114/23/20094/23/2009

BAMBAM--10201020Beta Attenuation Mass MonitorBeta Attenuation Mass Monitor

PM PM 2.52.5 FEM ConfigurationFEM ConfigurationThe New Evolution of BAM TechnologyThe New Evolution of BAM Technology

Dennis HartDennis HartMet One Instruments, Inc.Met One Instruments, Inc.

Rev C July 2008Rev C July 2008

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Overview Overview –– The Big PictureThe Big Picture

•• The success of any BAMThe success of any BAM--1020 monitoring program 1020 monitoring program is directly proportional to how well the site operators is directly proportional to how well the site operators and program administrators understand how and why and program administrators understand how and why the unit works.the unit works.

•• Basic knowledge of how and why (not just how) the Basic knowledge of how and why (not just how) the various setups, checks, and calibrations are performed various setups, checks, and calibrations are performed always leads to better end results. always leads to better end results.

•• Met One is making a strong effort to provide this Met One is making a strong effort to provide this information through improved documentation, field information through improved documentation, field training, and expanded technical service.training, and expanded technical service.

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Overview Overview –– Topics of DiscussionTopics of Discussion

•• Brief History of the BAMBrief History of the BAM--1020 PM2.5 Configuration1020 PM2.5 Configuration•• What is the FEM PM2.5 Configuration?What is the FEM PM2.5 Configuration?•• Basic Theory of OperationBasic Theory of Operation•• Three Basic Systems: Flow, Measurement, and DataThree Basic Systems: Flow, Measurement, and Data•• Critical Checks and MaintenanceCritical Checks and Maintenance•• Measurement ChallengesMeasurement Challenges

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Brief History of the PM2.5 FEM ConfigurationBrief History of the PM2.5 FEM Configuration•• 1930s 1930s -- Beta attenuation measurement technology first Beta attenuation measurement technology first

developed for industrial processes and paper manufacturing.developed for industrial processes and paper manufacturing.•• 1970s 1970s -- Beta attenuation technology adapted to measure Beta attenuation technology adapted to measure

airborne particulate levels.airborne particulate levels.•• 1990s 1990s –– The Met One BAMThe Met One BAM--1020 was developed with reduced 1020 was developed with reduced

size and advanced microprocessor control. EPA PM10 FEM size and advanced microprocessor control. EPA PM10 FEM approval obtained in 1998.approval obtained in 1998.

•• 2002 2002 –– The Met One EThe Met One E--BAM was developed as a sister product BAM was developed as a sister product for rapid deployment and emergency response with variable for rapid deployment and emergency response with variable data intervals.data intervals.

•• 2006 2006 –– The FEM PM2.5 BAMThe FEM PM2.5 BAM--1020 Configuration was 1020 Configuration was developed and FEM testing began.developed and FEM testing began.

•• 2007 2007 –– PM2.5 FEM Candidate Configuration released for sale.PM2.5 FEM Candidate Configuration released for sale.•• March, 2008 March, 2008 -- EPA PM2.5 FEM designation obtained for the EPA PM2.5 FEM designation obtained for the

BAMBAM--1020.1020.

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What is the PM2.5 FEM Configuration?What is the PM2.5 FEM Configuration?

•• The classic BAMThe classic BAM--1020 had appropriate accuracy and 1020 had appropriate accuracy and sensitivity for measuring PM10 levels, and was also often used sensitivity for measuring PM10 levels, and was also often used for PM2.5 monitoring with the addition of a standard SCC for PM2.5 monitoring with the addition of a standard SCC cyclone or WINS cyclone or WINS impactorimpactor, even without equivalency., even without equivalency.

•• Field results from these early PM2.5 systems showed that the Field results from these early PM2.5 systems showed that the BAM needed slight detection limit and YBAM needed slight detection limit and Y--intercept (offset) intercept (offset) improvements for accurate measurements below about 15 improvements for accurate measurements below about 15 micrograms. The slopes were typically quite adequate. micrograms. The slopes were typically quite adequate.

•• PM2.5 levels by nature are much more difficult to measure due PM2.5 levels by nature are much more difficult to measure due to low concentrations and greater volatile content. Small to low concentrations and greater volatile content. Small measurement errors may cause large proportional errors.measurement errors may cause large proportional errors.

