SIZE-SELECTIVE SAMPLING OF PARTICULATE MATTER FOR OCCUPATIONAL HYGIENE

1
SIZE-SELECTIVE SAMPLING OF PARTICULATE MATTER
FOR OCCUPATIONAL HYGIENE

• Presented by SKC Inc.

2
AIRBORNE PARTICLES

• Include solid and liquid matter such as
• Dusts-solid particles that become airborne during
  crushing of rock-like material
• Fumes-microscopic particles generated during
  welding and other operations
• Mists-liquid droplets in air
• Smokes-particles generated from incomplete
  combustion or burning

3
CLARIFICATIONS

• The word dust is used in the occupational health
  and safety profession and throughout this
  training module as a general term for particulate
  matter and airborne particles. Do not be confused
  by the general use of this term.
• Asbestos and other fibers are also hazardous
  particulate matter found in the workplace.
  Fibers however will not be covered in this
  training module.

4
HEALTH EFFECTS OF AIRBORNE PARTICLES

• Are determined by three parameters
• Chemical Composition-What is the chemical makeup
  of the particulate matter?
• Mass Concentration-How much particulate matter is
  being inhaled by exposed persons?
• Size Characteristics-How big are the individual
  particles?

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PARTICLE SIZE A CRITICAL PARAMETER

• The size of the airborne
• particles will determine where
• they will deposit in the
• respiratory system. Smaller
• particles are more hazardous
• as they will deposit deep into
• the lower regions of the lung
• and can enter the bloodstream.

6
PARTICLE SIZE DETERMINES HEALTH EFFECTS

• Government
• regulations and
• exposure guidelines
• have been issued for
• some compounds based
• on their particle size.

• These size-selective
• exposure limits specify
• different allowable
• levels for smaller versus
• larger particles of the
• same material.

7
DEFINING AND MEASURING PARTICULATES IN THE
OCCUPATIONAL ENVIRONMENT

• TRADITIONAL APPROACH

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PARTICULATES IN THE WORKPLACE

• Have traditionally been defined as
• TOTAL DUST
• RESPIRABLE DUST

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TOTAL DUST

• Is collected by using a filter of a type and pore
  size as specified in the published sampling and
  analytical method for that compound.
• The filter is loaded into a cassette and
  connected to a sampling pump that has been
  calibrated to a flowrate of at least 1 L/min.
• Samples are collected in a fixed point location
  or in the breathing zone of workers.

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37-mm FILTER CASSETTE WITH FILTER
Outlet of Cassette
Support Pad
Filter
Inlet of Cassette
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TOTAL DUST SAMPLINGIN THE BREATHING ZONE
Reference NIOSH Method 0500
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RESPIRABLE DUST

• Is also collected onto a filter of a type and
  pore size that is specified in the sampling and
  analytical method for designed compounds.
• Preceding the filter, however, is a
  size-selective sampler such as a cyclone that
  will separate the respirable fraction from the
  non-respirable fraction when connected to a pump
  sampling at the designated flow rate for that
  specific device.

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RESPIRABLE DUST SAMPLINGWITH CYCLONES
Reference NIOSH Method 0600
14
CYCLONE OPERATION

• Function on the same
• principle as a centrifuge.
• When the air comes in
• through a small slit
• opening on the side,
• cyclonic action occurs
• within the stem of the
• sampler.

• Large (non-respirable)
• particles hit the side of the
• cyclone and fall into the
• cap (grit pot) at the
• bottom of the cyclone and
• are discarded. Smaller
• respirable particles are
• thrown upwards onto the
• filter and are analyzed.

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DEFINING AND MEASURING WORKPLACE PARTICULATES

• NEW CONCERNS, DEFINITIONS, AND SAMPLERS

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NEW CONCERN WITH TRADITIONAL FILTER CASSETTES

• US NIOSH and OSHA scientists have been addressing
  sample losses with traditional 37-mm filter
  cassettes.
• Of particular concern, are sample losses that
  occur from particles that adhere to the interior
  cassette walls and are not analyzed.

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OSHA STATEMENT HEXCHROME METHOD ID 215 VERSION
2

• Tests showed that Cr (VI) equivalent to 0 to
  123 of the amounts found on the PVC filter were
  present on the interior walls of cassettes used
  for compliance samples. It is now routine
  procedure to wipe interior walls of sampling
  cassettes for all metal samples analyzed.

Source United States. Occupational Safety and
Health Administration. Hexavalent Chromium. 30
Apr 2009 lthttp//www.osha.gov/dts/sltc/methods/ in
organic/id215_v2/id215_v2.htmlgt
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NIOSH STATEMENTIN AIHA JOURNAL ARTICLE

• 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.

