SIST EN 17058:2019
(Main)Workplace exposure - Assessment of exposure by inhalation of nano-objects and their aggregates and agglomerates
Workplace exposure - Assessment of exposure by inhalation of nano-objects and their aggregates and agglomerates
This European Standard provides guidelines to assess workplace exposure by inhalation of nano-objects and their aggregates and agglomerates (NOAA). It contains guidance on the sampling and measurement strategies to adopt and methods for data evaluation.
While the focus of this document is on the assessment of nano-objects, the approach is also applicable for exposure to the associated aggregates and agglomerates, i.e. NOAA, and particles released from nanocomposites and nano-enabled products.
Exposition am Arbeitsplatz - Beurteilung der inhalativen Exposition gegenüber Nano-Objekten und deren Agglomeraten und Aggregaten
Diese Europäische Norm bietet eine Leitlinie zur Beurteilung der Exposition durch Einatmen gegenüber Nanoobjekten und deren Aggregaten und Agglomeraten (NOAA). Sie enthält Leitlinien zu anzuwendenden Probenahme- und Messstrategien sowie Verfahren zur Datenauswertung.
Obgleich der Schwerpunkt dieses Dokuments auf der Beurteilung von Nanoobjekten liegt, gilt diese Herangehensweise auch für die Exposition gegenüber zugehörigen Aggregaten und Agglomeraten, d. h. "NOAA", sowie für Partikel, die von Nanokompositen und nanotechnologischen Produkten freigesetzt werden.
Exposition sur les lieux de travail - Évaluation de l’exposition par inhalation aux nano-objets et à leurs agglomérats et agrégats
La présente Norme européenne fournit des lignes directrices pour évaluer l’exposition par inhalation aux nano-objets et à leurs agrégats et agglomérats (NOAA) sur les lieux de travail. Elle contient des recommandations relatives aux stratégies d’échantillonnage et de mesurage à adopter, ainsi que des méthodes pour l’évaluation des données.
Bien que le présent document soit essentiellement axé sur l’évaluation des nano-objets, l’approche est également applicable à l’exposition aux agrégats et agglomérats associés, c’est-à-dire aux NOAA, et aux particules libérées des nanocomposites et des produits obtenus par nanotechnologies.
Izpostavljenost na delovnem mestu - Ocena izpostavljenosti pri vdihavanju nanopredmetov ter njihovih agregatov in aglomeratov
Ta evropski standard opisuje različne stopnje ocene izpostavljenosti pri vdihavanju nanopredmetov ter njihovih agregatov in aglomeratov (NOAA) ter vrednotenje rezultatov v obliki samostojne ocene ali vdelano v okvir večstopenjskega pristopa. Medtem ko se ta evropski standard osredotoča na oceno nanopredmetov, se pristop uporablja za izpostavljenost povezanim aglomeratom in agregatom, tj. nanopredmetom ter njihovim agregatom in aglomeratom, ter delcem, ki se sproščajo iz nanokompozitov in izdelkov, ki jih omogoča nanotehnologija.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2019
Izpostavljenost na delovnem mestu - Ocena izpostavljenosti pri vdihavanju
nanopredmetov ter njihovih agregatov in aglomeratov
Workplace exposure - Assessment of exposure by inhalation of nano-objects and their
aggregates and agglomerates
Exposition am Arbeitsplatz - Beurteilung der inhalativen Exposition gegenüber Nano-
Objekten und deren Agglomeraten und Aggregaten
Exposition sur les lieux de travail - Évaluation de l’exposition par inhalation aux nano-
objets et à leurs agglomérats et agrégats
Ta slovenski standard je istoveten z: EN 17058:2018
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 17058
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2018
EUROPÄISCHE NORM
ICS 13.040.30
English Version
Workplace exposure - Assessment of exposure by
inhalation of nano-objects and their aggregates and
agglomerates
