Air quality -- General aspects -- Vocabulary

This document specifies terms and definitions that are related to air quality (see 3.1.1.1). These are either general terms or are used in connection with the sampling (see 3.3.3.1) and measurement of gases, vapours (see 3.1.5.8) and airborne particles (see 3.2.2.1) for the determination of air quality. The terms included are those that have been identified as being fundamental because their definition is necessary to avoid ambiguity and ensure consistency of use. An alphabetical index of the terms is provided in Annex A. This document is applicable to all International Standards, ISO Technical Reports, ISO Technical Specifications, and ISO Guides related to air quality.

Qualité de l'air -- Aspects généraux -- Vocabulaire

Le présent document spécifie les termes et définitions relatifs ŕ la qualité de l'air (voir 3.1.1.1). Ces termes sont soit de nature générique, soit ils sont utilisés en lien avec le prélčvement (voir 3.3.3.1) et le mesurage des gaz, des vapeurs (voir 3.1.5.8) et des particules en suspension dans l'air (voir 3.2.2.1) afin de déterminer la qualité de l'air. Les termes figurant dans le présent document ont été identifiés comme étant fondamentaux car leur définition est nécessaire pour lever toute ambiguďté et garantir la cohérence de leur emploi. L'Annexe A fournit un index alphabétique des termes définis. Le présent document est applicable ŕ toutes les Normes internationales ainsi qu'ŕ tous les rapports et spécifications techniques de l'ISO et aux guides de l'ISO liés ŕ la qualité de l'air.

Kakovost zraka - Splošni vidiki - Slovar

General Information

Status
Published
Publication Date
14-May-2020
Current Stage
6060 - International Standard published
Start Date
15-May-2020

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SLOVENSKI STANDARD
SIST ISO 4225:2021
01-maj-2021
Nadomešča:
SIST ISO 4225:1995
Kakovost zraka - Splošni vidiki - Slovar
Air quality - General aspects - Vocabulary
Qualité de l'air - Aspects généraux - Vocabulaire
Ta slovenski standard je istoveten z: ISO 4225:2020
ICS:
01.040.13 Okolje. Varovanje zdravja. Environment. Health
Varnost (Slovarji) protection. Safety
(Vocabularies)
13.040.01 Kakovost zraka na splošno Air quality in general
SIST ISO 4225:2021 en,fr

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 4225:2021
---------------------- Page: 2 ----------------------
SIST ISO 4225:2021
INTERNATIONAL ISO
STANDARD 4225
Third edition
2020-05
Air quality — General aspects —
Vocabulary
Qualité de l'air — Aspects généraux — Vocabulaire
Reference number
ISO 4225:2020(E)
ISO 2020
---------------------- Page: 3 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 General terms ........................................................................................................................................................................................... 1

3.1.1 Terms describing air quality .................................................................................................................................. 1

3.1.2 Agents ........................................................................................................................................................................................ 2

3.1.3 Terms related to aerosols ......................................................................................................................................... 2

3.1.4 Terms related to exposure ....................................................................................................................................... 3

3.1.5 Other terms .......................................................................................................................................................................... 3

3.2 Terms related to air pollution and pollution control ............................................................................................. 5

3.2.1 Terms generally describing air pollution .................................................................................................... 5

3.2.2 Components or forms of air pollution ........................................................................................................... 7

3.2.3 Terms related to control of air pollution ..................................................................................................... 9

3.3 Terms related to air quality sampling ..............................................................................................................................10

3.3.1 Samples .................................................................................................................................................................................10

3.3.2 Sampling equipment .................. ......................................................................................................................... .......10

3.3.3 Sampling methods .......................................................................................................................................................12

3.4 Terms related to air quality measurement ..................................................................................................................13

3.4.1 Measurement methods ............................................................................................................................................13

Annex A (informative) Alphabetical index of terms defined ....................................................................................................15

Bibliography .............................................................................................................................................................................................................................19

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 4,

General aspects.

This third edition cancels and replaces the second edition (ISO 4225:1994), which has been technically

revised. The main changes compared to the previous edition are as follows:

— where appropriate, terms and definitions have been harmonized with ISO 18158:2016;

— obsolete terms have been removed;
— references have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
Introduction

The work programme of ISO/TC 146, Air quality, includes the standardization of procedures for

sampling and measurement of gases, vapours and airborne particles. Many terms that are commonly

used in relation to air quality, sampling and measurement are defined within individual standards

or technical documents and are often defined differently from one standard or document to the next.

This creates ambiguities and inconsistencies in the use of such terms. This document was developed

to ensure that commonly used terms have agreed-upon definitions and to eliminate ambiguities and

inconsistencies in their usage. It will be of benefit to agencies concerned with air quality, sampling, and

laboratory analysis.

The terms given in this document are those in common use. The list should not be considered complete,

however, and further terms will be added as the need arises.
© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 4225:2021
---------------------- Page: 8 ----------------------
SIST ISO 4225:2021
INTERNATIONAL STANDARD ISO 4225:2020(E)
Air quality — General aspects — Vocabulary
1 Scope

This document specifies terms and definitions that are related to air quality (see 3.1.1.1). These are

either general terms or are used in connection with the sampling (see 3.3.3.1) and measurement of

gases, vapours (see 3.1.5.8) and airborne particles (see 3.2.2.1) for the determination of air quality.

The terms included are those that have been identified as being fundamental because their definition is

necessary to avoid ambiguity and ensure consistency of use.
An alphabetical index of the terms is provided in Annex A.

This document is applicable to all International Standards, ISO Technical Reports, ISO Technical

Specifications, and ISO Guides related to air quality.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1 General terms
3.1.1 Terms describing air quality
3.1.1.1
air quality

features of the air which have an impact on humans (e.g., safety and health) and/or the environment

Note 1 to entry: Air quality is typically expressed in terms of the presence or absence of air pollution (3.2.1.2) (e.g.

emissions (3.2.1.4) or conversions resulting from emissions, e.g., ozone), using one or more measurements.

Note 2 to entry: The concept of air quality can be used in reference to ambient air (3.1.1.3), indoor air (3.1.1.5), or

workplace air (3.1.1.7).
3.1.1.2
air quality standard

specified attribute of the air intended to prevent or minimize impacts on humans (e.g. safety and health)

and/or the environment

Note 1 to entry: Air quality standards are frequently defined statistically by setting a limit to the concentration

of an air pollutant (3.2.1.1) over a specified averaging time (3.1.1.9).

Note 2 to entry: Air quality standards can have legal or advisory status in one or more jurisdictions.

© ISO 2020 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
3.1.1.3
ambient air
outdoor air to which people, plants, animals or material can be exposed
3.1.1.4
ambient air quality standard
air quality standard (3.1.1.2) for the ambient air (3.1.1.3)
3.1.1.5
indoor air
air within an enclosed space, e.g., dwelling or public building
3.1.1.6
indoor air quality standard
air quality standard (3.1.1.2) for the indoor air (3.1.1.5)
3.1.1.7
workplace air

air to which a person is exposed, whether indoor or outdoor, during the hours of work at the person's

workplace
3.1.1.8
workplace air quality standard
air quality standard (3.1.1.2) for the workplace air (3.1.1.7)
3.1.1.9
averaging time

interval of time over which an attribute of air quality (3.1.1.1) has been expressed as an average

3.1.2 Agents
3.1.2.1
biological agent

one of a number of agents such as bacteria, viruses, fungi and other micro-organisms or parts of them

and their associated allergens or toxins, including those which have been genetically modified, cell

cultures or endoparasites which are potentially hazardous to human health
3.1.2.2
chemical agent

chemical element or compound on its own or admixed as it occurs in the natural state or as produced,

used, or released, including release as waste, by any work activity, whether or not produced intentionally

and whether or not placed on the market
3.1.3 Terms related to aerosols
3.1.3.1
aerosol

airborne particles (3.2.2.1) and the gas (and vapour (3.1.5.8)) mixture in which they are suspended

3.1.3.2
bioaerosol
aerosol (3.1.3.1) consisting of (a) biological agent(s) (3.1.2.1)
3.1.3.3
nanoaerosol

aerosol (3.1.3.1) comprised of, or consisting of, nanoparticles (3.1.3.4) and nanostructured particles

(3.1.3.5)
2 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
3.1.3.4
nanoparticle

material with all three dimensions in the size range from approximately 1 nm to 100 nm

3.1.3.5
nanostructured particle

particle with structural features smaller than 100 nm, which can influence its physical, chemical and/

or biological properties

Note 1 to entry: A nanostructured particle can have a maximum dimension substantially larger than 100 nm.

