ISO 11222:2002
(Main)Air quality — Determination of the uncertainty of the time average of air quality measurements
Air quality — Determination of the uncertainty of the time average of air quality measurements
ISO 11222:2002 provides a method for the quantification of the uncertainty of a time average of a set of air quality data obtained at a specified location over a defined averaging time period. The method is applicable to air quality data obtained by continuous or intermittent monitoring by means of a specified measuring system. The uncertainty of the time average depends on both the uncertainty of the measurement results and the uncertainty due to incomplete time coverage of the data set. ISO 11222:2002 is only applicable if the set of air quality data used to calculate the time average is representative of the temporal structure of the measurand over the defined time period, appropriate information on the uncertainty of the measurement results is available, and the measurement results have all been obtained at the same location. ISO 11222:2002 implements recommendations of the Guide to the Expression of Uncertainty in Measurement (GUM).
Qualité de l'air — Détermination de l'incertitude de mesure de la moyenne temporelle de mesurages de la qualité de l'air
L'ISO 11222:2002 fournit une méthode permettant de quantifier l'incertitude d'une moyenne temporelle d'un ensemble de données relatif à la qualité de l'air, obtenu à partir d'un point de mesurage spécifié, sur une période moyenne de temps définie. La méthode est applicable aux données relatives à la qualité de l'air obtenues par surveillance continue ou intermittente, au moyen d'un système de mesure spécifié. L'incertitude de la moyenne temporelle dépend à la fois de l'incertitude des résultats de mesure et de l'incertitude due à une couverture incomplète de l'ensemble de données. L'ISO 11222:2002 est applicable uniquement si l'ensemble de données relatif à la qualité de l'air utilisé pour calculer la moyenne temporelle est représentatif de la structure temporelle du mesurande sur la période de temps définie, les informations appropriées relatives à l'incertitude des résultats de mesure sont disponibles, et les mesurages ont été effectués au même endroit. L'ISO 11222:2002 met en oeuvre les recommandations du Guide pour l'expression de l'incertitude de mesure (GUM).
Kakovost zraka – Določanje negotovosti časovnih povprečij pri meritvah kakovosti zraka
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2004
.DNRYRVW]UDND±'RORþDQMHQHJRWRYRVWLþDVRYQLKSRYSUHþLMSULPHULWYDKNDNRYRVWL
]UDND
Air quality -- Determination of the uncertainty of the time average of air quality
measurements
Qualité de l'air -- Détermination de l'incertitude de mesure de la moyenne temporelle de
mesurages de la qualité de l'air
Ta slovenski standard je istoveten z: ISO 11222:2002
ICS:
13.040.01 Kakovost zraka na splošno Air quality in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 11222
First edition
2002-07-01
Air quality — Determination of the
uncertainty of the time average of air
quality measurements
Qualité de l'air — Détermination de l'incertitude de mesure de la moyenne
temporelle de mesurages de la qualité de l'air
Reference number
©
ISO 2002
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
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© ISO 2002
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
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Printed in Switzerland
ii © ISO 2002 – All rights reserved
Contents Page
Foreword.iv
Introduction.v
1 Scope.1
2 Normative reference.1
3 Terms and definitions .1
4 Symbols and abbreviated terms .4
5 Requirements on the input data.5
5.1 General.5
5.2 Specific requirements on input data .6
6 Procedure.8
6.1 General.8
6.2 Standard uncertainty induced by the measuring system .8
6.3 Standard uncertainty due to incomplete time coverage .10
6.4 Combined standard uncertainty .11
6.5 Expanded uncertainty.11
7 Reporting uncertainty.12
Annex A (informative) Example — Quantification of the uncertainty of a monthly average of nitrogen
dioxide in ambient air.13
A.1 Input.13
A.2 Uncertainty estimation of the monthly average .17
A.3 Discussion.19
Bibliography.20
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
The main task of technical committees is to prepare International Standards. Draft International Standards adopted
by the technical committees are circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11222 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 4, General aspects.