Source Ashley, Kevin, Harper, Martin and
Demange, Martine. Concerning Sampler Wall
Deposits in the Chemical Analysis of Airborne
Metals. Journal of Occupational and
Environmental Hygiene 49 Sept 2007 D81 - D86
lthttp//dx.doi.org/10.1080/15459620701493149gt
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ACCU-CAP EMERGESTO ADDRESS CONCERNS

• Filter insert that is placed into a 2-piece
  cassette with support pad.
• Consists of a clear plastic dome heat-sealed to a
  filter.
• Dust is collected onto the filter or within the
  dome for gravimetric analysis.

SKC 225-8516GLA PVC Filter
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A NEW SOLU-CAP EMERGESIN 2013

• Designed for the measurement of metals using
  chemical analysis
• Acid digestible dome material heat sealed to
  mixed cellulose ester filter
• Pre-loaded into 2-piece cassettes with support
  pads (SKC 225- 8517)
• Eliminates the need to wipe the inside of the
  cassette for analysis
• Ensures all collected sample is analyzed

21
NEW SIZE FRACTIONS FOR PARTICULATES

• Many occupational hygiene agencies and
• standard setting bodies around the world have
• abandoned the 2 traditional size
• fractions of total and respirable dust
• and have instead defined 3 particulate size
• fractions.

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NEW SIZE FRACTIONS FOR PARTICULATES

• Note that U.S. OSHA and MSHA have not adopted
  these new size fractions for particulates. They
  still measure and regulate total and respirable
  fractions.
• ACGIH has adopted these new size fractions for
  their Threshold Limit Values (TLVs).

• Inhalable Particulate Matter
• Thoracic Particulate Matter
• Respirable Particulate Matter

23

• Illustration
• of the 3 new
• particulate fractions
• adopted by most
• occupational hygiene
• organizations and
• standard setting bodies
• around the world
• including
• ACGIH, ISO, and CEN.

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NOTES ABOUT CUT-POINT

• You will frequently see the
• term 50 or median
• cut-point used to
• describe the performance
• of size-selective samplers
• like cyclones. It is
• important to understand
• this term.

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NOTES ABOUT CUT-POINT

• Sampling devices are not 100 efficient in
  collecting all sizes of particles from
  microscopic fumes to large dusts.
• The particle size that the sampling device
  collects with a 50 efficiency is described as
  the 50 or median cut-point.

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CONSIDER A VACUUM CLEANER

• Vacuum cleaners do not pick up all sizes of
  particles with the same efficiency.
• A vacuum cleaner may be 100 efficient in
  collecting a small piece of dust 0 effective
  for a big stone.
• There is a size where the vacuum is 50
  efficient.

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NOTES ABOUT CUT-POINT

• A size-selective sampler will always have the 50
  
• cut-point specified for a designated flowrate.
• Particles smaller than the 50 cut-point will be
  collected with an efficiency greater than 50.
• Particles larger than the 50 cut-point will be
  collected with an efficiency less than 50.

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INHALABLE PARTICULATEA NEW PARTICULATE
SIZE-FRACTION

• The new term for total dust.
• Is defined as dust that is hazardous when
  deposited anywhere in the respiratory system
  including the nose and mouth.
• Is collected using a sampler designed and tested
  to capture this size of particulate matter.
• Inhalable samplers have a 50 cut-point of
• 100 um.

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IOM SAMPLER A GOLD STANDARD FOR INHALABLE DUST
SKC 225-70A
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USING THE IOM SAMPLER GRAVIMETRIC ANALYSIS

• Load a 25-mm filter into the cassette using
  forceps and wearing gloves.
• Equilibrate the filter/cassette assembly
  overnight under controlled conditions, then weigh
  them as a unit.
• Collect the sample at 2 L/min.
• Equilibrate and weigh again for sample analysis.
  

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THE IOM ADVANTAGE NO SAMPLE LOSS

• Since the filter and cassette are weighed
  together, all particles which are drawn in
  through the sampling inlet are part of the
  analysis.
• Any particulate dislodged from the filter due to
  accidental knocking, will be retained inside the
  cassette and weighed.

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USING THE IOM SAMPLER FOR CHEMICAL ANALYSIS

• For this application, the stainless steel
  cassette is frequently used.
• The stainless steel cassette is often preferred
  since the lab will use chemical solvents to rinse
  the cassette for analysis.

