ASTM E1370-21

Standard Guide for Air Sampling Strategies for Worker and Workplace Protection

SIGNIFICANCE AND USE
4.1 This guide describes standard approaches used to formulate air sampling strategies before actual air sampling occurs.  
4.2 For most workplace air sampling purposes, and for the majority of materials sampled, air sampling strategies are matters of choice. Air sampling in the workplace may be done for single or multiple purposes, such as health impact, hazard or risk assessment, compliance assessment, or investigation of complaints. Problems can arise when a single air sampling strategy is expected to satisfy multiple diverse purposes.  
4.2.1 Proper consideration of limitations of cost, space, power requirements, equipment, analytical methods, training and personnel result in a best available strategy for each purpose.  
4.2.2 A strategy designed to satisfy multiple purposes must be a compromise among several alternatives, and will not be optimum for any one purpose; however, the strategy should be appropriate for the intended purpose(s).  
4.2.3 The purpose or purposes for sampling should be explicitly stated before a sampling strategy is selected in order to ensure that the sampling strategy is appropriate for the intended use. Good sampling practice, legal requirements, cost of the sampling program, and the utility of the results may be markedly different for different intended sampling purposes.  
4.3 This guide is intended for use by those who are preparing to evaluate air quality in a work environment of a location by air sampling, or who wish to obtain an understanding of what information can be obtained by carrying out air sampling.  
4.4 This guide should not be used as a stand-alone document to evaluate any given airborne contaminant(s).  
4.5 This guide cannot take the place of sound professional judgment in development and execution of any sampling strategy. In most instances, a strategy based on a standard practice or method will need to be adjusted due to conditions encountered in the field. Documentation of any professional judgments appli...
SCOPE
1.1 This guide describes criteria to be used in defining air sampling strategies for workplace health and safety monitoring or evaluation. Sampling criteria such as duration, frequency, number, location, method, equipment, and timing are all considered.  
1.2 Where air sampling is prescribed by law or regulation, this guide is not intended to take the place of any requirements that may be specified in such law or regulation.  
1.3 Guidance for surface sampling strategies for metals and metalloids is provided in Guide D7659.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 13.040.30 - Workplace atmospheres
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.04 - Workplace Air Quality

Relations

• Refers: ASTM D1356-20a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Sep-2020
• Refers: ASTM D1356-20 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Mar-2020
• Refers: ASTM E1542-20 - Standard Terminology Relating to Occupational Health and Safety
• Effective Date: 01-Jan-2020
• Refers: ASTM D4840-99(2018)e1 - Standard Guide for Sample Chain-of-Custody Procedures
• Effective Date: 15-Aug-2018
• Refers: ASTM E1542-18 - Standard Terminology Relating to Occupational Health and Safety
• Effective Date: 01-Feb-2018
• Refers: ASTM D1356-15a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Oct-2015
• Refers: ASTM D1356-15 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Jul-2015
• Refers: ASTM D1356-14b - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Dec-2014
• Refers: ASTM D1356-14a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-May-2014
• Refers: ASTM D1356-14 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Jan-2014
• Refers: ASTM D7659-10 - Standard Guide for Strategies for Surface Sampling of Metals and Metalloids for Worker Protection
• Effective Date: 01-Aug-2010
• Refers: ASTM E1542-10 - Standard Terminology Relating to Occupational Health and Safety
• Effective Date: 01-Aug-2010
• Refers: ASTM D1356-05(2010) - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Apr-2010
• Refers: ASTM D4840-99(2010) - Standard Guide for Sampling Chain-of-Custody Procedures
• Effective Date: 01-Feb-2010
• Refers: ASTM D1356-05 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-May-2005

Overview

ASTM E1370-21, "Standard Guide for Air Sampling Strategies for Worker and Workplace Protection," provides comprehensive guidance on developing air sampling strategies to safeguard worker health and ensure workplace safety. Published by ASTM International, this standard outlines the essential considerations in planning and executing air sampling programs in occupational environments. By systematically addressing factors such as sampling purpose, methodology, equipment selection, and interpretation of results, ASTM E1370-21 supports organizations in achieving reliable air quality monitoring and compliance with health and safety requirements.

Key Topics

This guide covers critical aspects of workplace air sampling strategies, including:

• Purpose Definition: Establishing the primary objectives before designing a sampling strategy, such as risk assessment, regulatory compliance, exposure documentation, or source identification.
• Sampling Criteria: Addressing parameters such as duration, frequency, number of samples, location, method, equipment, and timing to ensure strategies are fit for purpose.
• Strategy Selection: Considering the need for compromises when a strategy must serve multiple purposes, balancing factors like cost, equipment, analytical methods, space, and personnel.
• Professional Judgment: Emphasizing that sound professional judgment is essential and may override standard methodologies to account for real-world field conditions.
• Integration with Other Data Sources: Encouraging the use of air sampling data alongside bioassay, biomonitoring, clinical observations, and process control data for comprehensive hazard assessment.
• Quality Assurance: Recommending documentation of quality control measures and professional decisions made during sampling plan development.

Applications

The practical applications of ASTM E1370-21 extend across various workplace environments and industries. Typical use cases include:

• Occupational Exposure Assessment: Determining worker exposure levels to airborne hazards and comparing results to occupational exposure limits (OELs).
• Compliance Monitoring: Collecting the necessary data for regulatory reporting and demonstrating adherence to legal requirements for air quality.
• Risk and Hazard Evaluation: Identifying potential health risks from contaminants, supporting the recommendation of workplace controls, or deciding on personal protective equipment (PPE).
• Engineering Control Evaluation: Gauging the effectiveness of ventilation systems and other control measures in reducing airborne contaminant levels.
• Process Control and Incident Investigation: Monitoring process emissions, identifying sources of contamination, and investigating complaints or unexpected events.
• Workplace Characterization: Establishing baseline air quality for new facilities, during operational changes, or as part of decommissioning activities.

Related Standards

To ensure robust air quality management, users of ASTM E1370-21 may also reference these related standards:

• ASTM D1356: Terminology Relating to Sampling and Analysis of Atmospheres
• ASTM D4840: Guide for Sample Chain-of-Custody Procedures
• ASTM D7659: Guide for Strategies for Surface Sampling of Metals and Metalloids for Worker Protection
• ASTM D8358: Guide for Assessment and Inclusion of Wall Deposits in the Analysis of Single-Stage Samplers for Airborne Particulate Matter
• ASTM E1542: Terminology Relating to Occupational Health and Safety
• ISO 7708: Particle Size Fraction Definitions for Health-Related Sampling
• ISO/IEC 17025: General Requirements for the Competence of Testing and Calibration Laboratories

Conclusion

ASTM E1370-21 is an essential reference for environmental health and safety professionals developing air sampling strategies to monitor workplace exposures. By following this standard, organizations can design effective sampling plans that support both worker protection and regulatory compliance, fostering a safer occupational environment through reliable air quality monitoring practices.

