EPA/600/2-86/053
April 1986
ASSESSMENT OF ASSAY METHODS
FOR EVALUATING ASBESTOS
ABATEMENT TECHNOLOGY
by
PEI Associates, Inc.
Cincinnati, Ohio 45246-0100
Contract No. 68-03-3197
Project Officer
Thomas Powers
Manufacturing and Service Industries Branch
Water Engineering Research Laboratory
Cincinnati, Ohio 45268
WATER ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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TECHNICAL REPORT DATA
(Please read Insirucnom on the reverse before completing)
1. REPORT NO. 2.
EPA/600/2-86/053
3. RECIPIENT'S ACCESSION NO.
4, TITLE AND SUBTITLE
Assessment of Assay Methods for Evaluating
Asbestos Abatement Technology
5, REPORT DATE
April 1986
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Mark A. Karaffa, Robert S. Amick, and Ann Crone
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
PEI Associates, Inc.
11499 Chester Road
P.O. Box 46100
Cincinnati, Ohio 45246-0100
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-03-3197
12. SPONSORING AGENCY NAME AND ADDRESS
Water Engineering Research Laboratory-Cincinnati, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
March 1984 - March 1986
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Thomas J. Powers, Project Officer, U.S. EPA 513-569-7550 FTS 684-7550
1 "flmRproject focused on the adequacy of the EPA's previously recommended phase
contrast light microscope (PCM) method of analysis and sample collection technique.
The PCM method was compared with transmission electron microscope (TEM) methods and
the feasibility of an alternative "agressive" sampling technique was investigated.
The results of this study established the advantages and limitations of applying
both PCM and TEM analytical methods, both separately and in conjunction with an a
agressive sampling technique in the evaluation of air quality following asbestos
abatement. This project was conducted during the post abatement phase of asbestos
removal. Reliable methods of air sampling and analysis permit the use of monitoring
results to be included in evaluating the efficacy of asbestos abatement methods and
in developing better technical guidance for abatement contractors, building owners,
and other parties directly responsible for remedial asbestos programs.
,7, KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
86
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (R*v. 4-77) previous edition is obsolete
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DISCLAIMER
The information in this document has been funded wholly or in part by
the United States Environmental Protection Agency under Contract No. 68-03-
3197 to PEI Associates, Inc. It has been subject to the Agency's peer and
administrative review, and it has been approved for publication as an EPA
document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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FOREWORD
The U.S. Environmental Protection Agency is charged by Congress with
protecting the Nation's land, air, and water systems. Under a mandate of
national environmental laws, the agency strives to formulate and implement
actions leading to a compatible balance between human activities and the
ability of natural systems to support and nurture life. The Clean Water Act,
the Safe Drinking Water Act, and the Toxic Substances Control Act are three
of the major congressional laws that provide the framework for restoring and
maintaining the integrity of our Nation's water, for preserving and enhancing
the water we drink, and for protecting the environment from toxic substances.
These laws direct the EPA to perform research to define our environmental
problems, measure the impacts, and search for solutions.
The Water Engineering Research Laboratory is that component of EPA's
Research and Development program concerned with preventing, treating, and
managing municipal and industrial wastewater discharges; establishing prac-
tices to control and remove contaminants from drinking water and to prevent
its deterioration during storage and distribution; and assessing the nature
and controllability of releases of toxic substances to the air, water, and
land from manufacturing processes and subsequent product uses. This publica-
tion is one of the products of that research and provides a vital communica-
tion link between the researcher and the user community.
This publication evaluates a particular aspect of assessing the nature
and controllability of releases of toxic substances to the air. Specifical-
ly, it evaluates the sampling and analytical methods for determining the
concentration of asbestos fibers in buildings that have undergone asbestos
abatement. Aggressive and nonaggressive asbestos sampling methods are eval-
uated and compared, and the phase contrast and transmission electron micro-
scopy analytical methods are evaluated and compared.
Francis T. Mayo, Director
Water Engineering Research Laboratory
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ABSTRACT
Two methods were compared for analyzing the condition of a building
after the removal of asbestos-containing materials: Phase contrast micro-
scopy (PCM), the U.S. Environmental Protection Agency's (EPA's) current,
nonaggressive sampling method, and transmission electron microscopy (TEM), an
alternative aggressive sampling technique.
Air sampling was conducted at a large high school undergoing a multi-
phase abatement program. The aggressive sampling technique revealed that
air-entrainable asbestos remained in work areas after completion of abatement
actions. The ratio of aggressive to nonaggressive PCM fiber concentrations
was 3.4, whereas this ratio was 6.3 for TEM analyses. Study results also
confirm that under similar sampling conditions, TEM analysis detects more
fibers than PCM because of TEM's better resolving capability. The ratio of
TEM/PCM concentrations for nonaggressive sampling was 6.5 for ambient samples
and 5.2 for indoor samples; the ratio for aggressive sampling was 9.8. Be-
cause the PCM method does not discriminate between asbestos and other fibers
and cannot resolve fibers thinner than about 0.2 iim, PCM results may not
accurately reflect the true hazard potential.
Study conclusions led to the following recommendations. Although time-
consuming and expensive, TEM should be recommended as the analytical method
of choice for measuring airborne asbestos fiber concentrations for final
clearance testing of work areas after asbestos abatement. A criterion should
be established that defines an acceptable asbestos fiber concentration in
building areas after asbestos abatement, but not until a standardized TEM
protocol and an aggressive sampling procedure are incorporated into asbestos
guidelines. Continued research should focus on the development of a quicker,
less expensive method for monitoring buildings after asbestos abatement and
on more efficient abatement practices.
This report was submitted in fulfillment of Contract No. 68-03-3197 by
PEI Associates, Inc., under the sponsorship of the EPA. This report covers a
period from June 1984 to June 1985, and work was completed as of March 1986.
IV
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CONTENTS
Page
Foreword iii
Abstract iv
Figures vii
Tables viii
Acknowledgments ix
1. Introduction 1
Background 1
Objective 3
Report organization 3
2. Conclusions 4
3. Recommendations 6
4. Project Description 7
Site selection 7
Building description 7
Mechanical system description 8
Asbestos-containing materials 9
Abatement program 9
Monitoring approach 11
5. Methods of Air Sampling and Analysis 12
Overview of sampling strategy 12
Sampling methodology 13
Sampling equipment 13
Sample collection and handling 13
Nonaggressive sampling 15
Aggressive sampling 15
Methods of analysis 17
Phase-contrast microscopy 17
Transmission electron microscopy 20
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CONTENTS (continued)
Pa^e
Quality assurance 23
Filter preparation 23
Sampling 23
Chain of custody 24
Sample analysis 27
6. Results 28
Air monitoring results 28
Statistical comparisons , 28
Statistical method of analysis 28
Analytical methods 33
Sampling conditions .... 33
Indoor with ambient samples 33
Expanded TEM data from nonaggressive and
aggressive sampling conditions 36
Preabatement monitoring 36
Results of monitoring after dry removal 36
References 43
Appendices
A. Methodology for the Measurement of Airborne Asbestos by
Transmission Electron Microscopy - Level II Analysis
Protocol 45
B. I IT Research Institute Structure Analysis Data Report and
Summary Table for a Representative Sample 65
C. Statistical Method 70
D. Comparison of Nonaggressive and Aggressive Asbestos
Sampling Results 73
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FIGURES
Number Page
1 Photograph of a Typical Sampling Apparatus. Personal
Sampling Pump and Filter Cassette Are Positioned On
An Adjustable Tripod 14
2 Photograph of the Electric Power Blower Used for
Aggressive Sampling 16
3 Photographs Showing Aggressive Sampling in Progress ... 18
4 TEM Asbestos Analysis Report 22
5 PEI Air Sampling Data Sheet 25
6 PEI Chain-of-Custody Form 26
7 Comparison of Airborne Fiber Concentrations 32
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TABLES
Number Page
1 Results of PCM and TEM Analyses 29
2 Comparison of Nonaggressive and Aggressive Sampling
Results for Postabatement Testing 34
3 Summary Comparison of PCM and TEM Analyses of Air Samples
Collected During Nonaggressive and Aggressive Conditions 35
4 Expanded TEM Data From Nonaggressive and Aggressive Sam-
pling Conditions 37
5 Results of PCM and TEM Preabatement and Postabatement
Samples Collected in the Auditorium 41
6 Results of Nonaggressive PCM and TEM Postabatement
Analyses, After Dry Removal 42
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ACKNOWLEDGMENTS
Many individuals and groups have been helpful in conducting this study
and preparing this report. The able direction and guidance provided by Mr.
Roger Wilmoth, Chief of the Manufacturing and Service Industries Branch, EPA;
Mr. Tom Powers, EPA Project Officer; and Mr. William Cain of the EPA are sin-
cerely appreciated. The cooperation and assistance from Mr. Jeff Marshall,
Ms. Debbie Totten, and other staff members of the Bartholomew Consolidated
School Corporation, Columbus, Indiana, are also gratefully acknowledged.
Mr. Robert Amick served as Project Director and Mr. Mark Karaffa as
Project Manager for PEI Associates. Ms. Ann Crone and Mr. Charles Zimmer
assisted in the preparation of this report.
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SECTION 1
INTRODUCTION
BACKGROUND
The Technical Assistance Program of the Office of Pesticides and Toxic
Substances of the U.S. Environmental Protection Agency (EPA) provides guid-
ance and information on the identification of asbestos-containing materials
in buildings and on the correction of potential asbestos hazards. EPA Guid-
ance Documents contain much of the technical information about asbestos in
nonindustrial settings.1-1+ These documents describe how to establish an
asbestos identification and control program, provide background information
and direction to school officials and building owners on exposure assessment,
and describe how to develop and implement an asbestos abatement program. The
most recent asbestos guidance from EPA not only emphasizes recent experience
and new information on asbestos control, but it also introduces and discusses
criteria for developing an appropriate asbestos control plan.
Considerable scientific uncertainty still surrounds the technical con-
siderations involved in assessing specific abatement actions to reduce the
risk of asbestos exposure. One critical concern among the persons responsi-
ble for an program is how clean the asbestos-abatement contractor leaves a
building (or building area) after removing the asbestos material or after
completing work that could have disturbed an asbestos-containinq material
(e.g., encapsulation, enclosure, or special maintenance operations). The two
criteria recommended in the version of EPA guidance (1983) that was in effect
at the time of this study for evaluating the adequacy of the cleanup at the
worksite are visual inspection of the worksite and air monitoring after com-
pletion of the project. Visual inspection should detect incomplete removal,
any damage caused by abatement activity, and (most important) the presence of
debris or dust that could contain asbestos as a result of inadequate cleanup
of the work area. Air monitoring by the membrane filter collection technique
and phase-contrast microscopic (PCM) analysis are recommended to supplement
the visual inspection and to determine whether elevated levels of airborne
fibers generated during the removal process have been sufficiently reduced.
This currently recommended optical microscopic technique, one of two methods
specified by the National Institute for Occupational Safety and Health
(NIOSH) for determining airborne fiber concentrations, is used by the Occupa-
tional Safety and Health Administration (OSHA) for measurement of total
airborne fibers in occupational environments.
The EPA-recommended air-monitoring methodology for determining abatement
completion (NIOSH Method No. P&CAM 239) was as follows:
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Air sampling should begin after the project has been completed and all
surfaces in the abatement site have been cleaned, preferably within 48
hours after abatement work is finished. A minimum of three air monitors
per worksite and at least one per room is recommended. Air is drawn
through a membrane filter for about 8 hours at a flow rate of approxi-
mately 2 liters per minute. A total air volume of approximately 1,000
liters collected at the specified flow rate should be sampled. After
the sampling, a section of the filter is mounted on a microscope slide
and treated to form a transparent, optically homogenous gel. The fibers
are sized and counted by using a phase-contrast microscope at 400 to
450X magnification. For counting purposes, a fiber is defined as a
particle with a physical dimension longer than 5 micrometers and a
length-to-diameter ratio of 3 to 1 or greater.3
This method is intended to give an index of the airborne concentration of
asbestc" fibers of specified dimensional characteristics in an atmosphere
known or suspected to contain asbestos. It is not designed to count fibers
less than 5 micrometers long or to differentiate asbestos fibers from other
fibrous particulates.
The most significant limitation of the PCM method compared with the use
of transmission electron microscopy (TEM) and scanning electron microscopy
(SEM) is that the PCM method is limited in detecting fine particles (i.e.,
particles with submicron diameters, or lengths less than 5 ym) that are
potentially toxicologically significant. For example, in glove-box tests of
simulated industrial mechanical operations om asbestos-containing products
(drilling, sawing, and sanding), the PCM methodology counted less than one
percent of the fibers counted by TEM.5 Although conditions of this glove box
study are obviously different from asbestos-abatement activities, some con-
cern existed about the relative merits and capabilities of the different
analytical methods used to determine representative fiber concentrations. In
another study, it was estimated that 50 to 100 times as many small asbestos
fibers (i.e., fibers less than 0.2 ym wide and 5 ym long that are not detect-
ed by the PCM method) are present than the larger, optically visible fibers.6
The conditions in a work area during the time the final air samples are
collected can influence the results of a post-abatement assessment. After an
abatement action, the air is sampled while the area is sealed off, before
ventilation is restored, and usually after at least a 24-hour settling period
following the final wet cleaning. Consequently, this monitoring technique
may not detect residual fibers that were missed by the cleaning or that have
settled on horizontal surfaces during this static condition.
Residua] asbestos fibers constitute a potential exposure hazard because
they could be reentrained later when the air in the area is agitated by per-
sonnel traffic, air flow from ventilation systems, and custodial activities.
Thus for more accurate characterization of postabatement fiber concentra-
tions, the work area should have appreciable air movement, simulating actual
use conditions while air monitoring is being conducted, to determine whether
any reentrainable asbestos fibers remain in the area after completion of
abatement activities. This introduction of air turbulence into the work area
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during the collection of stationary air samples is termed "aggressive sam-
pling." This method entails the creation of air movement by the use of
blowers, fans, brooms, or compressed air streams to entrain any particulate
matter that may be present. Section 5 further describes air sampling meth-
ods. The advantage of the aggressive sampling technique over the static (or
nonaggressive) sampling is that the former reflects worst-case conditions and
the testing requires a relatively short period. The disadvantages are that
this technique is not readily standardized or reproducible, nor does it
reflect normal exposure levels to occupants. As with the nonaggressive
sampling method, no criteria have been established to define an acceptable or
"safe" level of fibers in a nonoccupational environment.
"Guidance for Controlling Asbestos-Containing Materials in Buildings'"*
issued by EPA in July 1985 recommends aggressive sampling and TEM analysis of
air samples taken after an abatement action. These new guidelines contain a
recommended protocol for aggressive sampling, a sampling strategy for post-
abatement clearance monitoring, and a statistical method for evaluating the
TEM results and the adequacy of the contractor's cleanup.
OBJECTIVE
This study posed a problem-defining task designed to assess the adequacy
of EPA's currently recommended optical microscopic method of analysis and
sample collection technique compared with an electron microscopic method
(TEM) and an alternative aggressive sampling technique. The results of this
study will help to evaluate the advantages and/or technical limitations that
could affect the application of the TEM analytical method and aggressive
sampling technique in the assessment of air quality following asbestos abate-
ment operations. In addition, the establishment of reliable methods of air
sampling and analysis will permit the use of postabatement monitoring results
to evaluate the efficacy of the methods for asbestos abatement and to develop
better technical guidance for abatement contractors, building owners, and
other parties directly responsible for remedial asbestos programs.
Because of the problem-defining nature of the study, the schedule and
limited funding for this task did not allow for the development and implemen-
tation of a quality assurance project plan, which normally precedes such a
field study. Active or recently completed abatement sites were selected for
monitoring in this problem-defining study because they provided an excellent
opportunity to collect real-world data and because the monitoring tasks could
be arranged with minimum lead time and coordination.
REPORT ORGANIZATION
Section 2 of this report presents the study's conclusions, and Section 3
presents the recommendations. Section 4 describes the site selection crite-
ria, sampling site, abatement program, and monitoring approach. Section 5
describes the nonaggressive and aggressive sampling procedures and the PCM
and TEM methods used to analyze the filter samples collected at this site.
Section 6 presents the air monitoring data, discusses their significance, and
describes the statistical methods used for comparing the monitoring results.
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SECTION 2
CONCLUSIONS
The following conclusions resulted from this study:
1. The aggressive sampling technique used in this problem-defining
study revealed that air-entrainable asbestos remained at this site
immediately after completion of abatement actions. The mean asbes-
tos fiber concentration during aggressive sampling, as determined
by TEM, was about 6 times higher than the mean asbestos fiber con-
centration during nonaggressive sampling. Because no standards or
guidelines had been established for evaluating building atmospheres
by the direct-transfer TEM method following asbestos-abatement
activities, the significance of these data was unclear. Different
analytical (and sampling) techniques usually produce different
results; therefore, definitive methods of fiber identification,
quantitation, and sampling must be established before a criterion
level can be specified.
2. Regardless of the analytical method used, the concentrations of
fibers measured under aggressive sampling conditions were higher
than those measured under nonaggressive conditions. The ratio of
aggressive to nonaggressive fiber concentrations during PCM analy-
ses was 3.4, whereas this ratio during TEM analyses was 6.3. The
average PCM concentration during aggressive sampling conditions
(0.03 fiber/cm3) is less than the NIOSH-recommended occupational
limit of 0.1 fiber/cm3, an 8-hour, time-weighted average that is
frequently cited in abatement contractor specifications as the
final, post-abatement acceptance criterion. Alternatively, the EPA
guidance document3 suggests the lower detection limit as a standard
for releasing the abatement contractor. A detection limit for a
typical 1000-liter air sample analyzed by the NIOSH P&CAM 239
method would be about 0.03 fiber/cm3. Thus based on the PCM data
collected during worst-case conditions (aggressive sampling), the
work practices, controls, and decontamination procedures used at
this abatement site appear to have been effective.