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What is the PM2.5 FEM configuration?What is the PM2.5 FEM configuration?•• The transport assembly was redesigned for filter tape The transport assembly was redesigned for filter tape

positioning accuracy of about 1/1000 of an inch.positioning accuracy of about 1/1000 of an inch.•• The beta source gap geometry was reduced 25%, resulting in The beta source gap geometry was reduced 25%, resulting in

higher signalhigher signal--toto--noise levels and reduced air density effects.noise levels and reduced air density effects.•• The beta count time was increased from 4 to 8 minutes, The beta count time was increased from 4 to 8 minutes,

improving the statistical noise stability by about 40%. Known improving the statistical noise stability by about 40%. Known as the as the ““2X2X”” effect.effect.

•• The firmware was extensively revised to provide flow The firmware was extensively revised to provide flow statistics, new settings, and improved field calibrations.statistics, new settings, and improved field calibrations.

•• The field zero background test was implemented to fineThe field zero background test was implemented to fine--tune tune the slope offset characteristics in the field.the slope offset characteristics in the field.

•• The BXThe BX--596 Temp/596 Temp/BaroBaro combination sensor was designed.combination sensor was designed.

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What is the PM2.5 FEM configuration?What is the PM2.5 FEM configuration?•• The combined effect of these improvements resulted in the The combined effect of these improvements resulted in the

typical detection limit (2typical detection limit (2σσ) of the unit improving from about ) of the unit improving from about 6ug to about 3ug for hourly measurements, and below 1ug for 6ug to about 3ug for hourly measurements, and below 1ug for 24 hour averages.24 hour averages.

•• Met One began PM2.5 FEM testing immediately upon release Met One began PM2.5 FEM testing immediately upon release of the final U.S. EPA specifications for candidate monitors.of the final U.S. EPA specifications for candidate monitors.

•• The units had to meet stringent requirements for both FRM The units had to meet stringent requirements for both FRM correlation and intercorrelation and inter--unit comparison during both winter and unit comparison during both winter and summer seasons at multiple sites around the country.summer seasons at multiple sites around the country.

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Factory Calibration ExampleFactory Calibration Example

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Data Example 1 Data Example 1 –– PM10 and PM2.5 LevelsPM10 and PM2.5 Levels

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Data Example 2 Data Example 2 –– PM10 and PM2.5 LevelsPM10 and PM2.5 Levels

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Data Example 3 Data Example 3 –– PM2.5 Slope / OffsetPM2.5 Slope / Offset

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Data Example 4 Data Example 4 –– PM10 Slope / OffsetPM10 Slope / Offset

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Typical older unimproved unit comparison to Typical older unimproved unit comparison to FRM for PM2.5, showing YFRM for PM2.5, showing Y--intercept offsetintercept offset

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What is the PM2.5 FEM configuration?What is the PM2.5 FEM configuration?•• Met One filed the official FEM PM2.5 application Met One filed the official FEM PM2.5 application

with the EPA in late summer 2007.with the EPA in late summer 2007.•• EPA review of the application took several months.EPA review of the application took several months.•• The BAMThe BAM--1020 was the first instrument to 1020 was the first instrument to

successfully complete PM2.5 FEM candidate testing, successfully complete PM2.5 FEM candidate testing, and is the first (and currently only) instrument to and is the first (and currently only) instrument to obtain EPA FEM status for PM2.5.obtain EPA FEM status for PM2.5.

•• All BAMAll BAM--1020 units built after March 2007 are FEM 1020 units built after March 2007 are FEM compatible when equipped with the appropriate compatible when equipped with the appropriate settings and accessories.settings and accessories.

•• The new BAMThe new BAM--1020 configuration maintains it1020 configuration maintains it’’s s longstanding FEM status for PM10 monitoring.longstanding FEM status for PM10 monitoring.