For more information, visit ASTM International.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1370 − 21
Standard Guide for
Air Sampling Strategies for Worker and Workplace
Protection
This standard is issued under the fixed designation E1370; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E1542 Terminology Relating to Occupational Health and
Safety
1.1 This guide describes criteria to be used in defining air
sampling strategies for workplace health and safety monitoring 2.2 ISO Standards:
or evaluation. Sampling criteria such as duration, frequency, ISO 7708 Particle size fraction definitions for health-related
number, location, method, equipment, and timing are all sampling
considered. ISO/IEC 17025 General requirements for the competence of
testing and calibration laboratories
1.2 Where air sampling is prescribed by law or regulation,
ISO 18158 Workplace exposure — Terminology
this guide is not intended to take the place of any requirements
that may be specified in such law or regulation.
3. Terminology
1.3 Guidance for surface sampling strategies for metals and
3.1 For definitions of terms relating to occupational health
metalloids is provided in Guide D7659.
and safety, see Terminology E1542.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.2 For definitions of terms relating to atmospheric sam-
responsibility of the user of this standard to establish appro-
pling and analysis, see Terminology D1356.
priate safety, health, and environmental practices and deter-
3.3 Definitions:
mine the applicability of regulatory limitations prior to use.
3.3.1 alarm sampler, n—sampling device that produces an
1.5 This international standard was developed in accor-
alarm (audible, visible, or both) when the concentration of a
dance with internationally recognized principles on standard-
substance exceeds a pre-set value.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 3.3.2 exposure (by inhalation), n—situation in which a
mendations issued by the World Trade Organization Technical
chemical or biological agent is present in the air that is inhaled
Barriers to Trade (TBT) Committee. by a person. ISO 18158
3.3.3 occupational exposure limit value, n—limit of the
2. Referenced Documents
time-weightedaverageoftheconcentrationofachemicalagent
2.1 ASTM Standards:
in the air within the breathing zone of a worker in relation to
D1356 Terminology Relating to Sampling and Analysis of
a specified reference period. ISO 18158
Atmospheres
3.3.4 professional judgment, n—application and appropriate
D4840 Guide for Sample Chain-of-Custody Procedures
use of knowledge gained from formal education, experience,
D7659 Guide for Strategies for Surface Sampling of Metals
experimentation, inference, and analogy. D7659
and Metalloids for Worker Protection
D8358 GuideforAssessmentandInclusionofWallDeposits 3.3.4.1 Discussion—The capacity of an experienced profes-
in the Analysis of Single-Stage Samplers for Airborne sional to draw correct inferences from incomplete quantitative
Particulate Matter data, frequently on the basis of observations, analogy, and
intuition.
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality
3.3.5 sampling excursion, n—duration of time during which
and is the direct responsibility of Subcommittee D22.04 on WorkplaceAir Quality.
active sampling is not being performed, typically between two
Current edition approved Sept. 1, 2021. Published October 2021. Originally
durations of active sampling.
approved in 1990. Last previous edition approved in 2014 as E1370 – 14. DOI:
10.1520/E1370-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from International Organization for Standardization (ISO), 1, ch. de
the ASTM website. la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1370 − 21
4. Significance and Use 6. Purposes for Air Sampling
6.1 Risk Evaluation—To estimate the contaminant concen-
4.1 This guide describes standard approaches used to for-
trations(expected,ormaximum,orboth)intheworkplace.The
mulate air sampling strategies before actual air sampling
information obtained is used to recommend worker protection
occurs.
requirements and to assess the probability of sensitization or
4.2 For most workplace air sampling purposes, and for the
hypersensitivity reactions.
majority of materials sampled, air sampling strategies are
6.2 Exposure Estimation—To measure the actual concentra-
matters of choice.Air sampling in the workplace may be done
tions of contaminant to which one particular worker is ex-
for single or multiple purposes, such as health impact, hazard
posed. The concentrations measured may or may not be
or risk assessment, compliance assessment, or investigation of
hazardous. In many cases, it is sufficient to show that any
complaints. Problems can arise when a single air sampling
exposures are less than half of applicable limits or standards. It
strategy is expected to satisfy multiple diverse purposes.
may be necessary to show that an exposure does not exceed an
4.2.1 Proper consideration of limitations of cost, space,
applicable limit value within a stated degree of confidence.
power requirements, equipment, analytical methods, training
and personnel result in a best available strategy for each
6.3 Exposure Documentation—To provide the data base
purpose.
necessary for epidemiological studies, when the existence of a
health hazard is postulated. It is similar to exposure estimation,
4.2.2 A strategy designed to satisfy multiple purposes must
be a compromise among several alternatives, and will not be but is focused more on job categories or job titles, rather than
optimum for any one purpose; however, the strategy should be on an individual worker, and requires the use of instruments
appropriate for the intended purpose(s). and methods that minimize the likelihood of obtaining results
that are below the limits of detection.
4.2.3 The purpose or purposes for sampling should be
explicitly stated before a sampling strategy is selected in order
6.4 Facility Characterization—To determine the levels of
to ensure that the sampling strategy is appropriate for the
the analyte or analytes of interest within a facility at an initial
intended use. Good sampling practice, legal requirements, cost
or baseline point, during or after process operations, or as part
of the sampling program, and the utility of the results may be
of facility decommissioning.
markedly different for different intended sampling purposes.
6.5 Selection of Engineering Controls—To determine, for
4.3 This guide is intended for use by those who are
contaminants that are not totally contained, the collection or
preparing to evaluate air quality in a work environment of a
capture efficiencies of control devices necessary to bring
location by air sampling, or who wish to obtain an understand-
specific contaminant concentrations below applicable limits at
ing of what information can be obtained by carrying out air
specific locations.
sampling.
6.6 Evaluation of Engineering Controls—To measure the
4.4 This guide should not be used as a stand-alone docu-
quantities of contaminants passing or escaping from a control
ment to evaluate any given airborne contaminant(s).
device due to leaks, wear, damage, inadequate maintenance,
overloading, or accidents.
4.5 This guide cannot take the place of sound professional
judgment in development and execution of any sampling 6.7 Selection of Personal Protective Equipment—To deter-
mine the protection factor required for personal protective
strategy. In most instances, a strategy based on a standard
practice or method will need to be adjusted due to conditions equipment in order for a person to work in a contaminated or
potentially contaminated area for a specific period of time.
encountered in the field. Documentation of any professional
judgments applied to development or execution of a sampling
6.8 Selection of Bioassay or Biomonitoring Procedures, or
strategy is essential.
Both—To determine the applicability of bioassay methods that