3. The results of the study clearly demonstrate that under similar
sampling conditions, TEM analysis detects more fibers than PCM.
(The ratio of TEM/PCM concentrations for nonaggressive sampling was
6.5 for ambient samples and 5.2 for indoor samples; the ratio for
aggressive sampling was 9.8) The PCM counting protocol specifies
that only fibers 5 um or longer are to be recorded. Because only
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fibers thicker than about 0.2 ym can be resolved by the light
microscope, regardless of their lengths, thin fibers on the filter
may not be detected by PCM. The TEM dimensional analysis reports
for samples from Columbus-East High School reveal that a majority
of the asbestos fibers identified on the filters have widths much
less than 0.2 ym and lengths less than 5 ym.
In addition, the PCM method does not discriminate between asbestos
fibers and any other types of fibrous particulate. Thus, the value
obtained from an environmental (nonoccupational) sample may be
totally unrelated to the presence or absence of any asbestos fibers.
After an asbestos removal project, any fibers left in the work area
might reasonably be expected to be asbestos; however, it is not
unusual for asbestos-containing building materials to contain other
fibrous components, such as mineral wool, cellulose, or fibrous
glass. Thus the fibers detected by PCM after an abatement action
are not always asbestos and may not accurately reflect the true
hazard potential.
4. Concentrations of work area asbestos fibers (as determined by TEM),
measured both by aggressive and nonaggressive sampling methods,
were significantly higher than ambient TEM concentrations. The
actual environmental conditions that exist in a building after
reoccupancy, reactivation of ventilation systems, and the return to
typical usage patterns are somewhere between the nonaggressive and
aggressive sampling conditions. It is not likely that indoor
conditions would ever be as rigorous as those created during the
aggressive sampling conditions for this project. In addition,
finishes applied during subsequent renovation of the building's
interior after abatement (e.g., paint, carpeting, and suspended
ceiling system), repeated cleanings, and continuous dilution of
indoor air with ambient air would further reduce the possibility of
residual fiber reentrainment and result in lower indoor concentra-
tions. Over time, these concentrations could approach ambient
levels. No data were obtained during this project to verify this
theory.
In summary, this study, which was essentially completed before issuance
of the 1985 EPA guidelines (Purple Book),1* was designed to evaluate the meth-
ods of air sampling and analysis in the 1983 EPA guidance document.3 The
conclusions presented in this report, which were based on actual air monitor-
ing data from a large-scale asbestos-abatement project, support the recommen-
dations for aggressive air sampling and TEM analysis for post-abatement air
quality evaluations presented in the latest EPA guidance document.
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SECTION 3
RECOMMENDATIONS
Based on the findings of this study, the following recommendations are
made:
1. TEM should be recommended as the analytical method of choice for
measuring airborne asbestos fiber concentrations for final clear-
ance testing in atmospheres of buildings that have undergone as-
bestos abatement. The current TEM protocols, however, are very
time-consuming and expensive for routine use in large abatement
projects.
2. PCM analyses should be conducted as a preliminary check to deter-
mine whether additional cleanings are necessary before final clear-
ance testing by TEM because PCM analyses are relatively inexpensive
and can be performed quickly.
3. A criterion should be established that defines an acceptable asbes-
tos fiber concentration in building areas after asbestos abatement,
but not until a standardized TEM protocol and an aggressive sam-
pling procedure have been developed and validated. Once developed,
these methods should be required for all postabatement assessments.
4. Research should continue in the areas of asbestos measurement, sam-
pling, hazard assessment, and abatement control technology so that
asbestos hazards in buildings can be effectively reduced. One im-
portant research avenue should be the development of quicker, less
expensive methods for monitoring the atmosphere in buildings after
asbestos abatement.
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SECTION 4
PROJECT DESCRIPTION
SITE SELECTION
Air monitoring was conducted at two selected sites where friable asbes-
tos building materials had been removed:
Site 1. Columbus East High School
230 South Marr Road
Columbus, Indiana
Site 2. U.S. EPA Environmental Research Laboratory
200 S.W. 35th Street
Corvallis, Oregon
This report describes only the results of the air monitoring survey
conducted at Site 1. The monitoring data from Site 2 and the significance of
these data are the subject of a separate report. These selected sites met
the following criteria:
° The abatement plan involved the removal of friable, spray-applied,
asbestos-containing material.
° The contractors carried out the work area preparation, removal, and
decontamination in accordance with the EPA-recommended specifica-
tions and requirements.1
° Multiple work areas containing homogeneous asbestos material were
available for monitoring.
0 The building owner and abatement contractor agreed to cooperate
with EPA and PEI and to provide access to selected areas of the
building.
BUILDING DESCRIPTION
The 50-acre (20-hectare) campus of Columbus East High School includes an
academic building, a gymnasium building, and a pool building. This facility,
located at 230 South Marr Road, Columbus, Indiana, is one of 17 schools in
the Bartholomew Consolidated School Corporation.
Design of the Columbus East facility was begun by Mitchel1/Giurgola
Architects of Philadelphia, Pennsylvania, in 1968, and construction was
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completed in 1972. The original cost of the facility was $12,200,000, and
the life expectancy of the buildings is a minimum of 50 years.
The academic building and the gymnasium are constructed of similar
materials, and their mechanical systems are similar in operation. No friable
asbestos-containing materials were found in the pool building, and its de-
scription is not included in this section. The academic building contains
280,625 ft2 (26,070 m2), and the gymnasium contains 60,530 ft2 (5,623 m2).
The total area of the two buildings is 341,155 ft2 (31,693 m2). The building
structure is steel, masonry, and reinforced concrete. The exterior walls are
made up of a combination of insulated, prefabricated, aluminum panels and
structural clay tile (SCT) with concrete block backup. The prefabricated
panels have 3£ inches (8.9 cm) of rigid insulation enclosed by an aluminum
skin. The metal panel system and the SCT system make up approximately 70
percent of the exterior building enclosure; the remaining 30 percent is made
up of a single-pane-window wall system. The roof system of the buildings is
composed of the following: structural steel support, U-inch (3.8-cm) steel
deck, lightweight insulating concrete, and 2-ply built-up roof membrane.
The major function of the academic building is to provide classrooms,
administrative space, lab space, and all other space necessary for the opera-
tion of a high school with an enrollment of approximately 2000 students.
This three-level structure, which is operated on a year-round basis for
education purposes, includes the following areas:
Administrative offices
Classrooms
Commons
Auditorium
Planetarium
T.V. studio
Bookstore
Music rooms
Industrial arts
Art studio
Kitchen
Laboratory spaces
Toilet rooms
Mechanical spaces
The gymnasium, a one-level building with a mezzanine, includes the
following areas:
A main playing floor
Shower, locker, and toilet rooms
Classrooms
Instructors' offices
Mezzanine playing floors
The main playing floor and the accessory areas are below grade. The
building's entrance is at the mezzanine level.
Mechanical System Description
In the existing mechanical system, heating is generated by two fire-tube
steam boilers, and the refrigeration is generated by one steam absorption
chiller and one reciprocal chiller.
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The air-moving system encompasses 32 air handlers (7 multizone and 25
single-zone), 282 fan coil units, convectors, and unit heaters. Air is
supplied via a ducted supply air system, and return air is provided by a
ceiling plenum system.
Asbestos-Containing Materials
Asbestos-containing fireproofing insulation had been spray-applied to
steel beams and columns on the first, second, and third floors and in
mechanical areas. The range of asbestos concentration for this moderately
friable material was 30 to 60 percent chrysotile asbestos, based on an anal-
ysis of 17 representative bulk samples by polarized-1ight microscopy and
dispersion staining,7 Throughout these areas, there was a considerable
amount of overspray on sections of the corrugated steel deck pan between the
treated beams. The treated beams are largely concealed by a suspended lay-in
or interlocking steel panel ceiling; however, in some areas the construction
design renders the fireproofed beams visible and exposed.
The structural beams on the lower level are also sprayed with friable
material, but this material does not contain asbestos. Many of these beams
are enclosed by drywall and therefore are not visible. Other beams on the
lower level are concealed above suspended ceilings, and still others are
exposed (visible).
Asbestos-containing fireproofing was also found in the gymnasium, on the
ceiling above the mezzanine level, and in the mechanical equipment and stor-
age rooms. The spray-applied material on beams above the suspended ceiling
on the lower level of the gymnasium contains no asbestos fibers; it is com-
prised primarily of fibrous glass.
ABATEMENT PROGRAM
A multiphase asbestos abatement and renovation program was conceived and
implemented. The first abatement phase (conducted during the summer of 1984)
included the following areas:
Academic Building:
Third floor - all rooms
North and south large-group instructional rooms (sidewall enclo-
sures)
Mechanical penthouses
Stairwells and elevator shafts
Industrial arts
TV studio/publications
Music rooms
Audi torium
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Gymnasium:
Storage rooms
Mechanical room
Concessions
Restrooms
Sources of friable asbestos-containing fireproofing were controlled by
removing the material or by enclosing the material in airtight enclosures in
areas where complete removal and replacement were not feasible. Decisions
regarding the most appropriate control method for each Phase I subspace were
based on EPA-recommended assessment factors for evaluating the potential for
fiber release.3
The procedures followed for the removal and enclosure of the asbestos-
containing fireproofing at Site 1 were consistent with those described in the
EPA guidance documents and complied with EPA and OSHA asbestos regulations.
Detailed specifications describing the scope of work, the work sequence, and
specific performance criteria for the abatement contractor were prepared by
the project team and distributed as part of the bid package. The technical
job specifications for the removal and enclosure of the asbestos-containing
fireproofing were based on the "Guide Specifications for the Abatement of
Asbestos Releases From Spray- or Trowel-Applied Materials in Buildings and
Other Structures," published by the Foundation of the Wall and Ceiling Indus-
try.8
An industrial hygiene technician was on site throughout the entire
abatement project. The field technician was under the direct supervision of
a certified industrial hygienist, who made weekly inspections of the job site
and was available for consultation should any problems arise during the
course of the project. The first phase of the asbestos-abatement program
began on May 30 and was completed (excluding final renovation items) by
August 11, 1984. The second phase of the abatement program was completed
during the summer months of 1985, and the third phase will be completed
during the summer of 1986.
The abatement activities were performed in three distinct stages, i.e.,
preparation, removal, and decontamination. Each of the building areas in-
cluded in Phase I (described previously) were isolated as separate abatement
work areas. Some work areas comprised multiple rooms (e.g., the third floor
classroom area, the music area) and some consisted of a single room (e.g.,
the penthouses, storage rooms, TV studio). Each work area was prepared by
turning off the ventilation and electrical systems; sealing off all air ducts
and openings; covering the floors, walls, and immovable objects with plastic
sheeting; installing HEPA-filtered exhaust units; antt constructing worker
decontamination facilities. Suspended ceilings and carpeting were removed
and disposed of as contaminated waste or cleaned and disposed of by conven-
tional means. Workers wearing full protective equipment and approved air-
purifying respirators removed the fireproofing by first wetting it with an
amended water solution and then scraping it off. The asbestos-containing
debris was placed in double 6-mil plastic bags and disposed of at a local
10
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EPA-approved sanitary landfill. All substrate materials from which asbestos
was removed were wire-brushed and wet-wiped repeatedly to remove as much of
the fireproofing material as possible. A "dry" removal method, which did not
utilize the amended water solution, was used in the TV studio room to prevent
damage to the acoustical panels and electronic equipment in this area.
All stripped or potentially contaminated surfaces were sprayed with an
approved asbestos sealant to bond any residual fibers to the substrate. The
work area was decontaminated by removing all loose debris, removing the plas-
tic sheeting from the walls and floors, and repeatedly wet-wiping or mopping
the walls and floors. When the work area had passed a thorough visual in-
spection and air monitoring showed that the fiber concentrations were less
than 0.05 fiber/cm3 (clearance level of contractor's specifications), the
barriers and HEPA-filtered exhaust units were removed and the area was opened
for occupancy by other tradesmen responsible for various components of the
renovation (e.g., fireproofers, painters, electricians, HVAC installers,
plasterers).
MONITORING APPROACH
Samples for subsequent PCM and TEM analysis were collected from two or
three representative locations within each designated work area after comple-
tion of all abatement activities but prior to any application of replacement
fibrous material (e.g., nonasbestos fireproofing). Plastic sheeting on walls
and floors had been removed, the substrate had been sprayed with a sealant,
and HEPA filter exhaust units had been removed. Air sampling was not con-
ducted until the abatement area had passed a rigorous visual inspection by
the onsite industrial hygienist and architect. In each designated work area,
both nonaggressive and aggressive sampling techniques were used. The non-
aggressive or static sampling was conducted first, followed by the aggressive
sampling. (The sampling procedures and analytical methods used in this study
are described fully in Section 5 of this report.) To summarize briefly, fil-
ter holders containing either 0.8-ym Millipore mixed-cellulose ester (PCM) or
0.4-ym Nuclepore polycarbonate filters (TEM) were positioned 4.5 to 5.5 feet
(1.4 to 1.7 m) above the floor at arbitrary locations. Battery-powered
sampling pumps were used to draw air through the filters. The constant-flow
pumps were calibrated to 2 to 3 liters per minute and were operated for 6 to
8 hours per test, depending on the contractor's schedule. Samples were
collected from several indoor work areas and at outdoor locations during each
monitoring period.
In addition to the postabatement monitoring, limited preabatement moni-
toring was conducted in an area of the auditorium to take advantage of the
one opportunity available for preabatement monitoring in the abatement pro-
gram schedule. Two PCM and two TEM preabatement samples were obtained and
analyzed.
Upon completion of each monitoring survey, samples were submitted to the
appropriate laboratory for preparation or analysis. The Nuclepore filters
were hand-carried to EPA for carbon coating before they were transported to
the laboratory for TEM analysis.
11
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SECTION 5
METHODS OF AIR SAMPLING AND ANALYSIS
OVERVIEW OF SAMPLING STRATEGY
Samples designated for PCM and TEM analysis were collected both aggres-
sively and nonaggressively in seven different work areas. Samples were also
collected from the surrounding environment outside the building. Each work
area consisted of a specific room or rooms and adjacent hallways, closets, or
other spaces that were treated as a separate component of the total abatement
project. The building areas sampled included the auditorium, gymnasium, in-
dustrial arts rooms, music rooms, projection booth, TV Studio, and elevators.
These sampling locations were not selected as part of a study design; selec-
tion was dictated by the contractor's abatement sequence and schedule. After
completion of abatement efforts in the individual work areas, representative
PCM and TEM samples were collected. All outdoor air samples were collected
in the parking lot adjacent to the school building, with the exception of one
sample, which was collected on the roof of the building.
All post-abatement air samples were collected while the work area was
still isolated (i.e., containment barriers were in place), but after 1) the
substrate had been sprayed with a sealant, 2) the plastic sheeting covering
the walls and floor had been removed, and 3) all surfaces had been wet-wiped.
Because of timing, limited preabatement monitoring in one area of the audito-
rium was conducted prior to any abatement activity in the auditorium. Inso-
far as possible, outdoor air sampling was conducted concurrently with indoor
sampling. Inclement weather or equipment availability sometimes made this
impossible.
Whenever possible, side-by-side (one PCM, one TEM) samples were collec-
ted in each work area under nonaggressive and aggressive sampling conditions.
Accessibility restrictions prevented aggressive sampling in some areas. As
each building area became available, sampling was performed in the following
sequence. Samples designated for both PCM and TEM analysis were collected
under nonaggressive conditions approximately 1 to 24 hours following a satis-
factory visual inspection of the work area by the architect and onsite indus-
trial hygienist, depending on the contractor's schedule for final cleaning.
Immediately afterward or on the following day, samples for PCM and TEM analy-
sis were again coveted, this time under aggressive conditions (i.e., turbu-
lent air movement). Placement of the sampling equipment within each work
area was the same during both nonaggressive and aggressive sampling. The
number of samples per work area was not specified by study design; however,
efforts were made to collect at least two of each type of sample within each
work area.
12
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SAMPLING METHODOLOGY
Sampling Equipment
Samples for subsequent PCM analysis were collected on 37-mm Millipore
Type AA, mixed-cellulose ester membrane filters (0.8-ym pore size). The
filters were preassembled in three-stage polystyrene cassettes by the manu-
facturer. Samples for TEM analysis were collected on 37-mm Nuclepore poly-
carbonate membrane filters (0.4-ym pore size). The polycarbonate membrane
filter was supported within a three-stage polystyrene cassette by means of a
support pad and backup filter (mixed-cellulose ester membrane, 5-ym pore
size). Each sample cassette was sealed with a cellulose shrink band to
prevent air from entering the sides of the unit during sampling.
Battery-operated personal sampling pumps equipped with rotameters and/or
constant-flow controls were used to draw air through the sample filters. All
sampling pumps were calibrated with a soap-film flowmeter before and after
sample collection. The rotameter setting of each calibrated sampling pump
was noted to provide a visual indication of proper pump functioning, and the
settings were checked periodically throughout the sampling period.
Sample Collection and Handling
Samples designated for both PCM and TEM analysis were collected at a
known flow rate of approximately 2 to 3 liters per minute (LPM). Sampling
duration was 6 to 8 hours. The average sample volume per filter was 1,200
1 iters.
All samples were collected open-faced (i.e., with the face cap of the
cassette device removed) to expose the maximum effective surface area of the
filter. During sampling, the face caps were carefully stored in clean,
resealable, plastic bags. The filter cassettes were positioned at breathing
zone height [4.5 to 5.5 feet (1.4 to 1.7 m) above the floor] and were sup-
ported by taping the end of the sampling hose to the wall or clipping it to
an adjustable tripod. The sample cassettes were also positioned so that the
membrane filters were angled (approximately 45 degrees) toward the floor.
