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INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by
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INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

Mar 31, 2015

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Page 1: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE PARTICULATE MASS

HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS

Presented by

Page 2: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

PLEASE NOTE

The word dust will frequently be used as a generic descriptor in lieu of aerosol or particulate mass. Don’t be confused by this.

References are provided on some of the slides. Complete reference articles are available upon request for most citations.

Page 3: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

TOTAL DUST: HISTORY OF THE TERM

Except in cases where diseases are caused by fine respirable dust, it has been common practice to sample “so-called” total dust.

This is in general recognition that all inhaled particles could present either a specific or non-specific risk to health. (Mark and Vincent, 1986.)

Total dust, however, was never defined by a specific size range and a 50% cut-point (D50) was never established for total dust samplers.

Page 4: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

THE FIRST DUST SAMPLERS:U.S.

The initial work on dust sampling was done by the U.S. Bureau of Mines.

In the 1920s, impingers were used to collect dust which was reported as TOTAL NUMBER OF PARTICLES i.e. millions of particles per cubic feet of air.

Since impingers are cumbersome, health and safety professionals in the U.S. replaced them with 37-mm filter cassettes over time. (Harper, 1997)

Page 5: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DUST SAMPLERS: GLOBAL

Not all countries have standardized a 37-mm filter cassettes for total dust sampling.

Given the vague definition of total dust, a number of personal samplers with various performance characteristics have been used for sampling total dust around the world.

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TOTAL DUST SAMPLERS:UNITED KINGDOM

Single Hole Lead Head for MDHS 6

Seven Hole Head for MDHS 14

SKC Cat. No. 225-52 SKC Cat. No. 225-50

Page 7: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

SURPRISING STATISTICS:SAMPLER PERFORMANCE

There is very limited data available on how well these samplers actually measure the true dust exposure.

Studies show considerable differences in results from these various samplers when sampling the very same dust under the identical environmental conditions.

≠≠

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SURPRISING STATISTICS:LIMITATIONS OF 37-MM CASSETTES

37-mm Filter Cassettes: Were never designed to represent a “physiologically

relevant exposure” to the respiratory system Aspiration efficiency is not very similar to the nose and

mouth Are not 100% efficient in collecting all sizes of dust

particles Have a upper size limit (approx. 20-30 µm) where

efficiency falls to zero

(T. Renee Anthony, AIHce 2011)

Page 9: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

SURPRISING STATISTICS:ERRORS WITH 37-MM CASSETTES

Sampling errors with 37-mm cassettes can

be evidenced from:

Ambient wind velocity effects Orientation effects Dust deposition on walls of cassette

Page 10: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

SO WHY DO WE USE THEM?

In the U.S., we have been using 37-mm

cassettes because: “Reductions in exposures as measured with these

have been associated with reductions in health effects”

Cheap and Easy Used by compliance officers History

Years of data on file

Page 11: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

SEARCHING FOR A BETTER WAY NEW CRITERIA FOR DUST SAMPLING

Beginning in the

1980s, occupational

hygiene experts from

around the world

began to investigate a

better way to

evaluate particulates in

the workplace.

First, was the need for

exposure limits (standards/guidelines) that reflect closely the nature of human exposure.

Secondly, was the need for samplers that collect the “physiologically relevant” size fraction of interest.

Page 12: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

WHY CHANGE?

Measuring dust concentrations with the same efficiency through which we inhale them makes better sense when evaluating the health-related dose.

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SEARCHING FOR A BETTER WAY NEW CRITERIA FOR STANDARDS

Committees from ISO, CEN, and ACGIH have come to an agreement on new criteria.

Many occupational hygiene bodies around the world have now adopted this criteria.

Health-related sampling should be based on the following particle size-selective fractions: Inhalable, Thoracic, and Respirable.

Page 14: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

NEW CRITERIA:DESCRIPTIONS

Inhalable-the fraction that enters the nose and/or mouth

during breathing (D50 of sampler= 100 µm)

Thoracic-the sub-fraction of inhalable that penetrates into the respiratory tract below the larynx

(D50 of sampler= 10 µm)

Respirable-the sub-fraction of inhalable that penetrates

to the alveolar region of the lung. (D50 of sampler= 4 µm)

(AIHA Aerosol Committee Publication)

Page 15: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

NEW CRITERIA:ILLUSTRATION

•Inhalable

•Thoracic

•Respirable

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ACGIH:ADOPTED NEW CRITERIA

In 1993, revisions to the Appendix “Particle Size-Selective Sampling Criteria for Airborne Particulate Matter” were made by ACGIH.

At this time, ACGIH adopted and defined inhalable, thoracic, and respirable particulate mass fractions.