estimateanindividual’stotaldoseorbodyburdenofamaterial
5. Air Sampling—General
andbiomonitoringmethodsthatestimateanindividual’srateof
exposure or rate of uptake of a material.
5.1 Results from air sampling are but one of many sources
of information about workplace health and safety of condi-
6.9 Compliance with Regulations and Standards—To obtain
tions. Air sampling should not be used to the exclusion or
the measurements required to satisfy legal requirements, or to
absence of other pertinent information.
determine if exposures in the workplace are below legal limits.
5.2 Bioassay and biomonitoring results, clinical
6.10 Source Identification—Tosingleoutthecontributionof
observations, visual observation, quality and process control
each of many potential sources of contamination, based on
data, and material balance studies, where applicable, should
each contaminant’s unique characteristics and other factors,
always be used in conjunction with air sampling data.
such as emission fluctuations, wind direction and variability,
dispersion conditions, and the presence or absence of distinct
5.3 Qualitative agreement among separately obtained
trace materials.
sources of information will typically increase confidence in the
interpretation of workplace hazard or risk assessments. Dis- 6.11 Process Control—To ensure that the process being
agreement among information sources or data should be cause monitored is proceeding according to design, that valuable
for concern, and will result in investigation into the source(s) materials are not being lost through leaks or side reactions, and
of disagreement. that only those effluents expected, in the quantities expected,
E1370 − 21
arebeingproduced.Thistypeofsamplingcanbeusedtodetect 7.6.1 Whenphysicallimitations,suchascollectingasample
and halt process changes before hazardous air concentrations on a small item or accessibility limitations, prevent the
are produced. collection of multiple samples;
7.6.2 When multiple operations are being performed simul-
6.12 Education and Training—To educate workers in the
taneously; in this instance, it may not be possible to collect
importance of sound control practices (for example, engineer-
more than one sample per operation.
ing controls, personal protective equipment, good housekeep-
7.7 In cases where sampling is performed in response to an
ing).
emergency or other urgent situation, the sampling plan typi-
6.13 Investigation of Complaints—To resolve concerns ex-
cally will be based primarily on professional judgment, since
pressed by workers, management, or other stakeholders.
planning time is at a minimum.
7.8 The sampling plan should include appropriate quality
7. Air Sampling Plans—General Considerations
assurance measures that will provide documentation, through-
7.1 Sampling plans should be fit for the intended purpose or
out the sampling event and subsequent collection and evalua-
purposes. In general, this means that the outcome of the
tion of data from the samples, that appropriate quality stan-
sampling campaign will be a set of data that meets data quality
dards have been met.
objectives and can be evaluated to provide the intended
7.9 Documentation of how the sampling plan was devel-
information. The intended purpose or purposes should be
oped is of great benefit in the event that issues arise in
explicitly stated before evaluating sampling options or select-
collecting or analyzing the samples, or in evaluating the data.
ing a sampling strategy. Sampling should, to the extent
Considerations include, for example, whether the sampling
practicable, be representative of the exposure being assessed.
plan was statistically based.
7.2 Principles of good practice, as well as applicable regu-
latory or legal requirements, should be considered and ad-
8. Factors Affecting Air Sampling
dressed during development of the sampling plan.
8.1 Some of the factors affecting contaminant air concen-
7.3 Limitations of the sampling plan should be considered
trations include the velocity and direction of air movement,
and addressed. These include, but may not be limited to, the
contaminant sinks, movement of personnel and equipment,
following:
source strength, and distance from the source. Small differ-
7.3.1 Ability to collect samples at desired sampling loca- ences in location can have major influences.
tions;
8.1.1 The volume of air movement affects dilution of the
7.3.2 Resource limitations such as time, cost, equipment, or contaminant(s). The more air that passes the source of con-
taminant per unit of time, the lower the contaminant concen-
trained personnel;
tration per unit volume is likely to be.
7.3.3 Abilityoftheanalyticallaboratorytodetectandreport
8.1.2 The direction of air movement determines areas of
the analyte or analytes of interest in the given sample matrix,
heaviest exposure downstream, and may prevent any exposure
with the required data quality objectives at the anticipated
upstream.Variationindirectionofairmovementdeterminesthe
concentration range; and
total area exposed. Where there is slow air movement, eddy
7.3.4 Ability to evaluate the data, especially from a statis-
currents, or air recirculation, there may be an increase in air
tical perspective.
contaminant concentration with time (or pockets of higher
7.4 Due to one or more of the limitations described in 7.3,
contaminant concentrations).
it may be necessary to develop a single sampling plan intended
8.1.3 Contaminants may be lost in a variety of sinks.
to accomplish multiple purposes (see 6.2). When this is the
Aerosol particles are subject to gravitational settling; vapor
case, conflicts may emerge with one or more of the criteria
contaminants can condense on surfaces or aerosol particles;
given in Sections9–11, and compromises will typically be
gases can be adsorbed on various surface and particles; and all
required to optimize the overall sampling strategy. When this
can react with each other, surfaces, or normal air components.
occurs, the resulting strategy may not be optimal for any one
8.1.4 Movement of personnel and equipment can change
purpose.
local air flow patterns significantly. Movement tends to in-
crease the number and size of eddy currents present, can
7.5 Whether to collect a single sample, or a set of samples,
re-suspend settled aerosols, and can deflect contaminants away
is a key decision. Collection of a set of samples, rather than a
from local exhaust ventilation, such as hoods.
single sample, is normally recommended for proper data
8.1.5 The rate and velocity of contaminant evolution also
evaluation. A set of samples, rather than a single sample, is
affects local air movement. Large or high velocity emissions
normally required in the following instances:
can overwhelm local airflow, while small or low velocity
7.5.1 When a comparison of “hot spots” to background
emissions have a smaller effect. High concentration emissions,
locations is needed;
emissions with compositions that differ significantly from
7.5.2 When required to meet regulatory requirements;
surrounding air, or emissions whose temperatures vary signifi-
7.5.3 When a statistical evaluation of the data is needed.
cantly from surrounding air, or combinations of these factors,
7.6 The following are examples of when a single sample may resist mixing with the air for considerable times and
may be appropriate: distances downwind.
E1370 − 21
8.1.6 Distance from the emission source is an important 8.3.3 Outdoor alarm samplers should be placed far enough
factor. Contaminants usually become more dilute with distance downwind of potential sources to allow mixing eddies to
from the source. Samples taken outdoors usually show more diffuse the plume enough to detect the contaminant(s) at the
variation with distance from the source compared to those sampler.
takenindoors,duetothegreaterairvolumetoconsider,greater
8.4 Samples taken for compliance purposes should use the