Exposition sur les lieux de travail - Évaluation de Exposition am Arbeitsplatz - Beurteilung der
l'exposition par inhalation aux nano-objets et à leurs inhalativen Exposition gegenüber Nanoobjekten und
agrégats et agglomérats deren Aggregaten und Agglomeraten
This European Standard was approved by CEN on 25 June 2018.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17058:2018 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 8
5 Measurement strategy . 10
5.1 General . 10
5.1.1 Objectives . 10
5.1.2 Source domains . 11
5.2 Measuring devices and measurement methods. 11
5.3 Levels of exposure assessment . 12
5.3.1 General . 12
5.3.2 Initial assessment – Determination of the potential for release and emission of NOAA
into the workplace air . 13
5.3.3 Basic assessment – Indication of exposure to NOAA . 14
5.3.4 Comprehensive assessment – Comprehensive characterization of the airborne
particles in the breathing zone . 18
6 Embedding of levels of exposure assessment in a tiered-approach framework . 21
6.1 General . 21
6.2 Building blocks for a tiered-approach . 22
6.3 Evaluation criteria and decision rules . 23
6.3.1 General . 23
6.3.2 Initial assessment (Tier 1) . 23
6.3.3 Basic assessment (Tier 2) . 24
6.3.4 Comprehensive assessment (Tier 3) . 26
Annex A (informative) Instruments . 27
A.1 General . 27
A.2 Real-time monitors . 27
A.2.1 General . 27
A.2.2 Aerosol photometer . 27
A.2.3 Optical Particle Counter (OPC) . 28
A.2.4 Condensation Particle Counter (CPC) . 28
A.2.5 Diffusion charger . 28
A.2.6 Differential Mobility Analysing System (DMAS) . 29
TM 2)
A.2.7 Electrical Low Pressure Impactor (ELPI ) . 29
)
TM 2
A.2.8 Tapered Element Oscillating Microbalance (TEOM ) . 29
A.3 Aerosol sampler . 29
A.4 Off-line analysis . 30
Annex B (informative) Checklist for minimum required information during the initial
assessment . 32
Annex C (informative) Template for contextual information for comprehensive assessment
(NECID) . 34
C.1 General . 34
C.2 Structure and contents of the database . 34
Annex D (informative) Statistical analysis of time series . 36
D.1 General . 36
D.2 Statistical analysis of a size integrated time series dataset . 36
D.2.1 ARIMA . 36
D.3 Statistical analysis of size resolved time series data . 40
Annex E (informative) Decision rules for basic assessment . 42
Annex F (informative) Example for calculation of fraction deposited in the gas exchange
region . 43
F.1 General . 43
F.2 Particle size distribution. 43
F.2.1 Particle equivalent diameters . 43
F.2.2 (Number- or mass-weighted) size distributions . 45
F.2.2.1 Particle size distribution 1 . 45
F.2.2.2 Particle size distribution 2 . 45
F.3 Estimation of the fraction of particles deposited in a region of the respiratory tract. 45
F.3.1 Deposition by diffusion . 45
F.3.2 Deposition by aerodynamics . 46
F.4 Deposited dose . 47
F.5 Numerical example . 48
Bibliography . 54
European foreword
This document (EN 17058:2018) has been prepared by Technical Committee CEN/TC 137 “Assessment
of workplace exposure to chemical and biological agents”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2019, and conflicting national standards shall be
withdrawn at the latest by May 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request given to CEN by the European
Commission and the European Free Trade Association.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
The rapidly advancing field of nanotechnologies and concern on its potential impact on occupational
health and safety has initiated efforts by Standardization bodies to provide guidance how health and
safety issues can be appropriately addressed. ISO has published a series of documents, which focus on
various aspects of exposure and risk assessment and risk mitigation, for example, ISO/TR 12885 [1],
ISO/TS 12901-1 [2], ISO/TS 12901-2 [3].
