EN ISO 20988:2007

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and abbreviated terms
5 Basic concepts
   5.1 Outline
   5.2 Measurement uncertainty
   5.3 Correction for systematic effects
   5.4 Provision of input data
6 Problem specification
   6.1 Objectives
   6.2 Measurement
   6.3 Uncertainty parameters
   6.4 Input data
       6.4.1 General
       6.4.2 Assessment of representativeness
   6.5 Effects not described by series of
       observations
7 Statistical analysis
   7.1 Objectives
   7.2 Indirect approach
   7.3 Direct approach
   7.4 Statistical validity
8 Estimation of variances and covariances
   8.1 General
   8.2 Variance estimates of Type A
   8.3 Variance estimates of Type B
   8.4 Estimation of covariances
9 Evaluation of uncertainty parameters
   9.1 Objective
   9.2 Combined standard uncertainty
   9.3 Expanded uncertainty
       9.3.1 General
       9.3.2 Expanded uncertainty of results exhibiting
             a Gaussian distribution
10 Reporting
Annex A (informative) Testing a coverage probability
Annex B (informative) Type A evaluation methods for
                      experimental designs A1 to A8
Annex C (informative) Examples
Bibliography

ISO 20988:2007 provides comprehensive guidance and specific statistical procedures for uncertainty estimation in air quality measurements including measurements of ambient air, stationary source emissions, indoor air, workplace atmospheres and meteorology. It applies the general recommendations of the Guide to the Expression of Uncertainty in Measurement (GUM) to boundary conditions met in air quality measurement. The boundary conditions considered include measurands varying rapidly in time, as well as the presence of bias in a series of observations obtained under conditions of intended use of methods of air quality measurement. The methods of measurement considered comprise methods corrected for systematic effects by repeated observation of reference materials, methods calibrated by paired measurement with a reference method, methods not corrected for systematic effects because they are unbiased by design, and methods not corrected for systematic effects in intended use deliberately taking into account a bias. Experimental data for uncertainty estimation can be provided either by a single experimental design in a direct approach or by a combination of different experimental designs in an indirect approach.