Figure 1 shows a typical sampling apparatus.
At the end of the sampling period, each filter cassette was turned
upright (i.e., the filter plane was parallel to the floor), the sampling pump
was turned off, the face cap of the three-stage filter cassette was reposi-
tioned tightly on the cassette, the cassette was disconnected from the sam-
pling hose, a plastic plug was inserted into the cassette outlet, and the
cassette was placed face-up in a box for transport. All PCM and TEM filter
samples were maintained in this upright position from the time of collection
until they were carbon-coated or were analyzed by the appropriate laboratory.
The PCM analysis equipment was available at the Columbus East site, and
a portion of the PCM samples (final-clearance samples collected under non-
aggressive conditions) were analyzed on site shortly after completion of
sampling. Rapid reporting of these sample results was essential so that the
13
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Figure 1. Photograph of a typical sampling apparatus. Personal sampling
pump and filter cassette are positioned on an adjustable tripod.
14
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building areas could be released to the contractor for additional nonabate-
ment work and renovation. The remaining PCM filters were hand-carried to the
laboratory, where they were subsequently analyzed.
The TEM samples were submitted to the EPA Project Officer (or his repre-
sentative) and hand-carried to EPA in Cincinnati, where they were carbon-
coated. The TEM samples were then either shipped via overnight courier or
hand-carried to the laboratory for analysis.
Nonaggressive Sampling
mtmmmmmmaimmim« W n n ¦ mm mi i ¦ i.i.nnniii.nt m i iii.hi mlfc
Samples for PCM and TEM analysis were collected under nonaggressive con-
ditions for comparison with similar samples collected under aggressive condi-
tions. The sampling condition was considered nonaggressive when air movement
in the work area was negligible and/or minimized to the greatest possible
extent. It is postulated that under this condition asbestos fibers (or any
other particulate matter) will "settle out" if given sufficient time. Any
work area, no matter how contaminated, can be totally "clean" as defined by
PCM as long as enough time is allowed to elapse prior to sampling (nonaggres-
sive). The probability of reentrainment of these asbestos fibers is much
lower during nonaggressive conditions than during conditions of typical
building use or aggressive sampling conditions. In this study, nonaggressive
sampling conditions existed when the work area was sealed off, all ventila-
tion was shut off, and personnel access was prohibited. These are the typi-
cal conditions under which air monitoring is conducted at a work site follow-
ing asbestos removal and decontamination.
Aggressive Sampling
Samples for PCM and TEM analysis were also collected under aggressive
sampling conditions. Aggressive conditions were created by introducing air
turbulence into the sampling area by intermittent use of a hand-held electric
blower. The air movement created was much greater than would exist under
conditions of normal building use. It is postulated that under these aggres-
sive sampling conditions most asbestos fibers susceptible to entrainment
would become airborne and remain suspended for the duration of the sampling
period, as long as the use of fans or the hourly introduction of air turbu-
lence is continued. Thus, an aggressive environment provided the best possi-
ble setting for high or "worst-case" airborne asbestos fiber concentrations
following abatement.
The blower used in this study was a 1-hp electric power blower, as shown
in Figure 2 and in the background in Figure 1. The airflow rate at the
blower outlet is approximately 300 ft3/min (8.5 m3/min). The electric blower
was equipped with a two-piece plastic tube extension and concentrator nozzle
that enabled the operator to direct the airstream at objects and surfaces
within the sampling area.
Aggressive sampling conditions were created in each of the work areas
sampled by an initial "blow-down" of all surfaces, followed by hourly agita-
tion with the blower throughout the duration of the sampling period. During
15
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Figure 2. Photograph of the electric blower used for
aggressive sampling.
16
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aggressive sampling, all containment barriers isolating the work area were
intact and building air handling systems remained shut off. In some instanc-
es, it was necessary for the contractor to remove the HEPA-filtration units
for use in another, active work area. Figure 3 shows photographs of the ag-
gressive sampling procedure in progress. The sequence of operations is
summarized below.
1. A technician entered the work area, positioned the sampling equip-
ment, and started the sampling pumps.
2. Using a back-and-forth motion, the technician directed the air-
stream of the electric blower at all surfaces within the sampling
area (walls; floors; ceilings; all junctures between walls, ceil-
ings, and floors; and any other exposed surfaces within the area
enclosure). The technician then exited the sampling area.
3. After an elapsed time of approximately 1 hour, the technician
reentered the work area and repeated the blow-down of all surfaces.
This procedure was then repeated hourly for the duration of the
sampling period. Unless actively engaged in manipulating the
electric blower, the technician did not remain within the enclo-
sure.
4. At the end of the sampling period, samples were collected, sam-
pling pumps were turned off, and the sampling equipment was removed
from the area.
The technician used appropriate respiratory protection and
decontamination procedures.
METHODS OF ANALYSIS
Phase-Contrast Microscopy
All PCM samples were analyzed in accordance with NIOSH Method No. P&CAM
239.9 This optical microscopic technique is the method the Occupational
Safety and Health Administration uses to measure total airborne fibers in
occupational environments. The EPA guidance document pertaining to asbestos
in buildings recommends a visual inspection followed by air monitoring by the
membrane filter collection technique and phase-contrast microscopic analysis
as one method for evaluating satisfactory completion of asbestos abatement
and decontamination of the worksite.3
Airborne fiber concentrations are determined by NIOSH Method No. P&CAM
239 through microscopic examination of the fibers collected on a mixed-cellu-
lose ester membrane filter. A triangular wedge comprising approximately
one-eighth of the entire surface area of the 37-mm-diameter filter is removed
from the sample cassette, mounted on a microscope slide, and examined. The
17
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filter wedge is rendered into an optically transparent homogeneous gel by the
use of a slide-mounting solution of 1:1 (by volume) dimethyl phthalate and
diethyl oxalate. A microscope equipped with a phase-contrast condenser is
used to size and count the fibers at 400-450X magnification. Only those
fibers longer than 5 micrometers and having a length-to-width ratio of 3 to 1
or greater are counted. Fibers are sized by comparing fiber length with the
diameters of the calibrated circles of a Porton reticle. Sample analysis
continues until at least 20 fibers or 100 microscopic fields have been counted.
Microscopic field areas generally range from 0.003 to 0.006 mm2. The fiber-
counting procedure follows the rules specified in the analytical method.
The estimated average airborne asbestos fiber concentration in the
filter sample is calculated by using the following formula:
where
AC = [(FB/FL) - (BFB/BFUKECA)
L (FR)(T)(MFA)
AC = Airborne fiber concentration in (fibers < 5 ym)/m3
BFB = Total number of fibers counted in the BFL fields of the
blank or control filters in fibers < 5 ym
BFL = Total number of fields counted on the blank or control
fiIters
ECA = Effective collecting area of filter (855 mm2 for a 37-mm
filter with an effective diameter of 33 mm)
FR = Pump flow rate in liters/min (LPM)
FB = Total number of fibers counted in the FL fields in fibers
< 5 ym
FL = Total number of fields counted on the filter
MFA = Microscope count field area in mm2 (a field area 0.003136
mm2 was used by the PEI Laboratory)
T = Sample collection time in minutes
The minimum total fiber count in 100 fields that is considered adequate
for reliable quantitation is 10 fibers. Thus, the lower limit of reliable
quantification for this method is approximately 27,300 fibers/m3 (or 0.027
fibers/cm3 when 1000 liters of air are sampled). During this study, most of
the PCM samples collected under nonaggressive conditions and several of the
PCM samples collected under aggressive conditions yielded fiber counts less
than the reliable quantitation limit (i.e., less than 10 fibers in 100
fields). The fiber concentrations of these samples were calculated and
reported based on the actual number of asbestos fibers counted rather than
merely "less than the limit of reliable quantitation" because it was believed
this would provide valuable information about these data that otherwise would
have been lost. The precision, accuracy, and coefficient of variation asso-
ciated with sample results below the reliable level of quantitation have not
been determined.
Analyses of several other PCM samples collected during this study yield-
ed counts of zero fibers per 100 fields. Because one-half of one fiber is
19
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the smallest quantity permitted to be counted in the counting rules specified
in P&CAM 239, these sample concentrations are reported as less than the
lowest limit of detection (e.g., the fiber concentration based on counting
1/2 of a fiber in 100 fields) as shown in the following calculations:
_ Number of fibers counted/100 fields
Detection limit - Volume of air sampled (m^)
Effective collecting area of the filter (mm2)
Microscopic field area (mm2/field)
m 0.5 fiber/100 fields
Sample calculation. DL - j—272 m^
v 855 mm2/filter = Q „ fi5ers/m3
x 0.003136 mnvVfield
Transmission Electron Microscopy
Nuclepore filters were prepared and analyzed for asbestos content by TEM
in accordance with the Methodology for the Measurement of Airborne Asbestos
by Electron Microscopy by Yamate, et al.10 The current TEM methodology was
developed particularly for application to samples collected from a volume of
air in which the asbestos concentration is considered a minor component of
the total particulate loading. Carbon-coating of the samples was performed
by the EPA staff. Completion of sample preparation and sample analyses were
performed by the TEM laboratory.
Three levels of TEM analysis are described in the methodology. Briefly
summarized, Level I TEM analysis involves examination of the particulates
deposited on the sample filter by a 100-kV transmission electron microscope.
Asbestos structures (fibers, bundles, clusters, and matrices) are counted,
sized, and identified as to asbestos type (chrysotile, amphibole, ambiguous,
or no identity) by morphology and by observing the selected area electron
diffraction (SAED) patterns. The width-to-length ratio of each particle that
is counted is recorded. Level II TEM analysis consists of a Level I analysis
plus chemical elemental identification by energy-dispersive spectrum (EDS)
analysis. Energy-dispersive analysis is used to determine the spectrum of
the X-rays generated by an asbestos structure. X-ray elemental analysis is
used for further categorization of the amphibole fibers, identification of
the ambiguous fibers, and confirmation or validation of chrysotile fibers.
All Nuclepore samples collected in this study were analyzed by Level II TEM.
Level III TEM analysis (not used in this study) consists of a Level II anal-
ysis plus quantitative SAED of individual fibers. Quantitative SAED is a
more extensive SAED analysis than that used for Level II. Fibers are exam-
ined from different orientations or viewing angles and compared with SAED
patterns from asbestos mineral standards.
After sampling was completed, the Nuclepore polycarbonate filters were
carbon-coated. Carbon-coating, the first step in the sample preparation
procedure, is accomplished by removing the face cap from the cassette holder
20
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to expose the surface area of the sample filter and then securing the open-
faced holder to a rotating turntable for carbon-coating within a high-vacuum
carbon evaporator. Once carbon-coated, a 3-mm diameter section of the poly-
carbonate filter (usually midway between the center and edge) is placed on a
3-mm diameter electron microscope grid. The polycarbonate membrane is then
dissolved with solvent, which results in a membrane-free EM grid with part-
icles embedded in the carbon film coating. An optional step in sample prepa-
ration is gold-coating (accomplished in a manner similar to that for carbon-
coating). The thin gold coating provides an internal standard for SAED
analysis.
The prepared samples were examined with the transmission electron micro-
scope at 20.000X magnification for particulate counting and sizing. A min-
imum of 100 fibrous structures or 20 grid openings, whichever came first,
were examined. (Analytical protocol requires that a minimum of 100 fibrous
structures or 10 grid openings be examined. In this study, 20 grid openings
were examined to lower the detection limit because very low fiber concentra-
tions were expected in these postabatement samples.) The exact counting
rules and sizing techniques are described in greater detail in Appendix A.
In addition to particulate counting and sizing, the SAED patterns from all
fibrous structures identified were observed. From visual examination of the
SAED pattern, a fibrous structure can be classified as belonging to one of
four categories: 1) chrysotile, 2) amphibole group (includes amosite, croci-
dolite, anthophyllite, tremolite, and actinolite), 3) ambiguous, or 4) no
identification. The SAED patterns cannot be identified for all particulates
(particularly matrices/debris, clusters/clumps) because of the absence of a
recognizable diffraction pattern. X-ray elemental analysis with EDS was used
to categorize the amphibole fibers, to identify the ambiguous fibers, and to
confirm or validate chrysotile fibers. A sample laboratory summary analysis
report is shown in Figure 4. The dimensional analysis and EDS results for
this sample are presented in Appendix B.
The fiber concentration of the filter sample is calculated by using the
following equation:
Total no. of fibers
No. of EM fields
Total effective filter area, cm2
Area of an EM field, cm2
1
Volume of air sampled, m3
The total effective filter area is 8.6 cm2. The areas of the grid
openings varied, typically ranging from 0.00005 to 0.00007 cm2. The average
grid opening area per sample was calculated and recorded on the laboratory
analysis report.
The theoretical limit of detection for the TEM analyses performed was
based on counting one fiber or structure in 20 grid openings. This limit of
detection is calculated by the following formula:
Fibers/m3 =
x
x
21
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TEH Asbestos Analysis Report
Sample I.O.: EPA 98-903 Date Analyzed: 1/3-4/85 IITRI Sample No.: C06610-018
Date Sample Received: 8/29/84 Sample Type: Dulk Water Misc. (circle one)
Filter Type: 37 mm Nuclepore Filtration Area (cm7) 8.6 Volume of Fluid Sampled: 1037 L
Number of Grid Openings: 16 Number of Grids Examined: 2 Average Area of Grid Opening (cm2) • 00006434
Total Area Examined (cm2) .0010294 Detection Limit: 8,056 asbestos structures per m3
Comments:
Area Examined Filtration Area No./Volume
No. No. No./L tlo./CC
Ho. of Fibrous Structures (Total) 102 852,147 822
No. of Chrysotlle Structures 92 768.603 741
No. of Amphibole Structures 2 16,709 16
No. of Other* Structures 8 66,835 64
No. of Fibers (Total) 41_ 342,530 330
llo. of Asbestos Fibers 35 292.403 292
Ho. of Chrysotlle Fibers 34 284.049 274
Ho. of Amphibole Fibers ] 8.354 fl.
No. of Matrix/Debris (Asbestos) 22 183.796 177
No. of Cluster/Clumps (Asbestos) 16 133.670 l?q
No. of Bundles (Asbestos) j>] 175.442 lfiQ
* Category of "other" Includes: Ambiguous, Non-Asbestos, and No E. 0. Pattern.
** DDL * Below Oetectable Limit.
Coments:
Figure 4. TEM asbestos analysis report.
-------
nn+n^+-iAn nm,-+ _ 1 fiber „ Area of filter (cm2)
No. of grid Area of grid opening (cm2)
openings scanned
1 1 fiber 8.6 cm2
Volume of air (m'J " 20 x 10-„ cm2
x OSTi3 " 9921 fibers<'m3
Analyses of several TEM samples collected during this study yielded
counts of zero fibers or structures per 20 grid openings. These samples are
reported at less than the detectable limit (as calculated by the aforemen-
tioned equation).
QUALITY ASSURANCE
The objective of quality assurance activities is to provide quality data
through the use of proper sampling procedures, careful handling of samples,
the use of calibrated analytical equipment and standardized analytical proto-
cols, and the checking of fiber analysis calculations. As standard procedure
for tasks performed under this EPA contract, a comprehensive, written Quality
Assurance Project Plan (QAPP) is prepared and submitted to EPA at least 30
days prior to the performance of any sampling, analyses, or data reductions.
In this instance, however, the abatement schedules at the sites selected for
monitoring and the dates of issuance of this task and work plan approval did
not allow sufficient time for the preparation, review, and approval of a
formal QAPP before the sampling had to begin. As a result, the requirement
for submittal of a written QAPP was waived to take advantage of a unique
opportunity to collect field data from this large-scale asbestos abatement
site. Under these conditions, the following QA/QC criteria were incorporated
into the scope of this project and documented field and laboratory procedures
to ensure the integrity of the data generated.
Filter Preparation
All Mi 11ipore membrane filters used in the collection of asbestos air
samples were preassembled by the manufacturer in three-piece plastic cas-
settes, and all were from the same production lot number. All the Nuclepore
polycarbonate filters used for sampling also were from the same lot and were
loaded into Millipore filter cassettes (on top of the 5.0-ym mixed-cellulose
ester filter and cellulose backup pad) by laboratory personnel in a remote,
clean area of the laboratory. The monitoring cassettes were reassembled, and
a cellulose shrink band was placed around the base and middle stages of each
cassette. The monitoring cassettes were labeled with a Field Sample ID
Number prior to sampling.
Sampling
Constant-flow and/or rotameter-equipped personal sampling pumps were
used to draw air through the filter/cassette assembly at a known flow rate
23
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between 2 and 3 liters/minute. Each pump was calibrated on site before
sampling and checked after sampling by the soap bubble-buret method. Rota-
meters on the sampling pumps were checked periodically during the sampling
period to ensure the constancy of the flow rate. No flow rate adjustments
were required during the sampling periods.
The sampling strategy was to collect two or three pairs of samples in
each completed work area (each pair consisting of one PCM and one TEM sam-
ple). The filter cassettes were positioned about 5 feet (1.5 m) above the
floor and were supported by taping the end of the hose to the wall or clip-
ping it to a tripod. The sampling locations were determined arbitrarily
rather than randomly. The sampling strategy was to have at least one sam-
pling location in the center of the area and one near the perimeter.
Field record books were maintained by the onsite field technicians or
supervisor at each sampling site. Air Monitoring Data Sheets (Figure 5) were
used to record the following information for each series of air tests:
0 Sampling site
° Date and time
° Location of sampling equipment
° Sample number
° Sample type
° Sampling method
° Sampling parameters (flow rates, start time, stop time, duration)
° Field technicians' observations
Upon completion of sampling, each filter cassette was turned upright
(i.e., the filter plane was parallel to the floor), the pump was turned off,
the face cap was positioned tightly on the filter cassette, and the cassette
was disconnected from the sampling hose. The filter cassettes were handcar-
ried to the appropriate laboratory for analysis or to an intermediate site
for carbon-coating and then carried or shipped via courier to the analytical
lab.