EXAMPLE A 500 nm diameter agglomerate (3.1.3.6) of nanoparticles (3.1.3.4) would be considered a

nanostructured particle.
3.1.3.6
agglomerate

group of particles held together by relatively weak forces, including van der Waals forces,

electrostatic forces and surface tension
3.1.4 Terms related to exposure
3.1.4.1
breathing zone
space around the nose and mouth from which air is inhaled

Note 1 to entry: Technically, the breathing zone corresponds to a hemisphere (generally accepted to be 30 cm

in radius) extending in front of the human face, centred on the midpoint of a line joining the ears. The base of

the hemisphere is a plane through this line, the top of the head and the larynx. This technical description is not

applicable when measuring air within respiratory protective equipment.
3.1.4.2
inhalation exposure

situation in which a chemical agent (3.1.2.2) or biological agent (3.1.2.1) is present in the air that is

inhaled by a person
3.1.4.3
dermal exposure

contact between a chemical agent (3.1.2.2) or biological agent (3.1.2.1) and human skin

3.1.5 Other terms
3.1.5.1
cyclone

large circulatory wind system around a region of low atmospheric pressure

3.1.5.2
stability

state of hydrostatic equilibrium of the atmosphere in which a parcel of air moved from

its initial level undergoes a hydrostatic force which tends to restore it to this level

3.1.5.3
chimney effect

phenomenon consisting of upwards movement of a localized mass of air or other gases caused by

temperature differences
3.1.5.4
effective chimney height

height used for the purposes of calculating the dispersion of emitted gases from a chimney, and which

differs from the real chimney height by an amount which depends on such factors as the exit velocity,

buoyancy effects and wind speed as well as topography
© ISO 2020 – All rights reserved 3
---------------------- Page: 11 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
3.1.5.5
dispersion parameters, Gaussian

parameters which describe the size of an assumed Gaussian plume (3.2.1.20) as a function of

atmospheric stability (3.1.5.2) and travel distance or time
3.1.5.6
lapse rate
variation of an atmospheric parameter with height
Note 1 to entry: The parameter is temperature unless otherwise stated.

Note 2 to entry: This variation is taken as positive when temperature decreases with increasing height. If

meteorological conditions are such that the atmospheric lapse rate is the same as that for an adiabatically rising

parcel of dry air (about 10 °C km ), the atmosphere is said to have a dry adiabatic lapse rate.

3.1.5.7
micrometeorology

part of meteorology that deals with observations and processes in the smallest scales of time and space,

approximately smaller than 1 km and less than a day (i.e., local processes)
[SOURCE: American Meteorological Society Glossary of Meteorology]
3.1.5.8
vapour

gas phase of a substance in a state of equilibrium or disturbed equilibrium with the same substance in

a liquid or solid state below its boiling or sublimation point
3.1.5.9
fog

type of aerosol (3.1.3.1) consisting of a suspension of droplets (3.1.5.12) in air

Note 1 to entry: In meteorology, fog refers to a suspension of water droplets (3.1.5.12) resulting in a visibility of

less than 1 km.
3.1.5.10
haze

type of aerosol (3.1.3.1) consisting of a suspension of extremely small airborne particles (3.2.2.1) in air,

individually invisible to the naked eye, but which are numerous enough to give the air an appearance of

opalescence together with reduced visibility
3.1.5.11
mist
suspension of droplets (3.1.5.12) in a gas

Note 1 to entry: A mist reduces visibility to a lesser extent than fog (3.1.5.9).

[SOURCE: ISO 29464:2017, 3.2.109]
3.1.5.12
droplet
liquid particle of small mass, capable of remaining in suspension in a gas

Note 1 to entry: In some turbulent systems, for example clouds, the diameter of a droplet can reach 200 μm.

3.1.5.13
particle aerodynamic diameter
aerodynamic diameter

diameter of a sphere of 1 g/cm density with the same terminal settling velocity in calm air as the

particle, under the prevailing conditions of temperature, pressure and relative humidity

Note 1 to entry: The particle aerodynamic diameter depends on the size, density and shape of the particle.

4 © ISO 2020 – All rights reserved
---------------------- Page: 12 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)

Note 2 to entry: Aerodynamic diameter is related to the inertial properties of aerosol particles.

3.1.5.14
equivalent diameter

diameter of a spherical particle which will give behaviour equivalent to that of the particle being

examined
[SOURCE: ISO 29464:2017, 3.2.39]
3.1.5.15
rain-out

mechanism by which airborne particles (3.2.2.1) in the clouds are removed by the formation of raindrops

Note 1 to entry: Rain-out can also be included as part of wash-out (3.1.5.16).
3.1.5.16
wash-out

removal from the atmosphere of gases and sometimes airborne particles (3.2.2.1) by their solution in or

attachment to raindrops as they fall
Note 1 to entry: Wash-out can include rain-out (3.1.5.15).
3.2 Terms related to air pollution and pollution control
3.2.1 Terms generally describing air pollution
3.2.1.1
air pollutant
contaminant

substance emitted into the air either by human activity or natural processes and adversely affecting

air quality
3.2.1.2
air pollution
contamination

presence of air pollutants (3.2.1.1) in sufficient concentration and for a sufficient time

3.2.1.3
background concentration

portion of the concentration of an air pollutant (3.2.1.1) which cannot be directly related to the sources

(3.2.1.23) under study

Note 1 to entry: The background concentration can be the same as the natural background concentration (3.2.1.10)

or can include other sources not under study.
3.2.1.4
emission
discharge of substances into the air

Note 1 to entry: The term “emission” is used to describe the discharge and the rate of discharge.

3.2.1.5
emission concentration

concentration of air pollutant (3.2.1.1) in an emission (3.2.1.4) at its point of discharge

3.2.1.6
emission factor

expression for the ratio of the rate at which an air pollutant (3.2.1.1) is emitted as a result of some

activity, to the rate of that activity
EXAMPLE Kilograms of sulfur dioxide emitted per tonne of steel produced.
© ISO 2020 – All rights reserved 5
---------------------- Page: 13 ----------------------
SIST ISO 4225:2021
ISO 4225:2020(E)
3.2.1.7
emission flux

emission rate (3.2.1.8) per unit area of the appropriate surface of an emitting source (3.2.1.23)

3.2.1.8
emission rate
mass (or other quantity) of pollutant transferred into the air per unit time
3.2.1.9
emission limit value
emission standard

specified limit on one or more components within an emission (3.2.1.4), typically having a legal or

advisory status

Note 1 to entry: Emission limit values are frequently defined statistically e.g. by setting a limit to the emission

rate (3.2.1.8) or to the emission concentration (3.2.1.5) at a defined dilution level.

3.2.1.10
natural background concentration

concentration of a given substance in a pristine air mass in which anthropogenic emissions (3.2.1.4) are

negligible
3.2.1.11
odour

sensation perceived by means of the olfactory organ in sniffing certain volatile substances

[SOURCE: ISO 5492:2008, 3.18]
3.2.1.12
odorant
substance which, when volat
...

SLOVENSKI STANDARD
oSIST ISO 4225:2021
01-februar-2021
Kakovost zraka - Splošni vidiki - Slovar
Air quality - General aspects - Vocabulary
Qualité de l'air - Aspects généraux - Vocabulaire
Ta slovenski standard je istoveten z: ISO 4225:2020
ICS:
01.040.13 Okolje. Varovanje zdravja. Environment. Health
Varnost (Slovarji) protection. Safety
(Vocabularies)
13.040.01 Kakovost zraka na splošno Air quality in general
oSIST ISO 4225:2021 en,fr

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST ISO 4225:2021
---------------------- Page: 2 ----------------------
oSIST ISO 4225:2021
INTERNATIONAL ISO
STANDARD 4225
Third edition
2020-05
Air quality — General aspects —
Vocabulary
Qualité de l'air — Aspects généraux — Vocabulaire
Reference number
ISO 4225:2020(E)
ISO 2020
---------------------- Page: 3 ----------------------
oSIST ISO 4225:2021
ISO 4225:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST ISO 4225:2021
ISO 4225:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 General terms ........................................................................................................................................................................................... 1

3.1.1 Terms describing air quality .................................................................................................................................. 1

3.1.2 Agents ........................................................................................................................................................................................ 2

3.1.3 Terms related to aerosols ......................................................................................................................................... 2

3.1.4 Terms related to exposure ....................................................................................................................................... 3

3.1.5 Other terms .......................................................................................................................................................................... 3

3.2 Terms related to air pollution and pollution control ............................................................................................. 5

3.2.1 Terms generally describing air pollution .................................................................................................... 5

3.2.2 Components or forms of air pollution ........................................................................................................... 7

3.2.3 Terms related to control of air pollution ..................................................................................................... 9

3.3 Terms related to air quality sampling ..............................................................................................................................10

3.3.1 Samples .................................................................................................................................................................................10

3.3.2 Sampling equipment .................. ......................................................................................................................... .......10

3.3.3 Sampling methods .......................................................................................................................................................12

3.4 Terms related to air quality measurement ..................................................................................................................13

3.4.1 Measurement methods ............................................................................................................................................13

Annex A (informative) Alphabetical index of terms defined ....................................................................................................15

Bibliography .............................................................................................................................................................................................................................19

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST ISO 4225:2021
ISO 4225:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 4,

General aspects.

