Transcript Introduction to Model 1130/35 Automated Ambient Air Speciated Mercury Monitor F.H. Schaedlich

Introduction to Model 1130/35
Automated Ambient Air
Speciated Mercury Monitor
F.H. Schaedlich
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Rev: 1.11 November 3, 2003
Acknowledgements
 Matt Landis
US EPA 1
 Robert K. Stevens
Florida DEP 2a
 Tom Atkeson
Florida DEP 2b
 Eric Prestbo
Frontier Geosciences 3
 Steve Lindberg
Oak Ridge Nat’l Labs 4
 Gerald Keeler
University of Michigan 5
1
2a
2b
3
4
5
Research Triangle Park, NC 27711
At US EPA, Research Triangle Park, NC 27711
Tallahassee, FL
414 Pontius Ave. N., Suite B, Seattle, WA 98109
PO Box 2008, Oak Ridge, TN 37831-6038
School of Public Health, 109 Observatory Street, MI 48109.
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Part 1
Total Gaseous Mercury
Monitoring
Why measure parts per Quadrillion
of Mercury ?
 Mercury is one of the most potent neurotoxins
known
 Bio-accumulates up the food chain by factors of
up to 10,000,000 times

Sub-ppt levels in air can accumulate to toxic ppm
levels in fish
 Levels are increasing worldwide
 Long life in the atmosphere means that mercury
emissions are of global concern
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Total Gaseous Mercury Monitoring
 Originally implemented manually
 Gold coated silica field cartridges
 Analysis using dual stage thermal desorption
with CVAFS (atomic fluorescence) detection
 Gold preconcentration with AA (atomic
absorption) detection had been shown to
be subject to serious artifacts when
attempting to measure ambient levels
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Model 2537A Mercury Analyzer
 Automated implementation of gold/AF manual method

Instrument protected by US and international patents
 Has largely supplanted manual cartridge methods
 Provides continuous total gaseous (TGM) readings with
update rate as low as 2.5 minutes
 Detection limit < 0.1 ng/m3 (5 min. samples)
 Automatic recalibration with internal Hg0 permeation
source
 Capable of unattended operation for extended periods
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Model 2537A Analyzer
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Principles of Operation
 Mercury in sample gas is preconcentrated
onto (pat’d) pure gold cartridge
 Adsorbed mercury is thermally desorbed
 Detected by atomic fluorescence detector
 Two cartridges are used to alternately
sample and desorb
 No
gaps in data stream
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Flow Diagram of Model 2537A
Mercury Analyzer (Pat’d)
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Pure Gold Cartridge (Pat’d)
 Pure gold only is used as adsorbent
 No quartz wool or silica
 No memory effect
 Extremely durable design
 Lasts for years of continuous use
 Cartridge design is protected by separate
US and international patents
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Pure Gold Cartridge
Mercury Adsorption Cartridge
4
1
5
2
3
Quartz Glass 6 mm O.D. X 4 mm I.D.
Retention Groove
(first seal)
Orifice
(second seal)
NOTE: Cartridge Length 5 inches.
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Pure Gold Matrix
Assembly
Flow Direction
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Atomic Fluorescence
 Much more sensitive than atomic adsorption
 MDL < 0.1 pg absolute
 Not subject to interferences
 AA requires some sort of compensation/correction
scheme
 Interfering compounds (e.g. SO2, O3, organics) often
present in concentrations thousands of times higher
than Hg
 Inherently linear
 Detector linear over >5 orders of magnitude
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Tekran AF Detector Features
 Most sensitive, most stable and lowest
noise AF detector available
 Some reasons why:
 Temperature controlled lamp block
 Optical feedback loop for constant lamp
intensity
 Optical path purged with argon for stability

