INHALABLE PARTICULATE
MATTER
SAMPLING OPTIONS FROM SKC INC
A GLOBAL DISCONNECTGlobal differencesin definitions of workplacecontaminants and standard sampling methods for thosecontaminantscreate a variety of problems.
GLOBAL DIFFERENCES IN DEFINTIONS
Complicate international comparisons and sharing of data
Make our profession seem illogical to lay people including legislators
Contribute to differences in worker protection in different countries
Complicate the choice of sampling equipment
GLOBAL DIFFERENCES IN SAMPLERS
Result in considerable differences in exposure measurements when sampling the same contaminant under identical environmental conditions.
A COMMON SENSE APPROACH
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.)
HISTORICAL EVENTS
A Move Toward
StandardizationACGIHISOCEN
HISTORICAL EVENTS In 1982, ACGIH appointed an ad hoc
committee on Air Sampling Procedures (ASP) with the task of preparing recommendations for size-selective sampling that would lead to an approach for establishing particle size-selective TLVs for particulates.
HISTORICAL EVENTS In 1983, ISO published Technical
Report 7708 giving definitions of particle size fractions corresponding to three regions of the respiratory tract. The fraction which would be measured would depend on the site of action of the particulate material under study.
HISTORICAL EVENTS In 1985, ACGIH published a report with
a similar proposal to that published by ISO.
In 1987, an ISO Working Group was established to revise TR7708 as an international standard and a CEN Working Group was established to produce a European standard.
HISTORICAL EVENTS 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 defined: inhalable, thoracic and respirable.
HISTORICAL EVENTS U.S. NIOSH nor OSHA have not officially
endorsed the three new international particulate definitions in total.
The only published method by U.S. government agencies using inhalable samplers is NIOSH 5700 for formaldehyde on dust specifying an IOM sampler or equivalent.
HISTORICAL EVENTSThe Health and Safety Executive
describes the use of inhalable and respirable samplers that meet the new definitions in MDHS 14/3, “General methods for sampling and gravimetric analysis of respirable and inhalable dust”.
HISTORICAL EVENTSAustralia has embraced the new
definitions of inhalable and respirable particulate mass in the new drafts of the Australian Standards for sampling and gravimetric determination of inhalable dust (AS 3640) and respirable dust (AS2985).
MOVING FORWARDDefinitions Performance
SpecificationsSamplersExposure Limits
INHALABLE PARTICULATE MASS
Defined as 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 m.
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 licensed for
manufacture by SKC.
IOM SAMPLER(SKC Cat. No. 225-70A)
Exploded View
USING THE IOM SAMPLERSAMPLE 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 SAMPLERSAMPLE LOGISTICS
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 (Cat. No. 225-73) or by placing in a calibration chamber.
Following sample collection, weigh the cassette/filter assembly again following the procedures described above.
USING THE IOM SAMPLERSAMPLE LOGISTICS
Transport clips are available to transport the filter/cassette assemblies to the sampling site or the laboratory (Cat. No. 225-72A).
ADVANTAGES OF THE IOMSince 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 IOMThe 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 m.
WEIGHING ACCURACY OF IOM SAMPLES
CONCERNS March/April 1999
AIHA Journal article discusses problems of water absorption by plastic IOM cassette and resulting instability of the tare weight
RESPONSE SKC has changed the
plastic material to address water. adsorption.
Do not desiccate Equilibrate under
controlled humidity conditions.
Consider stainless steel cassettes.
Studied the use of porous polyurethane foams as size-selectors
Placed in the inlet of the IOM sampler Allow for the collection of inhalable and
respirable sub fraction using existing IOM samplers
Followed by gravimetric analysis Used for a variety of particulates
including bioaerosols
NEW IOM RESEARCHBY U.K. HEALTH AND SAFETY
LABORATORY
IOM SAMPLERWITH MULTIDUST FOAM DISCS
InhalableRespirable
UNDER STUDY Thoracic PM10 Combination discs
New Cassette with Elongated Inlet Required
PUBLICATIONS ON IOMBY HSE LAB
HSE Lab Publication on Foam Discs, Project Leader: L C Kenny
Journal of Aerosol Science, Vol. 30, No. 5, pp. 627-638, 1999 on sampling efficiency with low air movement
AIHA Journal, Vol. 59, pp. 831-841, 1998 on sampling with foams for bioaerosols
Methods for the Determination of Hazardous Substances 14, Health and Safety Executive, January 1997
NEW INHALABLE RESEARCHBY UNIV OF CINCINNATI
Button Sampler -Alternative to the IOM sampler for inhalable dust
Inlet is formed from a spherical
shell with numerous, evenly
spaced holes Holes act as orifices and
provide multidirectional
sampling capabilities
Cat. No. 225-360
USING THE BUTTON SAMPLERSAMPLE LOGISTICS
Unscrew the sampler inlet and remove the PTFE O-ring.