See page 74 of the 2011 TLV handbook

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NIOSH:STATUS OF NEW CRITERIA

NIOSH has NOT formally adopted the new criteria in total. Inhalable-NIOSH Method 5700 for

formaldehyde on dust is the only method. Thoracic-NIOSH Method 5524 for

metalworking fluids is the only method. Respirable-NIOSH Methods for respirable dust

now specify a cyclone with a D50 of 4 µm with several options listed. See Definition on upper left of NIOSH Method 0600

Page 18: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

OSHA:STATUS OF NEW CRITERIA

OSHA has not officially adopted the new criteria

as it requires Congressional action like with PEL

updates.

OSHA Statement on the IOM Sampler: SKC has a letter on file from OSHA stating that the IOM Inhalable Sampler may be used for measuring compliance with the standard for particulates not otherwise regulated (PNOR).

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INHALABLE PARTICULATE MASS: DEFINED

Includes materials that are hazardous when deposited anywhere in the respiratory tract

Includes particulate matter that enter the head airways region including the nose and mouth

Also includes materials that can produce systemic toxicity from deposition anywhere in the respiratory system

Page 20: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABILITY CRITERION:FURTHER COMMENTS

The current criterion for inhalable dust is not perfect, but represents the best approach based on decades of research.

A known flaw: The current inhalability criterion underestimates human intake in calm air and low velocity environments.

(Volckens, AIHCE 2011)

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DUST SAMPLERSTO MEET THE NEW CRITERIA

After the creation of new criteria for standards researchers began to develop new samplers to meet the new criteria.

These new sampling devices were designed to collect a biologically relevant fraction of dust found in the workplace.

Page 22: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

THE IDEAL INHALABLE SAMPLER

An inhalable sampler is considered ideal “when a personal sampler mounted on the body gives the same measured dust concentration and aerodynamic size distribution as that inspired by its wearer, regardless of dust source location and wind conditions.” (Mark and Vincent, 1986)

(Note: Inhalable dust was originally called inspirable dust).

Inhalable samplers have a D50 of 100 microns.

Page 23: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

37-MM FILTER CASSETTES

Do not effectively sample the inhalable fraction Significantly underestimate the concentration

of larger dust particles from

20-100 µm Of particular concern are sample losses that

occur from particles that adhere to the interior cassette walls

Page 24: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

JOEH ARTICLE BY NIOSH

NIOSH Researchers report: Dust deposits on the walls of filter cassettes were 19%

of the total sample for lead and 25% of the total sample for copper.

Filter cassettes should be rinsed AND WIPED prior to analysis.

Results of wiped 37-mm filter cassettes are a closer match to results from inhalable samplers.

(Ashley, Harper, Demange, 2007)

Page 25: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE SAMPLERS:DESIGNED FOR THE NEW CRITERIA

The first personal sampler specifically designed for inhalable particulate mass was developed by Mark and Vincent in 1986 at the Institute of Occupational Medicine in Scotland.

The sampler was named the IOM Sampler and SKC Ltd. in the UK was the sole licensee and exclusive manufacturer of this sampler for more than 20 years.

The patent has now expired, but SKC is still the only company that can call this device the IOM Sampler.

Page 26: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

IOM SAMPLERA GOLD STANDARD

Exploded View

SKC Cat. No. 225-70A

Page 27: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

USING THE IOM SAMPLERGRAVIMETRIC ANALYSIS

Load a 25-mm filter into the cassette using forceps and wearing gloves.

Do not desiccate the filter/cassette. Equilibrate the filter/cassette assembly

overnight under controlled humidity conditions then weigh as a unit.

Allow the assembly to stabilize a few minutes before taking a reading.

Page 28: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

USING THE IOM SAMPLER GRAVIMETRIC ANALYSIS

Place the IOM cassette/filter assembly into the sampler body, screw on the cover cap, and connect to the pump.

Calibrate the flow rate to 2 L/min using the IOM calibration adapter or by placing in a calibration jar.

Following sample collection, weigh the cassette/filter assembly again.

Referenced in HSE Method MDHS 14/3

Page 29: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE PLUS RESPIRABLE WITH GRAVIMETRIC ANALYSIS

Aerosol physicists at the UK Health & Safety Laboratory have published on the use of polyurethane foam discs (SKC Cat. No. 225-772) inserted into the front of the IOM cassette for size-selective sampling. (Kenny, Chung, et. al., 2001)

The foam scrubs out large inhalable particles. Dust on Filter = Respirable Fraction Dust on Filter + Foam = Inhalable Fraction

Page 30: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

USING THE IOM SAMPLERWITH OTHER TYPES OF ANALYSES

The IOM Sampler is also available with a stainless steel cassette.

