Abstract
The peak-to-mean concentration ratio obtained from observations near a point source of pollution is a particular example of the ratio of any short-period concentration to the long-term mean. The value of this ratio may be obtained from the probability distribution function:
whereF(C) is the probability or frequency that the ratio of a short-period average concentration (C) to the long-term mean (M) exceeds the valueC/M, andF(0) is a parameter dependent on the length of the short period and the position of the sampler relative to the centre-line of the plume. From (1) the peak-to-mean concentration ratio is shown to be related to the two averaging times by the expression
wheret M andt P are, respectively, the averaging times of the long-term meanM and the short-term peakP.
Using recently published experimental data, Equation (1) and hence also (2) are shown to be valid for averaging timest P from 5 s to 24 h and oft M from 6 min to 5 yr providedt P ≪t M .
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References
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Barry, P. J.: (To be submitted for publication).
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Barry, P.J. A note on peak-to-mean concentration ratios. Boundary-Layer Meteorol 2, 122–126 (1971). https://doi.org/10.1007/BF00718092
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DOI: https://doi.org/10.1007/BF00718092