This third edition cancels and replaces the second edition (ISO 4225:1994), which has been technically

revised. The main changes compared to the previous edition are as follows:

— where appropriate, terms and definitions have been harmonized with ISO 18158:2016;

— obsolete terms have been removed;
— references have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST ISO 4225:2021
ISO 4225:2020(E)
Introduction

The work programme of ISO/TC 146, Air quality, includes the standardization of procedures for

sampling and measurement of gases, vapours and airborne particles. Many terms that are commonly

used in relation to air quality, sampling and measurement are defined within individual standards

or technical documents and are often defined differently from one standard or document to the next.

This creates ambiguities and inconsistencies in the use of such terms. This document was developed

to ensure that commonly used terms have agreed-upon definitions and to eliminate ambiguities and

inconsistencies in their usage. It will be of benefit to agencies concerned with air quality, sampling, and

laboratory analysis.

The terms given in this document are those in common use. The list should not be considered complete,

however, and further terms will be added as the need arises.
© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST ISO 4225:2021
---------------------- Page: 8 ----------------------
oSIST ISO 4225:2021
INTERNATIONAL STANDARD ISO 4225:2020(E)
Air quality — General aspects — Vocabulary
1 Scope

This document specifies terms and definitions that are related to air quality (see 3.1.1.1). These are

either general terms or are used in connection with the sampling (see 3.3.3.1) and measurement of

gases, vapours (see 3.1.5.8) and airborne particles (see 3.2.2.1) for the determination of air quality.

The terms included are those that have been identified as being fundamental because their definition is

necessary to avoid ambiguity and ensure consistency of use.
An alphabetical index of the terms is provided in Annex A.

This document is applicable to all International Standards, ISO Technical Reports, ISO Technical

Specifications, and ISO Guides related to air quality.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1 General terms
3.1.1 Terms describing air quality
3.1.1.1
air quality

features of the air which have an impact on humans (e.g., safety and health) and/or the environment

Note 1 to entry: Air quality is typically expressed in terms of the presence or absence of air pollution (3.2.1.2) (e.g.

emissions (3.2.1.4) or conversions resulting from emissions, e.g., ozone), using one or more measurements.

Note 2 to entry: The concept of air quality can be used in reference to ambient air (3.1.1.3), indoor air (3.1.1.5), or

workplace air (3.1.1.7).
3.1.1.2
air quality standard

specified attribute of the air intended to prevent or minimize impacts on humans (e.g. safety and health)

and/or the environment

Note 1 to entry: Air quality standards are frequently defined statistically by setting a limit to the concentration

of an air pollutant (3.2.1.1) over a specified averaging time (3.1.1.9).

Note 2 to entry: Air quality standards can have legal or advisory status in one or more jurisdictions.

© ISO 2020 – All rights reserved 1
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3.1.1.3
ambient air
outdoor air to which people, plants, animals or material can be exposed
3.1.1.4
ambient air quality standard
air quality standard (3.1.1.2) for the ambient air (3.1.1.3)
3.1.1.5
indoor air
air within an enclosed space, e.g., dwelling or public building
3.1.1.6
indoor air quality standard
air quality standard (3.1.1.2) for the indoor air (3.1.1.5)
3.1.1.7
workplace air

air to which a person is exposed, whether indoor or outdoor, during the hours of work at the person's

workplace
3.1.1.8
workplace air quality standard
air quality standard (3.1.1.2) for the workplace air (3.1.1.7)
3.1.1.9
averaging time

interval of time over which an attribute of air quality (3.1.1.1) has been expressed as an average

3.1.2 Agents
3.1.2.1
biological agent

one of a number of agents such as bacteria, viruses, fungi and other micro-organisms or parts of them

and their associated allergens or toxins, including those which have been genetically modified, cell

cultures or endoparasites which are potentially hazardous to human health
3.1.2.2
chemical agent

chemical element or compound on its own or admixed as it occurs in the natural state or as produced,

used, or released, including release as waste, by any work activity, whether or not produced intentionally

and whether or not placed on the market
3.1.3 Terms related to aerosols
3.1.3.1
aerosol

airborne particles (3.2.2.1) and the gas (and vapour (3.1.5.8)) mixture in which they are suspended

3.1.3.2
bioaerosol
aerosol (3.1.3.1) consisting of (a) biological agent(s) (3.1.2.1)
3.1.3.3
nanoaerosol

aerosol (3.1.3.1) comprised of, or consisting of, nanoparticles (3.1.3.4) and nanostructured particles

(3.1.3.5)
2 © ISO 2020 – All rights reserved
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3.1.3.4
nanoparticle

material with all three dimensions in the size range from approximately 1 nm to 100 nm

3.1.3.5
nanostructured particle

particle with structural features smaller than 100 nm, which can influence its physical, chemical and/

or biological properties

Note 1 to entry: A nanostructured particle can have a maximum dimension substantially larger than 100 nm.

EXAMPLE A 500 nm diameter agglomerate (3.1.3.6) of nanoparticles (3.1.3.4) would be considered a

nanostructured particle.
3.1.3.6
agglomerate

group of particles held together by relatively weak forces, including van der Waals forces,

electrostatic forces and surface tension
3.1.4 Terms related to exposure
3.1.4.1
breathing zone
space around the nose and mouth from which air is inhaled

Note 1 to entry: Technically, the breathing zone corresponds to a hemisphere (generally accepted to be 30 cm

in radius) extending in front of the human face, centred on the midpoint of a line joining the ears. The base of

the hemisphere is a plane through this line, the top of the head and the larynx. This technical description is not

applicable when measuring air within respiratory protective equipment.
3.1.4.2
inhalation exposure

situation in which a chemical agent (3.1.2.2) or biological agent (3.1.2.1) is present in the air that is

inhaled by a person
3.1.4.3
dermal exposure

contact between a chemical agent (3.1.2.2) or biological agent (3.1.2.1) and human skin

3.1.5 Other terms
3.1.5.1
cyclone

large circulatory wind system around a region of low atmospheric pressure

3.1.5.2
stability

state of hydrostatic equilibrium of the atmosphere in which a parcel of air moved from

its initial level undergoes a hydrostatic force which tends to restore it to this level

3.1.5.3
chimney effect

phenomenon consisting of upwards movement of a localized mass of air or other gases caused by

temperature differences
3.1.5.4
effective chimney height

height used for the purposes of calculating the dispersion of emitted gases from a chimney, and which

differs from the real chimney height by an amount which depends on such factors as the exit velocity,

buoyancy effects and wind speed as well as topography
© ISO 2020 – All rights reserved 3
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oSIST ISO 4225:2021
ISO 4225:2020(E)
3.1.5.5
dispersion parameters, Gaussian

parameters which describe the size of an assumed Gaussian plume (3.2.1.20) as a function of

atmospheric stability (3.1.5.2) and travel distance or time
3.1.5.6
lapse rate
variation of an atmospheric parameter with height
Note 1 to entry: The parameter is temperature unless otherwise stated.

Note 2 to entry: This variation is taken as positive when temperature decreases with increasing height. If

meteorological conditions are such that the atmospheric lapse rate is the same as that for an adiabatically rising

parcel of dry air (about 10 °C km ), the atmosphere is said to have a dry adiabatic lapse rate.

3.1.5.7
micrometeorology

part of meteorology that deals with observations and processes in the smallest scales of time and space,

approximately smaller than 1 km and less than a day (i.e., local processes)
[SOURCE: American Meteorological Society Glossary of Meteorology]
3.1.5.8
vapour

gas phase of a substance in a state of equilibrium or disturbed equilibrium with the same substance in

a liquid or solid state below its boiling or sublimation point
3.1.5.9
fog

type of aerosol (3.1.3.1) consisting of a suspension of droplets (3.1.5.12) in air

Note 1 to entry: In meteorology, fog refers to a suspension of water droplets (3.1.5.12) resulting in a visibility of

less than 1 km.
3.1.5.10
haze

type of aerosol (3.1.3.1) consisting of a suspension of extremely small airborne particles (3.2.2.1) in air,

individually invisible to the naked eye, but which are numerous enough to give the air an appearance of

opalescence together with reduced visibility
3.1.5.11
mist
suspension of droplets (3.1.5.12) in a gas

Note 1 to entry: A mist reduces visibility to a lesser extent than fog (3.1.5.9).