Annex A of this International Standard is for information only.
iv © ISO 2002 – All rights reserved
Introduction
Measurands in the field of air quality monitoring can be highly varying functions of time. Special considerations
are-required when estimating measurement uncertainties of time averages of air quality monitoring data. The
approach [3], using the standard deviation of the recorded measurement results divided by the square root of the
number of measurement, is applicable only to measurands that do not change with time and to measuring systems
that do not exhibit systematic uncertainties.
The statistical treatment of random and systematic deviations of measurement results has been harmonized by the
concept of measurement uncertainty introduced by the Guide to the expression of uncertainty in measurement in
1993 (GUM). This approach is based on the general application of the rule of uncertainty propagation. Although not
addressed explicitly by the GUM, the concept of uncertainty propagation and measurement uncertainty can also be
applied to measurands exhibiting distinct time structure.
Standard uncertainty may be required as a measure of data quality to be provided when reporting a time average
of air quality monitoring data. If appropriate, data quality objectives can be defined separately for:
a) the uncertainty of the time average induced by the measuring system,
b) the uncertainty of the time average induced by incomplete time coverage of the monitoring data,
c) the uncertainty of the time average due to limited spatial coverage of monitoring data.
These influences make up independent contributions to the mean square uncertainty of a time average. In this
International Standard, a time average of measured air quality data is intended to describe the air quality at a
specified location or within a specified stack within a given time period. The uncertainty of the time average due to
spatial coverage of monitoring data is not considered.
INTERNATIONAL STANDARD ISO 11222:2002(E)
Air quality — Determination of the uncertainty of the time average
of air quality measurements
1 Scope
This International Standard provides a method for the quantification of the uncertainty of a time average of a set of
air quality data obtained at a specified location over a defined averaging time period. The method is applicable to
air quality data obtained by continuous or intermittent monitoring by means of a specified measuring system. The
uncertainty of the time average depends on both the uncertainty of the measurement results and the uncertainty
due to incomplete time coverage of the data set.
This International Standard is only applicable if:
a) the set of air quality data used to calculate the time average is representative of the temporal structure of the
measurand over the defined time period,
b) appropriate information on the uncertainty of the measurement results is available, and
c) the measurement results have all been obtained at the same location.
This International Standard implements recommendations of the Guide to the expression of uncertainty in
measurement (GUM).
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent edition of the normative document indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
GUM:1995, Guide to the expression of uncertainty in measurement, First edition, BIPM/IEC/IFCC/ISO/IUPAC/
IUPAP/OIML
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
arithmetic mean
average
sum of values divided by the number of values
[ISO 3534-1:1993, 2.26]
3.2
combined standard uncertainty
standard uncertainty of the result of a measurement when that result is obtained from the values of a number of
other quantities, equal to the positive square root of a sum of terms, the terms being the variances and covariances
of these quantities weighted according to how the measurement result varies with changes in these quantities
[GUM:1995, 2.3.4]
NOTE The (combined) standard uncertainty of the result of a measurement is the positive square root of its mean square
uncertainty.
3.3
covariance
measure of the statistical dependence of two observable quantities which may be considered as random variables
NOTE Two observable quantities have a non-zero covariance if they are correlated, i.e. a change in one quantity results in
a change in the other quantity.
3.4
coverage factor
numerical factor used as a multiplier of the combined standard uncertainty in order to obtain an expanded
uncertainty
[GUM:1995, 2.3.6]
3.5
expanded uncertainty
quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction
of the distribution of values that could reasonably be attributed to the measurand
[GUM:1995, 2.3.5]
NOTE If the expanded uncertainty of a result X of measurement on the level of confidence p is given by U (X), the
p
unknown true value of X is expected with probability p to be located within the interval [X − U (X); X + U (X)].
p p
3.6
influence quantity
quantity that is not the measurand but that affects the result of the measurement
[GUM:1995, B.2.10]
3.7
mean square uncertainty
〈of a result of measurement〉 square of the combined standard uncertainty of a measurement result
NOTE The mean square uncertainty of a measurement result may also be estimated by the mean square deviation of the
measurement result from material measures of the “true” value.
