Sampling of Emitted Particulates

The representativeness of samples is a very important premise for true assessment of the state of air pollution. The following example demonstrates the temporal frequency necessary for objective assessment of the impact of emissions of total suspended dust at one sampling location [GEISS et al., 1991]  

It was necessary to answer the following question Is the applied sampling frequency appropriate for characterization of the average impact of emissions at the sampling point over the time period under investigation  

Chemometrics in Environmental Analysis. J. W. Einax, H. W. Zwanziger. S. GeiB Copyright 1997 WILEY-VCH Verlag GmbH ISBN 3-527-28772-8 

Because of the highly scattered temporal distributions of the individual loadings of the elements, the multivariate autocorrelation function was computed as described in Section 6.6.3. The results are demonstrated in Fig. 7-1. 

Comparison with the highest possible values of a multivariate random correlation (see also Section 6.6.3) shows a correlation period of approximately two weeks and two days. This means that sampling of suspended dust at intervals of two weeks is sufficient for the characterization of the average impact of multielement emissions (for all investigated elements simultaneously) at that particular sampling point. 

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