variations in air temperature, air pressure, wind speed, wind
rules of good practice to the maximum extent possible, while
direction, and precipitation washout. Outdoor samples can also
complying with all specific regulatory requirements. The user
be distributed and diluted over a much greater range of vertical
may also sample in additional locations, with additional types
and horizontal distance. Even indoor contaminant concentra-
of samplers, or with additional analytical methods, as neces-
tions may vary more than two orders of magnitude between
sary.
floorsandceilings,orbetweentwolocationsmorethanameter
apart in any direction (1, 2). Samples taken from within the
9. What to Sample
open face of local exhaust ventilation, with the sample inlet
9.1 For most sampling purposes, the contaminant(s) of
facing into the moving air, will almost always indicate higher
concern should be sampled using collection apparatus and
concentrationsthanthesametypeofsampletakenatorbeyond
media that will not alter the composition(s) or concentration(s)
the edge of the opening (3).
of the contaminant(s).
8.2 It is essential that air samples be taken as close as
9.2 Appropriate analytical methods that are fit for purpose
possible to the location of interest, as determined by the
will be used to determine the results that can be obtained.
purpose of sampling.
8.2.1 Samples taken for the purpose of selection of engi-
9.3 In some cases, such as source identification, selection of
neering controls, evaluation of engineering controls, source
engineering controls, and evaluation of engineering controls, a
identification, or process control should usually be taken
marker material other than the contaminant of interest may be
downwind of the source, and as close to it as possible.
sampled with greater ease or sensitivity, or both, as long as the
8.2.2 Samples taken for the purpose of risk evaluation,
marker material concentration is proportional to the contami-
exposure estimation, selection of personal protective
nant source strength.
equipment, selection of bioassay or biomonitoring procedures,
and investigation of complaints should be taken within the
10. How to Sample
breathing zone of the person affected.
10.1 Sampling procedures are dependent upon the type of
8.2.3 Where a worker’s activities cause the emission of a
sampling equipment available, analytical methods employed,
contaminant, breathing zone samples will usually indicate
and the purpose(s) of sampling. Other factors, such as staff
concentrationsuptooneorderofmagnitudehigherthannearby
training and available resources, may also be important.
fixed location samples (2, 4).
8.2.4 If the worker’s activities do not cause emission, then
10.2 Sampling instruments can influence sampling strategy,
breathingzonesampleswillusuallyindicateconcentrationsthe
due to their size, space requirements, and mass. For example:
same as, or lower than, nearby fixed location samplers (1).The
10.2.1 Vertical Elutriator—used in cotton dust sampling is
worker’s exposure will usually be lower than the concentration
too large to be placed on the worker.
indicated by fixed location samplers, if the worker is in and out
10.2.2 Dosimeter Badge—can be placed on the individual,
of the contaminated area and does not affect emissions.
over the entire shift, with little or no complaint from nor
8.2.5 When personal breathing zone samples are appropri-
hinderance to the worker.
ate but do not provide adequate sensitivity, fixed or portable
10.2.3 Detector Tubes—designed for taking very short term
samplers with higher sensitivities must be used and should be
samples.
placed at about breathing height above the ground or floor.
10.2.4 Personal Sampling Pumps—designedforeitherlong-
8.3 Alarm samplers are a special case. They may produce term or short-term sampling, or both.
false (as well as true) alarms.
NOTE 1—Many sampling instruments are capable of collecting more
8.3.1 Use of a large number of alarm samplers should be
than one contaminant simultaneously.
avoided.When used, they must be placed where there is a high
10.3 Selection of appropriate air sampling media is essen-
probability they will warn personnel of a contaminant or
tial.Considerationsforselectionofsamplingmediaincludethe
controlequipmentfailurethatresultsinhazardouscontaminant
following:
air concentrations.
10.3.1 Suitability for the application;
8.3.2 Agoodpracticeistoplaceindooralarmsamplersinor
10.3.2 Compatibilitywiththeanalyteoranalytesofinterest;
verynearexhaustventilation.Theymaynotsamplethehighest
10.3.3 Suitability for the analytical method which will be
concentrations at this location, but they are more likely to be
used.
exposed to some increase in concentration if a release occurs
anywhere in the room.
10.4 Analytical methods affect sampling strategy by placing
limitsonminimumandmaximumcollectiondurationsforeach
sample. Also, multiple contaminants may have to be sampled
separately, on different collection media. Even for materials
The boldface numbers in parentheses refer to the list of references at the end of
this standard. sampled in the same medium, separate samples may be
E1370 − 21
necessary, due to different methods of sample preparation and exposure limits (STELs) are based on 15 min exposures, but
analysis in the analytical laboratory. some are based on 5, 10 or 30 min exposures.
11.3.3.2 Equipment Limitations—Samples should not be so
10.5 The purpose of sampling will profoundly affect how
large that they overload the collector, but should, whenever
sampling is carried out.
possible, be large enough for the analyte or analytes of concern
10.5.1 Selection and evaluation of engineering controls,
to be detected by an analytical method that is fit for purpose.
selection of respiratory protection or bioassay/biomonitoring
11.3.3.3 Characteristics of the Operation Sampled—Brief
techniques, or both, source identification, and process control
periods of high exposure, followed by periods of significantly
samples are not usually correlated to health standards.
lower exposure, might be sampled only during the peak
10.5.2 Risk evaluation, exposure estimation, exposure
exposures. Full shift samples would be adequate for repetitive
documentation, and compliance samples are usually compared
operations with relatively constant exposure levels. Alarm
to health standards, such as the applicable occupational expo-
samplers might be run continuously.
sure limit (OEL), and are usually best collected with personal
11.3.3.4 Statistical Considerations—When more than one
samplers.
sample must be taken, the duration of each sampling period
10.6 For sampling of particulate matter, many OELs invoke
should be held constant, because the variability of a sample is
a size-selective sampling criterion, based on conventions in
afunctionofitsduration (9).Thatis,longersamplingdurations
ISO 7708. Where applicable, such criteria should be consid-
result in smaller confidence limits for the mean, while shorter
ered in selection of the sampling instrument.
durations result in larger confidence limits, on the average,
10.7 In addition, the potential for a fraction of the sampled assuming sampling durations do not vary in step with cycles in
particulate to deposit on interior walls of some sampling the operation. If different sampling durations must be used for
devices should be taken into account; see references (5-7) and multiple samples of the same process or operation, then each
Guide D8358 for more information. sample must be weighted in proportion to its duration when
calculating the mean.
11. When to Sample 11.3.3.5 Practical Considerations—It is often not practical
to run personal samplers beyond one shift, or to run static
11.1 Air sampling shall be carried out when required by law
samplers beyond 24 h. In some cases, it may satisfy the
or regulation.
purpose of sampling to show that the concentration sampled
11.2 Air sampling is typically done when there is a prob-