[SOURCE: ISO 29464:2017, 3.2.109]
3.1.5.12
droplet
liquid particle of small mass, capable of remaining in suspension in a gas

Note 1 to entry: In some turbulent systems, for example clouds, the diameter of a droplet can reach 200 μm.

3.1.5.13
particle aerodynamic diameter
aerodynamic diameter

diameter of a sphere of 1 g/cm density with the same terminal settling velocity in calm air as the

particle, under the prevailing conditions of temperature, pressure and relative humidity

Note 1 to entry: The particle aerodynamic diameter depends on the size, density and shape of the particle.

4 © ISO 2020 – All rights reserved
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oSIST ISO 4225:2021
ISO 4225:2020(E)

Note 2 to entry: Aerodynamic diameter is related to the inertial properties of aerosol particles.

3.1.5.14
equivalent diameter

diameter of a spherical particle which will give behaviour equivalent to that of the particle being

examined
[SOURCE: ISO 29464:2017, 3.2.39]
3.1.5.15
rain-out

mechanism by which airborne particles (3.2.2.1) in the clouds are removed by the formation of raindrops

Note 1 to entry: Rain-out can also be included as part of wash-out (3.1.5.16).
3.1.5.16
wash-out

removal from the atmosphere of gases and sometimes airborne particles (3.2.2.1) by their solution in or

attachment to raindrops as they fall
Note 1 to entry: Wash-out can include rain-out (3.1.5.15).
3.2 Terms related to air pollution and pollution control
3.2.1 Terms generally describing air pollution
3.2.1.1
air pollutant
contaminant

substance emitted into the air either by human activity or natural processes and adversely affecting

air quality
3.2.1.2
air pollution
contamination

presence of air pollutants (3.2.1.1) in sufficient concentration and for a sufficient time

3.2.1.3
background concentration

portion of the concentration of an air pollutant (3.2.1.1) which cannot be directly related to the sources

(3.2.1.23) under study

Note 1 to entry: The background concentration can be the same as the natural background concentration (3.2.1.10)

or can include other sources not under study.
3.2.1.4
emission
discharge of substances into the air

Note 1 to entry: The term “emission” is used to describe the discharge and the rate of discharge.

3.2.1.5
emission concentration

concentration of air pollutant (3.2.1.1) in an emission (3.2.1.4) at its point of discharge

3.2.1.6
emission factor

expression for the ratio of the rate at which an air pollutant (3.2.1.1) is emitted as a result of some

activity, to the rate of that activity
EXAMPLE Kilograms of sulfur dioxide emitted per tonne of steel produced.
© ISO 2020 – All rights reserved 5
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oSIST ISO 4225:2021
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3.2.1.7
emission flux

emission rate (3.2.1.8) per unit area of the appropriate surface of an emitting source (3.2.1.23)

3.2.1.8
emission rate
mass (or other quantity) of pollutant transferred into the air per unit time
3.2.1.9
emission limit value
emission standard

specified limit on one or more components within an emission (3.2.1.4), typically having a legal or

advisory status

Note 1 to entry: Emission limit values are frequently defined statistically e.g. by setting a limit to the emission

rate (3.2.1.8) or to the emission concentration (3.2.1.5) at a defined dilution level.

3.2.1.10
natural background concentration

concentration of a given substance in a pristine air mass in which anthropogenic emissions (3.2.1.4) are

negligible
3.2.1.11
odour

sensation perceived by means of the olfactory organ in sniffing certain volatile substances

[SOURCE: ISO 5492:2008, 3.18]
3.2.1.12
odorant
substance which, when volatilized in ne
...

INTERNATIONAL ISO
STANDARD 4225
Third edition
2020-05
Air quality — General aspects —
Vocabulary
Qualité de l'air — Aspects généraux — Vocabulaire
Reference number
ISO 4225:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 4225:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 4225:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 General terms ........................................................................................................................................................................................... 1

3.1.1 Terms describing air quality .................................................................................................................................. 1

3.1.2 Agents ........................................................................................................................................................................................ 2

3.1.3 Terms related to aerosols ......................................................................................................................................... 2

3.1.4 Terms related to exposure ....................................................................................................................................... 3

3.1.5 Other terms .......................................................................................................................................................................... 3

3.2 Terms related to air pollution and pollution control ............................................................................................. 5

3.2.1 Terms generally describing air pollution .................................................................................................... 5

3.2.2 Components or forms of air pollution ........................................................................................................... 7

3.2.3 Terms related to control of air pollution ..................................................................................................... 9

3.3 Terms related to air quality sampling ..............................................................................................................................10

3.3.1 Samples .................................................................................................................................................................................10

3.3.2 Sampling equipment .................. ......................................................................................................................... .......10

3.3.3 Sampling methods .......................................................................................................................................................12

3.4 Terms related to air quality measurement ..................................................................................................................13

3.4.1 Measurement methods ............................................................................................................................................13

Annex A (informative) Alphabetical index of terms defined ....................................................................................................15

Bibliography .............................................................................................................................................................................................................................19

© ISO 2020 – All rights reserved iii
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ISO 4225:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 4,

General aspects.

This third edition cancels and replaces the second edition (ISO 4225:1994), which has been technically

revised. The main changes compared to the previous edition are as follows:

— where appropriate, terms and definitions have been harmonized with ISO 18158:2016;

— obsolete terms have been removed;
— references have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
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ISO 4225:2020(E)
Introduction

The work programme of ISO/TC 146, Air quality, includes the standardization of procedures for

sampling and measurement of gases, vapours and airborne particles. Many terms that are commonly

used in relation to air quality, sampling and measurement are defined within individual standards

or technical documents and are often defined differently from one standard or document to the next.

This creates ambiguities and inconsistencies in the use of such terms. This document was developed

to ensure that commonly used terms have agreed-upon definitions and to eliminate ambiguities and

inconsistencies in their usage. It will be of benefit to agencies concerned with air quality, sampling, and

laboratory analysis.

The terms given in this document are those in common use. The list should not be considered complete,

however, and further terms will be added as the need arises.
© ISO 2020 – All rights reserved v
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INTERNATIONAL STANDARD ISO 4225:2020(E)
Air quality — General aspects — Vocabulary
1 Scope

This document specifies terms and definitions that are related to air quality (see 3.1.1.1). These are

either general terms or are used in connection with the sampling (see 3.3.3.1) and measurement of

gases, vapours (see 3.1.5.8) and airborne particles (see 3.2.2.1) for the determination of air quality.

The terms included are those that have been identified as being fundamental because their definition is

necessary to avoid ambiguity and ensure consistency of use.
An alphabetical index of the terms is provided in Annex A.

This document is applicable to all International Standards, ISO Technical Reports, ISO Technical

Specifications, and ISO Guides related to air quality.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1 General terms
3.1.1 Terms describing air quality
3.1.1.1
air quality

features of the air which have an impact on humans (e.g., safety and health) and/or the environment

Note 1 to entry: Air quality is typically expressed in terms of the presence or absence of air pollution (3.2.1.2) (e.g.

emissions (3.2.1.4) or conversions resulting from emissions, e.g., ozone), using one or more measurements.

Note 2 to entry: The concept of air quality can be used in reference to ambient air (3.1.1.3), indoor air (3.1.1.5), or

workplace air (3.1.1.7).
3.1.1.2
air quality standard

specified attribute of the air intended to prevent or minimize impacts on humans (e.g. safety and health)

and/or the environment

Note 1 to entry: Air quality standards are frequently defined statistically by setting a limit to the concentration

of an air pollutant (3.2.1.1) over a specified averaging time (3.1.1.9).

Note 2 to entry: Air quality standards can have legal or advisory status in one or more jurisdictions.