Place a 25-mm filter on the stainless steel support screen, replace the 0-ring and the sampler inlet.
A filter pore size of 1.0 m or higher is recommended due to the backpressure limitations of personal samplers.
USING THE BUTTON SAMPLERSAMPLE LOGISTICS
Calibrate the Button Sampler to a flowrate of 4 L/min using the calibration adapter (Cat. No. 225-361) or by placing in a calibration chamber.
After sampling, remove the filter for analysis. SKC offers a conductive plastic filter transport case for shipment to the lab. (Cat. No. 225-67)
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
PUBLICATIONS ON BUTTON SAMPLER
BY UNIV OF CINCINNATI AIHA Journal, Vol.
61, 398-404, 2000 on performance characteristics
Aerosol Science and Technology, Vol. 28, 247-258, 1998 on effects of wind velocity and direction
AIHA Journal, Vol. 58,713-719, 1997 on field testing of sampler
Atmospheric Environment, Vol. 29, No. 10, pp. 1105-1112, 1995 on design of prototype
CONCLUSIONS REPORTED For the Button Personal Sampler
Effects of wind direction: No significant effects
Effects of wind velocity: Lower than for IOM, GSP and 37-mm cassette
Accuracy (direction-averaged): Better an 37-mm cassette, comparable to GSP, lower than IOM
Precision (direction-specific): Equal or better than IOM, GSP, or 37-mm cassette
ABRASIVE BLASTING
A NIOSH Health Hazard Evaluation indicated that current methods do not provide reliable measurements of worker exposure to lead and other contaminants during abrasive blasting in small confined spaces.
ABRASIVE BLASTINGCurrent sampling
methods using 37-mm cassettes often grossly overestimate exposure to very large, noninhalable particulate.
In NIOSH HHEs, nearly all of the lead in the samples was due to grit that entered the cassettes due to rebound of grit in confined spaces.
JOURNAL ARTICLE
APPLIED OCCUPATIONAL AND
ENVIRONMENTAL HYGIENE, Vol. 15, p. 776-772, 2000 on use of Button
Sampler with screen for evaluating metal
exposures among abrasive blasting
workers at four US Air Force
Facilities
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.
INHALABLE TLVs2010 ADOPTED VALUES
Acrylamide Alachlor Aldrin Asphalt Fume Azinphos-methyl Benomyl Beryllium Borate cpds,
Inorganic Butylated
hydroxytoluene Calcium sulfate Caprolactam
Captan Carbaryl Carbofuran Chlorpyrifos Citral Coumaphos Cresol (all isomers) Demeton (and
Demeton-S-methyl) Diazinon Dibutyl Phosphate 2,2-Dichloropropionic
acid
INHALABLE TLVs2010 ADOPTED VALUES
Dichlorvos (DDVP) Dicrotophos Dieldrin Diesel Fuel Diethanolamine Dioxathion Diquat Disulfoton Endosulfan EPN Ethion 2-Ethylhexanoic acid Fenamiphos
Fensulfothion Fenthion Ferbam Flour Dust Fonofos Glyoxal Hexahydrophthalic
anhydride Iodine and Iodides Isobutyl nitrite Magnesium oxide Malathion Methyl demeton
INHALABLE TLVs2010 ADOPTED VALUES
Methyl parathion Mevinphos Mineral oil (excluding metal
working fluids) Molybdenum (Metal and
insoluble cpds.) Monochloroacetic acid Monocrotophos Naled Natural rubber latex as total
proteins Nickel, Elemental, Soluble
and Insoluble Cpds.
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
INHALABLE TLVs2010 ADOPTED VALUES
Silicon carbide, nonfibrous
Sulfotepp (TEDP) Sulprofos Synthetic Vitreous
Fibers (Continuous filament)
Temephos Terbufos 1,1,2,2-
Tetrabromomethane
Tetraethyl pyrophosphate (TEPP)
Thallium (and compounds, as TI)
Thiram Trichlorphon Trimellitic anhydride Vanadium Pentoxide Wood dusts Xylidine (mixed
isomers)
INHALABLE TLVs2010 INTENDED CHANGES
Carbon black Maleic anhydride Manganese (elemental
and inorganic cpds., as Mn)
Piperazine 4,4-Thiobis (6-tert-butyl-
m-cresol) Toluene 2,4- or 2,6-
diisocyanate (or as a mixture)
DATA CONVERSION??TOTAL TO INHALABLE
Aerosol Classification and Conversion Factor-Dust 2.5-Mist 2.0-Foundries 1.5-Welding 1.0-Smokes/fumes 1.0
Published by Werner et. al. in the Analyst, 121:1207
THE FUTURE OF SIZE-SELECTIVE SAMPLING
More inhalable TLVsNew thoracic TLVsDevelopment of thoracic samplersEnhanced use of foams as pre-
selectors
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