3.8
measurand
particular quantity subject to measurement
[VIM:1993, 2.6]
NOTE In the field of air quality monitoring, the measurand can be a highly varying function of time.
3.9
measuring system
complete set of measuring instruments and other equipment with operating procedures for carrying out specified air
quality measurements
2 © ISO 2002 – All rights reserved
NOTE The operating procedure includes or refers to a specification of the calibration routine, if calibration of the measuring
system is needed for its proper operation.
3.10
model equation
mathematical model of the measurement that transforms the set of (repeated) observations performed into the
measurem
...
INTERNATIONAL ISO
STANDARD 11222
First edition
2002-07-01
Air quality — Determination of the
uncertainty of the time average of air
quality measurements
Qualité de l'air — Détermination de l'incertitude de mesure de la moyenne
temporelle de mesurages de la qualité de l'air
Reference number
©
ISO 2002
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2002
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2002 – All rights reserved
Contents Page
Foreword.iv
Introduction.v
1 Scope.1
2 Normative reference.1
3 Terms and definitions .1
4 Symbols and abbreviated terms .4
5 Requirements on the input data.5
5.1 General.5
5.2 Specific requirements on input data .6
6 Procedure.8
6.1 General.8
6.2 Standard uncertainty induced by the measuring system .8
6.3 Standard uncertainty due to incomplete time coverage .10
6.4 Combined standard uncertainty .11
6.5 Expanded uncertainty.11
7 Reporting uncertainty.12
Annex A (informative) Example — Quantification of the uncertainty of a monthly average of nitrogen
dioxide in ambient air.13
A.1 Input.13
A.2 Uncertainty estimation of the monthly average .17
A.3 Discussion.19
Bibliography.20
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
The main task of technical committees is to prepare International Standards. Draft International Standards adopted
by the technical committees are circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11222 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 4, General aspects.
Annex A of this International Standard is for information only.
iv © ISO 2002 – All rights reserved
Introduction
Measurands in the field of air quality monitoring can be highly varying functions of time. Special considerations
are-required when estimating measurement uncertainties of time averages of air quality monitoring data. The
approach [3], using the standard deviation of the recorded measurement results divided by the square root of the
number of measurement, is applicable only to measurands that do not change with time and to measuring systems
that do not exhibit systematic uncertainties.
The statistical treatment of random and systematic deviations of measurement results has been harmonized by the
concept of measurement uncertainty introduced by the Guide to the expression of uncertainty in measurement in
1993 (GUM). This approach is based on the general application of the rule of uncertainty propagation. Although not
addressed explicitly by the GUM, the concept of uncertainty propagation and measurement uncertainty can also be
applied to measurands exhibiting distinct time structure.
Standard uncertainty may be required as a measure of data quality to be provided when reporting a time average
of air quality monitoring data. If appropriate, data quality objectives can be defined separately for:
a) the uncertainty of the time average induced by the measuring system,
b) the uncertainty of the time average induced by incomplete time coverage of the monitoring data,
c) the uncertainty of the time average due to limited spatial coverage of monitoring data.
These influences make up independent contributions to the mean square uncertainty of a time average. In this
International Standard, a time average of measured air quality data is intended to describe the air quality at a
specified location or within a specified stack within a given time period. The uncertainty of the time average due to
spatial coverage of monitoring data is not considered.
INTERNATIONAL STANDARD ISO 11222:2002(E)
Air quality — Determination of the uncertainty of the time average
of air quality measurements
1 Scope
This International Standard provides a method for the quantification of the uncertainty of a time average of a set of
air quality data obtained at a specified location over a defined averaging time period. The method is applicable to
air quality data obtained by continuous or intermittent monitoring by means of a specified measuring system. The
uncertainty of the time average depends on both the uncertainty of the measurement results and the uncertainty
due to incomplete time coverage of the data set.