< 10 ml/min required for optical purge
 Magnetic
shield on photomultiplier tube
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Tekran AF Detector
PMT
BLOCK
Magnetic
Shield
Lamp Stabilizer
Circuit Board
Assembly
Photomultiplier
Tube
Gasket
UPPER
BLOCK
Optical Feedback
Sensor
Foam Insulation
Temperature Sensor
Interference
Filter
Cuvette
Heaters (x2)
Purge Gas Inlet
LAMP
BLOCK
Lamp
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LOWER
BLOCK
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Internal Permeation Source
 Allows automated, unattended calibrations
 Ensures that analyzer results are always accurate
 Allows standard additions to sample gas
 Ensures that analyzer is working properly even when
confronted with difficult matrices
 Long life permeation tube
 Low emission rate: Approx 30 µg/yr
 Theoretical life: thousands of years!
 Special auto-flush feature ensures no carryover
after activation
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Perm Source Flow Diagram
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Integrates into Monitoring Networks
 Designed to look and operate like other
continuous ambient air monitors
 Rack
mountable
 Easy to use interface
 Two analog chart outputs
 Serial output provides hi-resolution results and:
Instrument performance variables
 Full record of each calibration
 Record of instrument setup parameters

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Operational Characteristics
 Lamp lasts in excess of one year of
continuous operation
 Inexpensive,
multi-sourced
 Unlimited shelf life
 No special isotopes required
 No zero drift !
 Each reading is an integrated peak value
 Detector drift does not affect results
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Reporting Basis
 Reports data readings based on sample
volumes corrected to 0°C, 760 mm
 All
Hg concentrations in the literature are
reported on this volume basis
 No reading-by-reading temperature and
pressure corrections required to normalize
data
 Reporting at other conditions (e.g. 20 °C) is
possible simply by changing internal menu
setting
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True Ambient Measurement
 Tekran Model 2537A is the only analyzer
available that is capable of accurately and
precisely measuring true ambient mercury
values
 Can measure mercury in actual gas
matrices
 Virtually
any analyzer (even uncompensated
AA units) can give correct answers when
measuring mercury in zero air!
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Other Applications
 With appropriate accessories and front ends
the Tekran Model 2537A can perform:
 Process
gas monitoring
 Continuous emissions monitoring (CEM)
 Mercury flux measurement

Both chamber & gradient methods!
 Standard
additions
 Speciation: ionic (reactive gaseous) mercury
 Speciation: particulate bound mercury
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Sample Data: Chlor-Alkali Plant
 Plot of wind direction vs.
ambient mercury values
 Two months of continuous
monitoring
 Plant is located 18 miles
distant
 Fish consumption
advisories in effect


