and Gases in Ambient Air ADI 2080 (MARGA).
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VERIFICATION TEST DESCRIPTION
This verification evaluated the ability of the MARGA to provide reliable quantitative measurements of soluble
gases and aerosol species in air, during continuous and largely unattended operation. The test was conducted over
a period of 30 days in the early fall of 2010 and involved continuous operation of duplicate MARGA units at an
existing ambient air monitoring site located on EPA's campus in Research Triangle Park, North Carolina. The
performance of the MARGA was determined partly through comparisons to modified EPA reference methods for
individual gaseous and particulate species. Modifications to the reference methods primarily involved increasing
the sampling flow rate to reduce sampling times and minimize measurement bias and uncertainties. Quantitative
comparisons of MARGA results to reference results were made for sulfur dioxide (SO2), nitric acid (HNO3), and
ammonia (NH3) and the aerosol components sulfate (SO42~), nitrate (NO3~), and ammonium (NH4+). Hourly
MARGA results for these species were averaged over the twice-daily 12-hour reference sampling periods and
compared to the results from duplicate filter/denuder reference sampling trains. Hourly MARGA SO2 results
were also compared to continuous pulsed fluorescence SO2 monitor data. MARGA results for aerosol sodium
(Na+), calcium (Ca2+), and chloride (Cl~) were also used in assessing the completeness of MARGA data.
MARGA performance was evaluated based on the quantitative performance goals set for EPA's Clean Air Status
and Trends Network (CASTNET) that were incorporated into the test/quality assurance (QA) plan for this
verification. The following are the parameters and CASTNET goals on which MARGA performance was
evaluated:
Accuracy - The measurement accuracy of each MARGA unit was evaluated based on the slope and intercept
of the linear regression of MARGA results against the mean of duplicate 12-hour reference results and on the
median absolute relative percent difference (MARPD) between the MARGA results and the mean of
duplicate reference measurement results. The CASTNET target goals are a regression slope between 0.80
and 1.2, an intercept within ±10 parts per billion by volume (ppbv) of zero, and MARPD < 40%.
Precision - The precision of the MARGA was determined by comparisons of paired data from the duplicate
MARGA units and by comparison of MARGA precision results to pooled results from the reference methods.
The CASTNET target goals are MARPD of paired hourly MARGA measurements < 25%, and an MARPD
of the paired MARGA data that was less than the 95th percentile of the pooled relative percent difference of
the reference method results.
Data Completeness - The MARGA data were evaluated for completeness based on the percentage of the
entire test period for which valid hourly data were available within 24 hours of collection and on the average
percentage of each reference measurement period that the MARGA unit provided valid data. The CASTNET
target goal is for both completion percentages to be > 80%.
Reliability - The reliability of the MARGA units was evaluated in terms of the percentage of the entire test
period that each unit was in measurement mode, with a target goal of > 90%. Reliability was also evaluated
by whether the MARGA could survive a power outage and return to routine operation within 4 hours and by
the average number of site visits per week required to keep the monitor operating (with a goal of < 2 visits per
week).
Operational Factors - Performance factors such as maintenance requirements, ease of use, and consumables
used/waste generated were assessed from observations by Battelle and EPA field testing staff.
QA oversight of verification testing was provided by Battelle and EPA. Battelle QA staff conducted a technical
systems audit of the field operations and the laboratory analysis of reference method samples and a data quality
audit of the test data. This verification statement, the full report on which it is based, and the test/QA plan for this
verification test are available at www.epa.gov/etv/centers/centerl.html.
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TECHNOLOGY DESCRIPTION
The following is a description of the Applikon MARGA
, based on information provided by the vendor: The
MARGA ADI 2080 is an on-line analyzer for semi -continuous measurement of gases and soluble ions in
aerosols. The MARGA utilizes a Wet Rotating Denuder
(WRD) to collect acid gases and ammonia by diffusion
into an aqueous film. Particles pass through the WRD and are collected in a Steam Jet Aerosol Collector
(SJAC). Within the SJAC, a supersaturated environment
is created which grows particles by a process known as
deliquescence, allowing them subsequently to be collected by inertial separation. As cooling takes place, steam
condenses and washes the collected particles into an aqueous sample stream. The aqueous
WRD and SJAC are subsequently analyzed by ion chromatography (1C) for soluble anions
solutions from the
and cations.
Software integrated within the MARGA calculates atmospheric concentrations based on air sample flow rate
and the ion concentrations in the collected solutions.
VERIFICATION RESULTS
Table VS-1 summarizes the results of the MARGA verification. A bolded entry in Table VS-1 indicates that the
CASTNET performance goal was met. Table VS-1 shows that the great majority of performance goals were met
by both MARGA units, with the regression slopes for J^NO3 and NO3", and the MARPD accuracy for NO3", being
the key exceptions.
