PARTICULATE MATTER

SAMPLING OPTIONS FOR THE EH&S PROFESSIONAL

SIZE-SELECTIVE SAMPLING IN THE WORKPLACE

TRADITIONAL

USA

CRITERIA

FOR SIZE-SELECTIVE SAMPLING

• Total • Respirable CRITERIA NOT USED GLOBALLY!

“

TOTAL

” PARTICULATE

• • A misnomer Only includes particulates that can be collected by a 37-mm filter cassette.

WANTED: A BETTER SAMPLER

• Since we are interested in health effects, researchers sought to design a personal sampler that would be based “on a biologically relevant definition of total dust, that is, one which represents the total of what the worker takes in through the nose and/or mouth during the act of breathing”. (Ann. Occup. Hyg. Vol. 30, 1986.)

A MOVE TOWARD STANDARDIZATION • • • • ACGIH ASTM ISO CEN

TLV CHANGE

• • In 1993 , revisions to Appendix D of the ACGIH TLV booklet, “Particle Size-Selective Sampling Criteria for Airborne Particulate Matter” were adopted by ACGIH. Three particulate mass fractions were now defined.

PARTICULATE FRACTIONS

NEW INTERNATIONAL CRITERIA •Inhalable •Thoracic •Respirable

INHALABLE PARTICULATE MASS DEFINED

• • • Those 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.

INHALABLE SAMPLERS

• Meet the inhalability criterion when a personal sampler mounted on the body gives the same measured dust concentration and aerodynamic size distribution as that inhaled by its wearer, regardless of dust source location and wind conditions. • Defined as having a 50% cut-point of 100 microns.

TRADITIONAL FILTER CASSETTES

• • • Do not effectively sample inhalable particulate matter They significantly underestimate the concentration of larger dust particles from 30-100 um. The inlets do not effectively capture the larger particles, particles adhere to the cassette walls and sample loss can occur when removing the filters.

INHALABLE SAMPLERS

A personal sampler for inhalable particulate was first developed by Mark and Vincent in 1986 at the Institute of Occupational Medicine and was named the IOM sampler.

IOM SAMPLER

A GOLD STANDARD Exploded View Cat. No. 225-70A

USING THE IOM SAMPLER

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

Equilibrate the filter/cassette assembly overnight under controlled humidity conditions then weigh them as a unit.

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

USING THE IOM SAMPLER

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

Calibrate the flowrate to 2 L/min using the IOM calibration adapter or by placing in a calibration chamber. Following sample collection, weigh the cassette/filter assembly again or do a chemical analysis with the S.S. cassette.

ADVANTAGES OF THE IOM

• • Since the filter and cassette are weighed together, all particles which enter 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.

ADVANTAGES OF THE IOM

• • The collection efficiency gives an acceptable match to the inhalability definition when worn on the lapel as a personal sampler.

The performance is relatively independent of wind speed for particles with aerodynamic diameter up to and including 75 um.

AN ALTERNATIVE INHALABLE SAMPLER • •

Button Sampler

Inlet has a screen with numerous, evenly spaced holes Holes act as orifices and provide multidirectional sampling capabilities Cat. No. 225-360

USING THE BUTTON SAMPLER SAMPLE LOGISTICS • • • Unscrew the sampler inlet and remove the Teflon ® O-ring.

Place a 25-mm filter on the stainless steel support screen, replace the 0-ring and the sampler inlet. Calibrate the Button Sampler to a flowrate of 4 L/min using the calibration adapter or by placing in a calibration chamber.

USING THE BUTTON SAMPLER SAMPLE LOGISTICS • • • A filter pore size of 1.0 um or higher is recommended due to the backpressure limitations of most personal samplers. After sampling, remove the filter for analysis. Use a conductive plastic filter transport or equivalent for shipment to the lab. case

ADVANTAGES OF BUTTON SAMPLER • • • • • Closed-face inlet keeps out large particles 25-mm filter directly behind inlet avoids transmission losses in sampler Uniform distribution of holes minimizes sensitivity to wind velocity and direction Flow rate of 4 L/min for personal sampling increases sensitivity Can be used for personal or area sampling

OTHER INHALABLE SAMPLERS

• 7-HOLE SAMPLING HEAD Traditional European method using a 25-mm filter and cassette with an end cap with 7 equispaced inlet holes with flows of 2.0 L/min. 7-HOLE (DEAD) HEAD ??