The Millipore filters for PCM analysis were checked into the laboratory,
where each sample was assigned an alphanumeric identity code. The Nuclepore
samples were submitted to the EPA, where the samples were carbon-coated. The
TEM analyses of the Nuclepore filters were then performed by the TEM labora-
tory.
Chain of Custody
A chain-of-custody form (Figure 6) was filled out in ink for each set of
samples collected in the field. Each form was initiated by the onsite field
technician who collected the samples. The next person having custody of the
samples noted receipt of the samples and completed the appropriate section of
the form. As standard procedure, samples arriving at the PEI laboratory are
checked in by the laboratory sample custodian, who examines the shipping
container and each filter cassette for any evidence of damage or tampering,
notes any damage or indication of tampering on the enclosed chain-of-custody
form, and then signs the form. Once samples are received by the laboratory,
24
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Sheet No.
AIR SAMPLING DATA SHEET
DATE
Facility
Address
City State _________ Zip ______
Sample
No.
Location
Equipment
Flow
rate,
/m1n
Time
Volume,
liters
Units,
Cone.,
Type
ID
On
Off
Net
Figure 5. Air sampling data sheet.
25
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SAMPLE SHIPPING/RECEIVING RECORD
1. NAME OF ESTABLISHMENT PN
2. SENDER
Signature
3.
Cc
Si
Dl
B /
CARRIER
impany
4. RECEIVER
Courier from Depot
Date
qnature
Signatu
Date
re
Sent from
te
i id riKTnntiu
L No.
Signatu
Date
re
Conditi
Receipt
un upon
5. SHIPMENT DESCRIPTION
Number of packages
Seal No.
Seal
Intact?
Seal No.
Seal
intact?
Sealed (ves or no)
Types of containers
Condition prior to Shipment
6. ".ONTENTS
Sample I.D. number
Type of
sample
Sealed
(yes or no)
Seal No.
if any
Condition (damaged,
loss of liquid, etc.)
Figure 6. Chain-of-custody form.
(Sample shipping/receiving record.)
26
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a similar intralaboratory chain-of-custody procedure is maintained so that
the location of the samples and the person having custody are always known.
Sample Analysis
The PCM samples were analyzed in accordance with NIOSH Method No. P&CAM
239. All microscopists performing PCM analyses have successfully completed
NIOSH Course No. 582, Sampling and Evaluating Airborne Asbestos Dust, and
have participated in the NIOSH Proficiency Analytical Testing (PAT) Program.
As part of the American Industrial Hygiene Association's laboratory accred-
itation program, the laboratory that conducted the PCM analyses participates
in the NIOSH PAT Program. This program currently includes bimonthly analyses
for asbestos and other occupational contaminants. Known reference standards
(i.e, PAT asbestos samples) are routinely analyzed to ensure the accuracy of
the PCM results. The results of analysis of PAT asbestos reference samples
have consistently fallen within the acceptable limits of variation for the
method. A record of the precision of the PCM analysis is generally kept by
calculating the coefficient of variation of the results of replicate analy-
ses. One sample blank is analyzed for every 10 samples to check the quality
of the filter media and sample preparation procedure.
All data generated by the laboratory and by the field technician during
this task were checked for technical accuracy by the laboratory supervisor or
the certified industrial hygienist. This involved verifying that the mathe-
matical computations were correct and that the appropriate formulae were
used. The laboratory supervisor reported the analytical data in writing to
the PEI project manager.
27
-------
SECTION 6
RESULTS
AIR MONITORING RESULTS
Table 1 presents a detailed listing of the results of PCM and TEM analy-
sis of samples collected during aggressive and nonaggressive sampling condi-
tions after abatement. The concentrations of asbestos fibers and total
structures under nonaggressive sampling conditions were higher than the
corresponding measurements made under aggressive sampling conditions in six
samples analyzed by TEM (nonaggressive samples 18, 20, and 61 and aggressive
samples 22, 24, and 67). This difference was in sharp contrast with the
overall results, in which concentrations of asbestos fibers and total struc-
tures for samples collected during aggressive sampling were generally higher
than the corresponding concentrations in samples collected under nonaggres-
sive conditions. A review of the results for these six samples revealed no
obvious cause for this apparent discrepancy.
Comparisons of the results of PCM and TEM analyses under nonaggressive
and aggressive sampling are presented graphically in Figure 7, which is based
on all of the results presented in Table 1. As shown in this figure, the
measured fiber concentrations after abatement varied widely under both non-
aggressive and aggressive sampling conditions, regardless of the analytical
method used. For example, fiber concentrations determined by PCM ranged from
less than 0,002 to 0.09 x 106 fibers/m3 for nonaggressive sampling and from
0.002 to 0.11 x 106 fibers/m3 for aggressive sampling. Similarly, concentra-
tions determined by TEM ranged from 0.006 to 0.583 x 106 fibers/m3 for nonag-
gressive sampling and from 0.0147 to 1.267 x 106 fibers/m3 for aggressive
sampling.
STATISTICAL COMPARISONS
Statistical Method of Analysis
The Mann-Whitney test was used to determine whether the observed dif-
ferences in analytical methods and sampling conditions were statistically
significant.11 Use of the Mann-Whitney test required no a priori assumption
regarding the nature of the underlying probability distribution function of
measurements of asbestos fiber concentrations. A detailed discussion of the
Mann-Whitney test and an example of its application are presented in Appen-
dix C.
28
-------
TABLE 1. RESULTS OF PCM & TEM ANALYSES
Nonaggressive
Aggressive
PCM
TEM
PCM
TEM
Work area/location
Sample
number
106 fibers/in3
Sample
number
106 asbestos3
fibers/m3
106 asbestos*3
structures/in3
Sample
number
10' fibers/m'
Sample
number
106 asbestos8
fibers/m3
10s asbestos6
structures/m5
Auditorium
Prop storage, west
515
0.007c
86
0.007
0.007
521
0.01c
95
0.047
0.199
Prop storage, east
516
0.004c
88
0.010
0.010
523
0.052
97
0.149
0.887
Prop storage, center
d
-
87
0.030
0.030
522
0.039
96
0.105
0.527
Mechanical room (at unit)
517
0.0Q8C
89
0.007
0.007
526
0.071
101
0.942
3.140
Mechanical room (back
room)
518
0.008c
91
0.007
0.021
527
0.050
103
0.885
1.986
Mechanical room (hall)
d
-
90
0.0K
0.014
d
-
102
0.578
1.733
Make-up room (center)
519
0.QQ6C
92
0.039
0.049
524
e
98
0.282
0.757
Women's dressing room
520
0.013C
93
0.035
0.059
525
0.020C
99
0.240
0.480
Men's dressing room
d
-
94
<0.Q12f
<0.012f
d
-
100
0.171
0.435
Elevators
Main elevator
489
490
o.of
o.or
79
80
0.006
0.007
0.006
0.013
d
d
-
d
d
-
Small elevator
507
508
<0.002;!
<0.002®
83
84
0.026
0.019
0.026
0.045
d
d
-
d
d
-
Gynnasium
South gym, second level
35
0.003C
34
0.088
0.164
40
0.015c
39
e
e
South gym, ground level
(north end)
36
0.002c
37
e
e
41
0.052
42
0.693
1.896
South gym, ground level
(south end)
d
d
-
38
0.162
d
0.328
d
d
-
43
44
1.267
0.702
3.411
1.703
North gym, second level
50
<0.002®
49
0.028
0.028
55
0.028
54
0.329
0.737
North gym, ground level
52
0.007c
51
0.011
0.011
57
0.076
56
0.443
1.302
North gym, ground level
at door
d
-
53
0.191
0.240
d
-
58
0.488
1.315
(continued)
-------
I
TABLE 1 (continued)
fionaggressive
Aggressive
PCM
TEH
PCM
TEH
Work area/location
Sample
number
106 fibers/m3
Sample
number
10f» asbestos4
fibers/m3
106 asbestos15
structures/m3
Sample
number
106 fibers/m3
Sample
number
106 asbestos3
fibers/m3
106 asbestosb
structures/m3
Industrial Arts
Room 1206
17
0.006c
18
0.275
0.540
22
0.026c
23
0.082
0.188
Room 1211
19
0.010c
20
0.583
0.946
24
0.11
25
0.221
0.612
Room 1204
d
-
21
0.173
0.357
d
-
26
0.106
0.261
Music Room
Room M102
62
0.008c
61
0.214
0.435
67
0.002c
66
0.017
0.022
Room HI 12
64
0.005c
63
0.034
0.067
69
e
68
0.551
1.111
Hallway
d
-
65
e
e
70
0.007c
d
-
-
Projection Booth
East
72
0.09
71
0.278
0.786
d
-
d
-
-
Center
d
-
73
0.328
1.078
d
-
d
-
-
West
78
0.07
77
0.162
0.418
d
-
d
-
-
Ambient (outdoors)
Ground level, 7/23/84
6
<0.002"
7
0.011
0.011
Ground level, 7/25/84
9
0.005c
8
0.055
0.055
Ground level, 7/30/84
32
0.001c
33
0.006
0.012
Ground level, 7/31/84
45
-------
TABLE 1 (continued)
a fiber concentration based upon the total number of asbestos fibers counted.
k Concentration based upon the total number of chrysotile and amphibole structures counted. These asbestos structures include asbestos fibers,
asbestos matrices/debris, asbestos clusters/clumps, and asbestos bundles.
c Less than 10 fibers in 100 fields were counted. Fiber concentration based upon the actual number of fibers counted in 100 fields. Fiber concen-
tration is below the reliable limit of quantitation (i.e., 10 fibers in 100 fields).2 Sample calculation:
_ 10 fibers/100 fields Effective collecting area of the filter (mm2) _ 10 fibers/100 fields
Lower limit of reliable quantitation - Vo1ume of alV smp)iTW) * Microscopic fJel3 area (mm3)/field L 07TP *
855 mm2/fi1ter
0.003136 nrnV-field
21,434 fibers/m3
d Area not sampled because of equipment availability or time constraints.
e Sample damaged or tampered with; not analyzed.
' Below detection limit (no fibers or structures counted in 20 grid openings). Sample calculation:
u.i, _ 1 fiber „ Area of filter (on2) „ 1 _ I fiber
No. of grid Area of grid opening (cm2) Volume of air (m3)
openings scanned
8.6 cm2 „ 1
0.63 X 10"* X cm2 0.688 m3
9921 fibers/m3
9 No fibers were detected in 100 fields. Below the detection limit (e.j., counting 0.5 fiber in 100 fields). Sample calculation:
_ 0.5 fiber/100 fields Effective collectinq area of the filter (mm2) _ 0.5 fiber/100 fields
Detection limit - volume of air sampled (m*) x Microscopic field area (nm^/fleld OTFP
855 nm2/fi1ter . ^ih„,c/m3
0.003136 mm2/field * 1072 f,bers/ln
h Total number of fibers counted in 100 fields.
1 Total number of asbestos fibers (or structures) counted in 20 grid openings.
-------
AGGRESSIVE
TEM
AGGRESSIVE
PCM
NOKAGf.RESSIVE
TEH
CO
ro
UNAGGRESSIVE
PCM
AMBIENT TEH
AMBIENT PCH
.001
.002 .003 .004 .005 .007 .010
.020
.030 .040 .050 .070
10 FIBEPS/m
.100
3
0.200 .300 .400.500 .700 1.00
2.00
Figure 7. Comparison of airborne fiber concentrations.
-------
Analytical Methods
Table 2 presents a comparison of the geometric averages of fiber concen-
trations determined by PCM and TEM analyses under nonaggressive and aggres-
sive sampling conditions. Table 3 presents a summary of these results. As
indicated earlier, it must be recognized that PCM and TEM concentrations re-
late to different fiber populations, as defined by their detection limits and
by their standard protocols. Based on the application of the Mann-Whitney
test and the assumption that the fiber/volume concentrations are comparable,
the difference between PCM and TEM results is statistically significant
(i.e., p <0.02) for ambient sampling and for indoor sampling under nonaggres-
sive and aggressive sampling conditions. The ratios of TEM/PCM concentra-
tions for nonaggressive sampling were 6.5 for ambient samples and 5.2 for
indoor samples. For aggressive sampling, the ratio of TEM/PCM was 9.8.
Sampling Conditions
Tables 2 and 3 also provide a comparison of nonaggressive and aggressive
sampling conditions for both PCM and TEM analyses. The difference between
the geometric average fiber concentrations under nonaggressive and aggressive
sampling conditions was statistically significant (i.e., p <0.001) for PCM
and TEM. The ratio of aggressive to nonaggressive fiber concentrations for
PCM analyses was 3.4; for TEM analyses, the ratio was 6.3.
Appendix D presents a comparison of TEM results from two air samples
taken from the same location during nonaggressive and aggressive conditions.
These figures exemplify the findings of this study, i.e., that the concentra-
tions of asbestos fibers and structures measured under aggressive sampling
conditions are considerably higher than those measured under nonaggressive
conditions.
Indoor Versus Ambient Samples
Also included in Tables 2 and 3 are the PCM and TEM analyses for samples
collected in the ambient atmosphere. For samples analyzed by PCM, the geo-
metric mean fiber concentration was 0.008 x 106 fibers/m3 for indoor samples
compared with 0.002 x 10e fibers/m3 for ambient samples--a ratio of 4 to 1.
The PCM method, however, is not sufficiently sensitive for effective detec-
tion of these ambient and indoor (nonaggressive) concentrations, because they
are below the lower limit of reliable quantitation by the method. Conse-
quently, the observed differences between the two sample groups are probably
not meaningful.
For the TEM samples collected indoors (under nonagressive conditions),
the geometric mean asbestos fiber concentration was 0.042 x 106 fibers/m3
compared with 0.013 x 106 fibers/m3 for ambient samples--a ratio of 3.2. The
observed difference between these indoor, nonaggressive, TEM asbestos fiber
concentrations and the ambient TEM asbestos fiber concentrations was statis-
tically significant (P = 0.009). The ratio of indoor asbestos concentrations
under aggressive sampling conditions to ambient asbestos concentrations was
20.5.
33
-------
TABLE 2. COMPARISON OF NONAGGRESSIVE AND AGGRESSIVE SAMPLING RESULTS FOR POST-ABATEMENT TESTING
Nonaggressive
Aggressive
PCM
TEH
PCM
TEM
PCM
aqgres-
sive/non-
aggressiye
fibers,
106/m3
TEM aggressive/
nonaggressive
Samples
included
in comparison
Asbestos
fibers,
106/m3
Asbestos
struc-
tures,
106/m3
Asbestos
fibers,
106/m3
Asbestos
struc-
tures,
106/m3
No. of
samples
Fibers,3
106/m3
No. of
samples
TEM/PCM
fibers
No. of
samples
Fibers,3
106/m3
No. of
samples
TEM/PCM
fibers
Asbestos
fibers
Asbestos
structures
Indoor
20
0.008
26
0.042
0.064
5.2
14
0.027
20
0.266
0.725
9.8
3.4
6.3
11.3
Outdoor
10
0.002
10
0.013
0.015
6.5
CO
a All concentrations are geometric means.
-------
TABLE 3. SUMMARY COMPARISON OF PCM AND TEM ANALYSES OF AIR SAMPLES COLLECTED
DURING NONAGGRESSIVE AND AGGRESSIVE CONDITIONSa
Sample location
Analytical technique
Outdoor (ambient)
Postabatement static
(Nonaggressive)
Postabatement
aggressive
Phase contrast microscopic (PCM) analysis,
fibers/m3
BDLb or BLRQC [10]
(2,000)
BDL or BLRQ [20]
(8,000)
27,000 [14]
Transmission electron microscopic (TEM)
analysis
Asbestos fibers/m3
13,000 [10]
42,000 [26]
266,000 [20]
Asbestos structures/m3
15,000
64,000
725,000
a All values are geometric means.
k BDL = Below detection limit (sllOO fibers/m3).
c BLRQ = Below limit of reliable quantitation (=21,000 fibers/m3).
[ ] = number of samples.
-------
Expanded TEM Data From Nonaggressive and Aggressive Sampling Conditions
Table 4 presents additional data from the TEM asbestos analysis reports,
including the types of asbestos fibers observed, the number of other fibrous
structures, and the numbers of nonfibrous asbestos particles (i.e, matrix/de-
bris, cluster/clumps, and bundles). The relationship and significance of
these other parameters, as influenced by different sampling conditons and
monitoring locations, are currently being investigated.
Preabatement Monitoring
Table 5 presents the results of the limited preabatement monitoring and
subsequent postabatement monitoring conducted in the prop storage area of the
auditorium. The concentrations of asbestos fibers and total structures
determined by TEM under nonaggressive sampling conditions were higher than
those under aggressive sampling conditions, which is in sharp contrast with
overall study results (Table 2). A possible explanation for this phenomenon
is the dilution that may have occurred as a result of opening the garage door
during the aggressive sampling period.
A comparison of preabatement fiber concentrations with postabatement
concentrations yields mixed results. Postabatement fiber concentrations
under nonaggressive sampling conditions were substantially lower for both PCM
and TEM analyses; however, the reverse was generally true for the same com-
parison during aggressive sampling conditions. Again, the dilution factor
that may have been introduced during the preabatement aggressive sampling
phase is a possible explanation.
In summary, the conditions during the preabatement sampling period that
may have affected the analytical results (variable air flow caused by the
open garage door and the presence of fibrous fireproofing material) preclude
the use of these data for drawing meaningful conclusions regarding the pre-
abatement monitoring.
Results of Monitoring After Dry Removal
The data from the monitoring conducted under nonaggressive sampling
conditions after dry removal in the TV studio area are presented in Table 6.