The present document focuses on the assessment of occupational exposure by inhalation of nano-
objects and their aggregates and agglomerates (NOAA). In general the objectives of an exposure
assessment can vary widely and can include exposure exploration and determination, evaluation of the
effectiveness of exposure control measures, check for compliance with any occupational exposure limit
or other benchmark level, and can contribute to risk assessment and epidemiological studies. The
measurement strategy used for the assessment will depend amongst other factors on the objective of
the assessment. ISO/TS 12901-1 for example, provides guidance for the measurement strategy for
evaluation controls. No EU legal workplace exposure limits for NOAA are established at the time of the
publication of this European Standard. However, existing non-nano OELs for many substances are in
force and these are measured as prescribed in national regulations/EN 689. Therefore, this document
concerns the elements of exposure assessment and provides guidance for various applications. In
addition, CEN has published documents (EN 16897 [4], EN 16966) that provide guidance of the use of
commonly used devices for detection of nano-sized and submicron-sized aerosols using different
metrics in the workplace air.
1 Scope
This European Standard provides guidelines to assess workplace exposure by inhalation of nano-
objects and their aggregates and agglomerates (NOAA). It contains guidance on the sampling and
measurement strategies to adopt and methods for data evaluation.
While the focus of this document is on the assessment of nano-objects, the approach is also applicable
for exposure to the associated aggregates and agglomerates, i.e. NOAA, and particles released from
nanocomposites and nano-enabled products.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 1540, Workplace exposure — Terminology
EN 689:2018, Workplace atmospheres — Guidance for the assessment of exposure by inhalation to
chemical agents for comparison with limit values and measurement strategy
EN 16966:2018, Workplace exposure — Metrics to be used for the measurements of exposure to inhaled
nanoparticles (nano-objects and nanostructured materials) such as mass concentration, number
concentration and surface area concentration
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1540, EN 16966 and the
following apply.
Note 1 to entry: With regard to EN 16966, in particular, the following terms are used in this document:
agglomerate, aggregate, BET method, nanomaterial, nano-object, nanoscale, particle aerodynamic diameter,
particle diffusive diameter, particle mobility diameter, particle and primary particle.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
appraiser
person who is sufficiently trained and experienced in occupational hygiene principles, working and
measurement techniques, to conduct the part of the assessment he or she is performing according to
the state of the art
Note 1 to entry: The appraiser may be supported by a team of qualified persons.
[SOURCE: EN 689:2018, 3.1.1]
3.2
background measurement
background particle measurement
measurement of the particle concentration, at a location or a time not affected by the activity/process
under investigation
[SOURCE: EN 16897:2017, 3.1, modified – The preferred term and its synonym have been taken over on
separate lines.] [4]
3.3
emission
transfer process of liberated nanomaterial or other material to the workplace air
Note 1 to entry: The emission is usually expressed as a flow, e.g. quantity as mass or number of particles per
unit time or unit area, or particle per mass of product.
3.4
exposure assessment
qualitative or quantitative determination of an employee’s exposure to a chemical or biological agent
performed by an appraiser
3.5
exposure monitoring
determination of exposure to airborne chemical and/or biological agents by using a sampling or
monitoring device for gases, vapours or airborne particles
3.6
far field
well-mixed compartment of the workspace that remains as the near field is centered on the worker
3.7
median diameter
median particle diameter
particle size of a particle distribution for which one-half the total number of particles are larger and
one-half are smaller
[SOURCE: ISO 16972:2010, 3.47] [5]
3.8
nano-activity
activity/task related to handling or processing nanomaterial
3.9
release
liberation of nanomaterial during a natural or technical process at any given lifecycle stage
Note 1 to entry: Liberation can occur in three main release forms, i.e. air dispersed (aerosols), liquid dispersed
(suspensions) and undispersed material, e.g. debris. Release can be expressed without a specific metric, as a
dispersion-specific fraction or percentage (in relation to air dispersed, liquid dispersed and undispersed) of the
total release, or as a mass per unit area or unit quantity of the matrix. Release will be dependent on the physical-
chemical properties of the nanomaterial and operational and environmental conditions.