(SKC Cat. No. 225-79A)

This cassette is typically used for chemical (elemental) analysis where a solvent rinse is done inside the cassette.

A stainless steel IOM body along with a stainless steel cassette is available for those using the sampler for bioaerosol sampling.

(SKC Cat. No. 225-76A)

This model allows for autoclaving.

Page 31: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

ADVANTAGES OF THE IOM

Developed specifically to match the inhalable definition.

Best fit with the inhalable curve under many circumstances.

Internal wall deposits are included in the sample analysis.

Can be combined with a foam insert to collect the respirable fraction simultaneously.

Page 32: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DISADVANTAGES OF THE IOM

Tends to oversample in low wind speed and when large particles are present.

Large inlet allows sampling of large projectiles Blasting operations

Higher limit of quantitation due to weighing of cassette.

Designed as a personal sampler only Not designed for area sampling

(Volckens, AIHCE 2011)

Page 33: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

WEIGHING ACCURACY OF IOM SAMPLES

CONCERNS March/April 1999

AIHA Journal article discussed problems of water absorption by plastic IOM cassette and resulting instability of the weight.

RESPONSE The type of plastic material

was changed to address water adsorption.

Do not allow cassette to desiccate.

Only equilibrate under controlled humidity conditions.

Consider stainless steel cassettes if necessary.

Page 34: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

OTHER INHALABLE SAMPLERS:FROM SKC

Button Sampler Developed by University

of Cincinnati Inlet has a stainless

steel inlet screen with numerous, evenlyspaced holes

Screen keeps out large, non-inhalable projectilesfrom impacting or splashing onto the filter

SKC Cat. No. 225-360

Page 35: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

USING THE BUTTON SAMPLERSAMPLE LOGISTICS

Unscrew the sampler inlet and remove the Teflon® O-ring.

Place a 25-mm filter on the stainless steel support screen Replace the O-ring and the sampler inlet.

Calibrate the Button Sampler to a flow rate of

4 L/min using the calibration adapter or by placing in a calibration jar.

Page 36: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

USING THE BUTTON SAMPLERSAMPLE LOGISTICS

A filter pore size of 1.0 µm or higher is recommended due to the back pressure limitations of most personal samplers.

After sampling, remove the filter for analysis. Use a conductive plastic filter transport case

(SKC Cat. No. 225-67) or Filter-Keeper (SKC Cat.

No. 225-8301) for shipment to the lab.

Page 37: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

ADVANTAGES OF BUTTON SAMPLER

Good precision and fit with the inhalable curve

Inlet screen keeps out large particles Low sensitivity to wind velocity and

direction Uniform collection on the filter Flow rate of 4 L/min for personal

sampling increases sensitivity Can be used for personal or area

sampling

Page 38: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DISADVANTAGES OF BUTTON SAMPLER

Inlet holes can become clogged (i.e. flour dust)

Liquid aerosols not collected as efficiently as solid aerosols

Dust deposited on sampler walls and O-ring are not included in sample analysis.

Page 39: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

OTHER INHALABLE SAMPLERS:FROM SKC IN UK

7-HOLE SAMPLING HEAD Traditional European method using a 25-mm filter and

cassette with an end cap and 7 equispaced inlet holes

with flows of 2.0 L/min. Listed in HSE MDHS Method 14, but not widely

studied.

7-HOLE HEAD

Page 40: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE SAMPLERS:FROM OTHER SUPPLIERS

Conical Inhalable Sampler (CIS) Also known as the GSP Sampler. This German sampler aspirates particles through the inlet at 3.5 L/min onto a37-mm filter. Limited commercial availability.

CIS SAMPLER

Page 41: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE SAMPLERS:FROM OTHER SUPPLIERS

CIP-10A French sampler with 2 key components:

1. Impactor/foam pre-separator to retain large particles

2. A rotating cup with a PUF ring that collects thesample for gravimetric analysis

CIP-10 SAMPLER

Page 42: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE SAMPLING OF BERYLLIUM: REUSE ISSUES

SKC recently

consulted with NIOSH

for advice on

decontamination and

reuse of inhalable

samplers used

to sample beryllium.

NIOSH does not clean/reuse samplers used for Be due to safety and cross-contamination concerns.

They recommend using 37-mm cassettes and wiping the walls to account for wall losses. The results will be comparable to those using inhalable samplers.