© ISO 2020 – All rights reserved 1
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ISO 4225:2020(E)
3.1.1.3
ambient air
outdoor air to which people, plants, animals or material can be exposed
3.1.1.4
ambient air quality standard
air quality standard (3.1.1.2) for the ambient air (3.1.1.3)
3.1.1.5
indoor air
air within an enclosed space, e.g., dwelling or public building
3.1.1.6
indoor air quality standard
air quality standard (3.1.1.2) for the indoor air (3.1.1.5)
3.1.1.7
workplace air

air to which a person is exposed, whether indoor or outdoor, during the hours of work at the person's

workplace
3.1.1.8
workplace air quality standard
air quality standard (3.1.1.2) for the workplace air (3.1.1.7)
3.1.1.9
averaging time

interval of time over which an attribute of air quality (3.1.1.1) has been expressed as an average

3.1.2 Agents
3.1.2.1
biological agent

one of a number of agents such as bacteria, viruses, fungi and other micro-organisms or parts of them

and their associated allergens or toxins, including those which have been genetically modified, cell

cultures or endoparasites which are potentially hazardous to human health
3.1.2.2
chemical agent

chemical element or compound on its own or admixed as it occurs in the natural state or as produced,

used, or released, including release as waste, by any work activity, whether or not produced intentionally

and whether or not placed on the market
3.1.3 Terms related to aerosols
3.1.3.1
aerosol

airborne particles (3.2.2.1) and the gas (and vapour (3.1.5.8)) mixture in which they are suspended

3.1.3.2
bioaerosol
aerosol (3.1.3.1) consisting of (a) biological agent(s) (3.1.2.1)
3.1.3.3
nanoaerosol

aerosol (3.1.3.1) comprised of, or consisting of, nanoparticles (3.1.3.4) and nanostructured particles

(3.1.3.5)
2 © ISO 2020 – All rights reserved
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ISO 4225:2020(E)
3.1.3.4
nanoparticle

material with all three dimensions in the size range from approximately 1 nm to 100 nm

3.1.3.5
nanostructured particle

particle with structural features smaller than 100 nm, which can influence its physical, chemical and/

or biological properties

Note 1 to entry: A nanostructured particle can have a maximum dimension substantially larger than 100 nm.

EXAMPLE A 500 nm diameter agglomerate (3.1.3.6) of nanoparticles (3.1.3.4) would be considered a

nanostructured particle.
3.1.3.6
agglomerate

group of particles held together by relatively weak forces, including van der Waals forces,

electrostatic forces and surface tension
3.1.4 Terms related to exposure
3.1.4.1
breathing zone
space around the nose and mouth from which air is inhaled

Note 1 to entry: Technically, the breathing zone corresponds to a hemisphere (generally accepted to be 30 cm

in radius) extending in front of the human face, centred on the midpoint of a line joining the ears. The base of

the hemisphere is a plane through this line, the top of the head and the larynx. This technical description is not

applicable when measuring air within respiratory protective equipment.
3.1.4.2
inhalation exposure

situation in which a chemical agent (3.1.2.2) or biological agent (3.1.2.1) is present in the air that is

inhaled by a person
3.1.4.3
dermal exposure

contact between a chemical agent (3.1.2.2) or biological agent (3.1.2.1) and human skin

3.1.5 Other terms
3.1.5.1
cyclone

large circulatory wind system around a region of low atmospheric pressure

3.1.5.2
stability

state of hydrostatic equilibrium of the atmosphere in which a parcel of air moved from

its initial level undergoes a hydrostatic force which tends to restore it to this level

3.1.5.3
chimney effect

phenomenon consisting of upwards movement of a localized mass of air or other gases caused by

temperature differences
3.1.5.4
effective chimney height

height used for the purposes of calculating the dispersion of emitted gases from a chimney, and which

differs from the real chimney height by an amount which depends on such factors as the exit velocity,

buoyancy effects and wind speed as well as topography
© ISO 2020 – All rights reserved 3
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ISO 4225:2020(E)
3.1.5.5
dispersion parameters, Gaussian

parameters which describe the size of an assumed Gaussian plume (3.2.1.20) as a function of

atmospheric stability (3.1.5.2) and travel distance or time
3.1.5.6
lapse rate
variation of an atmospheric parameter with height
Note 1 to entry: The parameter is temperature unless otherwise stated.

Note 2 to entry: This variation is taken as positive when temperature decreases with increasing height. If

meteorological conditions are such that the atmospheric lapse rate is the same as that for an adiabatically rising

parcel of dry air (about 10 °C km ), the atmosphere is said to have a dry adiabatic lapse rate.

3.1.5.7
micrometeorology

part of meteorology that deals with observations and processes in the smallest scales of time and space,

approximately smaller than 1 km and less than a day (i.e., local processes)
[SOURCE: American Meteorological Society Glossary of Meteorology]
3.1.5.8
vapour

gas phase of a substance in a state of equilibrium or disturbed equilibrium with the same substance in

a liquid or solid state below its boiling or sublimation point
3.1.5.9
fog

type of aerosol (3.1.3.1) consisting of a suspension of droplets (3.1.5.12) in air

Note 1 to entry: In meteorology, fog refers to a suspension of water droplets (3.1.5.12) resulting in a visibility of

less than 1 km.
3.1.5.10
haze

type of aerosol (3.1.3.1) consisting of a suspension of extremely small airborne particles (3.2.2.1) in air,

individually invisible to the naked eye, but which are numerous enough to give the air an appearance of

opalescence together with reduced visibility
3.1.5.11
mist
suspension of droplets (3.1.5.12) in a gas

Note 1 to entry: A mist reduces visibility to a lesser extent than fog (3.1.5.9).

[SOURCE: ISO 29464:2017, 3.2.109]
3.1.5.12
droplet
liquid particle of small mass, capable of remaining in suspension in a gas

Note 1 to entry: In some turbulent systems, for example clouds, the diameter of a droplet can reach 200 μm.

3.1.5.13
particle aerodynamic diameter
aerodynamic diameter

diameter of a sphere of 1 g/cm density with the same terminal settling velocity in calm air as the

particle, under the prevailing conditions of temperature, pressure and relative humidity

Note 1 to entry: The particle aerodynamic diameter depends on the size, density and shape of the particle.

4 © ISO 2020 – All rights reserved
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ISO 4225:2020(E)

Note 2 to entry: Aerodynamic diameter is related to the inertial properties of aerosol particles.

3.1.5.14
equivalent diameter

diameter of a spherical particle which will give behaviour equivalent to that of the particle being

examined
[SOURCE: ISO 29464:2017, 3.2.39]
3.1.5.15
rain-out

mechanism by which airborne particles (3.2.2.1) in the clouds are removed by the formation of raindrops

Note 1 to entry: Rain-out can also be included as part of wash-out (3.1.5.16).
3.1.5.16
wash-out

removal from the atmosphere of gases and sometimes airborne particles (3.2.2.1) by their solution in or

attachment to raindrops as they fall
Note 1 to entry: Wash-out can include rain-out (3.1.5.15).
3.2 Terms related to air pollution and pollution control
3.2.1 Terms generally describing air pollution
3.2.1.1
air pollutant
contaminant

substance emitted into the air either by human activity or natural processes and adversely affecting

air quality
3.2.1.2
air pollution
contamination

presence of air pollutants (3.2.1.1) in sufficient concentration and for a sufficient time

3.2.1.3
background concentration

portion of the concentration of an air pollutant (3.2.1.1) which cannot be directly related to the sources

(3.2.1.23) under study

Note 1 to entry: The background concentration can be the same as the natural background concentration (3.2.1.10)

or can include other sources not under study.
3.2.1.4
emission
discharge of substances into the air

Note 1 to entry: The term “emission” is used to describe the discharge and the rate of discharge.

3.2.1.5
emission concentration

concentration of air pollutant (3.2.1.1) in an emission (3.2.1.4) at its point of discharge

3.2.1.6
emission factor

expression for the ratio of the rate at which an air pollutant (3.2.1.1) is emitted as a result of some

activity, to the rate of that activity
EXAMPLE Kilograms of sulfur dioxide emitted per tonne of steel produced.
© ISO 2020 – All rights reserved 5
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ISO 4225:2020(E)
3.2.1.7
emission flux

emission rate (3.2.1.8) per unit area of the appropriate surface of an emitting source (3.2.1.23)

3.2.1.8
emission rate
mass (or other quantity) of pollutant transferred into the air per unit time
3.2.1.9
emission limit value
emission standard

specified limit on one or more components within an emission (3.2.1.4), typically having a legal or

advisory status

Note 1 to entry: Emission limit values are frequently defined statistically e.g. by setting a limit to the emission

rate (3.2.1.8) or to the emission concentration (3.2.1.5) at a defined dilution level.

3.2.1.10
natural background concentration

concentration of a given substance in a pristine air mass in which anthropogenic emissions (3.2.1.4) are

negligible
3.2.1.11
odour

sensation perceived by means of the olfactory organ in sniffing certain volatile substances

[SOURCE: ISO 5492:2008, 3.18]
3.2.1.12
odorant

substance which, when volatilized in neutral gas, has the potential to stimulate the human olfactory

system so that an odour (3.2.1.11) is perceived
3.2.1.13
odour panel
group of assessors performing the assessment of odour (3.2.1.11)
3.2.1.14
odour concentration

number of odour units (3.2.1.15) in a cubic metre of gas at standard conditions for olfactometry

3.2.1.15
odour unit

number of times the odour (3.2.1.11) in the air is to be diluted with odourless air to reach the

...