3.10
sensitivity
true positive rate
proportion of actual positives which are correctly identified as such, and is complementary to the false
negative rate
3.11
source domain
generation mechanism that determines particle emission characteristics for a particular life cycle stage
Note 1 to entry: Different mechanisms determine the emission rate, particle size distribution, source location
and transport of NOAA during the various life cycle stages (synthesis, downstream use, application or treatment of
products and end of life)
Note 2 to entry: The source domain can comprise similar exposure situations including the vast majority of
current and near future exposure situations [6].
[SOURCE: CEN ISO/TS 21623:2018-02, 3.17, modified – Note 2 to entry added] [7]
3.12
near field
well-mixed compartment consisting of a virtual cube with 2-m sides centred on the source of particles,
with volume of 8 m
Note 1 to entry: This near field space is a nominal definition and no sharp decline in concentration is envisaged
to occur at the boundary between the near field and the far field.
3.13
specificity
true negative rate
proportion of negatives which are correctly identified as such, and is complementary to the false
positive rate
4 Symbols and abbreviations
For the purposes of this document, the following symbols and abbreviations apply.
ACF Autocorrelation Function
AIC Aikaike Information Criterion
AR AutoRegressive
APS Aerodynamic Particle Sizer
ARIMA AutoRegressive Integrated Moving Average
BIC Bayesian Information Criterion
CCF Cross Correlation Function
CMD Count Median Diameter (the number-weighted median diameter)
CNF Carbon NanoFiber
CNT Carbon NanoTube
CPC Condensation Particle Counter
d Particle aerodynamic equivalent diameter
ae
d Particle diffusive equivalent diameter
de
d Particle mobility equivalent diameter
me
d Optical diameter
opt
DC Diffusion Charger
DEMC Differential Electrical Mobility Classifier
DMAS Differential Mobility Analysing System
DR Decision Rule
DRI Direct Reading Instrument
EDS Energy Dispersive X-Ray Spectroscopy
ELPI Electrical Low Pressure Impactor
EM Electron Microscopy
EoL End of Life
ESP Electrostatic Precipitator
FF Far Field
FMPS Fast Mobility Particle Sizer
HVAC Heating, Ventilation and Air Conditioning
ICP-AES Inductively Coupled Plasma – Atomic Emission Spectroscopy
ICP-MS Inductively Coupled Plasma – Mass Spectroscopy
LSL Lower Size Limit
MA Moving Average
MNO Manufactured Nano-Object
MSDS Material Safety Data Sheet
NECID Nano Exposure and Contextual Information Database
NF Near Field
NM NanoMaterial
NOAA Nano-Objects and their Aggregates and Agglomerates
NPV Negative Predictive Value
NSAM Nanoparticle Surface Area Monitor
OECD Organisation for Economic Co-operation and Development
OEL Occupational Exposure Limit
OPC Optical Particle Counter
PACF Partial Autocorrelation Function
PEROSH Partnership for European Research in Occupational Safety and Health
PGNP Process Generated NanoParticle
PM Particle size fraction with the aerodynamic cut-size equal to 2,5 µm
2,5
PM Particle size fraction with the aerodynamic cut-size equal to 10 µm
PSD Particle Size Distribution
QA Quality Assurance
QC Quality Control
R&D Research & Development
REL Recommended Exposure Limit (by NIOSH)
SD Source Domain
SEM Scanning Electron Microscopy
SMPS Scanning Mobility Particle Sizer
SOP Standard Operating Procedure
TEM Transmission Electron Microscopy
TEOM Tapered Element Oscillating Microbalance
TP Thermal Precipitator
TWA Time Weighted Average
XRD X-Ray Diffraction
XRF X-ray Fluorescence
5 Measurement strategy
5.1 General
5.1.1 Objectives
A measurement strategy for workplace exposure assessment might have a number of objectives to fulfil
including
a) determination of the substances to which exposure may take place;
b) measurement of the existing OELs for those substances in air;
c) selection of appropriate metrics and instruments to monitor exposure;
d) analysis and interpretation of the results.