Concentrations
in ng/m3
Chlor-Alkali Plant
N
6
4
2
W
E
0
Fish levels were > 1.5 ppm
even though air readings were
only slightly elevated
Global background:~1.5 ng/m3
WIND
DIRECTION
Plot Duration: 60 days
Data Interval: 15 min
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located bearing 60º
distance 18 miles
S
vs.
MERCURY
22
Depletions of Mercury in the Arctic
The 2537A is capable
of extremely precise
measurement of even
sub-ambient readings.
In cases where two instruments are
running, they track each other very closely.
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Validation of Depletion Events
This line shows the % recovery of periodic automated
standard additions of elemental mercury to the sample
matrix. The recoveries are ~ 100%, yielding absolute
confidence that these unusual values represented a
genuine, hitherto unknown phenomenon.
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Part 2
Reactive Gaseous
Mercury Monitoring
Tekran’s Objectives
 Development of an automated method to
measure and differentiate different forms of
mercury in ambient air
 Reactive
Gaseous Mercury (RGM)
 Fine Fraction Particulate Mercury (HgP)
 Elemental mercury (Hg0)
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Why Ambient Air Mercury Speciation ?
 Different forms of gaseous Hg have vastly
different behaviors and environmental
impacts
 Forms can interconvert in the atmosphere
and in various reservoirs
 Classes of mercury in ambient air:
 Elemental mercury: Hg0, GEM
 Reactive mercury: HgII, RGM, Hg2+
 Particulate mercury: HgP, TPM
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Elemental Mercury: Hg0
 Typically 90+% of atmospheric Hg
loadings
 Relatively inert. Long residence time
 Hg0 sources impact large areas
 Sources: chlor-alkali plants, gold and Hg
mining, thermal power plants
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Reactive Mercury: Hg(II) or RGM
 Consists of ionic, water soluble forms,
primarily HgCl2
 Usually only a few percent of total gaseous
mercury present in the atmosphere
 Short range: deposits relatively close to the
source of emission
 Primary sources: Coal burning power plants,
waste incinerators, chlor-alkali plants
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Difficulties Measuring RGM
 Method must be 1-2 orders of magnitude
more sensitive than total mercury methods
 Reject much larger elemental component
 Must exclude particulate bound mercury,
however, conventional particulate filters
cannot pass RGM
 Apparatus must pass RGM to the collector
quantitatively. (RGM is extremely “sticky”)
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Model 1130 - Principles of Operation
 Patented by Tekran. (US 6,475,802)
 Quartz, KCl coated annular denuder is
thermally desorbed and regenerated
 Sampling Phase
 Absorbs
RGM while passing all elemental Hg
 Model 2537A reads Hg0 during this phase
 Desorption/Analysis Phase
 Zero air used as carrier
 RGM released as elemental mercury
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RGM Sampling Phase
 Denuder is slightly warm
1 lpm
9 lpm
Sample
Pump
 Inlet slightly warm
 Denuder captures all
MERCURY VAPOUR ANALYZER 2537A
Optional
Model 1135
Particulate Unit
Denuder
Heater
RGM while passing Hg0
Annular
Denuder
Warm
50 ºC
 Total sample flow is 10
lpm
 Analyzer measures Hg0
during this time
Inlet
Heater
Zero
Air
off
Ambient Air
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Sampling Phase
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Analysis Phase
 Denuder is heated to 500C
 Inlet heated to clean up-
1 lpm
off
Sample
Pump
MERCURY VAPOUR ANALYZER 2537A
stream glassware. (75 C)
 Denuder releases captured
RGM as
Denuder
Heater
Annular
Denuder
Hg0
Heated
500 ºC
 Excess zero air flow and
heat cleans upstream
components
 Instrument measures
accumulated RGM as Hg0
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Inlet
Heater
Zero
Air
6 lpm
Excess
Zero Air
Desorption Phase
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Quartz Denuder Assembly
Elbow
Zero Air
Sample Air
Inlet
Inlet
(not used with 1135)
Annulus
Coupler
Coupler
Elutriator Jet
Impactor
Body & Disk
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Model 1130 Speciation System
 Denuder Module (top)
 Located out of doors
 Contains denuder element
within high performance
oven
 Impactor inlet removes
coarse particles (> 2.5 um)
 Climate controlled
enclosure
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Model 1130 Speciation System
 Pump Module (bottom)
 Located beside 2537A
 Provides extra flow
required during sampling
 Generates the zero air
required during desorption
 Also provides all zero air
required by Model 2537A!
 Heated line (not shown)

25 ft. length connects the two
modules
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Instrument Characteristics
 Fully automated, unattended operation
 Denuder exchanged every 1 or 2 weeks
 Operates in any environment
 Polar (Greenland, USA, Canada, Antarctica)
 Sub-tropical (Florida Everglades)
 Desert (Nevada)
 Marine (ocean cruises)
 High altitude (Mauna Loa)
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Data Characteristics
 High time resolution Hg0 data provided during
sampling phase
Typically every 2½ or 5 min
 Data is averaged to yield one Hg0 point per sampling
period

 Single RGM integrated value every sample
period
Sample period:
 Analysis Period:

0.5 – 3
25 – 60
hours
min
 Data values are for the exact same time period
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Method Validation
 Method was developed over a two year period at
Tekran before being announced
 Tested using both HgCl2 and HgI2 as surrogates
for RGM
 Two prototype units bought by State of Florida
 Units evaluated by Frontier Geosciences in Seattle
under contract with Florida DEP
 Subsequent field testing by Keeler et al,
University of Michigan & Lindberg et al., ORNL
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Lab RGM Apparatus - (1997)
Denuder
Model
2537A
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Coffee Can
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Preliminary Results - Toronto
RGM Comparison: SN:001, SN:002
60
Indoor Air
y = 1.0595x - 0.5374
R2 = 0.9959
50
RGM SN:001 (y)
RGM SN:002 (x)
30
RGM (pg/m3)
40
Denuder
Clean
Operation
20
Outdoor Air
(Sampling through long inlet manifold)
Successive
Desorption
(Blank Test)
10
0
May-23 12:00
May-24 00:00
May-24 12:00
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May-25 00:00
1998
May-25 12:00
May-26 00:00
May-26 12:00
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Preliminary Results - Toronto
Elemental Mercury: SN:001 & SN:002
18
16
14
Indoor Air
Two curves have been shifted
horizontally for visibility
3
Hg (ng/m )
12
Hg0 SN:001
Hg0 SN:002
0
10
8
Outdoor Air
6
4
2
0
May-23 12:00
May-24 00:00
May-24 12:00
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May-25 00:00
Date
May-25 12:00
May-26 00:00
May-26 12:00
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Lab Testing: Frontier Geosciences
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AmbientRGM
Air Hg(0) and
RGM in Downtown Seattle
Seattle
Data
10
350
Municipal
Incinerator
Plume
250
6
200
150
4
100
RGM (pg/m3)
300
3
Hg (0) (ng/m )
8
2
50
12:30
00:30
12:30
00:30
12:30
00:30
12:30
00:30
12:30
00:30
12:30
00:30
12:30
00:30
12:30
00:30
12:30
00:30
0
12:30
0
August 22-31, 1998
Hg(0) Tek-043
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RGM Tek-043
Courtesy: Frontier Geosciences
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Mercury Levels - Rural Michigan
35
2.0
Hg(II)
Hg(0)
30
1.8
1.6
1.4
Dew
20
1.2
Rain
1.0
15
0.8
0.6
10
Hg(0) (ng/m 3) .
RGM (pg/m 3) .
25
0.4
5
0.2
27-Aug-98
28-Aug-98
18:40
16:40
14:40
12:40
10:40
08:40
06:40
04:40
02:40
23:10
21:10
19:10
17:10
15:10
13:10
11:10
09:10
07:10
05:10
03:10
01:10
23:10
0.0
21:10
0
29-Aug-98
Time of Day (EDT)
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Courtesy: UMAQL
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Part 3
Particulate Mercury
Monitoring
Why Measure HgP ?
 Particulate bound mercury (TPM / HgP) is
created directly by some industrial
processes and also formed downwind of
sources by the combination of mercury
with existing particulates
 HgP is removed even more rapidly via wet
and dry deposition than is RGM
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Particulate Mercury: TPM
 Consists of various compounds of mercury
bound onto particles
 Size range: Generally thought to be < 3 um
 Usually only a few percent of total mercury
present in the atmosphere
 Short range: deposits relatively close to the
source of emission
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Difficulties Measuring HgP
 Method must be 1-2 orders of magnitude more
sensitive than total mercury methods
 Must reject much larger elemental component
 Method must also exclude reactive gaseous
mercury, however, normal particulate filters have
problems in that they retain some RGM
Virtually all conventional measurement methods have
recently been found to have serious analytical artifacts
due to RGM (Landis, et al, ES&T, 2002)
 Artifact is non-quantitative and cannot be subtracted
or corrected