did not exceed a percentage (for example 10 %) of any
ability that any individual will be exposed to significant
applicable OEL.
airborne concentrations of a hazardous material, and when
11.3.4 Number of Samples—Factors that should be consid-
there is an analytical method for determining the quantity of
ered include:
the hazardous material on/in a sampling medium.
11.3.4.1 Purpose of Sampling—Forcompliancewitharegu-
11.3 The following five considerations are important in lation or standard, the minimum number of samples required
deciding when to sample. may be specified in the standard.
11.3.1 Type of Operation—In practice, most operations 11.3.4.2 Equipment Limitations—The duration of the opera-
generateconditionsthatarecombinationsoftwoorthreeofthe
tion sampled, and the minimum and maximum feasible dura-
following: tions for a single sample, determined by limitations of the
11.3.1.1 Repetitive Operations, such as production lines, sampling and analytical methods, set outside limits on the
where the same operation or cycle of operations is carried out number of samples that can be taken. For example, an 8-h
day after day, with very little change. workshift could be sampled with one 8-h sample, two 4-h
samples, four 2-h samples, or eight 1-h samples, depending on
11.3.1.2 Non-repetitive or Irregular Operations, such as
maintenance or construction, where each operation is essen- the characteristics of the equipment available.
tially unique. 11.3.4.3 Characteristics of the Operation Sampled—For
relatively constant exposures, fewer samples are needed. Cy-
11.3.1.3 Enclosed Operations or Processes, where there is
little or no human contact with any hazardous material present, clic or irregular exposures should initially be sampled during
each identifiable phase of the operation, in order to gain
unless a leak or spill occurs.
understanding of the pattern of exposure.
11.3.2 Start Time—Sampling is best initiated at the time the
risk of significant exposure or release begins, or as soon as 11.3.4.4 Economics—Consider the minimum number of
feasible thereafter. In most cases, sampling should start at the samples required to accomplish the purpose for sampling. It is
beginning of a work shift, or at the beginning of the first cycle preferable to add one or more samplers than to have too few
capable of producing significant exposures or emissions. samplers for the task(s) at hand.
11.3.3 Duration of Sampling—Influenced by many things 11.3.4.5 Staffıng Limitations—The more samples that are
including:
taken,themorestaff-hourswillberequired.Caremustbetaken
11.3.3.1 Purpose of Sampling on Duration—If the purpose to ensure that the available personnel can carry out the work
of sampling is to determine compliance with a standard, then required.
the sampling duration shall be the same as that specified in the 11.3.4.6 Statistical Considerations (9, 10)—One sample for
standard (8). Most OELs are based on an 8 h exposure, but any operation is rarely adequate, because the uncertainty of a
some are based on 10 h. Most ceiling OELs and short term single sample value is large. For long duration operations, 2 to
E1370 − 21
4 samples may be sufficient. For short duration samples, from adjacent areas, and (2) the concentration of contaminant, both
a single grab sample up 4 to 7 samples of the same operation in the worker’s breathing zone and in the general workplace
or phase, are the minimum required. Other considerations air, continually varies throughout the day (due to drafts,
being equal, shorter-duration samples are often better than ventilation changes, employee movements, and changes in
fewer long-duration samples covering the same total sampling contaminant generation). Consequently, samples taken during
period, because they can provide more task-specific informa- thedaywillshowvariation.Thereisalsosomevariationdueto
tion.Forexample,thefullshiftexposurecanbeestimatedfrom inaccuracies in the sampling equipment and analytical method,
a number of back-to-back short duration samples taken over which will not be considered here, but which must be consid-
the entire shift, and the fluctuations in exposure levels during ered when evaluating any results (9, 10).
the day can be seen. A single full-s
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1370 − 14 E1370 − 21
Standard Guide for
Air Sampling Strategies for Worker and Workplace
Protection
This standard is issued under the fixed designation E1370; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide describes criteria to be used in defining air sampling strategies for workplace health and safety monitoring or
evaluation. Sampling criteria such as duration, frequency, number, location, method, equipment, and timing are all considered.
1.2 Where air sampling is prescribed by law or regulation, this guide is not intended to take the place of any requirements that
may be specified in such law or regulation.
1.3 Guidance for surface sampling strategies for metals and metalloids is provided in Guide D7659.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D4840 Guide for Sample Chain-of-Custody Procedures
D7659 Guide for Strategies for Surface Sampling of Metals and Metalloids for Worker Protection
D8358 Guide for Assessment and Inclusion of Wall Deposits in the Analysis of Single-Stage Samplers for Airborne Particulate
Matter
E1542 Terminology Relating to Occupational Health and Safety
2.2 ISO Standards:
ISO 7708 Particle Size Fraction Definitions for Health-Related Samplingsize fraction definitions for health-related sampling
ISO/IEC 17025 General Requirementsrequirements for the Competencecompetence of Testingtesting and Calibration Labora-
toriescalibration laboratories
EN 1540ISO 18158 Workplace Exposure—Terminologyexposure — Terminology
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.
Current edition approved April 1, 2014Sept. 1, 2021. Published May 2014October 2021. Originally approved in 1990. Last previous edition approved in 20082014 as
E1370 – 96 (2008).E1370 – 14. DOI: 10.1520/E1370-14.10.1520/E1370-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1370 − 21
3. Terminology
3.1 For definitions of terms relating to occupational health and safety, see Terminology E1542.
3.2 For definitions of terms relating to atmospheric sampling and analysis, see Terminology D1356.
3.3 Definitions:
3.3.1 alarm sampler—sampler, n—sampling device that produces an alarm (audible, visible, or both) when the concentration of
a substance exceeds a pre-set value.
3.3.2 exposure (by inhalation)—inhalation), n—situation in which a chemical or biological agent is present in the air that is inhaled
by a person. EN 1540ISO 18158
3.3.3 occupational exposure limit—limit value, n—upper bound on the acceptable limit of the time-weighted average of the
concentration of a hazardous substance in workplace air. chemical agent in the air within the breathing zone of a worker in relation
to a specified reference period.
3.3.3.1 Discussion—
Typically established by national authorities in efforts to protect workers’ health. ISO 18158
3.3.4 professional judgment—judgment, n—application and appropriate use of knowledge gained from formal education,
experience, experimentation, inference, and analogy. D7659
3.3.4.1 Discussion—
The capacity of an experienced professional to draw correct inferences from incomplete quantitative data, frequently on the basis
of observations, analogy, and intuition.
3.3.5 sampling excursion—excursion, n—duration of time during which active sampling is not being performed, typically between
two durations of active sampling.
4. Significance and Use
4.1 This guide describes standard approaches used to formulate air sampling strategies before actual air sampling occurs.
4.2 For most workplace air sampling purposes, and for the majority of materials sampled, air sampling strategies are matters of
choice. Air sampling in the workplace may be done for single or multiple purposes, such as health impact, hazard or risk
