BS ISO 11222-2007 Air quality - Determination of the uncertainty of the time average of air quality measurements《空气质量 空气质量测量所需平均时间不确定度的测定》.pdf

1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58average of air quality measurementsICS 13.040.01Air quality Determination of the uncertainty of the

2、 time BRITISH STANDARDBS ISO 11222:2002BS ISO 11222:2002This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 March 2007 BSI 2007ISBN 978 0 580 50368 9Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for i

3、ts correct application.Compliance with a British Standard cannot confer immunity from legal obligations. National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 11222:2002.The UK participation in its preparation was entrusted by Technical Committee EH/2, Air q

4、uality, to Subcommittee EH/2/4, General aspects.A list of organizations represented on EH/2/4 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a Reference numberISO 11222:2002(E)INTERNATIONAL STANDARD ISO11222First edition2002-0

5、7-01Air quality Determination of the uncertainty of the time average of air quality measurements Qualit de lair Dtermination de lincertitude de mesure de la moyenne temporelle de mesurages de la qualit de lair BS ISO 11222:2002ii iiiContents Page Foreword.iv Introduction.v 1 Scope 1 2 Normative refe

6、rence1 3 Terms and definitions .1 4 Symbols and abbreviated terms 4 5 Requirements on the input data.5 5.1 General5 5.2 Specific requirements on input data .6 6 Procedure .8 6.1 General8 6.2 Standard uncertainty induced by the measuring system .8 6.3 Standard uncertainty due to incomplete time cover

7、age .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 air13 A.1 Input 13 A.2 Uncertainty estimation of the monthly average .17 A.3 Discu

8、ssion19 Bibliography20 BS ISO 11222:2002iv 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

9、 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 Elect

10、rotechnical 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 adopte

11、d 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 sub

12、ject 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. BS ISO 11222:2002vIntrodu

13、ction 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 res

14、ults 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

15、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 propagat

16、ion 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

17、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

18、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 ti

19、me average due to spatial coverage of monitoring data is not considered. BS ISO 11222:2002blank1Air 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 avera

20、ge 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 unce

21、rtainty 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 t

22、ime 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

23、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 agreement

24、s 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 c

25、urrently 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

26、sum of values divided by the number of values ISO 3534-1:1993, 2.26 BS ISO 11222:20022 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 ter

27、ms, 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 uncert

28、ainty. 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

29、 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 distributio

30、n 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 Up(X), the unknown true value of X is expected with probability p to be located within the interval X Up(X); X + Up(

31、X). 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 r

32、esult 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

33、.9 measuring system complete set of measuring instruments and other equipment with operating procedures for carrying out specified air quality measurements BS ISO 11222:20023NOTE The operating procedure includes or refers to a specification of the calibration routine, if calibration of the measuring

34、 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

35、 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 sufficien

36、tly 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 g

37、iven 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 material or measuring system intended to define, realize

38、, conserve or reproduce a unit or one or more values of a quantity to serve as a reference VIM:1993, 6.1 3.17 standard deviation positive square root of the variance of the random variable considered NOTE Adapted from the GUM:1993, C.2.12. 3.18 standard uncertainty uncertainty of the result of a mea

39、surement expressed as a standard deviation GUM:1995, 2.3.1 BS ISO 11222:20024 3.19 time average mean value of a set of measurement results (air quality data) recorded within a defined time period 3.20 uncertainty parameter, associated with the result of a measurement, that characterises the dispersi

40、on of the values that could reasonably be attributed to the measurand VIM:1993, 3.9 NOTE The uncertainty of a result of a measurement may be described by the (combined) standard uncertainty or by an expanded uncertainty on a stated level of confidence. 3.21 variance of a random variable or of a prob

41、ability distribution central moment of order 2 NOTE The variance of a random variable may be defined equivalently as the expected value of the quadratic deviation of the random variable about its expected value. 4 Symbols and abbreviated terms Ciindividual measurement result recorded in the time per

42、iod T TC time average of air quality monitoring data Cif number of degrees of freedom feffeffective number of degrees of freedom fMnumber of degrees of freedom assigned to the standard uncertainty M()TuC induced by the measuring system applied fS number of degrees of freedom assigned to the standard

43、 uncertainty S()TuC due to incomplete time coverage ( )()f uj number of degrees of freedom when assessing the standard uncertainty u(j) ( )r()f uj number of degrees of freedom when assessing the standard uncertainty ur(j) ( )nr()f uj number of degrees of freedom when assessing the standard uncertain

44、ty unr(j) ( )nrfu number of of degrees of freedom when assessing the standard uncertainty unr( )r()if uC number of of degrees of freedom when assessing the standard uncertainty ur(Ci) kp(f) coverage factor for confidence level p and number of degrees of freedom f M number of time intervals T(j) cove

45、ring the time period T Max maximum of set of values N number of measurement results Cirecorded in the time period T Nmaxnumber of measurement results Cinecessary for complete coverage of the time period T n(j) number of observed measurement results in time interval T(j) BS ISO 11222:20025s(Ci) stand

46、ard deviation of the set of N individual measurement results Ciused to calculate the time average TC T time period allocated to the time average TC Tstime period allocated to an individual measurement result CiT(j) sub-interval of time period T u(Ci) standard uncertainty of Ciur(Ci) random part of t

47、he standard uncertainty of Ciurconstant random part of the standard uncertainty of Ciunrnon-random part of the standard uncertainty of Ciu(j) standard uncertainty of Ciin time interval T(j) ur(j) random part of the standard uncertainty of Ciin time interval T(j) unr(j) non-random part of the standar

48、d uncertainty of Ciin time interval T(j) ()TuC (combined) standard uncertainty of the time average TC M()TuC standard uncertainty of the time average TC induced by the measuring system S()TuC standard uncertainty of the time average TC due to incomplete coverage of the time period T by the data set

49、used to calculate the time average r()TuC random part of M()TuC nr()TuC non-random part of M()TuC ()pTUC expanded uncertainty ofTCon the stated level of confidence p vrconstant relative standard uncertainty of Ci5 Requirements on the input data 5.1 General This International Standard provides methods to estimate the uncertainty of the time average of a set of scalar measurement results quantifying a time series of an air quality measurand within a defined time period. The measurand may exhibit signifi