This International Standard is only applicable if:
a) the set of air quality data used to calculate the time average is representative of the temporal structure of the
measurand over the defined time period,
b) appropriate information on the uncertainty of the measurement results is available, and
c) the measurement results have all been obtained at the same location.
This International Standard implements recommendations of the Guide to the expression of uncertainty in
measurement (GUM).
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent edition of the normative document indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
GUM:1995, Guide to the expression of uncertainty in measurement, First edition, BIPM/IEC/IFCC/ISO/IUPAC/
IUPAP/OIML
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
arithmetic mean
average
sum of values divided by the number of values
[ISO 3534-1:1993, 2.26]
3.2
combined standard uncertainty
standard uncertainty of the result of a measurement when that result is obtained from the values of a number of
other quantities, equal to the positive square root of a sum of terms, the terms being the variances and covariances
of these quantities weighted according to how the measurement result varies with changes in these quantities
[GUM:1995, 2.3.4]
NOTE The (combined) standard uncertainty of the result of a measurement is the positive square root of its mean square
uncertainty.
3.3
covariance
measure of the statistical dependence of two observable quantities which may be considered as random variables
NOTE Two observable quantities have a non-zero covariance if they are correlated, i.e. a change in one quantity results in
a change in the other quantity.
3.4
coverage factor
numerical factor used as a multiplier of the combined standard uncertainty in order to obtain an expanded
uncertainty
[GUM:1995, 2.3.6]
3.5
expanded uncertainty
quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction
of the distribution of values that could reasonably be attributed to the measurand
[GUM:1995, 2.3.5]
NOTE If the expanded uncertainty of a result X of measurement on the level of confidence p is given by U (X), the
p
unknown true value of X is expected with probability p to be located within the interval [X − U (X); X + U (X)].
p p
3.6
influence quantity
quantity that is not the measurand but that affects the result of the measurement
[GUM:1995, B.2.10]
3.7
mean square uncertainty
〈of a result of measurement〉 square of the combined standard uncertainty of a measurement result
NOTE The mean square uncertainty of a measurement result may also be estimated by the mean square deviation of the
measurement result from material measures of the “true” value.
3.8
measurand
particular quantity subject to measurement
[VIM:1993, 2.6]
NOTE In the field of air quality monitoring, the measurand can be a highly varying function of time.
3.9
measuring system
complete set of measuring instruments and other equipment with operating procedures for carrying out specified air
quality measurements
2 © ISO 2002 – All rights reserved
NOTE The operating procedure includes or refers to a specification of the calibration routine, if calibration of the measuring
system is needed for its proper operation.
3.10
model equation
mathematical model of the measurement that transforms the set of (repeated) observations performed into the
measurement result
3.11
number of degrees of freedom
in general, the number of terms in a sum minus the number of constraints on the terms of the sum
[GUM:1995, C.2.31]
3.12
random variable
a variable that may take any of the values of a specified set of values and with which is associated a probability
distribution
[GUM:1995, C.2.2]
3.13
reference material
material or substance one or more of whose property values are sufficiently homogeneous and well established to
be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to
materials
[VIM:1993, 6.13]
3.14
reference standard
standard, generally having the highest metrological quality available at a given location or in a given organization,
from which measurements made there are derived
[VIM:1993, 6.6]
3.15
result of a measurement
value attributed to a measurand, obtained by measurement
[VIM:1993, 3.1]
3.16
standard
material measure, measuring instrument, reference mate
...