assessment, compliance assessment, or investigation of complaints. Problems can arise when a single air sampling strategy is
expected to satisfy multiple diverse purposes.
4.2.1 Proper consideration of limitations of cost, space, power requirements, equipment, analytical methods, training and
personnel result in a best available strategy for each purpose.
4.2.2 A strategy designed to satisfy multiple purposes must be a compromise among several alternatives, and will not be optimum
for any one purpose; however, the strategy should be appropriate for the intended purpose(s).
4.2.3 The purpose or purposes for sampling should be explicitly stated before a sampling strategy is selected in order to ensure
that the sampling strategy is appropriate for the intended use. Good sampling practice, legal requirements, cost of the sampling
program, and the utility of the results may be markedly different for different intended sampling purposes.
4.3 This guide is intended for use by those who are preparing to evaluate air quality in a work environment of a location by air
sampling, or who wish to obtain an understanding of what information can be obtained by carrying out air sampling.
4.4 This guide should not be used as a stand-alone document to evaluate any given airborne contaminant(s).
4.5 This guide cannot take the place of sound professional judgment in development and execution of any sampling strategy. In
most instances, a strategy based on a standard practice or method will need to be adjusted due to conditions encountered in the
field. Documentation of any professional judgments applied to development or execution of a sampling strategy is essential.
E1370 − 21
5. Air Sampling—General
5.1 Results from air sampling are but one of many sources of information about workplace health and safety of conditions. Air
sampling should not be used to the exclusion or absence of other pertinent information.
5.2 Bioassay and biomonitoring results, clinical observations, visual observation, quality and process control data, and material
balance studies, where applicable, should always be used in conjunction with air sampling data.
5.3 Qualitative agreement among separately obtained sources of information will typically increase confidence in the
interpretation of workplace hazard or risk assessments. Disagreement among information sources or data should be cause for
concern, and will result in investigation into the source(s) of disagreement.
6. Purposes for Air Sampling
6.1 Risk Evaluation—To estimate the expected, contaminant concentrations (expected, or maximum, or both contaminant
concentrations both) in the workplace. The information obtained is used to recommend worker protection requirements and to
assess the probability of sensitization or hypersensitivity reactions.
6.2 Exposure Estimation—To measure the actual concentrations of contaminant to which one particular worker is exposed. The
concentrations measured may or may not be hazardous. In many cases, it is sufficient to show that any exposures are less than half
of applicable limits or standards. It may be necessary to show that an exposure does not exceed an applicable limit value within
a stated degree of confidence.
6.3 Exposure Documentation—To provide the data base necessary for epidemiological studies, when the existence of a health
hazard is postulated. It is similar to exposure estimation, but is focused more on job categories or job titles, rather than on an
individual worker, and requires the use of instruments and methods that minimize the likelihood of obtaining results that are below
the limits of detection.
6.4 Facility Characterization—To determine the levels of the analyte or analytes of interest within a facility at an initial or baseline
point, during or after process operations, or as part of facility decommissioning.
6.5 Selection of Engineering Controls—To determine, for contaminants that are not totally contained, the collection or capture
efficiencies of control devices necessary to bring specific contaminant concentrations below applicable limits at specific locations.
6.6 Evaluation of Engineering Controls—To measure the quantities of contaminants passing or escaping from a control device due
to leaks, wear, damage, inadequate maintenance, overloading, or accidents.
6.7 Selection of Personal Protective Equipment—To determine the protection factor required for personal protective equipment in
order for a person to work in a contaminated or potentially contaminated area for a specific period of time.
6.8 Selection of Bioassay or Biomonitoring Procedures, or Both—To determine the applicability of bioassay methods that estimate
an individual’s total dose or body burden of a material and biomonitoring methods that estimate an individual’s rate of exposure
or rate of uptake of a material.
6.9 Compliance with Regulations and Standards—To obtain the measurements required to satisfy legal requirements, or to
determine if exposures in the workplace are below legal limits.
6.10 Source Identification—To single out the contribution of each of many potential sources of contamination, based on each
contaminant’s unique characteristics and other factors, such as emission fluctuations, wind direction and variability, dispersion
conditions, and the presence or absence of distinct trace materials.
6.11 Process Control—To ensure that the process being monitored is proceeding according to design, that valuable materials are
not being lost through leaks or side reactions, and that only those effluents expected, in the quantities expected, are being produced.
This type of sampling can be used to detect and halt process changes before hazardous air concentrations are produced.
E1370 − 21
6.12 Education and Taining—Training—To educate workers in the importance of sound control practices (for example,
engineering controls, personal protective equipment, good housekeeping).
6.13 Investigation of Complaints—To resolve concerns expressed by workers, management, or other stakeholders.
7. Air Sampling Plans—General Considerations
7.1 Sampling plans should be fit for the intended purpose or purposes. In general, this means that the outcome of the sampling
campaign will be a set of data that meets data quality objectives and can be evaluated to provide the intended information. The
intended purpose or purposes should be explicitly stated before evaluating sampling options or selecting a sampling strategy.
Sampling should, to the extent practicable, be representative of the exposure being assessed.
7.2 Principles of good practice, as well as applicable regulatory or legal requirements, should be considered and addressed during
development of the sampling plan.
7.3 Limitations of the sampling plan should be considered and addressed. These include, but may not be limited to, the following:
7.3.1 Ability to collect samples at desired sampling locations;
7.3.2 Resource limitations such as time, cost, equipment, or trained personnel;
7.3.3 Ability of the analytical laboratory to detect and report the analyte or analytes of interest in the given sample matrix, with
the required data quality objectives at the anticipated concentration range; and
7.3.4 Ability to evaluate the data, especially from a statistical perspective.
7.4 Due to one or more of the limitations described in 7.3, it may be necessary to develop a single sampling plan intended to
accomplish multiple purposes (see 6.2). When this is the case, conflicts may emerge with one or more of the criteria given in
Sections 9 – 11, and compromises will typically be required to optimize the overall sampling strategy. When this occurs, the
resulting strategy may not be optimal for any one purpose.
7.5 Whether to collect a single sample, or a set of samples, is a key decision. Collection of a set of samples, rather than a single
sample, is normally recommended for proper data evaluation. A set of samples, rather than a single sample, is normally required