33
IOM SAMPLER FOAM DISCSFOR SIMULTANEOUS
INHALABLE AND RESPIRABLE SAMPLING

• Multi-Dust Foam Discs
• Developed by the UK Health and Safety Laboratory
• A foam plug (SKC 225-772) is inserted into the
  IOM cassette in front of the filter
• Larger particles are trapped in the foam plug
  smaller particles in the filter.
• Dust collected on filter only is the respirable
  fraction. Filter plus foam is inhalable
  fraction.

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IOM SAMPLERS FROM SKC

• Plastic Sampler with Plastic Cassette-
• SKC 225-70A
• Lightweight for gravimetric analysis.
• Plastic Sampler with Stainless Steel Cassette-SKC
  225-79A
• Suitable for chemical or gravimetric analysis.

35
IOM SAMPLERS FROM SKC

• Stainless Steel Sampler with Stainless Steel
  Cassette-
• SKC 225-76A
• Can be autoclaved for bioaerosol sampling.

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ALTERNATIVE INHALABLE SAMPLER

• Button Sampler
• Inlet has a screen to keep out large,
  non-inhalable particles.
• Uses higher flow rate which enhances sensitivity
  of measurement for compounds with low exposure
  limits.

SKC 225-360
37
USING THE BUTTON SAMPLER SAMPLE LOGISTICS

• Unscrew the sampler inlet and remove the O-ring.
• Place a 25-mm filter on the stainless steel
  support screen, replace the 0-ring and the
  sampler inlet.
• Collect the sample at a flowrate of 4 L/min.
• After sampling, remove and transport the filter
  only to the laboratory.

38
USING THE BUTTON SAMPLER SAMPLE LOGISTICS

• A filter with a pore size of 1.0 um or larger is
  recommended to keep pressure drop low.
• Otherwise, the pump may fault with any
  accumulation of sample on the filter due to
  excessive backpressure.

• Since there is no cassette with the Button
  Sampler, users will need to have a device to
  transport the filters with collected sample to
  the laboratory.
• Options include conductive filter transport cases
  (SKC 225-67).

39
TIPS ON CALIBRATION

• SKC offers calibration adapters that allow the
  IOM and Button Samplers to be directly attached
  to external flowmeters including the Defender
  primary flow calibrators.

• CALIBRATION ADAPTER
• for the IOM Sampler is SKC
• 391-01.
• CALIBRATION ADAPTER
• for the Button Sampler
• (shown here) is
• SKC 225-361.

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THORACIC PARTICULATE

• Defined as those materials that are hazardous
  when deposited anywhere within the lung airways
  and the gas-exchange region.
• Thoracic samplers have a 50 cut-point of
• 10 um.

Thoracic region includes bronchioles as well as
air sacs in the lower lung.
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THORACIC TLVsAS OF 2014

• Sulfuric acid-TLV
• of 0.2 mg/m3 as
• thoracic particulate.
• Cotton Dust-TLV
• of 0.1 mg/m3 as
• thoracic particulate.

42
THORACIC NIOSH METHOD

• Metalworking Fluids
• NIOSH Method 5524, Issue 1 specifies a 2-um
• PTFE filter in a 37-mm filter cassette with an
  optional thoracic particulate sampler.
• At the time the method was published, the only
  thoracic sampler available commercially was a
  cyclone from BGI Incorporated.

43
SKC THORACIC SAMPLERS

• Thoracic Parallel Particle Impactors (PPI)
• Designed to give a precise match to the thoracic
  criteria
• Used with any suitable 37-mm filter at 2 L/min
• SKC thoracic PPIs are not listed in the NIOSH
  method for metalworking fluids since the samplers
  were developed after the method was published.

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SKC THORACIC PPIs

• REUSABLE SAMPLER
• Made of anodized aluminum

• DISPOSABLE SAMPLER
• Made of conductive plastic

SKC 225-381
SKC 225-386
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PPI SCHEMATIC
Plate with four suitably sized inlet orifices
Plate with disposable, pre-oiled porous plastic
impaction substrates and outlet orifices
Main collection filter (37mm) and filter support
pad or screen
Outlet to pump
2 LPM
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COLLECTION EFFICIENCY CURVESOF THORACIC SAMPLERS
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DEFINITIONS OF RESPIRABLE PARTICULATES

• Throughout the history of occupational air
  sampling, several definitions of respirable
  particulate matter have been adopted by various
  organizations around the world.
• All definitions describe respirable particulate
  as that small enough to reach the gas-exchange
  region.
• Differences involve the 50 (median) cut-point of
  respirable dust samplers.