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Model 1135 - Principles of Operation
 Sampling Phase
 Sample passes through impactor to eliminate coarse
particles (> 2.5 um)
 Coated denuder captures RGM and eliminates RGM
artifact
 Quartz, Regenerable Particulate Filter (RPF) captures
fine fraction (< 2.5 um) particulates
 Desorption/Analysis Phase
 Zero air used as carrier
 Downstream pyrolyser is activated first
 RPF is then heated to desorb captured particulates
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RPF
Tail
Quartz Wool
 Quartz wool captures bulk of
particulate matter
 Quartz filter membrane
Pyrolyzer
(quartz chips)
provides sharp cut-off (<0.1
um)
 Built in pyrolyzer section
converts desorbed species to
Hg0
Air Gap
 Carbon based particulate
matter on the filter is oxidized
to CO2 during desorption cycle
Quartz membrane filter disk
Quartz Wool
 Tail provides cooling
Inlet
(from denuder)
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Model 1135 – Particulate Mercury Monitor
 Unit stacks on top of Model
1130
 Allows simultaneous deter-
mination of Hg0, RGM and
HgP
 Detection limit < 2 pg/m3
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Fan
Pyrolyzer
Oven
Exhaust
Particulate
Filter
Model 1135
Fan
PARTICULATE
MODULE
Sample
Line
Quartz
Wool
600
Model 1130
& Model 1135
Flow Path
Teflon Union (90º)
Tail
600
40
Quartz
Chips
Fan
Case
Exhaust
Frit
Filter
Wool
Oven
Cooling Fan
Dimples
Control
Cable
Case
Heater
Control
Connector
GL14-GL18 Union
NC
C
V1 NO
Fan
Case
Exhaust
500
Restrictor
(100
ml/min)
Particulate
Filter
Packs
(Shown in Sampling Mode)
Model 1130
Model 1130
PUMP MODULE
RGM
MODULE
Denuder
Module
Control
cable
Control Cable
Zero
Scrubber
50
Zero
Scrubber
(1st stage)
75
Zero Air (to Denuder Module)
40
ZERO
AIR
SAMPLE
FILTER
Oven
Exhaust
Zero
Out
Air
Inlet
V2
Sample NO
In
NC
C
HEATED LINE
Case
Heater
Vent
Buffer
Tank
Sample
Pump
MFM
Back
Pressure
Regulator
(1-5 PSI)
MFM-1
Sodalime
Trap
Oven
Cooling Fan
(Heated)
Heater &
Temperature
Sensor
Leads
Interchangeable inlets: Impactor for ambient air or
'Tee' piece for manifold
Rev 2.40
INLET
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CONTROLLER
Control & Status
Signals
Sample
Inlet
Zero Filter
(provided
with 2537A)
Zero
Inlet
MODEL 2537A
ANALYZER
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man_pics\1135flow.dsf
Ambient Air Speciation
Model 1130 - Reactive Gaseous Mercury (RGM)
Model 1135 - Total Particulate Mercury (TPM)
Model 2537A - Elemental Mercury (Hg00)
Model
Model 1130
1130 &
& Model
Model 1135
1135
Mercury Species: Hg°, TPM & RGM
St.Anicet (Quebec)
Elemental Mercury - Hg°
.
Total Particulate Mercury - TPM
Reactive Gaseous Mercury - RGM
400
300
200
1.0
RGM &TPM - pg/m³
Elemental Mercury - ng/m³
.
2.0
100
0.0
Jan-26
0
Jan-27
Jan-28
Jan-29
Jan-30
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Jan-31
Feb-01
Feb-02
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Sample Installations
Figure 1 - Temporary
Model 1130/35
Installation (AES,
Quebec Canada)
Figure 2 - Permanent
Arctic Model 1130
Installation (NOAA,
Barrow Alaska)
Figure 3 - Model 1130-P
(prototype) Mounted on
roof of trailer
(US EPA, NERL)
Figure 4 - Temporary Model
1130-P Installation (US EPA
& Florida DEP)
Figure 5 - Model 1130-P
sampling in Antarctica
(GKSS & AWI, Germany)
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Conclusion
 Measurement of mercury species at
ambient levels is now practical
 Equipment has shown its utility and
reliability in a wide variety of sampling
situations around the world
 Some additional commitment in resources
is required to implement a successful
speciated mercury monitoring program
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