The exposure measurements are part of risk assessment and the objectives can be exposure
assessment, compliance with any occupational exposure limit or benchmark level, evaluation of the
effectiveness of exposure control measures or epidemiology. The design of the actual measurement
strategy shall be consistent with the study objectives. Exposure measurement studies that attempt to
identify exposure pathways (transport processes of the contaminant from source to the receptor (the
worker)) and exposure-modifying factors/determinants shall include both measurements at the source
as well as at the receptor, i.e. the breathing zone. Exposure assessments for use in compliance
assessment, epidemiologic studies, or risk assessment shall focus on the individual worker using
breathing zone samples collected over a full work shift or a suitable time weighted average. In contrast,
studies of the efficacy of a technical control measure may for example be carried out using static
measurements at or near the workstation or the location where the task is performed.
Depending on the objective of the assessment, the resources and the expertise, the assessment can be
performed at a specific level. The levels of exposure assessment are addressed in 5.3.
5.1.2 Source domains
For exposure assessment to NOAA, the concept of the source domains (SD) was developed [6], which
describes different processes during the lifecycle of a nanomaterial:
— During the production phase (synthesis) prior to harvesting the bulk material, point source or
fugitive emission, e.g. emissions from the reactor, leaks through seals and connections, and
incidental releases, can take place (SD1). In these cases, discrete nanoparticles and agglomerates
will be formed;
— During the manufacturing of products, the handling and transfer of bulk manufactured
nanomaterial powders with relatively low energy can release nanoparticles, e.g. collection,
harvesting, bagging, bag dumping, bag emptying, scooping, weighing, dispersion/ compounding in
composites (SD2). However, the powders are already in agglomerated stage and high shear forces
are needed for deagglomeration [8], [9]. Therefore, the majority of the released particles will be
agglomerates;
— During further processing or in the use phase of a ready-to-use nanoproduct, release can be
expected during the relatively high energy dispersion of either a) solid, powdery or (liquid)
intermediates containing highly concentrated (> 25 %) nanoparticles or b) application of
(relatively low concentrated < 5 %) ready-to-use products (SD3). Examples of SD3a are pouring,
injection molding, (jet) milling, stirring, mixing. As higher shear forces can occur during high energy
dispersion de-agglomeration can occur. Examples of SD3b are application of coatings or spraying of
solutions that can form nanosized aerosols after evaporation of the liquid phase component,
usually of mixed composition;
— During the use phase of a product or its end-of-life (EoL) phase, activities resulting in fracturing
and abrasion of manufactured nanoparticles-enabled end products at work sites, e.g. low energy
abrasion, manual sanding, or, high energy machining, e.g., sanding, grinding, drilling cutting,
shredding. High temperature processes like incineration which can occur during the EoL of a
material or product are included (SD4). Most likely it will be multi-composed aerosols, and in case
of machining also matrix-bound nanoparticles, whereas during thermal processes nanoparticles
can also be formed following nucleation and condensation of vapours [10].
Relevant contextual information achieved during the identification of a source domain will facilitate the
selection of an appropriate measurement strategy, since the source domain concept reflects different
mechanisms of release and consequently possible different nature of released aerosols, e.g. state of
agglomeration and composition.
5.2 Measuring devices and measurement methods
A range of metrics and hence measurement instruments are currently used, because there are NOAA
without a nanospecific OEL, and there is no agreed measurement metric to measure the exposure.