NORME ISO
INTERNATIONALE 11222
Première édition
2002-07-01
Qualité de l'air — Détermination de
l'incertitude de mesure de la moyenne
temporelle de mesurages de la qualité de
l'air
Air quality — Determination of the uncertainty of the time average of air
quality measurements
Numéro de référence
©
ISO 2002
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Droits de reproduction réservés. Sauf prescription différente, aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque
forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l’ISO à
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Tel. + 41 22 749 01 11
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Web www.iso.ch
Imprimé en Suisse
ii © ISO 2002 – Tous droits réservés
Sommaire Page
Avant-propos .iv
Introduction.v
1 Domaine d'application.1
2 Références normatives.1
3 Termes et définitions.1
4 Symboles et abréviations .4
5 Exigences relatives aux données d’entrée .5
5.1 Généralités.5
5.2 Exigences spécifiques relatives aux données d'entrée .6
6 Procédure.8
6.1 Généralités.8
6.2 Incertitude-type due au système de mesure.8
6.3 Incertitude-type due à une couverture temporelle incomplète.10
6.4 Incertitude-type composée.11
6.5 Incertitude élargie.11
7 Rapport sur l’incertitude.12
Annexe A (informative) Exemple — Quantification de l'incertitude d'une concentration moyenne
mensuelle en dioxyde d’azote présente dans l'air ambiant .13
A.1 Entrée.13
A.1.1 Système de mesure.13
A.1.2 Procédure de contrôle.13
A.1.3 Procédure d’estimation de l’incertitude des moyennes horaires .13
A.2 Estimation de l’incertitude de la moyenne mensuelle.17
A.2.1 Incertitude de mesure .17
A.2.2 Incertitude due aux valeurs manquantes.18
A.2.3 Déclarations d’incertitude de la moyenne temporelle .18
A.3 Discussion.19
Bibliographie.20
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 (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,
Partie 3.
La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes
internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur publication
comme Normes internationales requiert l'approbation de 75 % au moins des comités membres votants.
L'attention est appelée sur le fait que certains des éléments de la présente Norme internationale 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.
L'ISO 11222 a été élaborée par le comité technique ISO/TC 146, Qualité de l'air, sous-comité SC 4, Aspects
généraux.
L’annexe A de la présente Norme internationale est donnée uniquement à titre d’information.
iv © ISO 2002 – Tous droits réservés
Introduction
En matière de surveillance de la qualité de l’air, les mesurandes peuvent connaître d’importantes variations en
fonction du temps. Des précautions particulières sont requises lors de l’estimation des incertitudes de mesure des
moyennes temporelles des données relatives à la qualité de l’air. L’approche [3], qui utilise l’écart-type des
résultats de mesure relevés divisé par la racine carrée du nombre de mesurages, s’applique uniquement aux
mesurandes qui ne varient pas dans le temps et aux systèmes de mesure qui ne présentent pas d’incertitudes
systématiques.
Le traitement statistique des écarts aléatoire et systématique des résultats de mesure a été harmonisé par le
concept d’incertitude de mesure introduit par le Guide pour l’expression de l’incertitude de mesure en 1993 (GUM).
Cette approche est fondée sur l’application générale de la loi de propagation de l’incertitude. Bien que le GUM ne
traite pas explicitement de la propagation de l’incertitude ni de l’incertitude de mesure, ces concepts peuvent
également s’appliquer aux mesurandes présentant une structure temporelle distincte.
L’incertitude-type peut s’avérer nécessaire pour évaluer la qualité des données obtenues dans le domaine de la
surveillance de la qualité moyenne de l’air dans le temps. Le cas échéant, des objectifs de qualité des données
peuvent être définis séparément pour
a) l’incertitude de la moyenne temporelle due au système de mesure;
b) l’incertitude de la moyenne temporelle due à une couverture temporelle incomplète des données de
surveillance;
c) l’incertitude de la moyenne temporelle due à une couverture spatiale limitée des données de surveillance.
Chacune de ces grandeurs d’influence contribue de façon indépendante à l’incertitude quadratique moyenne d’une
moyenne temporelle. Dans la présente Norme internationale, une moyenne temporelle des données calculées
relatives à la qualité de l’air vise à décrire la qualité de l’air dans un endroit précis ou dans une cheminée spécifiée,
sur une période de temps donnée. La présente Norme internationale ne couvre pas l’incertitude de la moyenne
temporelle due à la couverture spatiale des données de surveillance.