NORME ISO
INTERNATIONALE 4225
Troisième édition
2020-05
Qualité de l'air — Aspects généraux —
Vocabulaire
Air quality — General aspects — Vocabulary
Numéro de référence
ISO 4225:2020(F)
ISO 2020
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ISO 4225:2020(F)
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ii © ISO 2020 – Tous droits réservés
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ISO 4225:2020(F)
Sommaire Page

Avant-propos ..............................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Domaine d’application ................................................................................................................................................................................... 1

2 Références normatives ................................................................................................................................................................................... 1

3 Termes et définitions ....................................................................................................................................................................................... 1

3.1 Termes généraux ................................................................................................................................................................................... 1

3.1.1 Termes décrivant la qualité de l’air ................................................................................................................. 1

3.1.2 Agents ........................................................................................................................................................................................ 2

3.1.3 Termes relatifs aux aérosols .................................................................................................................................. 2

3.1.4 Termes relatifs à l’exposition ................................................................................................................................ 3

3.1.5 Autres termes ..................................................................................................................................................................... 3

3.2 Termes relatifs à la pollution de l’air et au contrôle de la pollution ......................................................... 5

3.2.1 Termes généraux décrivant la pollution de l’air ................................................................................... 5

3.2.2 Composés ou formes de la pollution de l’air ............................................................................................ 8

3.2.3 Termes relatifs au contrôle de la pollution de l’air............................................................................. 9

3.3 Termes relatifs aux prélèvements des contrôles de qualité de l’air .......................................................10

3.3.1 Échantillons .......................................................................................................................................................................10

3.3.2 Matériel de prélèvement ........................................................................................................................................11

3.3.3 Méthodes de prélèvement ....................................................................................................................................13

3.4 Termes relatifs au mesurage de la qualité de l’air .................................................................................................14

3.4.1 Méthodes de mesurage............................................................................................................................................14

Annexe A (informative) Index alphabétique des termes définis ..........................................................................................16

Bibliographie ...........................................................................................................................................................................................................................20

© ISO 2020 – Tous droits réservés iii
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ISO 4225:2020(F)
Avant-propos

L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes

nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est

en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude

a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,

gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.

L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui

concerne la normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents

critères d’approbation requis pour les différents types de documents ISO. Le présent document a été

rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www

.iso .org/ directives).

L’attention est attirée sur le fait que certains des éléments du présent document peuvent faire l’objet de

droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable

de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de

brevets reçues par l’ISO (voir www .iso .org/ brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion

de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir le lien suivant: www .iso .org/ iso/ fr/ avant -propos.

Le présent document a été élaboré par le comité technique ISO/TC 146, Qualité de l’air, sous-comité SC 4,

Aspects généraux.

Cette troisième édition annule et remplace la deuxième édition (ISO 4225:1994), qui a fait l’objet d’une

révision technique. Les principales modifications par rapport à l’édition précédente sont les suivantes:

— aux endroits appropriés, les termes et définitions ont été harmonisés par rapport à l’ISO 18158:2016;

— les termes obsolètes ont été supprimés;
— les références ont été mises à jour.

Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent

document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes

se trouve à l’adresse www .iso .org/ fr/ members .html.
iv © ISO 2020 – Tous droits réservés
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ISO 4225:2020(F)
Introduction

Le programme de travail de l’ISO/TC 146, Qualité de l’air, comprend la normalisation des modes

opératoires de prélèvement et de mesurage des gaz, vapeurs et particules en suspension dans l’air.

De nombreux termes d’usage courant en lien avec la qualité de l’air, le prélèvement et le mesurage

sont définis dans des normes ou documents techniques individuels et leur définition diffère souvent

d’une norme ou d’un document à l’autre. Ces différences créent des ambiguïtés et des incohérences

dans l’emploi de ces termes. Le présent document a été élaboré afin de s’assurer que les termes d’usage

courant sont définis de manière consensuelle et de lever les ambiguïtés et les incohérences dans leur

emploi. Il sera utile aux organismes en charge de la qualité de l’air, des prélèvements et des analyses en

laboratoire.

Les termes figurant dans le présent document sont d’usage courant. Il convient toutefois de ne pas

considérer que cette liste est exhaustive et d’autres termes seront ajoutés en fonction des besoins.

© ISO 2020 – Tous droits réservés v
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NORME INTERNATIONALE ISO 4225:2020(F)
Qualité de l'air — Aspects généraux — Vocabulaire
1 Domaine d’application

Le présent document spécifie les termes et définitions relatifs à la qualité de l’air (voir 3.1.1.1). Ces

termes sont soit de nature générique, soit ils sont utilisés en lien avec le prélèvement (voir 3.3.3.1) et le

mesurage des gaz, des vapeurs (voir 3.1.5.8) et des particules en suspension dans l’air (voir 3.2.2.1) afin

de déterminer la qualité de l’air.

Les termes figurant dans le présent document ont été identifiés comme étant fondamentaux car leur

définition est nécessaire pour lever toute ambiguïté et garantir la cohérence de leur emploi.

L’Annexe A fournit un index alphabétique des termes définis.

Le présent document est applicable à toutes les Normes internationales ainsi qu’à tous les rapports et

spécifications techniques de l’ISO et aux guides de l’ISO liés à la qualité de l’air.

2 Références normatives
Le présent document ne contient aucune référence normative.
3 Termes et définitions

Pour les besoins du présent document, les termes et définitions suivants s’appliquent.

L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en

normalisation, consultables aux adresses suivantes:

— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp

— IEC Electropedia: disponible à l’adresse http:// www .electropedia .org/
3.1 Termes généraux
3.1.1 Termes décrivant la qualité de l’air
3.1.1.1
qualité de l’air

caractéristiques de l’air ayant un impact sur l’homme (sécurité et santé, par exemple) et/ou sur

l’environnement

Note 1 à l'article: La qualité de l’air est généralement exprimée en termes de présence ou d’absence de pollution de

l’air (3.2.1.2) [émissions (3.2.1.4, par exemple)] ou de conversions résultant d’émissions (ozone, par exemple), en

utilisant un ou plusieurs mesurages.

Note 2 à l'article: Le concept de qualité de l’air peut être utilisé en référence à l’air ambiant (3.1.1.3), à l’air intérieur

(3.1.1.5) ou à l’air des lieux de travail (3.1.1.7).
3.1.1.2
norme de qualité de l’air

critère spécifié de l’air destiné à empêcher ou réduire le plus possible des impacts sur l’homme (sécurité

et santé, par exemple) et/ou sur l’environnement

Note 1 à l'article: Les normes de qualité de l’air sont souvent définies statistiquement en fixant une limite de

concentration d’un polluant de l’air (3.2.1.1) sur un temps de moyennage (3.1.1.9) spécifié.

© ISO 2020 – Tous droits réservés 1
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ISO 4225:2020(F)

Note 2 à l'article: Les normes de qualité de l’air peuvent avoir un statut légal ou consultatif dans une ou plusieurs

juridictions.
3.1.1.3
air ambiant

air extérieur auquel les personnes, les plantes, les animaux ou les matériaux peuvent être exposés

3.1.1.4
norme de qualité de l’air ambiant
norme de qualité de l’air (3.1.1.2) applicable à l’air ambiant (3.1.1.3)
3.1.1.5
air intérieur

air contenu dans un espace clos (une habitation ou un bâtiment public, par exemple)

3.1.1.6
norme de qualité de l’air intérieur
norme de qualité de l’air (3.1.1.2) applicable à l’air intérieur (3.1.1.5)
3.1.1.7
air des lieux de travail

air auquel est exposée une personne, à l’intérieur ou à l’extérieur, pendant ses heures de travail sur son

lieu de travail
3.1.1.8
norme de qualité de l’air des lieux de travail

norme de qualité de l’air (3.1.1.2) applicable à l’air des lieux de travail (3.1.1.7)

3.1.1.9
temps de moyennage

laps de temps pendant lequel une caractéristique de la qualité de l’air (3.1.1.1) a été exprimée sous forme

de moyenne
3.1.2 Agents
3.1.2.1
agent biologique

bactéries, virus, champignons et autres micro-organismes ou parties de ceux-ci ainsi que les toxines

ou les allergènes qui leur sont associé(e)s, y compris ceux qui ont été génétiquement modifiés, cultures

cellulaires ou endoparasites, qui sont potentiellement dangereux pour la santé humaine

3.1.2.2
agent chimique

élément ou composé chimique, seul ou mélangé, tel qu’il se présente à l’état naturel ou tel qu’il est

produit, utilisé ou libéré, y compris sous forme de déchet, du fait d’une activité professionnelle, qu’il soit

ou non produit intentionnellement et qu’il soit ou non mis sur le marché
3.1.3 Termes relatifs aux aérosols
3.1.3.1
aérosol

particules en suspension (3.2.2.1) et le mélange de gaz [et de vapeurs (3.1.5.8)] dans lequel elles sont en

suspension
3.1.3.2
bioaérosol
aérosol (3.1.3.1) constitué d’un ou plusieurs agents biologiques (3.1.2.1)
2 © ISO 2020 – Tous droits réservés
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ISO 4225:2020(F)
3.1.3.3
nanoaérosol

aérosol (3.1.3.1) constitué ou composé de nanoparticules (3.1.3.4) et de particules nanostructurées

(3.1.3.5)
3.1.3.4
nanoparticule

matériau ayant les trois dimensions dans l’échelle de longueur s’étendant approximativement de 1 nm

à 100 nm
3.1.3.5
particule nanostructurée

particule ayant des caractéristiques structurelles inférieures à 100 nm, qui peuvent influencer ses

propriétés physiques, chimiques et/ou biologiques

Note 1 à l'article: Une particule nanostructurée peut être de dimension sensiblement supérieure à 100 nm.