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What is the PM2.5 FEM configuration?What is the PM2.5 FEM configuration?•• The unit must use the EPAThe unit must use the EPA--mandated VSCCmandated VSCC--AA™™ cyclone from cyclone from

BGI Inc., and the standard EPA PM10 inlet.BGI Inc., and the standard EPA PM10 inlet.•• The unit must be equipped with revision 3.2.4 or later firmware,The unit must be equipped with revision 3.2.4 or later firmware,

and must be operated per the revision F or later manual.and must be operated per the revision F or later manual.•• The unit must use the BXThe unit must use the BX--596 AT/BP sensor.596 AT/BP sensor.•• The unit must be operated with 8 minute counts and 42 minute The unit must be operated with 8 minute counts and 42 minute

samples on standard glass fiber filter tape.samples on standard glass fiber filter tape.•• The unit must use the inlet Smart Heater, with an RH control setThe unit must use the inlet Smart Heater, with an RH control set--

point of 35%.point of 35%.•• The unit must be set for Actual volumetric flow control.The unit must be set for Actual volumetric flow control.•• The BKGD value must be audited in the field with the BXThe BKGD value must be audited in the field with the BX--302 zero 302 zero

filter kit upon deployment.filter kit upon deployment.

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What is the PM2.5 FEM configuration?What is the PM2.5 FEM configuration?

•• Many older units can be upgraded to the latest hardware and Many older units can be upgraded to the latest hardware and the FEM PM2.5 version. The upgrade involves a complete the FEM PM2.5 version. The upgrade involves a complete rebuild and calibration of the unit at the factory.rebuild and calibration of the unit at the factory.

•• Units built before March, 2007 will need mechanical upgrades Units built before March, 2007 will need mechanical upgrades to the hardware before they can be configured for PM2.5. All to the hardware before they can be configured for PM2.5. All BAMBAM--1020 units built after this have the latest hardware parts.1020 units built after this have the latest hardware parts.

•• Most units built after 2003 (serial prefix C) are upgradeable. Most units built after 2003 (serial prefix C) are upgradeable. Met One does not recommend upgrades for older units.Met One does not recommend upgrades for older units.

•• Contact the Sales Dept for the current price of upgrades.Contact the Sales Dept for the current price of upgrades.•• Met One now offers substantial discounts for tradeMet One now offers substantial discounts for trade--ins of old ins of old

units. This also results in much faster turn around time than anunits. This also results in much faster turn around time than anupgrade of an old unit.upgrade of an old unit.

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Theory of OperationTheory of Operation•• At the beginning of the hour, a small At the beginning of the hour, a small

Carbon 14 element emits a constant Carbon 14 element emits a constant source of beta rays through a clean spot source of beta rays through a clean spot of filter tape to determine a zero reading.of filter tape to determine a zero reading.

•• The unit advances this spot to the sample The unit advances this spot to the sample nozzle where air containing particulate is nozzle where air containing particulate is sampled and deposited on the filter tape.sampled and deposited on the filter tape.

•• At the end of the hour, the dirty spot is At the end of the hour, the dirty spot is placed back at the source where is it replaced back at the source where is it re--measured with beta rays.measured with beta rays.

•• The difference between the two The difference between the two measurements is proportional to the mass measurements is proportional to the mass concentration. concentration.

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Mass CalculationMass Calculation

0

0

1 ln

xI I e

IxI

AxCV

μ

μ

−=

⎛ ⎞= − ⎜ ⎟

⎝ ⎠

=

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Mass CalculationMass Calculation

•• DEFINITIONS:DEFINITIONS:–– II00–– beta measurement across clean filterbeta measurement across clean filter–– I I –– beta ray measurement across dirty filterbeta ray measurement across dirty filter–– μμ –– calibration coefficient calibration coefficient –– x x –– mass density on filter tape (mg/cmmass density on filter tape (mg/cm22) ) –– A A –– dust spot deposition area on filter tape (cmdust spot deposition area on filter tape (cm2 2 ))–– V V –– sampled volume (msampled volume (m33))–– C C –– particulate matter concentration (mg/mparticulate matter concentration (mg/m33))

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General Beta Gauge AdvantagesGeneral Beta Gauge Advantages•• Seasonal and geographical correction factors are not Seasonal and geographical correction factors are not

needed.needed.•• It is not necessary to ever calibrate the beta It is not necessary to ever calibrate the beta

measurement system in the field.measurement system in the field.•• BAMs are calibrated to provide excellent agreement BAMs are calibrated to provide excellent agreement

with FRM gravimetric standards when properly with FRM gravimetric standards when properly maintained and operated.maintained and operated.

•• Beta technology is virtually unaffected by the Beta technology is virtually unaffected by the chemical composition of the sampled particulate.chemical composition of the sampled particulate.