A comparison of these limited data (two samples) with the overall nonaggres-
sive postabatement results obtained after the use of the wet method (Table 2)
indicates that postabatement fiber concentrations after the use of the dry
removal method, as determined by the PCM and TEM methods, are slightly higher
than those following the use of the wet removal method.
36
-------
TABLE 4. EXPANDED TEM DATA FROM UNAGGRESSIVE AND AGGRESSIVE SAMPLING CONDITIONS
-
Nonaggressive
Concentration, 10* units/"1
Work area/location
Sample
number
Asbestos,
10* fibers/m'
10* asbestos
structures/a®
Tot
asb
fib
Chry
fib
Amp
f 1 b
Tot
f 1b
Tot
fib
struc-
tures
Chry
Struc-
tures
Amp
struc-
tures
Other
struc-
tures
Asb
mat/
deb
Auditorium
Prop storage, west
86
0.007
0.007
0.007
0.007
NO®
0.195
0.240
0.007
ND
0.232
NO
Prop storage, east
88
0.010
0.010
0.010
0.010
NO
0.076
0.095
0.010
ND
0.086
ND
Prop storage, center
87
0.030
0.030
0.030
NO
0.030
0.040
0.040
ND
0.D30
0.010
ND
Mechanical room (at unit)
89
0.007
0.007
0.007
0.007
ND
0.087
0.087
0.007
ND
0.080
NO
Mechanical room (back
room)
91
0.007
0.021
0.007
ND
0.007
0.065
0.079
0.014
0.007
0.057
ND
Mechanical room (hall)
90
0.014
0.014
0.014
0.007
0.007
0.101
0.101
0.007
0.007
0.087
ND
Make-up room (center)
92
0.039
0.049
0.039
0.039
NO
0.779
0.808
0.049
ND
0.759
0.010
Women's dressing room
93
0.035
0.059
0.035
0.024
0.012
1.024
1.060
0.047
0.012
1.001
NO
Wen's dressing rocn
94
<0.012
NO
ND
NO
NO
0.168
0.168
ND
NO
0.168
NO
Elevators
Main elevator
79
80
0.006
0.007
0.006
0.013
0.006
0.007
NO
0.007
0.006
ND
0.032
0.119
0.038
0.153
ND
0.013
0.006
ND
0.032
0.139
ND
0.007
Small elevator
4 83
84
0.026
0.019
0.026
0.045
0.026
0.019
0.013
0.006
0.013
0.013
0.070
0.096
0.070
0.148
0.070
0.032
0.013
0.013
0.013
0.013
0.045
0.103
Gymnasit*
South gym, second level
34
0.068
0.164
0.088
0.088
NO
NRb
NR
0.164
ND
NR
0.006
South gym, oround level
{north endj
37
C
c
c
C
C
c
C
C
C
South gy*i, oround level
(south endj
38
0.162
0.328
0.162
0.151
0.010
NR
NR
0.318
0.010
NR
0.099
North gym. second level
49
0.028
0.028
0.028
ND
0.028
0.049
0.049
ND
0.028
0.021
ND
North gym, ground level
SI
0.011
0.011
0.011
0.011
ND
0.016
0.022
0.011
ND
O.OU
ND
North gyc. ground level
at door)
53
j 0.191
0.240
0.191
0.181
0.011
0.255
0.308
0.229
o.ou
0.069
0.011
(continued)
-------
TABLE 4 (continued)
Aggressive
Concentration, 10* units/m*
Hork area/location
Asb
clus/
ctu«p
Asb
bun-
dles
Sample
lumber
Asbestos,
10* fibers/m5
106 asbestos
structures/**5
Tot
asb
fib
Chry
fib
tap
-fit
Tot
fib
Tot
fib
struc-
tures
Chry
struc-
tures
top
struc-
tures
Other
struc-
tures
Asb
eat/
deb
Asb
clus/
clump
Asb
bun-
dles
AudUorlim
Prop storage, west
NO
NO
95
0.047
0.199
0.047
0.047
ND
0.111
0.269
0.199
NO
O.Q70
0,012
0.041
0.099
Prop storage. e«st
ND
K0
97
0.1*9
0.88?
0,149
0.149
NO
0.187
0.953
0.88?
NO
0.065
0.336
0.243
0.159
Prop storage, center
WD
HO
96
0.105
0.527
0.105
0.100
0.006
0.138
0.571
0.521
0,006
0.044
0.183
0.122
0.116
Mechanical roon (at unit)
ND
NO
101
0.942
3.140
0.942
0.942
HO
0.999
3.198
3.140
NO
0.057
1.028
0.685
0.485
Mechanical room (back
roo«}
NO
0.014
103
0.885
1.986
0.S85
0.885
NO
1.003
2.124
1,985
m
0.138
0.570
0.315
0.216
Mechanical room (hall)
ND
HO
102
0.578
1.733
0.578
0.578
TO
0.630
1.803
1.733
ND
0.070
0,718
0.315
0.123
Make-up room (center)
ND
NO
98
0.282
0.757
D.282
0.274
0.008
0.330
0.822
0.741
0.016
0.064
0.177
0.129
0.169
Jfoaien's dressing room
NO
0.024
99
0.240
0.480
0.240
0,228
0.012
0.302
0.542
0.468
D.012
0.062
0.092
0.055
0.092
Men's dressing room
KD
NO
100
0.171
0.435
0.171
0.171
NO
0.404
0.729
0,435
ND
0.295
0.14D
0.031
0.093
Elevators
Main elevator
NO
ND
ND
NO
Saw 11 elevator
ND
KD
NO
0.006
Gyonasiutn
South gjw, second level
0.018
0.053
5e«th qym, around level
(north end]
c
c
42
0,693
1.896
0.693
0.693
KD
0.784
2.041
1.896
ND
0.146
0.456
0.292
0.456
South gya, around level
(south end)
0.026
0.04?
43
1.267
3.411
1.267
1.267
NO
1.332
3.574
3.411
NO
G. 162
1.137
0.487
0.520
Horth gy®, second level
NO
ND
54
0.329
0.737
0.329
0.329
KD
0.442
0.867
0.737
NO
0.130
0.208
0.095
0.104
north fyw, ground level
IfO
ND
56
0.443
1.302
0.443
0.443
ND
0.470
1.356
1.30?
ND
0.054
0.537
0.121
0.201
North gy», ground level
(at door)
0 027
0.011
58
0.488
1.315
0.4B8
0.447
0.041
0.529
1.451
1.274
0.041
0.136
0.393
0.190
0.244
-------
TABLE 4 (continued)
Aggressive
Concentration, 10* units/in3
Horfc area/location
Asb
clus/
CllMp
Asb
bun-
dles
Sample
number
Asbestos,
10* fibers/m'
106 asbestos
structures/in'
Tot
asb
fib
Chry
fib
Amp
fib
Tot
fib
Tot
fib
struc-
tures
Chry
struc-
tures
Amp
Struc-
tures
Other
struc-
tures
Asb
mat/
deb
Asb
clus/
clump
Asb
bun-
dles
Industrial Arts
Roc* 1206
0,081
0.110
23
0.082
0.188
0.082
0.082
NO
0.196
0.335
0.188
NS
0.1*7
0.041
0.008
0.057
Room 1211
o.evs
0.152
25
0.22!
0.612
0.221
0.206
0,014
0.343
0.747
0.598
0.014
0.135
0.100
0.085
0.206
Room 1204
0,018
0.083
26
0.106
C.261
0.106
0.106
ND
0.148
0.303
0.261
NO
0.Q42
0.077
0.035
0.042
Music Room
Room Ml02
0.058
0.081
66
0.017
0.022
0.017
0.006
0.011
0.028
0.039
o.on
0.011
0.017
NS
0.006
ND
Soon Ml12
SO
0.017
SB
0.551
i.m
0.551
0.514
0.037
0.560
1.121
1.074
0.037
0.009
0.224
0,131
0.205
Hallway
c
c
d
d
4
d
d
d
d
d
a
d
d
d
d
d
Projection Booth
East
0.090
0.147
Center
0,070
0.305
West
0.047
0.084
Aabient (outdoors)
Sround level, 7/23/84
11
ND
Ground level, 7/25/84
MI)
NO
Ground level, 7/30/84
NO
0.006
Ground level, 7/31/84
*r
ND
Ground leve', 8/2/84
so
NO
Ground level, 8/3/84
nt
NO
On roof, 8/6/84
w
ND
Ground level, 8/8/84
NO
NO
Ground level, 8/9/84
NO
NO
Ground level, 8/10/84
*r
NO
Blanks
w
m
NO
NO
NO
ND
NO
NO
(continued)
-------
TABLE 4 (continued)
Nonaggresslve
Mork area/location
Sample
number
Asbestos,
106 fibers/m*
10* asbestos
structures/m3
Concentration, 10* un1ts/mJ
Tot
asb
fib
Chry
fib
Amp
fib
Tot
fib
Tot
fib
struc-
tures
Chry
Struc-
tures
Amp
struc-
tures
Other
struc-
tures
Asb
mat
deb
Industrial Arts
Rook 1206
16
0.275
0.540
0.275
0.270
0.006
0.297
0.561
0.534
0.006
0.022
0.07
Room 1211
20
0.583
0.946
0.563
0.566
0.017
0.608
0.979
0.929
0.017
0.034
0.14
Room 1204
21
0.173
0.357
0.173
0.167
0.006
0.233
0.428
0.351
0.006
0.071
0.08
Music Room
Room K102
61
0.214
0.435
0.214
0.209
0.006
0.249
0.475
0.429
0.006
0.041
o.oe
Room HI 1?
63
0.034
0.067
0.034
0.008
0.025
0.042
0.084
0.042
0.025
0.017
O.Ol
Hallway
65
c
c
c
c
c
c
c
c
c
c
c
Projection Booth
East
71
0.278
0.786
0.276
0.270
0.008
0.328
0.893
0.776
0.008
0.106
0.?7
Center
73
0.328
1.078
0.328
0.293
0.035
0.363
1.230
1.043
0.035
0.152
0.37
West
77
0.162
0.418
0.162
0.151
0.010
0.193
0.475
0.402
0.016
0.057
0.12
tabient (outdoors)
Ground level, 7/23/84
7
0.011
0.011
0.011
NO
0.011
0.032
0.03?
NO
0.011
0.021
ND
Ground level, 7/2S/84
8
0.055
0.055
0.055
NO
0.055
NR
NR
NO
0.055
NR
ND
Ground level, 7/30/84
33
0.006
0.012
0.006
NO
0.006
0.019
0.026
0.006
0.006
0.013
NO
Ground level, 7/31/84
46
0.017
0.018
0.017
0.006
0.012
0.087
0.098
0.006
0.012
D.081
NO
Ground level, 8/2/84
47
<0.010
<0.010
NO
NO
NO
0.010
0.010
NO
ND
0.010
NO
Ground level, 8/3/84
59
<0.008
<0.008
NO
NO
NO
0.023
0.023
NO
NO
0.023
NO
On roof, 8/6/84
74
0.020
0.020
0.020
0.007
0.013
0.027
0.027
0.007
0.013
0.007
ND
6round level, 8/8/84
81
0.01?
0.01B
0.012
NO
0.012
0.087
0.099
0.006
0.012
0.06?
0.00
6round level, 8/9/84
82
0.018
0.024
0.018
NO
0.018
0.036
0.042
NO
0.D24
0.018
0.00
Ground level, 8/10/84
65
0.006
0.006
0.006
NO
0,006
0.045
0.051
ND
0.006
0.045
NO
Blanks
15
2
2
2
NO
2
2
2
NO
2
NO
ND
104
2
2
2
2
NO
2
2
2
ND
NO
NO
105
NO
NO
NO
NO
NO
NO
NO
NO
NO
ND
NP
106
6
6
6
1
5
6
6
1
5
ND
ND
a NO « None detected 1n the grid openings examined.
^ NR « Not recorded In the laboratory analysis report.
c Sample damaged or tampered with; not analyzed.
^ Area net sampled because of equipment availability cr time constraints.
* Total number of asbestos fibers (or structures, flumps, etc.) counted in ?0 grid openings.
-------
TABLE 5. RESULTS OF PCM AND TEM PRE-ABATEMENT AND POST-ABATEMENT SAMPLES COLLECTED IN THE AUDITORIUM
Nonaggressive
Aggressive
PCM
TEH
PCM
TEH
Sample
Sample
106 asbestos3
106 asbestosb
Sample
Sample
106 asbestos3
106 asbestos''
Work area/location
number
106 fibers/m3
number
fibers/m3
structures/m3
number
106 fibers/m3
number
fibers/m3
structures/m3
Auditorium - Preabatement
Prop storage, west
11
0.014°,d
10
0.083°
0.155°
27
0.036e
28
0.031e
0.066e
Prop storage, east
13
0.014°,d
12
0.063°
0.222°
29
0.038e
30
0.023e
0.082e
Prop storage, center
f
-
14
0.043°
0.135°
f
-
31
0.011e
0.032e
Geometric mean
0.014
0.061
0.167
0.037
0.020
0.056
Auditorium - Postabatement
Prop storage, center
f
-
87
0.030
0.030
522
0.039
96
0.105
0.527
Prop storage, west
515
0.007d
86
0.007
0.007
521
0.01d
95
0.047
0.199
Prop storage, east
516
0.004d
88
0.010
0.010
523
0.052
97
0.149
0.887
Geometric mean
0.005
0.013
0.013
0.027
0.090
0.453
a Fiber concentration based upon the total number of asbestos fibers counted.
^ Concentration based upon the total number of chrysotile and amphibole structures counted. These asbestos structures include asbestos fibers,
asbestos material debris, asbestos clusters/dumps, and asbestos bundles.
c
During the nonaggressive sampling period, the garage door was open in the morning, closed during the afternoon. The contractor used this area to
store Monokote fireproofing material.
d Fiber concentration below the reliable limit of quantitation (i.e., less than 10 fibers in 100 fields).
e Monokote fireproofing stored in garages in bags. Garage door opened occasionally to remove bags.
f Area not sampled because of time constraints, or unavailability of equipment.
-------
TABLE 6. RESULTS OF N0NA66RESSIVE PCM AND TEM POST-ABATEMENT
ANALYSES AFTER DRY REMOVAL
PCM
TEM
Work area/
location
Sample
number
106
fibers/m3
Sample
number
106 asbestos3
fibers/m3
106 asbestos^
structures/m3
TV studio
South
1
0.028
2
c
c
North
3
0.007e
4
0.051
0.051
West
d
-
5
0.029
0.117
Geometric
mean
0.012
0.038
0.077
a Fiber concentration based upon the total number of asbestos fibers counted.
k Concentration based upon the total number of chyrsotile and amphibole
structures counted. These asbestos structures include asbestos fibers,
asbestos matrices/debris, asbestos clusters/clumps, and asbestos bundles.
c Sample damaged; not analyzed.
^ Area not sampled because of equipment availability or time constraints.
e Below the reliable limit of quantitation.
42
-------
REFERENCES
1. U.S. Environmental Protection Agency. Asbestos-Containing Materials in
School Buildings: A Guidance Document, Part 1. Office of Toxic Sub-
stances, Washington, D.C. 1979.
2. Sawyer, R. N., and D. M. Spooner. Asbestos-Containing Materials in
School Buildings: A Guidance Document, Part 2. Office of Toxic Sub-
stances, U.S. Environmental Protection Agency, Washington, D.C. 1979.
3. U.S. Environmental Protection Agency. Guidance for Controlling Friable
Asbestos-Containing Materials in Buildings. Office of Toxic Substances,
Washington, D.C. 1983.
4. U.S. Environmental Protection Agency. Guidance for Controlling Asbes-
tos-Containing Materials in Buildings. Office of Toxic Substances,
Washington, D.C. 1985.
5. Falgout, D. Environmental Release of Asbestos From Conmercial Product
Shaping. Engineering-Science, Fairfax, Virginia. 1984.
6. Chatfield, E. J. Measurement of Asbestos Fibre Concentrations in Am-
bient Atmospheres. Study No. 10, Ontario Research Foundation. 1983.
7. PEDCo Environmental, Inc. Inventory of Friable Asbestos-Containing
Materials in Columbus East High School with Recommendations for Correc-
tive Action. Final Report. Volume I. January 1984.
8. Association of the Wall/Ceiling Industries - International, Inc. Guide
Specifications for the Abatement of Asbestos Release From
Spray-or-Trowel-Applied Materials In Buildings and Other Structures.
The Foundation of the Wall and Ceiling Industry, Washington, D.C.
December 1981.
9. National Institute for Occupational Safety and Health. Asbestos Fibers
in Air. NIOSH Method No. P&CAM 239. NIOSH Manual of Analytical
Methods, Second Ed., Vol. 1. U.S. Department of Health, Education, and
Welfare, Cincinnati, Ohio. April 1977.
10. Yamate, G., S. C. Agarwal, and R. D. Gibbons. Methodology for the
Measurement of Airborne Asbestos by Electron Microscopy (Draft). Pre-
pared by 11T Research Institute for the Office of Research and Develop-
ment, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina. July 1984.
43
-------
Mosteller, F., and R. E. K. Rourke. Sturdy Statistics: Nonparametrics
and Order Statistics. Addison Wesley, Reading, MA. 1973, pp. 56-72 and
Table A-9, pp. 337-338,
44
-------
APPENDIX A
METHODOLOGY FOR THE MEASUREMENT OF AIRBORNE ASBESTOS
BY TRANSMISSION ELECTRON MICROSCOPY - LEVEL II
ANALYSIS PROTOCOL*
LEVEL II ANALYSIS*
SUMMARY OF PROTOCOL
Level II analysis is a regulatory technique consisting of Level I
analysis plus chemical elemental analysis. Morphology, size, SAED pattern,
and chemical analysis are obtained sequentially. By a process of elimination,
mineral fibers are identified as chrysotile, amphibole, ambiguous, or "no-
identity" by morphology and SAED pattern. X-ray elemental analysis is used to
categorize the amphibole fibers, identify the ambiguous fibers, and confirm or
validate chrysotile fibers.