OTHER INHALABLE SAMPLERS

• Conical Inhalable Sampler (CIS) Also known as the GSP Sampler. This German sampler aspirates particles through the inlet at 3.5 L/min onto a 37-mm filter. Optional foam plugs collect multiple size fractions. CIS SAMPLER

OTHER INHALABLE SAMPLERS

• Respicon Particles are aspirated through the inlet at 3.1

L/min and then separated into the 3 fractions: inhalable; thoracic; respirable. RESPICON ™

OTHER INHALABLE SAMPLERS

• CIP-10 A French sampler with 2 key components: -Impactor/foam pre-separator to retain large particles -A rotating cup with a PUF ring that collects the sample for gravimetric analysis CIP-10 SAMPLER

OSHA COMPLIANCE??

• If a compound has a PEL as

total

all your samples are collected as “red flags will be raised with the compliance officer”. dust and

inhalable

, • • Be prepared to provide evidence that your results gave equivalent or “safer” results than the OSHA reference method. Evidence includes side by-side studies or compound-specific industry research.

DATA CONVERSION??

INHALABLE TO TOTAL • • • Inhalable particulate is typically greater than total particulate mass.

Aerosol Classification and Conversion Factor -Dust 2.5

-Mist -Foundries 2.0

1.5

-Welding -Smokes/fumes 1.0

1.0

Published by Werner et. al. in the

Analyst

, 121:1207.

INHALABLE TLVs

2006 ADOPTED VALUES • • • • • • • • • • Acrylamide Asphalt Fume Azinphos-methyl Borate cpds, Inorganic Butylated hydroxytoluene Calcium sulfate Caprolactam Captan Carbofuran Chlorpyrifos • • • • • • • • • Coumaphos Demeton (and Demeton S-methyl) Diazinon 2,2-Dichloropropionic acid Dichlorvos (DDVP) Dicrotophos Dioxathion Diquat Disulfoton

INHALABLE TLVs

• • • • • • • • • • • 2006 ADOPTED VALUES EPN Ethion 2-Ethylhexanoic acid Fenamiphos Fensulfothion Fenthion Flour Dust Fonofos Glyoxal Hexahydrophthalic anhydride Isobutyl nitrite • • • • • • • • • Magnesium oxide Malathion Mevinphos Molybdenum (Metal and insoluble cpds.) Monocrotophos Naled Natural rubber latex as total proteins Nickel, Elemental, Soluble and Insoluble Cpds. Nickel Subsulfide

INHALABLE TLVs

• • • • • • • 2006 ADOPTED VALUES p,p-Oxybis(benzene sulfonyl hydrazide) Parathion Particulates Not Otherwise Specified (now a guideline; not a TLV) Phorate Ronnel Silica, Amorphous (Diatomaeous earth) Silicon carbide, nonfibrous • • • • • • • • Sulfotepp (TEDP) Synthetic Vitreous Fibers (Continuous filament) Temephos Terbufos 1,12,2-Tetrabromoethane Trichlorphon Wood Dusts Xylidine (mixed isomers)

INHALABLE TLVs

2006 INTENDED CHANGES • • • • • • • Alachlor Aldrin Beryllium Carbaryl Copper, Elemental/Metal and Copper oxides, as Cu Methyl demeton Mineral Oil used in metal working • • • • • • • 5-Nitro-o-toluidine Portland cement Sulprofos Tetraethyl pyrophosphate (TEPP) Thiram Toluene 2,4- or 2,6 diisocyanate Vanadium Pentoxide

FIRST THORACIC TLV

• Sulfuric acid TLV of 0.2 mg/m3 as thoracic particulate matter.

FIRST THORACIC NIOSH METHOD THORACIC CYCLONE • 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.

NEW THORACIC SAMPLER Parallel Particle Impactor • • • (PPI) Designed to give a precise match to the thoracic definition Has 4 internal impactors in one sampler Used with any suitable 37 mm filter at 2 L/min Cat. No. 225-381

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

SAMPLER COMPARISONS TO THORACIC CONVENTION

100 75 50 25 PPI 10



m, 2.0 Lpm GK2.69 Cyclone, 1.6 Lpm Thoracic Convention 0 0 5 10 15 20 Aerodynamic Particle Diameter, d a ,



m 25

RESPIRABLE DUST

• Conflict and confusion in the USA • NIOSH ≠ OSHA 50% cut-point of respirable samplers

CYCLONE CONFUSION

Spinning with centrifugal force • • • Cut-point?

Cyclone?

Flow Rate?

RESPIRABLE DEFINITION: GLOBAL • • In 1952, the British Medical Research Council (BMRC) adopted a definition of respirable dust as that fraction reaching the alveolar region of the lung.

• The BMRC defined respirable dust samplers as having a 50% cut-point of 5 microns .

In 1959, the BMRC definition was adopted by the Johannesburgh Conference on Pneumoconiosis.