EXEMPLE Un agglomérat (3.1.3.6) de nanoparticules (3.1.3.4) d’un diamètre de 500 nm pourrait être

considéré comme une particule nanostructurée.
3.1.3.6
agglomérat

groupe de particules liées ensemble par des forces relativement faibles, notamment des

forces de van der Waals, des forces électrostatiques et des forces de tension superficielle

3.1.4 Termes relatifs à l’exposition
3.1.4.1
zone respiratoire
volume autour du nez et de la bouche à partir duquel l’air est inhalé

Note 1 à l'article: D’un point de vue technique, la zone respiratoire correspond à un hémisphère (généralement

d’un rayon de 30 cm) s’étendant devant le visage de la personne, centré sur le milieu d’un segment qui joint les

deux oreilles. La base de l’hémisphère est un plan passant par ce segment, le sommet de la tête et le larynx.

Cette description technique ne s’applique pas en cas de mesurage d’air à l’intérieur d’un appareil de protection

respiratoire.
3.1.4.2
exposition par inhalation

situation dans laquelle un agent chimique (3.1.2.2) ou un agent biologique (3.1.2.1) est présent dans l’air

inhalé par une personne
3.1.4.3
exposition cutanée

contact entre un agent chimique (3.1.2.2) ou un agent biologique (3.1.2.1) et la peau humaine

3.1.5 Autres termes
3.1.5.1
cyclone

phénomène engendrant des vents en rotation autour d’une zone à basse pression

atmosphérique
3.1.5.2
stabilité

état d’équilibre hydrostatique de l’atmosphère dans lequel un volume d’air écarté

verticalement de son niveau initial est soumis à une force hydrostatique qui tend à le ramener à ce niveau

© ISO 2020 – Tous droits réservés 3
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ISO 4225:2020(F)
3.1.5.3
effet cheminée

phénomène consistant en un mouvement ascendant d’une masse d’air locale ou d’autres gaz, dû à des

différences de température
3.1.5.4
hauteur effective de cheminée

hauteur utilisée pour calculer la dispersion de gaz émis par une cheminée, et qui diffère de la hauteur

réelle de la cheminée d’un écart qui dépend de facteurs tels que la vitesse d’éjection des gaz, la

différence de température et de densité entre effluent émis et atmosphère, la vitesse du vent ainsi que

la topographie
3.1.5.5
paramètres gaussiens de dispersion

coefficients qui permettent de décrire la dimension d’un panache (3.2.1.20) supposé gaussien en

fonction de la stabilité (3.1.5.2) atmosphérique et de la distance parcourue ou du temps

3.1.5.6
gradient vertical
variation d’un paramètre atmosphérique en fonction de l’altitude
Note 1 à l'article: Le paramètre est la température, sauf indication contraire.

Note 2 à l'article: Cette variation est considérée comme positive lorsque la température décroît quand l’altitude

augmente. Si les conditions météorologiques sont telles que le gradient atmosphérique vertical est le même que

celui d’un volume d’air sec s’élevant de manière adiabatique (environ 10 °C km ), on dit que l’atmosphère a un

gradient vertical adiabatique sec.
3.1.5.7
micrométéorologie

partie de la météorologie qui traite des observations et des processus dans les plus petites échelles

de temps et d’espace, généralement inférieures à 1 km et à une journée (c’est-à-dire des phénomènes

météorologiques locaux)
[SOURCE: Glossaire de météorologie de l’American Meteorological Society]
3.1.5.8
vapeur

phase gazeuse d’une substance à l’état d’équilibre ou dont l’équilibre a été perturbé avec la même

substance à l’état liquide ou solide à son point d’ébullition ou de sublimation
3.1.5.9
brouillard

type d’aérosol (3.1.3.1) constitué d’une suspension de gouttelettes (3.1.5.12) dans l’air

Note 1 à l'article: En météorologie, le brouillard désigne une suspension de gouttelettes (3.1.5.12) d’eau conduisant

à une visibilité inférieure à 1 km.
3.1.5.10
brume sèche

type d’aérosol (3.1.3.1) constitué de particules en suspension dans l’air (3.2.2.1), extrêmement petites,

individuellement invisibles à l’œil nu, mais suffisamment nombreuses pour donner à l’air un aspect

opalescent et pour réduire la visibilité
3.1.5.11
brume
suspension de gouttelettes (3.1.5.12) dans un gaz

Note 1 à l'article: Une brume réduit moins la visibilité qu’un brouillard (3.1.5.9).

[SOURCE: ISO 29464:2017, 3.2.109, modifiée - Remplacement du terme «brouillard» par «brume» pour

éviter la confusion en français]
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ISO 4225:2020(F)
3.1.5.12
gouttelette
particule liquide de faible masse capable de rester en suspension dans un gaz

Note 1 à l'article: Dans certains systèmes turbulents, par exemple les nuages, le diamètre d’une gouttelette peut

atteindre 200 μm.
3.1.5.13
diamètre aérodynamique d’une particule
diamètre aérodynamique

diamètre d’une sphère de masse volumique 1 g/cm dont la vitesse limite de chute dans l’air calme est

la même que celle de la particule, dans les mêmes conditions de température, de pression et d’humidité

relative

Note 1 à l'article: Le diamètre aérodynamique d’une particule dépend de la taille, de la masse volumique et de la

forme de la particule.

Note 2 à l'article: Le diamètre aérodynamique est lié aux propriétés d’inertie des particules d’aérosol.

3.1.5.14
diamètre équivalent

diamètre d’une particule sphérique produisant un comportement équivalent à celui de la particule

examinée
[SOURCE: ISO 29464:2017, 3.2.39]
3.1.5.15
entraînement par la pluie

mécanisme par lequel les particules en suspension (3.2.2.1) dans les nuages sont éliminées par la

formation de gouttes de pluie

Note 1 à l'article: L’entraînement par la pluie peut également être considéré comme faisant partie intégrante du

lessivage par la pluie (3.1.5.16).
3.1.5.16
lessivage par la pluie

élimination des gaz et parfois des particules en suspension (3.2.2.1) de l’atmosphère, par leur dissolution

ou leur capture par les gouttes de pluie au moment de leur chute

Note 1 à l'article: Le lessivage par la pluie peut inclure l’entraînement par la pluie (3.1.5.15).

3.2 Termes relatifs à la pollution de l’air et au contrôle de la pollution
3.2.1 Termes généraux décrivant la pollution de l’air
3.2.1.1
polluant de l’air
contaminant

substance émise dans l’air, soit par une activité humaine soit par des processus naturels, et qui affecte

la qualité de l’air
3.2.1.2
pollution de l’air
contamination

présence de polluants de l’air (3.2.1.1) en concentration suffisante et pendant une durée suffisante

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ISO 4225:2020(F)
3.2.1.3
concentration de fond

part de la concentration d’un polluant de l’air (3.2.1.1) qui ne peut pas être directement imputée

aux sources (3.2.1.23) étudiées

Note 1 à l'article: La concentration de fond peut être la même que la concentration de fond naturelle (3.2.1.10) ou

elle peut inclure d’autres sources non étudiées.
3.2.1.4
émission
rejet de substances dans l’air

Note 1 à l'article: Le terme «émission» est utilisé pour décrire le rejet et le flux du rejet.