Level II analysis is summarized as follows:
(1) A known volume of air is passed through a polycarbonate
membrane filter (pore diameter, 0.4 pra; filter diameter,
37 or 47 mm) to obtain approximately 5 to 10 pg of
particulates per cm^ of filter surface.
(2) The particulate-laden filter is transported in its own
filter holder.
(3) The filter is carbon-coated in the holder.
(4) The particulates are transferred to an EM grid using a
refined Jaffe wick washer.
(5) The EM grid, containing the particulates, is gold-coated
lightly.
(6) The EM grid is examined under low magnification (250X to
1000X) followed by high-magnification (16.000X on the
fluorescent screen) search and analysis.
(7) A known area (measured grid opening) is scanned, and the
asbestos structures (fibers, bundles, clusters, and
matrices) are counted, sized, and identified as to
asbestos type (chrysotile, amphibole, ambiguous, or no
identity) by morphology and by observing the SAED pattern;
and finally by elemental analysis using EDS.
(8) The observations are recorded—a minimum of 100 fibrous
structures or 10 grid openings, whichever is first.
(9) The data are reduced and the results reported.
~
Reprinted from Yamate, G., S. C. Agarwal, and R. D. Gibbons. 1984.
Methodology for the Measurement of Airborne Asbestos by Electron
Microscopy. Draft Report. Office of Research and Development, U.S.
Environmental Protection Agency, Washington, D.C. Contract No.
68-02-3266.
45
-------
EQUIPMENT, FACILITIES, AND SUPPLIES
The following items are required for Level I analysis:
(1) A modern 100-kV TEM equipped with an EDS. A scanning
accessory as found in a STEM will increase the versatility
and analytical capability for very small fibers and for
fibers adjacent to other particulate matter. The
microscope should be equipped with the fluorescent viewing
screen inscribed with graduation of known radii to
estimate the length and width of fibrous particulates.
(2) A vacuum evaporator with a turntable for rotating
specimens during coating, for such uses as carbon-coating
polycarbonate filters, gold-coating EM grids, and
preparing carbon-coated EM grids.
(3) An EM preparation room adjacent to the room housing the
EM. This room should either be a clean-room facility, or
contain a laminar-flow class-100 clean bench to minimize
contamination duing EM grid preparation. Filter handling
and transfer to EM grids should be performed in a clean
atmosphere. Laboratory blanks should be prepared and
analyzed weekly to ensure quality of work.
(A) Several refined Jaffe wick washers for dissolving membrane
filters.
(5) Miscellaneous EM supplies and chemicals, including carbon-
coated 200-mesh copper grids, grid boxes, and chloroform.
(6) Sample collection equipment, including 37-mm-diameter or
47-mm-diameter filter holders, 0.4-pm (pore size)
polycarbonate filters, 5.0-|jm (pore size) cellulose ester
membrane filters for back-up, a sampling pump with
ancillary equipment, a tripod, critical orifices or flow
meters, and a rain/wind shield.
DESCRIPTION OF METHODOLOGY
1. Type of Samples—Source
This protocol is an expansion of the method originally developed for the
EPA for measuring airborne asbestos (Samudra et al., 1977; Samudra et al.,
1978). A broad interpretation of airborne has been to apply the term to
samples obtained from ambient air (the original purpose), aerosolized source
materials (such as the asbestos workplace environment, and fugitive dust
emissions), bulk-air material (such as total suspended particulate (TSP)
samples, dust, and powders) and any other type of sample obtained by nonre-
strictive use of (1) collection of a volume of air, (2) separation from the
air, and (3) concentration of the particulates onto a substrate. The airborne
protocol has also been applied to samples collected in the regulatory areas of
the EPA, as compared with, for example, the workplace environment (National
46
-------
Institute of Occupational Safety and Health), mining activities (U.S. Bureau
of Mines), and shipboard atmosphere (Federal Maritime Administration).
The present methodology has been optimized for application specifically
to samples collected from a volume of air in which the asbestos concentration
is considered a minor component of the total particulate loading (other analy-
tical methods are available for samples known to contain high concentrations
of asbestos); and in which the particles are less than 15 ym in diameter,
since particles greater than 15 pm either are not inhaled or are deposited in
the upper respiratory tract and expelled, and preferably less than 10 jim in
diameter as recommended by the Clean Air Scientific Advisory Committee
(Hileman, 1981), since particles up to 10 pm can be absorbed by the alveolar
region of the lung. These concentration and size restrictions will preclude
many air samples collected in an asbestos-processing environment and in bulk-
air material from the complete methodology. However, such samples can still
be examined with the TEM, within the limitations of the instrument by changes
in preparation techniques—provided the effects on the final results, such as
fractionation of size and representativeness of the sample, are carefully
considered.
2. Sample Collection and Transport
Sample Collection—
Sampling procedures vary depending on the nature of the sample, purpose
of collection, analytical method to be used, sample substrate, and time and
cost of sample collection relative to the total analytical effort. Neverthe-
less, the primary objective of sample collection always is to obtain a
representative, unbiased sample.
Impingers, impaction devices, electrostatic precipitators, and thermal
precipitators have been used in sample collection, but each has limitations.
Presently, the preferred substrates are membrane filters, which are manufac-
tured from different polymeric materials, including polycarbonate, mixed
esters of cellulose, polystyrene, cellulose acetate, and cellulose nitrate.
Polycarbonate membrane filters differ from the others in being thin, strong,
and smooth-surfaced, and in having sieve-like construction (circular pores
from top surface to the bottom). The other membrane filters are thicker, have
irregular-surfaces, and have depth-filter construction (tortuous paths from
top surface to bottom).
Consequently, polycarbonate filters have been selected for airborne
asbestos analysis. The collection of small-sized particles (prefer less than
10 um in diameter), the light loading of particulates, the uniform distribu-
tion of particulates attainable using a depth-type backing filter, the smooth
surface and circular holes (which aid in determining size and instrument tiif-
axis), and the relative ease in grid transfer (thin and strong) minimize
disadvantages of lack of retention and/or movement of large particles during
handling. Other membrane materials, such as the cellulose ester type, are
recommended for phase contrast and PLM, heavy particle loadings, and physical
retention of large particles.
47
-------
In microscopical analysis, uniformity of particulate distribution and
loading is critical to success. Air samples are taken on 37-mm-diameter or
47-mm-diaraeter, 0.4-ym (pore size) polycarbonate membrane filters using the
shiny, smooth side as the particle-capture surface. Cellulose ester-type
membrane filters (pore size, 5.0 ym) are used to support the polycarbonate
filter on the support pad (37-mra-diameter personal sampler) or on the support
plate (47-mm-diameter holder).
Field monitoring cassettes (37-mm-diameter) of three-piece construction
are available from several manufacturers. As with the 47-mm-diameter filters,
loading the cassettes with the support pad, back-up filter, and 0.4 ym (pore
size) polycarbonate filter should be carefully performed on a class-100 clean
bench. Since the filters are held in place by pressure fit rather than by
screw tightening, air must not enter from the sides of the unit; a plastic
band or tape (which can double as a label) should be used as a final seal.
Collecting airborne samples with proper loading requires experience.
Each of the following techniques is useful in collecting airborne samples for
direct microscopy, preserving representative sizes, without diluting
particulate deposits:
(1) For long-terra sampling at a site, test samples should be
returned to the laboratory by express mail service, or air
express service or by being hand-carried, and should then
be analyzed by scanning electron microscopy.
(2) The estimated particulate loading (deposit is barely
visible to the naked eye) should be bracketed by varying
the filtration rate-and using the same time, or by varying
the time and using the same filtration rate.
(3) An automatic particle counter, such as a light-scattering
instrument (0.3-ym detection) or a real-time mass monitor
(0.1-ym detection), should be used to obtain an
approximate particulate-loading level of the area.
Although any one of the three techniques will work, the suggested
technique is to take the samples as a set, varying the sampling rates and
using the same time so as to obtain filter samples with different particulate
loadings. Each set is composed of a minimum of four 37-mra-diameter or 47-mm-
diameter filter units—three for different particulate loadings (low, medium,
high), and the fourth for a field blank. Suggested sampling rates are 0 for
the field blank, 2.48 1/min for the low loading, 7.45 1/m for the medium, and
17.62 l/'min for the high, for a 30 min sampling period using a 47-mm-diameter
filter holder. Simultaneous sampling will provide at least one sample with a
particulate loading suitable for direct EM analysis.
TSP's range from 10 yg/m3 in remote, nonurban areas, to 60 yg/m3 in near-
urban areas, to 220 yg/m3 in urban areas. However, for heavily polluted
areas, TSP levels may reach 2000 yg/m3. A loading of 5 to 10 yg per cm2 of
filter is adequate for EM analysis; values beyond 20 to 25 yg per cm2 require
a dilution treatment. As an example, for 47-mm-diameter filters at face
velocities of 3.0 cm/s (2.48 1/min), 9.0 cm/s (7.45 1/min), and 21.2 cm/s
-------
(17.62 1/min), respectively, air volumes of 74.4 1, 223.5 1, and 528.6 1 are
sampled in 30 min. For a TSP level of 200 yg/m3, 14.88 yg (1.07 yg/cm2),
44.7 yg (3.23 yg/cm2), and 105.7 yg (7.63 yg/cm2), respectively, would be
collected on •47-mm-diameter filters (which would have effective filtration
areas of 13.85 cm2). The sampling time could be increased to 60 min for areas
having lower TSP levels, or reduced in a heavily polluted area (source
emissions).
Airborne samples from emission sources contain coarse particles (above
the respirable size) of large matrix structures, binder materials, road dust,
clay minerals, fillers, and other materials. For these samples, a fifth
filter unit can be added that has a size-selective inlet (cyclone, impactor,
or elutriator) attached prior to the filter unit. The flow pattern and flow
rates of the tandem sampling arrangement must be checked before use. A
satisfactory, tested combination presently used in California is a cyclone-
filter unit with a D50 cut-off of 2.5 ym at 21.7 1/min, and a D50 cut-off of
3.5 ym at 15.4 1/min (John and Reischl, 1980). Additional sampling devices,
such as impingers (used in biological sampling), impactors, and other
designated filter units (for TSP, XRD, or x-ray fluorescence (XRF), for
example) can be added to the system to obtain supplementary as well as inter-
related data.
This expandable multifilter sampling unit, designated Hydra, offers the
following advantages;
(1) It is small, inexpensive, and compact, so that an adult
can easily handle it.
(2) It is efficiently designed, and includes a tripod,
sampling pump, manifold, critical orifices, and a row of
preloaded 37-mm-diameter or 47-mm-diameter filter
holders. A rain/wind shield, size-selective cyclone-
filter units, tubing, and other extras can be added as
needed.
(3) Its sample preparation steps and handling are minimized.
(4) It allows complementary as well as supplementary analysis
(TSP, size fractionation, bacteria, and XRF, for example),
although additional air sampling capacity is required.
(5) It accommodates ambient air and source emission samples,
with or without a size-selective inlet.
(6) It allows synchronous sampling in several places in the
vicinity following the same sampling procedure, thereby
accommodating particulate concentration fluctuations.
(7) It includes filter holders that serve as transport and
storage units.
Hydra's disadvantages are a short sampling period, which may catch an episode;
a small sampling quantity or volume, which may not indicate the presence of
asbestos fibers; and a detection limit of 2 x 104 fibers/m3 for sampling 1 m3
of air with the 47-mm-diameter filter.
49
-------
Using 8 inch x 10 inch, or 102-rain-diameter filter sizes, is not
recommended. The sampling units are designed for purposes other than
microscopy. Interchanging the type of sample substrate filter (glass fiber or
paper to polycarbonate) does not correct the inherent problems of filter size
and sampling unit.
Sample Storage and Transport—
Once the sample is acquired, its integrity must be assured, and
contamination and loss of fibers prevented, until it is examined under the
EM. The low cost and small size of the 37-mm-diameter and 47-mm-diameter
filter holders enables them to be used as combination storage and transport
containers. The filter holders should be maintained in a horizontal position
during storage and transport to the laboratory so that the particulate-loaded
filters can be removed under optimally controlled conditions in the
laboratory.
For 47-mm-diameter holders (open-face) to be used in transport or
storage, the screw cap is carefully removed, and the shiny, waxy, stiff
separator paper used to keep the polycarbonate filters apart is carefully
placed on the retaining ring. The cap is then carefully screwed back on so
that the separator paper seals and protects the particulate-loaded filter
without touching it. The 37-mm-diameter, three-piece filter holder (aerosol
monitor) is used in its open-face position, and capped after usage for
transport and storage.
When the more expensive 47-mm-diameter holder is to be re-used
immediately, the particulate-loaded filter should be carefully removed and
placed in a 47-mm-diameter Petri-slide (such as that manufactured by the
Millipore Corp.*) This transfer takes place in the field rather than in the
laboratory, so that the Petri-slide should be taken into the field. The 37-
mm-diameter filter holder or the 47-mm-diameter holder/Petri-slide should be
secured and all necessary sample identification marks and symbols applied to
the holder.
3. Sample Preparation for Analysis—Grid Transfer
Carbon-Coating the Filter—
The polycarbonate filter, with the sample deposit and suitable blanks,
should be coated with carbon as soon as possible after sampling is
completed. To begin this procedure, the particulate-loaded 47-mm-diameter
polycarbonate filter is removed from the holder and transferred carefully to
an open-faced 47-mm-diameter Petri-slide for carbon-coating in the vacuum
evaporator (see Figure A1, Appendix A). If the 47-mm-diameter filter is
already in the Petri-slide, the cover is replaced with an open-face cover,
minimizing filter disruption. The 37-mm-diameter filter is left in the
holder, but the upper lid is removed to create an open-faced filter. The
open-faced holders are placed on the rotating turntable in the vacuum
* Millipore Corp., 80-T Ashby Rd., Bedford, Mass. 01730
-------
evaporator for carbon-coating. Figure A2 shows the multiple-coating
arrangement in the evaporator; Figure A3 shows a close-up of the 37-mm-
diameter and the modified 47-mm-diameter holders for carbon-coating.
For archival filters and those of larger sizes, portions of about 2.5 cm
x 2.5 cm should be cut midway between the center and edge using a scalpel.
The portions are then attached with cellophane tape to a clean glass
microscope slide and placed on the turntable in the vacuum evaporator for
coating.
Any high-vacuum carbon evaporator may be used to carbon-coat the filters
(CAUTION: carbon sputtering devices should not be used). Typically, the
electrodes are adjusted to a height of 10 cm above the level of the filters.
A spectrographically pure carbon electrode sharpened to a neck of 0.1 cm x
0.5 cm is used as the evaporating electrode. The sharpened electrode is
placed in its spring-loaded holder so that the neck rests against the flat
surface of a second carbon electrode.
The manufacturer's instructions should be followed to obtain a vacuum of
about 1.33 x 10~3 Pa (1 x 10~5 torr) in the bell jar of the evaporator. With
the turntable in motion, the neck of the carbon electrode is evaporated by
increasing the electrode current to about 15 A in 10 s, followed by 20 to 25 A
for 25 to 30 s. If the turntable is not used during carbon evaporation, the
particulate matter may not be coated from all sides, resulting in an undesir-
able shadowing effect. The evaporation should proceed in a series of short
bursts until the neck of the electrode is consumed. Continuous prolonged
evaporation should be avoided, since overheating and consequent degradation of
the polycarbonate filter may occur, impeding the subsequent step of dissolving
the filter. The evaporation process may be observed by viewing the arc
through welders goggles (CAUTION: never look at the arc without appropriate
eye protection). Preliminary calculations show that a carbon neck of 5 mm3
volume, when evaporated over a spherical surface 10 cm in radius, will yield a
carbon layer that is AO nm thick.
Following carbon-coating, the vacuum chamber is slowly returned to
ambient pressure, and the filters are removed and placed in their respective
holders or in clean, marked Petri dishes for storage on a clean bench.
Transfer of the Sample to the EM Grid—
Transferring the collected particulates from the carbon-coated
polycarbonate filter to an EM grid is accomplished in a clean room or on a
class-100 clean bench. The transfer is made in a Jaffe wick washer, which is
usually a glass Petri dish containing a substrate to support the EM
grid/carbon-coated membrane filter combination. Solvent is added to a level
to just wet the combination and cause gentle dissolution of the membrane with
minimum loss or dislocation of the particulates, resulting in a membrane-free
EM grid with particles embedded in the carbon film coating. The substrate
support can be stainless steel mesh bridges, filter papers, urethane foams, or
combinations of these.
51
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The refined Jaffe wick washer is described as follows:
(1) The glass Petri dish (diameter, 10 cm; height, 1.5 cm) is
made airtight by grinding the top edge of the bottom dish
with the bottom of the cover dish, with water and
carborundum* powder (80 mesh); this creates a ground-
glass seal (closer fit) and minimizes the need to refill
the Petri dish with added solvent. (The usual glass
Petri dish was found not to retain the solvent for long
periods of time, and unless the wicking substrate is kept
continuously wet, poor solubility of the membrane filter
results, leading to a poor-quality EM grid).
(2) A combination of foam and a single sheet of 9-cm filter
paper is used as the substrate support. A 3-cm x 3-cm x
0.6-cm piece of polyurethane foam (the packing in
Polaroid film boxes) is cut and placed in the bottom
dish. A 0.5-inch V-shaped notch is cut into the filter
paper; the notch is oriented in line with the side of the
foam, creating a well for adding solvent.
Spectrographic-grade chloroform (solvent) is poured into
the Petri dish through the notch until it is level with
the top of the foam (also level with the paper). The
foam will swell, and care is needed to avoid adding
solvent above the filter paper.