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DEFINITIONS OF RESPIRABLE DUST SAMPLERS

• The British Medical Research Council (BMRC)
  originally defined respirable dust samplers as
  having a 50 cut-point of 5 microns.
• In the US, OSHA/MSHA define respirable dust
  samplers as having a 50 cut-point of 3.5
  microns. OSHA is trying to change/update this
  definition in their 2013 Notice of Proposed
  Rulemaking on silica.

49
A CONSENSUS DEFINITION ON RESPIRABLE DUST SAMPLERS

• In an attempt, to reach a
• global consensus on the
• definition of respirable
• dust in the workplace,
• a compromise definition
• was developed for respirable
• dust samplers specifying a
• 50 cut-point of 4 microns.

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SKC CYCLONES AND FLOWRATESFOR 50 CUT-POINT OF 4
UM
SKC Aluminum Cyclone at 2.5 L/min SKC 225-01-01
25 mm SKC 225-01-02 37 mm
51
SKC CYCLONES AND FLOWRATESFOR 50 CUT-POINT OF 4
UM

• SKC GS-3 Cyclone
• at 2.75 L/min
• SKC 225-103 25 mm
• SKC 225-100 37 mm

52
SKC CYCLONES AND FLOWRATESFOR 50 CUT-POINT OF 4
UM

• SKC GS-1 Cyclone
• at 2.0 L/min

• SKC Plastic Cyclone
• at 2.2 L/min
• (From SKC Ltd. in UK)

SKC 225-105
SKC 225-69
53
A NEW RESPIRABLE DUST SAMPLER FROM SKC

• SKC has developed a new impaction based sampler
  for respirable dust called the Parallel Particle
  Impactor or PPI.
• The PPI was designed to improve performance
  characteristics evidenced with older traditional
  cyclones.

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SKC RESPIRABLE PPIFUNCTIONALITY

• The disposable models of the PPI look and
  function very much like a traditional 37-mm
  cassette.
• But the inlet comes pre-loaded with
  size-selective impactor plates that scrub out
  non-respirable dust.
• PPI samplers are smaller than traditional
  cyclones and can fit under a welders helmet or
  other PPE.

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SKC RESPIRABLE PPIFLOWRATES

• Single-use, disposable PPI models are available
  for use at either 2, 4, or 8 L/min.
• This provides flexibility in pump option and
  sample duration for various airborne
  concentrations.
• A calibration adapter (SKC 225-389) is also
  available for the disposable PPI.

2 L/min 225-385
8 L/min 225-384
4 L/min 225-387
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PPI SAMPLER PERFORMANCECOMPARED TO CRITERIA
57
SUB-MICRON RESPIRABLE DUST DIESEL PARTICULATE
MATTER (DPM)

• In a coal mine, workers may be exposed to both
  respirable coal dust and respirable DPM.
• Sampler was developed by NIOSH to separate these
  two contaminants based on particle size.
• DPM is less than 1.0 um in size
• Coal dust is greater than 1.0 um.

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SKC 225-317 DPM Cassette with cyclone
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DPM SAMPLER UTILIZES THREE STAGES

• Cyclone
• Removes non-respirable particles that may
  overload the filter
• Impactor inside the filter cassette
• Removes respirable particles greater than 1.0 um
  in diameter
• Heat-treated quartz filter
• Collects particles less than 1.0 um in diameter
  for analysis of total or elemental carbon by
  NIOSH Method 5040

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PORTABLE INSTRUMENT FOR MONITORING DUST EXPOSURES
SKC 770-4004
61
HAZ-DUST IV

• Real-Time Dust Monitor based on light scattering
  (aerosol photometer)
• Displays TWA, STEL, MIN, and MAX levels in mg/m3
• Internal pump to collect sample with filter
  cassette simultaneously
• Can add IOM sampler or GS cyclone to inlet for
  size-selection

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NOTE ON CALIBRATION OF HAZ-DUST IV

• Calibration Standard (SKC 770-140) is a metal
  adapter that causes a known value to appear on
  LCD.
• The instrument will have a k value assigned by
  the factory when it is new.
• The k value should not deviate more than 10
  during subsequent checks.

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NOTE ON CALIBRATION OF HAZ-DUST IV

• Haz-Dust monitors are factory calibrated using
  Arizona Road Dust (ARD).
• For higher accuracy, users can collect concurrent
  samples using filter cassettes, compare lab
  results to LCD readings, and generate a
  correction factor for their particular dust
  under study.

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THANK YOU FOR TAKING THE TIME TO COMPLETE THIS
TRAINING MODULE!

• If you have further technical questions, email
  SKC at skctech_at_skcinc.com.