in the following instances:
7.5.1 When a comparison of “hot spots” to background locations is needed;
7.5.2 When required to meet regulatory requirements;
7.5.3 When a statistical evaluation of the data is needed.
7.6 The following are examples of when a single sample may be appropriate:
7.6.1 When physical limitations, such as collecting a sample on a small item or accessibility limitations, prevent the collection of
multiple samples;
7.6.2 When multiple operations are being performed simultaneously; in this instance, it may not be possible to collect more than
one sample per operation.
7.7 In cases where sampling is performed in response to an emergency or other urgent situation, the sampling plan typically will
be based primarily on professional judgment, since planning time is at a minimum.
E1370 − 21
7.8 The sampling plan should include appropriate quality assurance measures that will provide documentation, throughout the
sampling event and subsequent collection and evaluation of data from the samples, that appropriate quality standards have been
met.
7.9 Documentation of how the sampling plan was developed is of great benefit in the event that issues arise in collecting or
analyzing the samples, or in evaluating the data. Considerations include, for example, whether the sampling plan was statistically
based.
8. Factors Affecting Air Sampling
8.1 Some of the factors affecting contaminant air concentrations include the velocity and direction of air movement, contaminant
sinks, movement of personnel and equipment, source strength, and distance from the source. Small differences in location can have
major influences.
8.1.1 The volume of air movement affects dilution of the contaminant(s). The more air that passes the source of contaminant per
unit of time, the lower the contaminant concentration per unit volume is likely to be.
8.1.2 The direction of air movement determines areas of heaviest exposure downstream, and may prevent any exposure upstream.
Variation indirection of air movement determines the total area exposed. Where there is slow air movement, eddy currents, or air
recirculation, there may be an increase in air contaminant concentration with time (or pockets of higher contaminant
concentrations).
8.1.3 Contaminants may be lost in a variety of sinks. Aerosol particles are subject to gravitational settling; vapor contaminants can
condense on surfaces or aerosol particles; gases can be adsorbed on various surface and particles; and all can react with each other,
surfaces, or normal air components.
8.1.4 Movement of personnel and equipment can change local air flow patterns significantly. Movement tends to increase the
number and size of eddy currents present, can re-suspend settled aerosols, and can deflect contaminants away from local exhaust
ventilation, such as hoods.
8.1.5 The rate and velocity of contaminant evolution also affects local air movement. Large or high velocity emissions can
overwhelm local airflow, while small or low velocity emissions have a smaller effect. High concentration emissions, emissions with
compositions that differ significantly from surrounding air, or emissions whose temperatures vary significantly from surrounding
air, or combinations of these factors, , may resist mixing with the air for considerable times and distances downwind.
8.1.6 Distance from the emission source is an important factor. Contaminants usually become more dilute with distance from the
source. Samples taken outdoors usually show more variation with distance from the source compared to those taken indoors, due
to the greater air volume to consider, greater variations in air temperature, air pressure, wind speed, wind direction, and
precipitation washout. Outdoor samples can also be distributed and diluted over a much greater range of vertical and horizontal
distance. Even indoor contaminant concentrations may vary more than two orders of magnitude between floors and ceilings, or
between two locations more than a meter apart in any direction (1, 2). Samples taken from within the open face of local exhaust
ventilation, with the sample inlet facing into the moving air, will almost always indicate higher concentrations than the same type
of sample taken at or beyond the edge of the opening (3).
8.2 It is essential that air samples be taken as close as possible to the location of interest, as determined by the purpose of sampling.
8.2.1 Samples taken for the purpose of selection of engineering controls, evaluation of engineering controls, source identification,
or process control should usually be taken downwind of the source, and as close to it as possible.
8.2.2 Samples taken for the purpose of risk evaluation, exposure estimation, selection of personal protective equipment, selection
of bioassay or biomonitoring procedures, and investigation of complaints should be taken within the breathing zone of the person
affected.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
E1370 − 21
8.2.3 Where a worker’s activities cause the emission of a contaminant, breathing zone samples will usually indicate concentrations
up to one order of magnitude higher than nearby fixed location samples (2, 4).
8.2.4 If the worker’s activities do not cause emission, then breathing zone samples will usually indicate concentrations the same
as, or lower than, nearby fixed location samplers (1). The worker’s exposure will usually be lower than the concentration indicated
by fixed location samplers, if the worker is in and out of the contaminated area and does not affect emissions.
8.2.5 When personal breathing zone samples are appropriate but do not provide adequate sensitivity, fixed or portable samplers
with higher sensitivities must be used and should be placed at about breathing height above the ground or floor.
8.3 Alarm samplers are a special case. They may produce false (as well as true) alarms.
8.3.1 Use of a large number of alarm samplers should be avoided. When used, they must be placed where there is a high
probability they will warn personnel of a contaminant or control equipment failure that results in hazardous contaminant air
concentrations.
8.3.2 A good practice is to place indoor alarm samplers in or very near exhaust ventilation. They may not sample the highest
concentrations at this location, but they are more likely to be exposed to some increase in concentration if a release occurs
anywhere in the room.
8.3.3 Outdoor alarm samplers should be placed far enough downwind of potential sources to allow mixing eddies to diffuse the
plume enough to detect the contaminant(s) at the sampler.
8.4 Samples taken for compliance purposes should use the rules of good practice to the maximum extent possible, while
complying with all specific regulatory requirements. The user may also sample in additional locations, with additional types of
samplers, or with additional analytical methods, as necessary.
9. What to Sample
9.1 For most sampling purposes, the contaminant(s) of concern should be sampled using collection apparatus and media that will
not alter the composition(s) or concentration(s) of the contaminant(s).
9.2 Appropriate analytical methods that are fit for purpose will be used to determine the results that can be obtained.
9.3 In some cases, such as source identification, selection of engineering controls, and evaluation of engineering controls, a marker
material other than the contaminant of interest may be sampled with greater ease or sensitivity, or both, as long as the marker
material concentration is proportional to the contaminant source strength.
10. How to Sample
10.1 Sampling procedures are dependent upon the type of sampling equipment available, analytical methods employed, and the
purpose(s) of sampling. Other factors, such as staff training and available resources, may also be important.
10.2 Sampling instruments can influence sampling strategy, due to their size, space requirements, and mass. For example:
10.2.1 Vertical Elutriator—used in cotton dust sampling is too large to be placed on the worker.
10.2.2 Dosimeter Badge—can be placed on the individual, over the entire shift, with little or no complaint from nor hinderance
to the worker.
10.2.3 Detector Tubes—designed for taking very short term samples.
10.2.4 Personal Sampling Pumps—designed for either long-term or short-term sampling, or both.
NOTE 1—Many sampling instruments are capable of collecting more than one contaminant simultaneously.
E1370 − 21
10.3 Selection of appropriate air sampling media is essential. Considerations for selection of sampling media include the
following:
10.3.1 Suitability for the application;
10.3.2 Compatibility with the analyte or analytes of interest;
10.3.3 Suitability for the analytical method which will be used.
10.4 Analytical methods affect sampling strategy by placing limits on minimum and maximum collection durations for each
sample. Also, multiple contaminants may have to be sampled separately, on different collection media. Even for materials sampled
in the same medium, separate samples may be necessary, due to different methods of sample preparation and analysis in the
analytical laboratory.
10.5 The purpose of sampling will profoundly affect how sampling is carried out.
10.5.1 Selection and evaluation of engineering controls, selection of respiratory protection or bioassay/biomonitoring techniques,
or both, source identification, and process control samples are not usually correlated to health standards.
10.5.2 Risk evaluation, exposure estimation, exposure documentation, and compliance samples are usually compared to health
standards, such as the applicable occupational exposure limit (OEL), and are usually best collected with personal samplers.
10.6 For sampling of particulate matter, many OELs invoke a size-selective sampling criterion, based on conventions in ISO 7708.
Where applicable, such criteria should be considered in selection of the sampling instrument.
10.7 In addition, the potential for a fraction of the sampled particulate to deposit on interior walls of some sampling devices should
be taken into account; see references (5-7) and Guide D8358 for more information.
11. When to Sample
11.1 Air sampling shall be carried out when required by law or regulation.
11.2 Air sampling is typically done when there is a probability that any individual will be exposed to significant airborne
concentrations of a hazardous material, and when there is an analytical method for determining the quantity of the hazardous
material on/in a sampling medium.
11.3 The following five considerations are important in deciding when to sample.
11.3.1 Type of Operation—In practice, most operations generate conditions that are combinations of two or three of the following:
11.3.1.1 Repetitive Operations, such as production lines, where the same operation or cycle of operations is carried out day after
day, with very little change.
11.3.1.2 Non-repetitive or Irregular Operations, such as maintenance or construction, where each operation is essentially unique.
11.3.1.3 Enclosed Operations or Processes, where there is little or no human contact with any hazardous material present, unless
a leak or spill occurs.
11.3.2 Start Time—Sampling is best initiated at the time the risk of significant exposure or release begins, or as soon as feasible
thereafter. In most cases, sampling should start at the beginning of a work shift, or at the beginning of the first cycle capable of
producing significant exposures or emissions.
11.3.3 Duration of Sampling—Influenced by many things including:
11.3.3.1 Purpose of Sampling on Duration—If the purpose of sampling is to determine compliance with a standard, then the
E1370 − 21
sampling duration shall be the same as that specified in the standard (8). Most OELsare OELs are based on an 8 h exposure, but
some are based on 10 h. Most ceiling OELs and short term exposure limits (STELs) are based on 15 min exposures, but some are
based on 5, 10 or 30 min exposures.
11.3.3.2 Equipment Limitations—Samples should not be so large that they overload the collector, but should, whenever possible,
be large enough for the analyte or analytes of concern to be detected by an analytical method that is fit for purpose.
11.3.3.3 Characteristics of the Operation Sampled—Brief periods of high exposure, followed by periods of significantly lower
exposure, might be sampled only during the peak exposures. Full shift samples would be adequate for repetitive operations with
relatively constant exposure levels. Alarm samplers might be run continuously.
11.3.3.4 Statistical Considerations—When more than one sample must be taken, the duration of each sampling period should be
held constant, because the variability of a sample is a function of its duration (9). That is, longer sampling durations result in
smaller confidence limits for the mean, while shorter durations result in larger confidence limits, on the average, assuming
sampling durations do not vary in step with cycles in the operation. If different sampling durations must be used for multiple
samples of the same process or operation, then each sample must be weighted in proportion to its duration when calculating the
mean.
11.3.3.5 Practical Considerations—It is often not practical to run personal samplers beyond one shift, or to run static samplers
beyond 24 h. In some cases, it may satisfy the purpose of sampling to show that the concentration sampled did not exceed a
percentage (for example 10 %) of any applicable OEL.
11.3.4 Number of Samples—Factors that should be considered include:
11.3.4.1 Purpose of Sampling—For compliance with a regulation or standard, the minimum number of samples required may be
specified in the standard.
11.3.4.2 Equipment Limitations—The duration of the operation sampled, and the minimum and maximum feasible durations for
a single sample, determined by limitations of the sampling and analytical methods, set outside limits on the number of samples
that can be taken. For example, an 8-h workshift could be sampled with one 8-h sample, two 4-h samples, four 2-h samples, or
eight 1-h samples, depending on the characteristics of the equipment available.
11.3.4.3 Characteristics of the Operation Sampled—For relatively constant exposures, fewer samples are needed. Cyclic or
irregular exposures should initially be sampled during each identifiable phase of the operation, in order to gain understanding of
the pattern of exposure.
11.3.4.4 Economics—Consider the minimum number of samples required to accomplish the purpose for sampling. It is preferable
to add one or more samplers than to have too few samplers for the task(s) at hand.
11.3.4.5 Staffıng Limitations—The more samples that are taken, the more staff-hours will be required. Care must be taken to ensure
that the available personnel can carry out the work required.
11.3.4.6 Statistical Considerations (9, 10)—One sample for any operation is rarely adequate, because the uncertainty of a single
sample value is large. For long duration operations, 2 to 4 samples may be sufficient. For short duration samples, from a single
grab sample up 4 to 7 samples of the same operation or phase, are the minimum required. Other considerations being equal,
shorter-duration samples are often better than fewer long-duration samples covering the same total sampling period, because they
can provide more task-specific information. For example, the full shift exposure can be estimated from a number of back-to-back
short duration samples taken over the entire shift, and the fluctuations in exposure levels during the day can be seen. A single
full-shift sample would also estimate the full-shift exposure, but would not provide information on exposure fluctuations. For
repetitive operations, conducted over a prolonged period of time, the question is not how many total samples to take, but how many
samples to take each day, week, m
...