ISO/TC 146/SC 4/WG 2 - Uncertainty of air quality measurements

ISO 4226:2008 lays down the units to be used when reporting results 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).

This is by estimating percentiles and means of the frequency distribution of measurements of characteristics. The application to the estimation of means is restricted to certain cases. The procedure enables results which are independent of the actual meteorological conditions prevailing during the interval of time of measurement to be calculated for a longer time.

Lays down the units and symbols to be used when reporting results of measurements. For general guidance on the International System of Units, reference should be made to ISO 1000-1992.