AIR QUALITY - STRATIFIED SAMPLING METHOD FOR ASSESSMENT OF AMBIENT AIR QUALITY (ISO 9359:1989, IDT)
This Malaysian Standard specifies a method for the assessment of certain aspects of ambient air quality in terms of percentiles and means using the principle of stratified sampling.
This is by estimating percentiles and means of the frequency distribution of measurements of ambient air quality characteristics. The application to the estimation of means, however, is restricted to cases where certain assumptions about the frequency distribution of the ambient air quality characteristic can be made using a priori knowledge or when a sufficient number of statistically independent measurements are available (see IS0 2854 and IS0 2602).
The results may be used to assess ambient air quality during the period of the measurement survey. (For length of period see also IS0 7168.) By using information on the longer-term occurrence of the various strata, an assessment for a longer period can be obtained using the same database.
Thus, although meteorological conditions have a profound effect o