Hence, exposure assessment methodologies and measurement strategies often rely on multiple metrics
and instruments, including real-time monitors and sampling devices to enable off-line analysis, in order
to conduct an adequate exposure assessment. The most commonly reported combination of real-time
and off-line instruments include direct-reading, handheld instruments (Condensation Particle Counter
(CPC), Diffusion Charger (DC) and Optical Particle Counter (OPC)) to detect releases of airborne nano-
objects accompanied by sampling (Electrostatic Precipitator (ESP), Thermal Precipitator (TP) or filter)
and subsequent chemical and electron microscopic (EM) analyses (SEM or TEM with Energy Dispersive
X-Ray Spectroscopy (EDS)) and or XRF/ICP-MS for particle identification and elemental composition
are given in Table 1.
Table 1 — Overview of type of monitor or sampler and associated exposure metric
(see also EN 16966:2018, Table 1)
Metric Measured or Size-integrated, Monitor Type of device
calculated aerosol fraction or (example)
metric or size-resolved sampler
Number measured size-integrated Monitor DC
CPC
Surface area measured size-integrated Monitor DC
Mass measured aerosol fraction Sampler Cyclone, impactor
Diffusive collection
size-integrated Sampler Sampler for EM analysis,
e.g. ESP, TP, cyclone)
Sampler for XRF – ICPMS
analysis
Number calculated size-resolved Monitor a
DMAS, OPC, APS
ELPI
Mass calculated size-resolved Sampler Cascaded diffusion
collectors
calculated size-resolved Sampler Cascade impactor
Diffusive collection
a
APS is an example of a suitable product available commercially. This information is given for the convenience
of users of this European Standard and does not constitute an endorsement by CEN of this product.
A more comprehensive suite of real-time and off-line instruments as well as the methods to collect off-
line samples that are also reported for conducting exposure measurements are summarized in Annex A.
5.3 Levels of exposure assessment
5.3.1 General
Three levels of assessment of (the potential for) exposure to NOAA will be distinguished, i.e. initial
assessment, basic assessment and comprehensive assessment. They differ with respect to their
objectives, methodologies and accuracy of the outcome, as well as with the information input
requirements and the level of expertise needed for application. The decision rules for interpreting the
outcome for all three tiers are given in Clause 6.
5.3.2 Initial assessment – Determination of the potential for release and emission of NOAA into
the workplace air
The aim of the initial assessment is to determine the potential for release and emission of NOAA into the
workplace air resulting from processes and handling with nanomaterials. Information shall be gathered
structurally, according to established best practices in occupational hygiene on the occupational
workplace under consideration, including workplace activities and the materials handled. All gathered
information is then analysed and used to determine if potential for release of NOAA exists.
The initial assessment consists of a paper study, but it shall include a visit to the workplace to inspect
potential locations where the NOAA of concern can be released and consequently emitted into the
occupational environment. In general, air samples or air measurements are not needed for an initial
assessment, however, it may include the analysis of material samples in a laboratory to verify if the
material handled is a nanomaterial.
The minimum information that shall be gathered during the initial assessment is listed below. An
example of a checklist is given in Annex B. The examples provided are meant to be illustrative rather
than comprehensive. Therefore, the appraiser shall expand this list to be sufficiently comprehensive
during the information gathering stage.
a) Information related to the workplace:
1) type of workplace and its potential variability, considering e.g., the quantity of different nano-
objects (nanomaterials) produced or handled, their production volumes and quantities
handled, dimensions (volume) of the production zone, and the volume of the facility in general,
such as a manufacturing environment in which larger volumes batches and continuous
production of nano-objects are processed; versus a research environment in which smaller
volumes of diverse arrays of nano-objects are processed;
2) relevant information related to previous exposure assessment results, for example, for a given
process step, information on dust exposure as part of a background assessment from other
work processes, engines or welding using e.g. spatial and/or temporal information;
3) location and type of exposure control measures;
4) any occupational guidance already in place, such as a company’s internal recommendations on
exposure limits for a given workplace if such exist.