(3) On top of the filter paper, pieces of 100-mesh stainless
steel screen (0.6 cm x 0.6 cm) are placed, usually in two
rows, to make several grid transfers at one time (for
such uses as replicas), and to facilitate maintenance of
proper identity of each transfer.
(4) A 3-mm section (usually midway between the center and
edge) of the carbon-coated polycarbonate filter is cut in
a rocking motion with a scalpel. The section may be a
square, rectangle, or triangle, and should just cover the
3-mm EM grid.
(5) A section is laid carbon-side down on a 200-mesh carbon-
coated EM grid. (Alternatively, Formvar-coatedt grids or
uncoated EM grids may be used. Here, the carbon coating
on the polycarbonate filter forms the grid substrate.)
Minor overlap or underlap of the grid by the filter
section can be tolerated, since only the central 2-mm
portion of the grid is scanned in the microscope. The EM
grid and filter combination is picked up at the edges
with the tweezers and carefully laid on the damp 100-mesh
stainless steel screen. The EM grid-filter combination
will immediately "vet out" and remain on the screen.
* Carborundum is a registered trademark of the Carborundum Co., Carborundum
Center, Niagara Falls, N.Y. 14302.
t Formvar is a registered trademark of the Monsanto Company, R00 N. Lindbergh
Blvd., St. Louis, Mo.
52
-------
(6) Once all specimens are placed in the washer, more solvent
is carefully added through the notch to maintain the
liquid level so that it just touches the top of the paper
filter. Raising the solvent level any higher may float
the EM grid off the raesh or displace the polycarbonate
filter section.
(7) The cover is placed in the washer and oriented in place
over the specimen, and a map of the filter/grid/screen
arrangement is made on the glass cover and in the
logbook.
(8) Solvent (chloroform) is added periodically to maintain
the level within the washer until the filter is
completely dissolved by the wicking action (24 to 48 h).
(9) The temperature in the room must remain relatively
constant to minimize condensation of solvent on the
bottom of the cover and subsequent falling of solvent
drops on the EM grid. Should day-night or other
temperature differentials occur, solvent condensation on
the under-surface of the cover can be minimized by
placing the Jaffe washer at a slight tilt (three glass
slides under one edge of the Petri dish parallel to the
row of grids) to allow the condensation drops to flow
toward the lower edge rather than fall on the EM grids.
At temperatures lower than 20°C (68°F), the complete
filter solution may take longer than 72 h.
(10) After the polymer is completely dissolved, the stainless
steel mesh screen with the EM grid is picked up while wet
and set on lens paper tacked to the bottom of a separate
Petri dish. The EM grid is then lifted from and placed
next to the screen to dry. When all traces of solvent
have evaporated, the grid is stored in a grid box and
identified by location and grid box in the logbook.
Figure A4 illustrates the Jaffe wick washer method; Figure A5 shows the
washer. The foam/filter combination is presently preferred, as is use of a
closely fitted (by means of the ground-glass seal) Petri dish.
Gold Coating—
An additional step will aid in subjectively evaluating the SAED pattern.
This step is required for specimens from the upper Great Lakes area and for
those of unknown origins. After the particulates on the filter are
transferred to the EM grid, the grid is held to a glass slide with double-
stick tape for gold-coating in the vacuum evaporator. Several EM grids may be
taped to the glass slide with double-stick tape for gold-coating in the vacuum
evaporator. For comparison, one-half of the EM grids may be coated and the
other one-half not coated; recognition of the gold-coating is helpful in
searching and x-ray analysis. Several EM grids may be taped to the glass
slide for coating at one time. Approximately 10 mm of 0.015-cm-diameter
53
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(0.006-inch) pure gold wire is placed in a tungsten basket (10 cm from the
rotating table holding the EM grids) and evaporated onto the grid.
The thin gold-coating establishes an internal standard for SAED analysis.
For some mineral species, an internal standard will clarify visual identifica-
tion of the pattern of a fibrous particulate as being or not being an
amphibole species (for example, Minnesotaite as opposed to Amosite). With
experience, differentiation in SAED patterns can be observed. For samples of
known geographic origins, gold-coating is optional, since the additional
coating hinders observation and identification of small-diameter chrysotile
fibers.
4. TEH Examination and Data Collection
Figure A10 shows a modern TEM with capabilities for elemental analysis
with an EDS. The grid is observed in the TEM at magnifications of 250X and
1000X to determine its suitability for detailed study at higher magnifica-
tion. The grid is rejected and a new grid used if: (1) the carbon film over
a majority of the grid openings is damaged and not intact; (2) the specimen is
dark due to incomplete dissolution of the polycarbonate filter; or (3) the
particulate loading is too light (unless a blank) or too heavy with particle-
particle interactions or overlaps.
TEM Analysis (Morphology, SAED, and X-Ray Analysis)—
The following guidelines are observed for consistency in the analytical
protocol:
(1) Magnification at the fluorescent screen is determined by
calibration with a diffraction-grating replica in the
specimen holder.
(2) A field of view or "gate" is defined. On some
microscopes, the central rectangular portion of the
fluorescent screen, which is lifted for photographic
purposes, is convenient to use. On others, a scribed
circle or the entire circular screen may be used as the
field of view. The area of the field of view must be
accurately measurable.
(3) The grid opening is selected on a random basis.
(4) The analysis, morphology, and SAED are performed at a
tilt angle of 0°.
(5) The recommended instrument settings are: accelerating
voltage, 100 kV; beam current, 100 yA; film magnifi-
cation, 20,000X (which is equivalent to 16,000X on the
fluorescent screen for this instrument); and concentric
circles of radii 1, 2, 3, and 4 cm on the fluorescent
screen.
54
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The grid opening is measured at low magnification (about
1000X).
Since asbestos fibers are found isolated as well as with
each other or with other particles in varying arrange-
ments, the fibrous particulates are characterized as
asbestos structures:
Fiber (F) is a particle with an aspect ratio of 3:1 or
greater with substantially parallel sides.
Bundle (B) is a particulate composed of fibers in a
parallel arrangement, with each fiber closer than the
diameter of one fiber.
Cluster (CI) is a particulate with fibers in a random
arrangement such that all fibers are intermixed and no
single fiber is isolated from the group.
Matrix is a fiber or fibers with one end free and the
other end embedded or hidden by a particulate.
Combinations of structures, such as matrix and cluster,
matrix and bundle, or bundle and cluster, are categorized
by the dominant fiber quality—cluster, bundle, and
matrix.
Counting rules for single fibers, which are illustrated
in Figure A7 are as follows:
(a) Particulates meeting the definition of fiber are
isolated by themselves. With this definition, edge
view of flakes, fragments from cleavage planes, and
scrolls, for example, may be counted as fibers.
(b) Count as single entities if separation is equal to
or greater than the diameter of a single fiber.
(c) Count as single entities if three ends can be seen.
(d) Count as single entities if four ends can be seen.
(e) In general, fibers that touch or cross are counted
separately.
(f) Two or more fibers are counted as a bundle if the
distances between fibers are less than the diameter
of a single fiber, or if the ends cannot be
resolved.
(g) Fibrils attached longitudinally to a fiber are
counted as part of the fiber and the size (width) is
estimated based on the fiber-to-fibril relationship.
55
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(h) A fiber partially hidden by grid wires (one or two
sides of the grid opening) is counted, but labeled
as an X-fiber (X-F) in the structure column. If the
number of X-fibers is high enough to affect the size
distribution (mass, etc.), a large-mesh EM grid
should be used, such as 100 mesh (about 200 gra
wide).
(9) Sizing rules for asbestos structures are:
(a) For fibers, widths and lengths are obtained by
orienting the fibers to the inscribed circles on the
fluorescent screen. Since estimates are within
±1 mm, small-diameter fibers have greater margins of
error. Fibers less than 1 mm at the fluorescent
screen magnification level are characterized as
being 1 mm. A cylindrical shape is assumed for
fibers. X-fibers are sized by measuring their
entire visible portions in the grid opening.
(b) Bundles and clusters are sized by estimating their
widths and lengths. The sum of individual diameters
is used to obtain the total width, and an average
length for the total length. A laminar-sheet shape
is assumed, with the average diameter of the
individual fiber as the thickness.
(c) Matrices are sized by adding the best estimates of
individual fiber components. A laminar or sheet
structure is assumed for volume calculation.
(10) The method of sizing is as follows:
(a) An asbestos structure is recognized, and its
location in the rectangular "gate" relative to the
sides, inscribed circles, and other particulates is
memorized.
(b) The structure is moved to the center for SAED
observation and sizing.
(c) Sizing is performed using the inscribed circles. If
the structure, such as a fiber, extends beyond the
rectangular gate (field of view), it is superimposed
across the series of concentric circles (several
times, if necessary) until the entire structure is
measured.
(d) The structure is returned to its original location
by recall of the location, and scanning is
continued.
56
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Analytical Procedure—
The analytical procedure is as follows:
(1) EM grid quality is assessed at 250X.
(2) Particulate loading is assessed at 1000X.
(3) A grid opening is selected at random, examined at 1000X,
and sized.
(4) A series of parallel traverses is made across the grid
opening at the film magnification of 20,000X. Starting
at one corner, and using the tilting section of the
fluorescent screen as a "gate" or "chute," the grid
opening is traversed. Movement through the "gate" is not
continuous, but rather is a stop/go motion. On reaching
the end of one traverse, the image is moved the width of
one "gate," and the traverse is reversed. These parallel
traverses are made until the entire grid opening has been
scanned.
(5) Asbestos structures are identified morphologically and
counted as they enter the "gate."
(6) The asbestos structure is categorized as fiber (with or
without X-) bundle, cluster, or matrix, and sized through
use of the inscribed circles.
(7) The structure (individual fiber portion) is centered and
focused, and the SAED pattern is obtained through use of
the field-limiting aperture.
(a) SAED patterns from single fibers of asbestos
minerals fall into distinct groups. The chrysotile
asbestos pattern has characteristic streaks on layer
lines other than the central line, and some
streaking also on the central line. Spots of normal
sharpness are present on the central layer line and
on alternate lines (that is, 2nd, 4th etc.) The
repeat distance between layer lines is about 0.53 nm.
(b) Amphibole asbestos fiber patterns show layer lines
formed by very closely spaced dots, and have repeat
distances between layer lines also of about 0.53 nm.
Streaking in layer lines is occasionally present due
to crystal structure defects.
(c) Transmission electron micrographs and SAED patterns
obtained with asbestos standard samples should be
used as guides to fiber identification. An example
is the "Asbestos Fiber Atlas" (Mueller et al.,
1975).
57
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(8) From visual examination of the SAED pattern, the struc-
ture is classified as belonging to one of four cate-
gories: (1) chrysotile, (2) amphibole group (includes
amosite, crocidolite, anthophyllite, tremolite, and
actinolite), (3) ambiguous (incomplete spot patterns), or
(4) no identification. SAED patterns cannot be inspected
for some fibers. Reasons for the absence of a recog-
nizable diffraction pattern include contamination of the
fiber, interference from nearby particles, fibers that
are too small or too thick, and nonsuitable orientation
of the fiber. Some chrysotile fibers are destroyed in
the electron beam, resulting in patterns that fade away
within seconds of being formed. Some patterns are very
faint and can be seen only under the binocular micro-
scope. In general, the shortest available camera length
must be used, and the objective lens current may need to
be adjusted to give optimum pattern visibility for
correct identification. A 20-cm camera length and a 10X
binocular are recommended for inspecting the SAED pattern
on the tilted screen.
(9) The specimen holder is tilted for optimum x-ray detection
(40° tilt for the JEOL* 100C instrument's Tracor
Northernt NS 880 analyzer and Kevextt detector). The
categorized asbestos structure is maintained in its
centered position for x-ray analysis by means of the Z-
Lontroi.
(10) The spot size of the electron beam is reduced and
stigmated to overlap the fiber. As an option for STEM
instruments, the electron beam may be used in the spot
mode and the x-ray analysis performed on a small area of
the structure.
(11) The EOS is used to obtain a spectrum of the x-rays
generated by the asbestos structure.
(12) The profile of the spectrum is compared with profiles
obtained from asbestos standards; the best (closest)
match identifies and categorizes the structure. The
image of the spectrum may be photographed, or the peak
heights (Na, Mg, Si, Ca, Fe) recorded for normalizing at
a later time. No background spectra or constant acquisi-
tion time is required since the shape of the spectrum
(profile) is the criteria. Acquisition of x-ray counts
may be to a constant time; to a constant peak height for
a selected element, such as silicon (1.74 keV); or just
* JEOL (U.S.A.) Inc., 11 Dearborn Road, Peabody, Mass. 01960
t Tracor Northern Inc., 2551-T.W. Beltway Hwy., Middleton, Wis. 53562
tt Kevex Corp., Chess Dr., Foster City, Calif. 94404
58
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long enough to get an adequate idea of the profile of the
spectra, and then aborted. Figure All illustrates
spectra obtained from various asbestos standards and used
as referenced profiles.
(13) The specimen holder is returned to 0° tilt to examine
other asbestos structures.
(14) Scanning is continued until all structures are
identified, measured, analyzed, and categorized in the
grid opening.
(15) Additional grid openings are selected, scanned, and
counted until either the total number of structures
counted exceeds 100 per known area, or a minimum of 10
grid openings has been scanned, whichever is first.
(16) The TEM data should be recorded in a systematic form so
that they can be processed rapidly. Sample information,
instrument parameters, and the sequence of operations
should be tabulated for ease in data reduction and
subsequent reporting of results. Figure A12 shows an
example of a data sheet used in Level II analysis.
Figure A9 illustrates the method of scanning a full-grid opening. The
"field of view" method of counting, which is based on randomly selected fields
of view, has been discontinued. Originally, the method was recommended for
medium loading level on the filter (50 to 300 fibers per grid opening).
However, if samples are collected at three different loading levels and the
optimum is selected, this medium loading on the filter will not be used.
Samples with grid openings containing 50 to 300 fibers may be used as
laboratory fiber preparations or selected source samples, but in field
samples, the particulate loading is usually of much higher concentration than
the fiber. Filter loading is characterized by particulate concentration, not
by fiber concentration.
EDS is relatively time-consuming, and becomes redundant if used as
repetitive analysis for a confirmatory check on chrysotile fibers. Chrysotile
identity by morphology and visual SAED analysis is not as controversial as
amphibole identification and categorization.
The following rules are recommended for EDS analysis (Level II):
(1) For chrysotile structure identification, the first five
are analyzed by EDS, then one out of every 10.
i2) For amphibole structure identification, the first 10 are
analyzed by EDS, then one out of every 10.
(3) For amphibole structure identification and categorization,
all confirmed amphiboles are analyzed by EDS.
(4) For ambiguous structure identification and categorization,
all are analyzed by EDS.
59
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Energy dispersive x-ray analysis as used in asbestos analysis is
semiquantitative at best. X-ray analyzer manufacturers may claim quantitative
results based on calibration standards and sophisticated computer software,
but such claims are based on stoichiometric materials and extension of work
with XRF instrumentation. Asbestos has a varying elemental composition. The
electron beam in an EM is of varying size, and not all instruments are
equipped to measure the beam current hitting the specimen. The size of the
specimen has an effect on the X-ray output, and nearby materials may fluoresce
and add to the overall x-ray signals being generated. Moreover, specimen
tilting results in a loss of x-ray acquisition from particles hidden by grid
wires or by other particles.
The only consistency in x-ray analysis is that the intensity of the
output, within restrictions, is proportional to the mass, therefore providing
the semiquantitative analytical possibility. Asbestos minerals have been
found to have a characteristic profile, although not an exact duplicate of
each other. For example, the Mg:Si ratio of chrysotile may vary from 5:10 to
10:10, averaging about 7:10. The ratio can be used to confirm the morphology
and visual SAED analysis.
Table 1 illustrates the phenomena of variability with resemblance for
some of the amphibole fibers. Peak heights and profile measurements were
taken.
To aid in the visual perspective of the spectrum profile, the peak
heights were normalized to a silicon value of 10, resulting in a five-number
series that is relatively easy to visualize—as in the following examples:
chrysotile ~ 0-7-10-0-0
tremolite ~ 0-4-10-3-
-------
TABLE 1. PROFILE COMPARISON OF ASBESTOS STANDARDS
Asbestos Type
Size, u
Na
HK
SI
Ca '
Fe
Profile
Amoslte (GF-38A)
0.19 x 1.44 (stlgmate)
1R2
497
386
0-4-10-0-8
0.19 x 0.75 (STEM)
186
528
387
0-4-10-0-7
0.19 x 1.25
1R1
352
289
0-5-10-0-8
0.19 x 0.88 (100 s)
226
870
674
0-3-10-0-8
0.25 x 1.81 (100 s)
576
4207
3338
0-1-10-0-8
0.12 X 1.56
253
2049
1515
0-1-10-0-7
0.31 x 2.38
256
2127
1613
0-1-10-0-8
0.19 x 1.56
276
1696
1116
0-2-10-0-7
Repeat
477
2945
1959
0-2-10-0-7
Anthophylllte (AF-45)
0.56 x 2.38 (stlgmate)
631 t
2577
349
0-2-10-0-1
0.31 x 2.38 (stlgmate)
640
1670
71
0-4-10-0-0
0.31 x 5.19 (stlgmate)
1064
3610
466
0-3-10-0,-1
0.19 x 1.56 (stlgmate)
507
2191
309
0-2-10-0-1
0.19 x 1.BR (stlgmate)
787
2286
257
0-3-10-0-1
CrocldoLlte (CR-37)
0.19 x 0.81 (stlgmate)
131
100
885
501
2-1-10-0-6
0.06 x 0.50 (stlgmate)
28
28
205
115
1-1-10-0-6
0.06 x 0.69 (stlgmate)
37
35
171
96
2-2-10-0-6
0.12 x 1.00 (stlgmate)
44
53
379
204
1-1-10-0-5
Repeat (STEM)
70
64
612
333
1-1-10-0-5
0.12 x 0.62 (stlgmate)
56
65
479
260
1-1-10-0-5
0.12 x 1.12 (stlgmate)
53
56
326
166
2-2-10-0-5
0.19 x 1.5b (stlgmate)
78
83
735
421
1-1-10-0-6
0.06 x 1.69 (stlgmate)
45
48
290
159
2-2-10-0-6
Repeat (STEM)
72
85
892
463
1-1-10-0-5
Repeat (STEM)
35
42
373
237
1-1-10-0-6
Repeat (STEM)
16
22
166
104
1-1-10-0-6
Tremollte (T-79)
0.38 x 2.19 (stlgmate)
138
368
93
0-4-10-2-0
0.38 x 2.19 (spot)
114
327
80
0-4-10-2-0
0.25 x 1.75 (stlgmate)
80
197
65
0-4-10-3-0
0.25 x 1.75 (spot)
95
252
62
0-4-10-2-0
Repeat (stlgmate)
70
211
51
0-3-10-2-0
(STEM-100 s)
376
1118
24 5
1-3-10-2-0
(STEM-100 s)
135
364
72
0-4-10-2-0
(STEM-lOfl s)
1454
4810
1235
0-3-in-3-n
(STEM-100 s)
64
191
48
0-3-10-2-0
(STF.M-100 s)
1072
31 14
882
o-i-in-3-o
(STEM-40 s)
46
113
27
0-4-10-2-0
(STF.M-40 s)
123
333
94
o-4-in-i-o
61
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(area of deposit). Size measurements of X-fibers may be doubled and noted, or
kept as a separate category.