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Beta Gauge SafetyBeta Gauge Safety•• The BAMThe BAM--1020 contains a small amount of 1020 contains a small amount of 1414C C

(Carbon 14), a naturally occurring radioactive isotope (Carbon 14), a naturally occurring radioactive isotope of carbon, in the form of barium carbonate.of carbon, in the form of barium carbonate.

•• Activity level of the 60 Activity level of the 60 µµCi Ci 1414C source is similar to C source is similar to several commercial smoke detectors, and is licensed several commercial smoke detectors, and is licensed with the NRC under the same provisions.with the NRC under the same provisions.

•• Sources with activity under 100 Sources with activity under 100 µµCi require no Ci require no special government licensing to own.special government licensing to own.

•• Met One Instruments has an Met One Instruments has an ““Exempt Distribution Exempt Distribution LicenseLicense”” from the USfrom the US--NRC to distribute the beta NRC to distribute the beta sources.sources.

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Beta Gauge SafetyBeta Gauge Safety•• Users are not required to take any specific Users are not required to take any specific

precautions when handling the BAMprecautions when handling the BAM--1020 unit.1020 unit.•• USA customers do not require any licenses to own a USA customers do not require any licenses to own a

Met One beta gauge.Met One beta gauge.•• The end user will never need to remove, replace, or The end user will never need to remove, replace, or

handle the beta source.handle the beta source.•• The unit may be returned to the factory for disposal at The unit may be returned to the factory for disposal at

the end if its service life, although this is not required.the end if its service life, although this is not required.

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BAMBAM--1020 Tape Transport1020 Tape Transport

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Simplicity Simplicity –– Flow SystemFlow System

•• The BAMThe BAM--1020 airflow 1020 airflow system consists of a few system consists of a few simple components:simple components:–– Inlet/NozzleInlet/Nozzle–– Filter Temp/RH/BP sensorsFilter Temp/RH/BP sensors–– Debris filterDebris filter–– Honeywell mass flow sensorHoneywell mass flow sensor–– Flow controllerFlow controller–– Pump (external)Pump (external)

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Simplicity Simplicity –– Measurement SystemMeasurement System

•• The BAMThe BAM--1020 measurement 1020 measurement system consists of a few system consists of a few components:components:–– Carbon 14 Beta sourceCarbon 14 Beta source–– Filter tape control systemFilter tape control system–– Photomultiplier detectorPhotomultiplier detector–– Preamp circuitryPreamp circuitry–– Automatic hourly span checkAutomatic hourly span check

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Simplicity Simplicity –– Data SystemData System

•• The BAMThe BAM--1020 data system consists of the CPU, 1020 data system consists of the CPU, data reports, user interface, error handling system, data reports, user interface, error handling system, and telemetry.and telemetry.

•• All units are equipped with a six channel external All units are equipped with a six channel external data logger for external sensors.data logger for external sensors.

•• The BAMThe BAM--1020 may also function as a sensor in a 1020 may also function as a sensor in a larger data collection system using an external larger data collection system using an external datalogger.datalogger.

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Critical ChecksCritical Checks•• Leak Check, Flow Check, Nozzle Cleaning!Leak Check, Flow Check, Nozzle Cleaning!•• The flow system should be calibrated or verified on a The flow system should be calibrated or verified on a

regular basis. Flow errors affect the concentration.regular basis. Flow errors affect the concentration.•• A leak check is performed with every flow check. A leak check is performed with every flow check.

Leaks cause measurement errors, and the unit cannot Leaks cause measurement errors, and the unit cannot automatically detect a leak.automatically detect a leak.

•• The nozzle and support vane must be cleaned to The nozzle and support vane must be cleaned to prevent leaks and tape damage.prevent leaks and tape damage.

•• The nozzle and vane may need to be cleaned more The nozzle and vane may need to be cleaned more frequently in humid environments.frequently in humid environments.

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Critical ChecksCritical Checks

•• The nozzle seal against The nozzle seal against the filter tape is the filter tape is important for proper important for proper airflow regulation.airflow regulation.

•• The nozzle and support The nozzle and support vane need to be cleaned vane need to be cleaned at least as often as the at least as often as the filter tape is changed.filter tape is changed.

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BAMBAM--1020 Span Check1020 Span Check•• The BAMThe BAM--1020 makes an automatic span check 1020 makes an automatic span check

each hour by measuring a Mylar calibration foil each hour by measuring a Mylar calibration foil with a constant and known mass density.with a constant and known mass density.