b) Information related to the workplace activities:
1) identification of the source domain and activities related to handling nanomaterials; type of
activities, e.g. synthesis or production. Processes and handling steps, such as weighing,
packaging, pouring, and mixing of nano-objects in the open versus conveying or high
temperature synthesis in a fully enclosed system; processing of nano-containing intermediates,
including the machining or milling of nanocomposite, compounding using nano-enabled
intermediates; or use of nanomaterials to facilitate production;
2) identification of the presence of other processes in the workplace that can affect measurements
or the measurement strategy employed, such as a docking door that opens to allow a forklift to
enter the facility periodically;
3) identification of the presence or absence of ventilation, heating, ventilating and air conditioning
(HVAC), or air currents that could create positive or negative pressure possibly influencing the
measurement strategy for airborne NOAA.
c) Information related to the NOAA in the occupational environment (see source domains), including
1) type of nanomaterials/NOAA processed or handled as e.g. powders, aerosols, liquid dispersion,
slurries or as components in a nanocomposite or a product intermediate;
2) chemical composition of the nanomaterials/NOAA;
3) morphology of the nanomaterials/NOAA. For fibrous materials which can be potentially
hazardous, specific detection techniques, such as EM analysis, can be required for the basic and
comprehensive assessment;
4) any known or suspected hazards (including health, fire, and explosion) associated with the
nanomaterials/NOAA or chemically comparable analogue bulk material.
Alternatively, control and/or risk banding tools can be used, since most of the tools have a structured
set of questions focussed on determination of the potential for release or exposure. The control banding
tools directly link the assessment outcome, i.e. a combination of release potential, and hazard, with a
level of control, whereas the risk banding tools can provide a ranking of activities with respect to
potential for exposure. Examples of such tools are listed in ISO/TS 12901-2 [3].
5.3.3 Basic assessment – Indication of exposure to NOAA
5.3.3.1 General
The aim of the basic assessment is to get an indication of exposure to NOAA. The basic assessment
focuses on a straightforward approach for determining whether an exposure to NOAA can occur by:
— utilizing easy-to-use, portable equipment (direct reading instruments, samplers);
— applying up-to-date knowledge.
The basic assessment includes assessment of the workstation/breathing zone air and the ‘background’
and is supported by field measurements and laboratory analysis. The outcome of the assessment is an
indication of the likelihood of exposure to NOAA.
5.3.3.2 Measuring procedures to be utilized
The basic assessment focuses on conducting measurements using personal and easy-to-use, portable
equipment to sample and measure airborne NOAA. This type of assessment shall comply with general
recommendations for exposure measurements and sampling of aerosols in workplace air (see
EN 482 [11]). The strategy is informed by the findings in the initial investigations and the order of
magnitude of dust that is present. The order of magnitude of dust exposure can support the decision on
an appropriate measurement strategy for NOAA. However, a single commercial instrument capable of
conducting exposure measurements for airborne NOAA in occupational environments does not yet
exist. For this reason, utilization of multiple instruments, including monitors that provide real-time
number concentration (commonly CPC, DC, or OPC) and/or sampling for off-line analysis is strongly
recommended.
One or both of the following metrics shall be used:
a) time-resolved and size-integrated number and/or airborne particle surface area concentration,
either by using monitors and/or analysis of samples;
b) time-integrated sampling of the respirable fraction for off-line size-integrated characterization, e.g.
mass concentration by chemical analysis. In the following cases the chemical analysis shall be
completed by collecting a sample for electron microscopy:
— if a doubt exists on the presence of NOAAs in the mass measured by chemical analysis;
— to confirm the absence of exposure to investigated NOAA;
— if no chemical method exists that is sensitive enough for quantifying the mass concentration of
the investigated substance.
The limitations previously noted for these various instruments (see EN 16966:2018, Annexes D to J)
shall be taken into account.
NOTE 1 The offline chemical analysis is carried out in order to determine whether the measurements
associated with the possible exposure actually have the chemical composition as the investigated engineered/
manufactured nanomaterial.