Fiber number concentration is calculated from the equation
, q Total no. of fibers
Fibers/m3 = — ¦ c, .
No. of EM fields
Total effective filter area, cm2
Area of an EM field, cm2
1
..m. —- n ¦ ¦ .. ¦ i ¦ ¦ -i.-
Volume of air sampled, m3
The number of X-fibers, bundles, clusters, and matrices are calculated in a
similar manner. X-fibers may be included with fibers if they are few in
number. Similarly, their corresponding mass (from their size measurements)
may be included.
Fiber mass for each type of asbestos (chrysotile or amphibole) in the
sample is calculated by assuming that both chrysotiles and amphiboles have
circular cross-sections (cylindrical shape) and that the width measurements
are one diameter. The density of chrysotile is assumed to be 2.6 g/cm3, and
of amphiboles to be 3.0 g/cm3. The individual mass is calculated from the
equation
Mass, yg = ^ x (length, ym) x (diameter, pm)2
x (density, g/cm3) x 10 6
The total mass concentration of fibers for each type of asbestos is then
calculated from the total mass of all the individual fibers of that type.
The individual masses of bundles, clusters, and matrices are calculated
by assuming a laminar or sheet-like structure with an average thickness of the
fiber make-up of the structure. Again, the density of chrysotile is assumed
to be 2.6 g/cm3, and of amphiboles to be 3.0 g/cm3. The individual masses are
calculated from the equation
Mass, yg = (length, pm) x (width, ym) x (thickness, ym)
x (density, g/cm3) x 10 6
The total mass for each type of structure for each type of asbestos is the sum
of all the individual masses.
62
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Other characterizing parameters of the asbestos structures are: (1)
length and width distribution of fibers, (2) aspect ratio distribution of
fibers, and (3) relationships of fibers, bundles, clusters, and matrices.
Reporting of Results—
The data and their subsequent reduction are reported as summarized, or
can be further reduced to present the interrelationships of the various
characterizing parameters. Figure A13 is an example of the EM data report;
Figure A14 is an example of the sample summary report.
The methodology can establish the limits of identity for unknown samples,
act as a QC/QA method for Level I analysis, and satisfy most of the
identification criteria for asbestos.
6. Quality Control/Quality Assurance
Sampling procedures will vary depending on the type of sample, objectives
of the sampling, and time/cost factors. The primary goals of sampling are to
obtain a representative sample at the location and time of sampling, and to
maintain sample integrity. The sampling team will have written sampling
procedures, and the field chief and/or designated individual will be respon-
sible for all record-keeping (including sample identification, labeling,
logging of data, site description, and meteorological conditions), pre- and
post-collection checks, and continuous sample custody and sign-outs until the
sample is delivered to the laboratory and transferred to the appropriate
quality assurance officer (QAO). Verification of sampling times, flow rates,
equipment calibration, and taking of field blanks will be checked and recorded
in the field logbook.
Samples are turned over to the QAO for logging into a project logbook.
Each sample is carefully examined for gross features, such as tears, breaks,
and overall condition of container. The QAO registers the as-received sample
number and other designated information, and assigns a simple internal code
number that will accompany the sample through the preparation stage, grid
transfer, grid analysis, data reduction, and reporting of results.
After being logged into the project logbook, the sample is transferred to
the custody of the electron microscopy staff, where every precaution is taken
to maintain sample integrity and to prevent contamination and loss of
collected particulates. During storage and transport, the filters in their
respective holders are maintained in a horizontal position at all times.
The sample logging, handling, and storing procedures ensure that all
samples can be readily located and identified throughout the course of a
program. The 0A0 has divisional responsibility for OC/OA activities, and must
see that the laboratory maintains high standards. He must be aware of current
standards of analysis, and must ensure that internal quality control
standards, instrument calibration, and records of samples and completed
analyses are kept for ease of later retrieval and use.
63
-------
For quality control, internal laboratory blanks are analyzed at least
once a week, which may or may not coincide with a sample batch blank. In
addition, a magnification calibration of the EM using a carbon grating replica
(2,160 lines'per mm) is performed once a week. The results are recorded in an
EM instrument log, along with other routine instrumental performance checks.
All photographs, TEM, SEM, and STEM images are recorded in a photo log. These
QC results are documented for inspection by the QAO.
64
-------
CT1
in
I I I W'.FARnH institute structure analysis HATA
IjilituruilAI OBJECT DATA TAM.E m)
Rrd
Not
No
ri
Oh.!
St, r
pprth
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1
1
F
0.000
0.062
1.19
19.0
0.009
1
2
F
0.000
0.125
2.30
19.0
0.076
1
3
F
0.000
O.062
2.88
46.0
0.023
1
4
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1
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12
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13
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0.000
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49.0
0.195
1
14
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0.000
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0.81
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0.006
2
15
M
0.062
0.062
0.94
15.0
0.010
2
16
F
0.000
0.062
0.62
10.0
0.005
2
17
F
0.000
0.062
1.19
19.0
0.009
n
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0.000
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1.13
9.0
0.036
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19
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0.62
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•
3
20
F
0.000
0.062
3.00
48.0
0.024
3
21
F
0.000
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2.75
44.0
0.022
3
22
B
O.J07
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3
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73
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iili iiK.r iiATo TACLK (F«FJ.fcER. F^I.iUMliLL, i;-CLUSTER> H=MA1RIX>
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3
29
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0.062
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s
30
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0.000
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10.31
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0.500
1.87
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11
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I. IT Rf ;>frARCH INSTITUTE STRUCTURE ANALYSIS fiATA
nUHVIWiAl nR.n.CT VATA TAPLE
•—I
(ird
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Str
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8
f58
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0.06?
2.69
43.0
0.021
a
59
H
0.062
0.062
3.25
52.0
•
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60
H
0.062
0.062
J .25
20.0
0.013
9
61
B
0.1 B7
0.625
8,12
13.0
2.476
9
67
c;
0.187
1 .250
2.69
2.2
1.638
9
6Z
F
0.000
0.062
0.62
10.0
,
9
64
C
0.187
5.000
5.00
1.0
12.188
10
65
f"
0.000
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0.75
12.0
0.006
1 0
66
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0.500
3.75
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,
1 0
67
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0.11)7
1 .875
11.25
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10.283
10
60
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1.25
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0.051
10
69
C
(>.062
0.1 87
2.50
13.3
0.076
1.0
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72
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1.87
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73
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74
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75
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76
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2.01
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-------
ii r research institute structure analysis oata
TNriTyjUUAI. OBJECT DATA TABLE C=CLUSTER, M=MATRIX)
TABLE PREPARATION DATE J 15-MAR-85
Soil PI I" CODE! C06610-018-078
•i-e (Micron)
CD
oo
t \.i
: fi
ill. i
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1'oF-th
Width
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0.000
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0.81
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1 1
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1 .00
16.0
0.008
I 1
M
0.062
0.312
1 . 1.5
3.6
0. 057
1 4
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3.00
24.0
o. <¦>/¦ J.
J 4
90
H
0.062
0.107
1.06
5./
<>. 032
14
91
C
0.062
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1.30
2.2
0.140
1.4
92
E
0.000
0.062
0.75
12.0
•
15
93
C
0.125
0.500
1.13
2.3
0.103
15
74
r
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0.062
0.75
12.0
0.006
i 5
M
0.062
0.062
2.13
34.0
0.022
15
96
r<
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0.625
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24.0
4 .570
15
97
r
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0.94
15.0
(>. 007
15
98
M
0.062
0.062
0.94
15.0
0.010
16
-------
TIT RESEARCH INSTITUTE STRUCTURE ANALYSIS DATA
SINGLE SAMPLE SUMMARY TABLES
SAMPLE CODE: C06610-018-098 TABLE PREPARATION DATE: 15-MAR-85
Aerosol Object Count And Calculated ObJect
Moss Characteristics
Numbpr
Mass
Average
Actual
Concen.
Concen.
Average
Ave ra;Se
l.en.iih
flb.ir'r 1
Object
(Numbe r
(Pi cos r ft hi
Width
l. engt.h
fo i-iidth
Structure Tyre
Count
Pe r Cu M)
Per Cu M)
(Mic ron)
(M i r t 'in )
i o
fiber Chrysotile
34.
33020.
V60. 3
0.07 1
0.02
2.77
J
2.10
32.59
J 30.43
Amphibole
1 .
971.
4.5
0.06 ±
0.00
0.50
.1
0.00
0.00
1 0.00
Other
6.
5828.
0.19 1
0.13
2.06
i
1.82
10.27
.1 3.22
All Fiber
41.
39827.
0.09 ±
0.07
2.19
2.04
28.72
.4:28.98
Bundle Chrysotile
21.
20399.
42514.2
0.52 ±
0.40
7.79
J:
9.18
19.48
12A.92
Amphibole
0.
0.
0.0
0.00 ±
0.00
0.00
¦i
0.00
0.00
i 0.00
Other
1.
971.
0.50 1
0.00
3.75
0.00
7. SO
& 0.00
All Bundle
22.
21371.
0.52 ±
0.39
7.61
J.
9.00
18.94
±26.40
Cluster Chrysotile
16.
15542.
31362.8
1.05 1
1 .23
3.:->7
3.18
5.63
1 4.42
Amphibole
0.
0.
0.0
0.00 i
0.00
0.00
+
0.00
0.00
J: 0.00
Other
1.
971.
0.94 ±
0.00
2.19
i
0.00
2.^.3
.1 0.00
All Cluster
17.
16514.
1 .04 t
1 .20
S. ? 1
•J:
3.09
1: 4.36
Mat ri::
Chrysotile
21.
20399.
2404.2
0.25
1
0.29
1.60
4
0.75
12.21
i. 9.27
Amphibole
1.
971.
37.0
0.06
0.00
3.25
i
0.00
52.00
.1: 0.00
Other
0.
0.
0.00
±
0.00
0.00
0.00
0.00
.1 0.00
All Matrix
22.
21371.
0.24
±
0.28
1.67
±
00
o
14.02
±12.40
fipdiple Collection and Preparation Data
Air Volume = 1.00 Cu M
Deposit Area = 1.00 Pa Cm
Ashed Area = 1.00 So Cm
F>'pc(ppos j t Area = 1.00 So Cm
Grid Data
Grid in: PEI'CO H/E4&5
Individual Grid Opening =
Number of Grid Openings =
Eilm Maanification =
0.000064 So Cm
16
20000
-------
APPENDIX C
STATISTICAL METHOD
The statistical significance of the observed difference between results
obtained by PCM and TEM analyses of samples collected under nonaggressive and
aggressive conditions and the difference between nonaggressive and aggressive
sampling conditions obtained by PCM and TEM analyses was determined through
the application of the Mann-Whitney* test. The Mann-Whitney test was select-
ed from among several procedures for hypothesis testing because its applica-
tion does not require any prior knowledge of the underlying probability
distribution function of the data. A cursory inspection of the data suggests
a positive skewness (i.e., a few values that are very high compared with the
other members of a data set). For this reason, the geometric mean, rather
than the arithmetic mean, was used as a measure of central tendency.
Mann-Whitney is used to test the null hypothesis that two different
samples were taken from the same population. Rejection of the null hypoth-
esis implies that the two samples are from two different populations. The
test assumes that sample A consists of m observations and sample B consists
of n observations, where n < m. The data values from the two samples are
ranked into a single set with m + n observations. The statistic T is calcu-
lated next; this is the sum of the ranks of the values in sample B. Finally,
it is necessary to determine the probability that the calculated value of T
would differ as much or more from the expected value of T for the m + n
observations. Tables of exact probabilities of T are available for small
values of m and n. In situations (as is the case with the data from this
study) where m and n are not small, the normal approximation can be used to
calculate the necessary probability. When this probability is small (i.e.,
less than 0.05), the null hypothesis is rejected.
As an example, consider the data in Table C-l, which shows results
obtained by PCM under nonaggressive and aggressive sampling conditions. A
procedure described by Lehman and D'Abrera** is used to make an adjustment in
the calculation of the probability that the calculated value of T would be
~
Mosteller, F. and R. E. K. Rourke. Sturdy Statistics, Nonparametric and
Order Statistics, Addison-Wesley. 1973. pp. 54-88.
Lehman, E.L., and H.J.M. D'Abrera. Nonparametrics, Statistical Methods
Based on Ranks. McGraw-Hill International Book Company. 1975.
pp. 18-21.
70
-------
TABLE C-l. APPLICATION OF THE MANN-WHITNEY TEST TO NONAGGRESSIVE
AND AGGRESSIVE RESULTS OBTAINED BY PCM
Nonaggressive
Aggressive
Value
Rank
Value
Rank
0.002
3
0.002
3
0.002
3
0.010
16.5
0.002
3
0.015
19
0.002
3
0.020
21
0.003
6
0.026
23
0.004
7
0.028
24
0.005
8
0.039
25
0.006
9.5
0.050
26
0.006
9.5
0.052
27.5
0.007
11.5
0.052
27.5
0.007
11.5
0.071
30
0.008
14
0.076
31
0.008
14
0.110
33
0.008
14
T
3US.5
0.010
16.5
0.013
18
0.020
21
0.020
21
0.070
29
0.090
32
d.
(0.002) 5
(0.006) 2
(0.007) 2
(0.008) 3
(0.010) 2
(0.020) 3
(0.052) 2
120
6
24
6
24
6
192
d.
1
N =
Pt =
m + n o
20 + 13
33
n(N + 1)
2
nm (N + 1) nm E(di " di)
Y2 12(N)(N - 1)
_ (13)(20)(34) (13)(20)(192)
~ 12 ¦ 12(335(32)
_ 13(34)
~ 2
221
Z =
736.67 - 3.94
732.73
27.07
306.5 - 221
= 3.16
p = 0.001
71
-------
greater than the expected value of T under the null hypothesis. This proce-
dure requires determining the number of distinct data values and then count-
ing the number of observations, dj, which are equal to the smallest data
value, d2, to the next smallest, ...and so on. The variance of T is then
calculated as follows:
2 mn (m + n + 1) MUi ' V
°T 12 " 12(m + n)(m + n - 1)
Note that when there are no ties for a particular data value, the quantity
d? - d. is equal to zero. Thus, in calculating the quantity d| - d., it is
only necessary to consider the d.'s for the data values with ties.
The conclusion is that the probability that T would be greater than or
equal to 306.5 for a sample of n = 13 when m = 20 is 0.001. This is suffi-
cient cause to reject the null hypothesis that the two sets of data were tak-
en from a single population. On this basis, it is concluded that aggressive
sampling yields concentrations of fibers that are much higher than those
measured under nonaggressive sampling.
72
-------
APPENDIX D
COMPARISON OF N0NA66RESSIVE AND AGGRESSIVE ASBESTOS SAMPLING RESULTS
Figures D-l and D-2 show graphical comparisons of sample results taken
under nonaggressive and aggressive post-abatement conditions. These figures
clearly demonstrate that asbestos fibers and structures measured under ag-
gressive conditions are higher than those measured under nonaggressive condi-
tions.
73
-------
*
~
*
o
0.01
LEGEND
A CHRYSOTILE FIBER
~ CHRYSOTILE BUNDLE
O CHRYSOTILE MATRIX
* AMBIGUOUS BUNDLE
* AMPHIBOLE FIBER
I I I I I I ll I I I I I I I tl
I ill
0.1 1
STRUCTURE DIAMETER, micrometers
10
Figure D-l. Plot of fiber length and fiber diameter for a
nonaggressive post-abatement air sample in Room Ml 12.
74
-------
"1 1—I-T
10
I 111
A
A
A
A
l—l l l l l
A
~
~
o a
~
n
PCM METHOD
~ 7400
%
[]
D /
I I III
O
~
a on
A
8
Ss*'
D n
~ D
O
O
o ~ o
o
5P
o
o°
o
o
LEGEND
A CHRYSOTILE FIBER
~ CHRYSOTILE BUNDLE
O CHRYSOTILE MATRIX
* CHRYSOTILE CLUSTER
~ AMPHIBOLE FIBER
0.1
0.01
II
11
0.1 1
STRUCTURE DIAMETER, micrometers
10
Figure D-2. Plot of fiber length and fiber diameter for an aggressive
post-abatement air sample in Room Ml 12.
75
------- |