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  • Author or Editor: J. M. Hales x
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J. M. Hales

Abstract

Over the past several years, a number of Gaussian plume–based computer codes have been produced. These codes describe transport, transformation, and deposition of air pollutants under a variety of atmospheric conditions. For a number of reasons, there is increasing interest in simulating wet-deposition processes in such codes, and several approaches have been applied to this end. Some of these approaches involve elaborate solubility and chemistry characterizations, but many of them resort to a diversity of approximate techniques. This paper presents a procedure that can be used as a practical guide to improve many of these formulations, especially for the case of pollutant gases. The approach takes the form of a set of analytical equations that correspond to five kinds of Gaussian plume formulations: standard bivariate-normal point-source plumes, line-source plumes, unrestricted instantaneous puffs, and point-source plumes and puffs that experience reflection from inversion layers aloft. These equations represent the concentration of scavenged pollutants in falling raindrops and are similar in complexity to their associated gas-phase plume equations. They are strictly linear, thus allowing superposition of wet-deposition contributions by multiple plumes.

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D. L. Sisterson, J. D. Shannon, and J. M. Hales

Abstract

The diurnal variation of the structure of pollutant transport and diffusion in the Ohio River Valley is examined by combining meteorological cross sections with vertical profiles of several air pollutants. An increased frequency of rawinsonde releases from NWS stations at Salem, Dayton and Pittsburgh during the period 1–10 August was supplemented on 5 and 6 August by vertical profiles taken along the cross-section line by an aircraft. The data on 5 August, a day without convective activity to complicate analyses, merit special study. Analyses of the b scat structure superimposed on the meteorological cross sections lend support to the theory of horizontal transport of polluted layers above the nocturnal inversion or developing mixed layer without significant dilution. The effect of the daily breathing of the planetary boundary layer on the vertical structure of pollutants can be seen in the sequence of cross sections.

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