3.2.1.5
concentration de l’émission

concentration d’un polluant de l’air (3.2.1.1) dans l’émission (3.2.1.4) au point de rejet

3.2.1.6
facteur d’émission

expression du rapport entre la quantité émise d’un polluant de l’air (3.2.1.1) résultant d’une activité, et

le volume de cette activité
EXEMPLE Kilogrammes de dioxyde de soufre émis par tonne d’acier produit.
3.2.1.7
flux d’émission surfacique

flux d’émission (3.2.1.8) par unité d’aire de la surface appropriée d’une source (3.2.1.23) émettrice

3.2.1.8
flux d’émission

masse (ou autre grandeur physique) de polluant transféré dans l’air par unité de temps

3.2.1.9
valeur limite d’émission
norme d’émission

limite spécifiée pour un ou plusieurs composés dans une émission (3.2.1.4), ayant généralement un

statut légal ou consultatif

Note 1 à l'article: Les valeurs limites d’émission sont souvent définies statistiquement en fixant une limite pour

le flux d’émission (3.2.1.8) ou la concentration de l’émission (3.2.1.5) à un niveau de dilution défini.

3.2.1.10
concentration de fond naturelle

concentration d’une substance donnée dans une masse d’air pur dans laquelle les émissions (3.2.1.4)

d’origine anthropique sont négligeables
3.2.1.11
odeur

ensemble de sensations perçues par l’organe olfactif en «flairant» certaines substances volatiles

[SOURCE: ISO 5492:2008, 3.18]
3.2.1.12
substance odorante

substance qui, lorsqu’elle est à l’état volatil dans un gaz neutre, a la capacité de stimuler le système

olfactif humain, de sorte qu’une odeur (3.2.1.11) est perçue
3.2.1.13
jury de nez
groupe d’individus effectuant l’évaluation d’une odeur (3.2.1.11)
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ISO 4225:2020(F)
3.2.1.14
concentration d’odeur

nombre d’unités d’odeur (3.2.1.15) dans un mètre cube de gaz dans des conditions standard pour

l’olfactométrie
3.2.1.15
unité d’odeur

nombre de fois que l’odeur (3.2.1.11) présente dans l’air doit être diluée avec de l’air inodore pour

atteindre le seuil
3.2.1.16
seuil de détection d’odeur

concentration minimale à laquelle la moitié d’une population peut déceler l’odeur (3.2.1.11)

Note 1 à l'article: Pour la détermination du seuil de détection d’odeur, les jurys de nez (3.2.1.13) sont considérés

comme représentatifs d’une population.
3.2.1.17
seuil de reconnaissance d’odeur

concentration minimale à laquelle la moitié d’une population peut identifier l’odeur (3.2.1.11)

Note 1 à l'article: Pour la détermination du seuil de reconnaissance d’odeur, les jurys de nez (3.2.1.13) sont

considérés comme représentatifs d’une population.
3.2.1.18
seuil d’odeur

terme pouvant se rapporter à un seuil de détection d’odeur (3.2.1.16) ou à un seuil de reconnaissance

d’odeur (3.2.1.17)
3.2.1.19
opacité

degré avec lequel les émissions (3.2.1.4) de particules en suspension

dans l’air (3.2.2.1) réduisent l’intensité de la lumière du jour transmise et obscurcissent la vision d’un objet

3.2.1.20
panache

dispersion d’une émission (3.2.1.4), souvent visible, d’une source (3.2.1.23) spécifique

3.2.1.21
détection à distance

détermination des substances présentes dans l’air ou dans les émissions (3.2.1.4), ou détermination de

paramètres météorologiques dans l’air au moyen d’instruments qui ne sont pas en contact physique

direct avec l’échantillon (3.3.1.1) examiné
3.2.1.22
séparateur

appareil conçu pour séparer les gaz ou les particules solides ou liquides d’un flux gazeux dans lequel ils

sont mélangés ou en suspension

Note 1 à l'article: Un séparateur (également connu sous le nom de séparateur inertiel ou collecteur) extrait les

contaminants (3.2.1.1) les plus gros du flux d’air, souvent afin de les empêcher d’atteindre les filtres en aval.

[SOURCE: ISO 29464:2017, 3.2.156]
3.2.1.23
source
source d’émission
zone ou point à partir duquel une émission (3.2.1.4) se produit
© ISO 2020 – Tous droits réservés 7
---------------------- Page: 12 ----------------------
ISO 4225:2020(F)
3.2.2 Composés ou formes de la pollution de l’air
3.2.2.1
particules en suspension (dans l’air)
matière particulaire

matières particulaires fines, sous forme solide ou liquide, dispersées dans l’air

3.2.2.2
cendre
résidu solide résultant d’une combustion complète
[SOURCE: ISO 29464:2017, 3.2.20]
3.2.2.3
dépôt

transfert d’un polluant de l’air (3.2.1.1) sur une surface, dû à la pesanteur ou à un autre mécanisme

Note 1 à l'article: Le dépôt peut être humide (en raison des précipitations, par exemple) ou sec (toutes les autres

formes de dépôt, par exemple).
3.2.2.4
cendres volantes
cendres (3.2.2.2) entraînées par les gaz de combustion
[SOURCE: ISO 29464:2017, 3.2.21]
3.2.2.5
fumée

aérosol (3.1.3.1) solide généré par condensation, en général après volatilisation de substances fondues

telles que les métaux, et souvent accompagné de réactions chimiques telles que l’oxydation

Note 1 à l'article: Dans l’usage populaire, effluent gazeux souvent désagréable et malodorant, pouvant provenir

de procédés chimiques.
[SOURCE: ISO 29464:2017, 3.2.99]
3.2.2.6
smog photochimique

résultat des réactions qui se produisent dans l’atmosphère entre les oxydes d’azote, les composés

organiques et les oxydants sous l’influence du soleil, conduisant à la formation de composés oxydants

ou pouvant entraîner une mauvaise visibilité, une irritation des yeux ou des dommages aux matériaux

et à la végétation, lorsqu’ils sont suffisamment concentrés

Note 1 à l'article: Le smog photochimique peut être un composant du smog (3.2.2.12).

3.2.2.7
précurseur de l’ozone

composé chimique, par exemple composés organiques volatils (3.2.2.8) ou oxydes d’azote (NOx), qui,

en présence du rayonnement solaire, réagit avec d’autres composés chimiques pour former de l’ozone,

généralement dans la troposphère
3.2.2.8
composé organique volatil
COV

composé organique à l’état gazeux ou qui se volatilise spontanément à la température et la pression de

l’atmosphère avec laquelle il est en contact
3.2.2.9
composé organique semi-volatil
COSV

sous-groupe de composés organiques volatils (3.2.2.8) qui a tendance à posséder une masse moléculaire

plus importante et une température de point d’ébullition supérieure
8 © ISO 2020 – Tous droits réservés
---------------------- Page: 13 ----------------------
ISO 4225:2020(F)
3.2.2.10
polluant primaire
polluant de l’air (3.2.1.1) directement émis par une source (3.2.1.23)

Note 1 à l'article: Les polluants primaires peuvent être comparés aux polluants secondaires (3.2.2.11) qui sont

formés dans l’air.
3.2.2.11
polluant secondaire

polluant de l’air (3.2.1.1) qui peut être produit dans l’air par des processus physiques ou chimiques, à

partir d’un ou plusieurs polluants primaires (3.2.2.10) ou d’autres substances, dont la présence est liée à

des émissions (3.2.1.4) de sources (3.2.1.23) fixes ou mobiles
3.2.2.12
smog

pollution atmosphérique par des aérosols (3.1.3.1), due en partie à des processus naturels et en partie

aux activités humaines

Note 1 à l'article: Le terme «smog» découle des termes anglais «smoke» [aérosol de combustion (3.2.2.13)] et «fog»

[brouillard (3.1.5.9)].

Note 2 à l'article: Le smog photochimique (3.2.2.6) peut être un composant du smog.

3.2.2.13
aérosol de combustion

aérosol (3.1.3.1) solide ou liquide résultant de la combustion de matériaux organiques, y compris les

combustibles fossiles, le bois et les cigarettes
Note 1 à l'article: Cette définition exclut la vapeur.
3.2.2.14
suie
particules carbonées agglomérées formées par une combustion incomplète
3.2.3 Termes relatifs au contrôle de la pollution de l’air
3.2.3.1
réduction
diminution d’un type de rejet ou de polluant de l’air (3.2.1.1)
Note 1 à l'article: La réduction se différencie de l’élimination complète.
3.2.3.2
séparateur de particules
appareil conçu pour enlever la matière particulaire (3.2.2.1) d’un milieu gazeux
3.2.3.3
manche filtrante

manche en tissu conçue pour séparer, par filtration, la matière particulaire (3.2.2.1) d’un écoulement de

gaz
3.2.3.4
filtre à manches
ensemble d’une ou plusieurs manches filtrantes (3.2.3.3) et d’un mécanisme perm
...

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