Table VS-1. Summary of Verification Results for the MARGA ADI 2080
Parameter
Accuracy
Accuracy
Comparison
Regression analysis
comparison to
reference samples
Calculation of
MARPD between
MARGA results
and reference
method results
Results
Analyte
SO2
HNO3
NH3
SO42
NO3
NH4+
SO2a
MARGA 1 MARGA 2
Slope
1.16
0.780
0.930
1.02
2.48
1.02
0.962
Analyte
SO2
HNO3
NH3
SO42
NO3
NH4+
SO2a
Intercept
(ixg/m3) Slope
0.16 1.08
0.35 0.596
-0.14 0.987
0.30 0.986
-0.15 1.73
-0.23 0.993
0.50 0.890
Intercept
(HS/m3)
0.13
0.28
-0.08
0.22
-0.05
-0.25
0.44
MARPD
MARGA 1
31.2%
34.1%
33.1%
17.3%
86.9%
19.2%
19.8%
MARGA 2
18.9%
25.8%
18.2%
9.1%
58.7%
25.3%
14.1%
Comparison to continuous FEM analyzer (1 hr data), all other comparisons relative to 12-hr denuder/filter pack.
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Table VS-1. (Continued)
Parameter
Precision
Precision
Data
completeness
Reliability
Reliability
Reliability
Comparison
Comparison of results
from duplicate
monitoring systems
Comparison of
MARPD of 12-hour
average MARGA data
and 95th percentile of
pooled RPD results
from reference
measurements (RPD95)
Ratio of number of
hourly data points
successfully collected
to number of potential
hourly data points that
could have been
collected
Percentage of time in
operating mode
Time to start-up after
power interruption
Number of site visits
per week
Results
Analyte
Analyte
SO2
HNO3
NH3
SO42
NO3
NH4+
Analyte
SO2
HNO3
NH3
SO42
NO3
NH4+
Ref.
Method RPD95
20.5%
29.9%
40.7%
11.4%
59.9%
13.0%
% of Valid Data
MARGA 1
SO2 99.3%
HNO3 99.3%
NH3 99.3%
SO42 99.3%
NO3 99.3%
NH4+ 99.3%
Na+ 99.3%
Ca2+ 99.4%
Cl 99.3%
MARGA 1:
MARGA 1: <
MARGA 2
96.3%
96.3%
96.3%
96.1%
96.1%
96.3%
96.3%
96.3%
96.1%
1-Hour MARPD
10.4%
24.8%
22.4%
6.5%
27.3%
6.3%
MARGA 12-Hour
MARPD
8.7%
26.5%
18.8%
6.8%
23.9%
6.5%
Average % of Valid
Data per Reference
Sampling Period (e.g.,
per 12 hours)
MARGA MARGA
1 2
99.4% 96.3%
99.4% 96.5%
99.4% 96.3%
99.4% 96.1%
99.4% 96.1%
99.4% 96.3%
99.2% 96.5%
99.2% 96.8%
b b
99.4% MARGA 2: 96.8%
I hour MARGA 2: Not tested
MARGA 1: Approximately one
MARGA 2: Approximately one
b Not applicable; Cl" was never detected in both reference method samples for a given sampling period.
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Table VS-1. (Continued)
Parameter
Ease of use
Maintenance
Consumable s/waste
generated
Comparison
Operator observations
Operator observations
Operator observations
Results
Installation of two MARGA units completed in a few
days
Full operational readiness of two units required
extensive effort, including correction of apparent
bacterial contamination
Routine operations of the instrument were easy with
the only regularly scheduled tasks being solution
preparation and changing, and filter replacement
Routine maintenance consisted of preparing and
changing/refilling solutions and replacement of
particle filters
Non-routine maintenance included SJAC pump motor
replacement, and cleaning of sample inlets.
Cation and anion eluents, absorbing solution, supressor
regenerant, and internal standard periodically refilled
Internal filters replaced weekly
Approximately 31 liters of waste solutions generated
weekly by each MARGA unit
Signed by Tracy Stenner
9/28/2011
Signed by Sally Gutierrez
10/3/2011
Date
Tracy Stenner
Manager
Environmental Solutions Product Line
Energy, Environment, and Materials Sciences
Battelle
Date
Sally Gutierrez
Director
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
NOTICE: ETV verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. EPA and Battelle make no
expressed or implied warranties as to the performance of the technology and do not certify that a technology
will always operate as verified. The end user is solely responsible for complying with any and all applicable
federal, state, and local requirements. Mention of commercial product names does not imply endorsement.
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