NORME INTERNATIONALE ISO 11222:2002(F)
Qualité de l'air — Détermination de l'incertitude de mesure de la
moyenne temporelle de mesurages de la qualité de l'air
1 Domaine d'application
La présente Norme internationale fournit une méthode permettant de quantifier l’incertitude d'une moyenne
temporelle d’un ensemble de données relatif à la qualité de l’air, obtenu à partir d’un point de mesurage spécifié,
sur une période moyenne de temps définie. La méthode est applicable aux données relatives à la qualité de l’air
obtenues par surveillance continue ou intermittente, au moyen d’un système de mesure spécifié. L’incertitude de la
moyenne temporelle dépend à la fois de l’incertitude des résultats de mesure et de l’incertitude due à une
couverture incomplète de l’ensemble de données.
La présente Norme internationale est applicable uniquement si
a) l’ensemble de données relatif à la qualité de l’air utilisé pour calculer la moyenne temporelle est représentatif
de la structure temporelle du mesurande sur la période de temps définie,
b) les informations appropriées relatives à l’incertitude des résultats de mesure sont disponibles, et
c) les mesurages ont été effectués au même endroit.
La présente Norme internationale met en œuvre les recommandations du Guide pour l’expression de l’incertitude
de mesure (GUM).
2 Référence normative
Le document normatif suivant contient des dispositions qui, par suite de la référence qui y est faite, constituent des
dispositions valables pour la présente Norme internationale. Pour les références datées, les amendements
ultérieurs ou les révisions de ces publications ne s'appliquent pas. Toutefois, les parties prenantes aux accords
fondés sur la présente Norme internationale sont invitées à rechercher la possibilité d'appliquer l’édition la plus
récente du document normatif indiqué ci-après. Pour les références non datées, la dernière édition du document
normatif en référence s'applique. Les membres de l'ISO et de la CEI possèdent le registre des Normes
internationales en vigueur.
GUM:1995, Guide pour l’expression de l’incertitude de mesure, première édition, BIPM/CEI/FICC/ISO/OIML/
UICPA/UIPPA
3 Termes et définitions
Pour les besoins de la présente Norme internationale, les termes et définitions suivants s'appliquent.
3.1
moyenne arithmétique
moyenne
somme des valeurs divisée par le nombre de valeurs
[ISO 3534-1:1993, 2.26]
3.2
incertitude-type composée
incertitude-type du résultat d’un mesurage, lorsque ce résultat est obtenu à partir des valeurs d’autres grandeurs,
égale à la racine carrée positive d’une somme de termes, ces termes étant les variances ou covariances de ces
autres grandeurs, pondérées selon la variation du résultat de mesure en fonction de celle de ces grandeurs
[GUM:1995, 2.3.4]
NOTE L’incertitude-type (composée) du résultat d’un mesurage est la racine carrée positive de son incertitude quadratique
moyenne.
3.3
covariance
mesure de la dépendance statistique de deux grandeurs observables qui peuvent être considérées comme deux
variables aléatoires
NOTE Deux grandeurs observables ont une covariance non nulle si elles sont corrélées, c’est-à-dire si la variation de l’une
de ces deux grandeurs entraîne la variation de l’autre grandeur.
3.4
facteur d’élargissement
facteur numérique utilisé comme multiplicateur de l’incertitude-type composée pour obtenir l’incertitude élargie
[GUM:1995, 2.3.6]
3.5
incertitude élargie
grandeur définissant un intervalle, autour du résultat d’un mesurage, dont on puisse s’attendre à ce qu’il
comprenne une fraction élevée de la distribution des valeurs qui pourraient être attribuées raisonnablement au
mesurande
[GUM:1995, 2.3.5]
NOTE Si l’incertitude élargie d’un résultat X de mesurage au niveau de confiance p est donnée par U (X), la valeur vraie
p
inconnue de X est attendue avec une probabilité p dans l’intervalle [X − U (X); X + U (X)].
p p
3.6
grandeur d’influence
grandeur qui n’est pas le mesurande mais qui a un effet sur le résultat du mesurage
[GUM:1995, B.2.10]
3.7
incertitude quadratique moyenne
〈d'un résultat de mesure〉 carré de l’incertitude-type composée d’un résultat de mesure
NOTE L’incertitude
...
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