NOTE 2 In some circumstances, sufficient respirable mass fraction will be collected on the filter to enable
gravimetric analysis.
NOTE 3 For risk management purposes, the monitoring data and analysis results can be used alongside an
occupational hygiene assessment of the effectiveness of the control measures (using techniques such as, air
velocity measurements, smoke tubes and expert knowledge to determine the level of control achieved).
NOTE 4 If an element of interest is found on horizontal surfaces such as a ledge or a shelf, then this could
indicate airborne migration due to ventilation or engineering control problems. These samples can be collected
1)
e.g. by GhostWipe™ and analysed for elemental analysis of a wide variety of metals (cadmium, chromium, nickel,
silver, zinc, zirconium, etc.).
5.3.3.3 Guidance on specific monitoring strategies
In order to determine the airborne number and/or airborne particle surface area concentration and to
collect samples for off-line analysis, a suitable measurement strategy shall be employed that is tailored
for the measurement scenario being conducted. As previously discussed, several factors shall be
considered in developing and implementing a suitable measurement strategy. As such, data from the
initial assessment, if available, will be useful in developing the appropriate measurement strategy. Key
factors and illustrative examples include the following:
a) selection of suitable instruments and analyses
1) The goal of the exposure assessment shall be considered and instruments selected capable of
measuring the appropriate exposure metric, taking into account any limitations on the
instruments (see EN 16966).
2) The use of real-time- and off-line techniques should be combined for measuring airborne
characteristics as well as compositional and/or morphological characteristics of interest, both
during specific activities related to the emission of NOAA and ‘background’ or non-nano
activities.
3) Instruments shall be within the manufacturer’s recommended service and recalibration
intervals .
NOTE Pre-use checks against a background can be made for which previous typical
measurements are available (e.g. normal laboratory air, internal reference or by generating a known
1) TM
GhostWhipe is an example of a suitable product available commercially. This information is given for the
convenience of users of this European Standard and does not constitute an endorsement by CEN of this product.
aerosols for size classification and/or comparisons using parallel measurements with duplicate
instruments).
4) Ideally for each instrument an (internal) Standard Operating Procedures (SOP) is available.
Alternatively, the manufacturer’s instruction manual may be used.
5) Examples of such SOPs can be downloaded from the NanoCare project website [12]. General
performance criteria shall be established for the different measurement values according to the
needs in the corresponding level of assessment. This can be done, for example, by co-locating
two instruments of the same make and model in a field comparison prior to and after a
measurement campaign. The ratio of the readings of the two instruments shall be within the
manufacturer’s stated range of accuracy for that instrument. If the results are not within the
range needed for the assessment, the field values may need to be discarded and the assessment
measurements shall be repeated. Additional examples for evaluating the performance of
instruments and measurement values include testing for drifts, cross sensitivities, etc. These
tests shall be specified in detail in the corresponding SOPs, with consideration given to
instrument, metric, and level of assessment.
Alternatively, in case two instruments of the same make and model are lacking, two instruments
measuring the same metric could be used, however, a comparison of these two devices at one place
is needed for a certain time period, which shall contain the same type of aerosol, i.e. size
distribution, composition, morphology etc. and concentrations as in the processes later, when these
are used at two different places. In practice, this will be difficult to achieve.
b) determination of suitable measurement durations and frequencies
1) Identifying crucial information on the release processes (source domains) and emission
sources provides insight for the subsequent exposure assessment. The size range of selected
(panel of) DRI(s) shall cover the expected size range of the emitted NOAA. Especially for SD2,
SD3 and SD4 size ranges of emitted NOAA can well exceed 1 µm.
2) For a given process, any temporal fluctuations that can occur as well as any characteristic times
for the process (such as ramp up time, time at steady state, and time for shut down) shall be
considered and the measurement duration and/or measurement frequency tailored
accordingly. Additionally, the instrument selected shall have a sufficient time resolution to be
able to complete the measure
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