•• No calibration changes are made based on the No calibration changes are made based on the span check however.span check however.

•• If the span check falls outside of an acceptance If the span check falls outside of an acceptance band, an error is generated.band, an error is generated.

•• The span check may be manually audited.The span check may be manually audited.

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Measurement ChallengesMeasurement Challenges

•• Environmental conditions can play a role in Environmental conditions can play a role in the accuracy of beta attenuation measurements. the accuracy of beta attenuation measurements. The main factors are:The main factors are:–– Enclosure internal air temperature stability.Enclosure internal air temperature stability.–– Relative humidity and sample moisture.Relative humidity and sample moisture.–– Electromagnetic and radio interference sources.Electromagnetic and radio interference sources.

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Measurement ChallengesMeasurement Challenges

•• Enclosure Temperature Stability:Enclosure Temperature Stability:–– The BAMThe BAM--1020 should be in a stable temperature 1020 should be in a stable temperature

environment, to the extent possible.environment, to the extent possible.–– The exact temperature is not critical as long as it is The exact temperature is not critical as long as it is

fairly stable during the hour.fairly stable during the hour.–– Changes in air density between the source and Changes in air density between the source and

detector may be measured as mass noise.detector may be measured as mass noise.

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Measurement ChallengesMeasurement Challenges

•• Humidity:Humidity:–– The filter tape is semiThe filter tape is semi--hydrophobic, but particulate hydrophobic, but particulate

on the tape is not.on the tape is not.–– Moisture accumulation on the sample spot may be Moisture accumulation on the sample spot may be

measured as mass noise.measured as mass noise.–– BAMBAM--1020 uses smart heater technology to lower 1020 uses smart heater technology to lower

the RH of incoming air to about 35%.the RH of incoming air to about 35%.–– Mild heat and hourly spot changes limit the effects Mild heat and hourly spot changes limit the effects

on VOCs.on VOCs.–– Humid conditions can increase nozzle fouling.Humid conditions can increase nozzle fouling.

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Electromagnetic InterferenceElectromagnetic Interference

•• Sources of high RF energy may cause noise in the Sources of high RF energy may cause noise in the BAMBAM--1020 if in close proximity. Examples: Radio 1020 if in close proximity. Examples: Radio towers or cell antennas in very close proximity.towers or cell antennas in very close proximity.

•• Sources of high EMI fields may cause noise in the Sources of high EMI fields may cause noise in the system. Examples: Large AC motors, Medical imaging system. Examples: Large AC motors, Medical imaging equipment.equipment.

•• Static electricity (ESD) may cause measurement errors.Static electricity (ESD) may cause measurement errors.•• Lightning strike on the inlet will damage the unit.Lightning strike on the inlet will damage the unit.•• Solutions: Proper site selection and grounding.Solutions: Proper site selection and grounding.

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ConclusionConclusion•• Met One Instruments, Inc. is constantly testing and Met One Instruments, Inc. is constantly testing and

experimenting to improve the beta gauge product experimenting to improve the beta gauge product lines and documentation.lines and documentation.

•• We welcome suggestions for future improvements.We welcome suggestions for future improvements.

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Supplemental MaterialsSupplemental Materials

•• BAMBAM--1020 Manual: Completely reorganized and 1020 Manual: Completely reorganized and rewritten for more value to the operator and rewritten for more value to the operator and administrator. Available in electronic format for administrator. Available in electronic format for SOPs. Current Revision G. SOPs. Current Revision G.

•• BAMBAM--1020 data sheet and specifications: Dependable 1020 data sheet and specifications: Dependable and defensible. and defensible.

•• www.metone.comwww.metone.com BAM users area:BAM users area:Login: metone Password: oregon Login: metone Password: oregon

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ContactsContacts•• Sales:Sales: David David GobeliGobeli, Ph.D., Ph.D.

Jo Ann Jo Ann PottbergPottbergPeter Peter PomponiPomponi

•• Science:Science: Herbert Herbert SchloesserSchloesser, Ph.D., Ph.D.•• Engineering:Engineering: Dennis HartDennis Hart•• Service:Service: Mike Putnam, Service Mgr.Mike Putnam, Service Mgr.

•• Phone: Phone: (541) 471(541) 471--71117111