Page 43: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONSIDERATIONS2011 INHALABLE TLVs

Acrylamide Alachlor Aldrin Asphalt Fume Azinphos-methyl Benomyl Beryllium Borate cpds,

Inorganic Butylated

hydroxytoluene

Calcium sulfate Caprolactam Captan Carbaryl Carbofuran Carbon Black Chlorpyrifos Citral Coumaphos Cresol, all isomers

Page 44: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONSIDERATIONS2011 INHALABLE TLVs

Demeton (and Demeton- S-methyl)

Diazinon Dibutyl phosphate 2,2-Dichloropropionic

acid Dichlorvos (DDVP) Dicrotophos Dieldrin Diesel fuel Diethanolmine Dioxathion

Diquat Disulfoton Endosultan EPN Ethion 2-Ethylhexanoic acid Fenamiphos Fensulfothion Fenthion Ferbam Flour dust Fonofos Glyoxal

Page 45: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONSIDERATIONS2011 INHALABLE TLVs

Iodine and iodides Isobutyl nitrite Magnesium oxide Malathion Maleic anhydride Methyl demeton Methyl parathion Mevinphos Mineral oil, excluding

metalworking fluids

Molybdenum (metal and insoluble compounds)

Monochloroacetic acid Monocrotophos Naled Natural rubber latex as

total proteins Nickel, elemental,

soluble and insoluble compounds

Page 46: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONSIDERATIONS2011 INHALABLE TLVs

Nickel Subsulfide 5-Nitro-o-toluidine p,p-Oxybis(benzene

sulfonyl hydrazide) Parathion Particulates Not

Otherwise Specified (now a guideline; not a TLV)

Phorate m-Phthalodinitrile Ronnel

Silicon carbide, nonfibrous

Sulfotepp (TEDP) Sulprofos Synthetic Vitreous

Fibers (continuous filament)

Temephos Terbufos 1,1,2,2-

Tetrabromomethane

Page 47: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONSIDERATIONS2011 INHALABLE TLVs

Tetrethyl pyrophosphate (TEPP)

Thallium 4,4-Thiobis(6-tert-butyl-

m-cresol) Thiram Trichlorphon

Trimellitic anhydride Vanadium pentoxide Wood dusts Xylidine (mixed isomers)

Page 48: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

INHALABLE TLVs2011 INTENDED CHANGES

Diethylene glycol monobutyl ether

Manganese, elemental and inorganic compounds

o-Phthalodinitrile Piperazine and salts Toluene 2,4- or 2,6-

diisocyanate

For TLVs with IFV notation

(Inhalable fraction and

vapor)

There is no single sampler that can be used.

Requires (2) separate samples: one for each contaminant phase.

Page 49: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONSIDERATIONSTOTAL VS INHALABLE

KEY REFERENCES Journal article-Werner, et al. (1996) “Investigation into

the impact of introducing workplace aerosol standards based on the inhalable fraction”. Analyst 121:1207-1214.

AIHCE 2011 Session-T. Renee Anthony. “How to Relate Total and Inhalable Dust Exposures”. From the science symposium titled Inhalable Particles: The State of the Science on a Big Particle Problem. (An electronic copy of this is available upon request.)

Page 50: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONVERSIONTOTAL VS INHALABLE

Inhalable particulate mass is typically greater than so-called total particulate mass.

How much greater will depend upon the SIZE of the particles.

With larger particles, inhalable particulate mass will be much greater than total particulate mass.

With smaller particles, inhalable and total particulate mass will be comparable.

Page 51: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONVERSIONTOTAL VS INHALABLE

Type of Particulate Ratio of Results IOM/37-mm cassette

Dust from powder handling, grinding 2.5

Mist from paint spray or oil mist 2.0

Fumes from welding 1.0

*Werner, et al. (1996)

Page 52: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONVERSIONTOTAL VS INHALABLE

Dr. Anthony’s AIHCE 2011 session makes the point that it is really not enough to use a simple conversion factor as given on the previous slide.

Ratio of results can also vary with particle size distribution.

“Using a standard correction factor without knowing your aerosol distribution may under- or over-estimate inhalable-converted exposure levels.”

Page 53: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

DATA CONVERSIONTOTAL VS INHALABLE

So what do you do? Collect both 37-mm

cassette and inhalable samples and determine process-specific ratios for YOUR unique operation.

Page 54: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

SIDE-BY-SIDE SAMPLING:37-MM VS INHALABLE SAMPLERS

Will bridge your past data using total dust filter cassettes to inhalable samplers.

Will provide backup data for any compliance related issues.

Page 55: INHALABLE PARTICULATE MASS HISTORY, CURRENT TECHNOLOGY, AND DATA CONSIDERATIONS Presented by.

THANKS FOR YOUR ATTENTION.

PLEASE EMAIL SKC WITH ANY QUESTIONS ON SAMPLING.

[email protected]