RESPIRABLE DEFINITION:

USA • In 1968, the American Conference of Governmental Industrial Hygienists (ACGIH) defined respirable dust samplers as having a 50% cut-point of 3.5 um.

• Definition was later adopted into OSHA and MSHA standards and is still used today.

RESPIRABLE DEFINITION:

INTERNATIONAL In the early 1990’s , a new international definition was developed to achieve worldwide consensus. Respirable samplers were defined as having a 50% cut-point of 4 microns .

NIOSH RESPIRABLE DUST METHODS

•

Nylon

at 1.7 L/min •

Higgins-Dewell

at 2.2 L/min

CYCLONES LISTED IN CURRENT NIOSH METHODS •

Aluminum

at 2.5 L/min • • Each cyclone has different operating specifications and performance criteria. Be sure you know the flow rate specified to achieve the desired cut-point before using a cyclone. Cat. No. 225-01-02

COMPARISON OF NIOSH AND OSHA DEFINITIONS

Cyclones with a 4 cut-point will theoretically collect MORE dust than those with a 3.5 micron cut-point.

US OSHA NOTE

• OSHA inspectors must use the only cyclone currently specified in the Federal Register--. the Dorr-Oliver 10-mm nylon cyclone operated at 1.7 L/min. • Otherwise, use your professional judgment.

DIESEL PARTICULATE MATTER (DPM)

ISSUES FOR EXPOSURE ASSESSMENTS

DIESEL: HEALTH EFFECTS

• • •

NIOSH in 1988

recommended whole diesel exhaust be regarded as a potential occupational carcinogen

IARC in 1989

-declared that diesel engine exhaust is probably carcinogenic to humans

EPA in 2002 -

released a Health Assessment Document and is still actively studying the public health effects

DIESEL: OELs

ACGIH •

ACGIH in 1995

added DPM to list of intended changes with a recommended TLV-TWA of 0.15 mg/m 3; In 2001, listed as 20 ug/m 3 measured as elemental carbon.

AS OF 2004 –TLV WITHDRAWN FOR FURTHER STUDY

DIESEL: OELs

OSHA • • OSHA currently evaluates the components of diesel such as CO, CO 2 , SO 2 and formaldehyde.

They do not have a standard for DPM.

DIESEL: OELs

SUMMARY • See a summary of diesel standards from OSHA, EPA, MSHA along with OSHA directives, interpretations and compliance letters on-line @ www.osha.gov/SLTC/dieselexhaust/standards.html

EC-THE PREFERRED OPTION FOR SAMPLING AND ANALYSIS • • • • Diesel exhaust is a “complex mixture of an elemental carbon core surrounded by condensed hydrocarbon gases”. EC acts as a carrier of suspected mutagens and carcinogens.

EC analysis is more specific and sensitive than gravimetric.

EC is easily detectable by thermal-optical methods.

AIHA JOURNAL ARTICLE

MAY/JUNE 2003 • • EC is the most sensitive and specific marker of diesel exhaust.

As OELs decrease, the need to use EC as the marker increases.

• • • •

ISSUE: AIR SAMPLING IN COAL MINES

Coal dust will interfere with the measurement of DPM in coal mines. 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 in size

DPM SAMPLER UTILIZES THREE STAGES

• • •

Cyclone

Removes non-respirable particles that may overload the filter

Impactor

Removes respirable particles greater than 1.0 um in diameter

After-filter assembly

Collects particles less than 1.0 um in diameter

DPM FILTER CASSETTES FOR EC SAMPLING • • Contain a special heat-treated quartz filter for thermal optical analysis using NIOSH Method 5040. (Cat. No. 225-401) For coal mining other applications with an interfering respirable dust, a DPM with an inline impactor plate may be necessary. (Cat. No. 225-317)

SIZE-SELECTIVE SAMPLING IN AMBIENT AIR

THE ENVIRONMENTAL PERSPECTIVE

• • Initially, ambient particulate matter was regulated in terms of

total suspended particulates (TSP)

which is particulate matter captured on a filter with a particle size less than

100 um

.

TSP is comparable to the inhalable definition used by occupational health professionals.

HISTORICAL EVENTS

• • Later, the TSP standard was replaced with a

PM10

standard, which includes only particles with an aerodynamic diameter of

10 um

or less.

PM10 is comparable to the thoracic definition used by occupational health professionals.

HISTORICAL EVENTS

• • • The USA now also has a standard for

PM 2.5

, particulate matter less than diameter.

2.5 um

in aerodynamic PM2.5, referred to as fine particulate matter, is emitted from combustion sources and is a major public health concern. PM2.5 is similar to the respirable definition used by occupational health professionals.

US EPA REFERENCE METHODS FOR PM IN AMBIENT AIR

TRANSPORTABLE SAMPLERS FOR PM IN AMBIENT AIR

Deployable Particulate Sampler (DPS)

(PM10 Cat. No. 100-3901)

REAL-TIME MONITORS FOR PM IN AMBIENT AIR • • • Light-scattering device with internal datalogger Internal pump and size selective impactor for PM Real-time monitor with concurrent sample collection

EPAM-5000

(Cat. No. 770-)

SIZE-SELECTIVE SAMPLING IN INDOOR AIR

SAMPLING APPROACH TO INDOOR AIR

• Traditional stationary ambient PM monitors used for ambient measurements do not provide reliable exposure measurements susceptible subpopulations.

of • In addition, traditional stationary ambient PM monitors do not permit researchers to assess the health effects of PM on vulnerable individuals.

A

NEW

APPROACH TO INDOOR AIR

• US EPA researchers have begun to sample “microenvironments” (personal exposures) of PM to get better epidemiological data of the actual health effects .

PM IN INDOOR AIR USING A PERSONAL IMPACTOR

• • Developed by researchers at the University of S. California to collect data on the relationship between outdoor and indoor PM levels and to assess personal exposures. Designed to partner with a pump at 9 L/min for 24-hr .

SIOUTAS IMPACTOR

SIOUTAS PERSONAL CASCADE IMPACTOR

Four impaction stages • • • • • and after-filter: 2.5-10 um 1.0-2.5 um 0.5-1.0 um 0.25-0.5

<0.25 um

SAMPLE ANALYSIS

•

TOTAL MASS

Gravimetric analysis •

CHEMICAL SPECIES

See EPA IO-3 for a variety of methods including AA, XRF, ICP, proton induced X-ray emission spectroscopy and neutron activation. (See www.epa.gov)

PM IN INDOOR AIR

USING THE PERSONAL ENVIRONMENTAL MONITOR (PEM) • • Personal single-stage impactor of various models for use with pumps at 2, 4 or 10 L/min Referenced in EPA method IP-10A for particles in indoor air using gravimetric analysis

JUST WHEN YOU THOUGHT…

WAIT THERE’S MORE. Another type of particle in a new state of matter…..

NANOPARTICLES

• • Nanosized particles can be regarded as neither liquid or solid. They are a new state of matter: • • • Nanophase particles have a high fraction of molecules located at the surface which makes them very reactive.

Main mechanism of deposition is diffusion.

Behavior is more like that of a vapor than a particle.

PARTICLE FORMATION

• • • Nano-sized particles are not formed by crushing/grinding operations.

Particle formation is only by condensation from a vapor. Particle growth can occur through condensation or coagulation. Hot processes and/or combustion are required to generate these nano-sized particles such as internal combustion engines, smelting, welding.

PARTICLE TOXICITY

• • Experts still are not sure of the metric driving the toxicity of nano-sized particles.

Is the toxicity dependent on their increased reactivity or surface area? • • KEY FACTOR Nano-sized particles can “translocate” far beyond the original site of deposition in the respiratory system to other target organs.

One study reports on translocation from posterior nasal passages to the brain.

NANOSCALE MATERIALS

• • Nanoscale materials are being used in electronics, magnetic, medical imaging, drug delivery, catalytic and materials applications, and consumer products. These engineered structures, devices, and systems use materials of a nanoscale size from 1-100 nm.

EXAMPLE: NANOTUBES

• Compressed carbon:The hardest material ever made by the human race • • Can be woven into a hollow pipe and filled with “payload molecules” Applications include lightweight, fireproof, and earthquake-proof buildings and levees as thin as Saran Wrap that are impervious to surges

NANOPARTICLES vs ULTRAFINES • • Nanoparticles Particles intentionally engineered for specific applications.

Large surface to mass ratio allows them to bind, adsorb, and carry other compounds such as drugs, probes, and protein.

• • Ultrafines Nano-sized particles

air

produced

in

unintentionally in combustion processes, etc.

Have similar properties as the engineered nanoparticles

EVALUATING EXPOSURES

• • • • Currently, particulate exposures are evaluated using mass concentrations. This may not be the right choice for nano-sized particles.

Particle number and/or surface area appropriate parameters.

may be more Be sure to measure background levels which may result from combustion sources or photochemical processes in ambient air.

CONTROLLING EXPOSURES

• The good news is that traditional controls such as HEPA filters do appear to work effectively in controlling nano-sized particles.

FOR MORE INFORMATION

• NIOSH www.cdc.gov/niosh/topics/nanotech/ • UK HEALTH AND SAFETY EXECUTIVE www.hse.gov.uk/research/rrhtm/rr274.htm

THANK YOU

FOR YOUR ATTENTION BREAK TIME