A radon-only technique for quantifying the effects of atmospheric stability on air pollution concentrations
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Date
2015-01-21
Journal Title
Journal ISSN
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Publisher
Australian Nuclear Science and Technology Organisation
Abstract
Radon-222 is a useful tool for quantifying stability influences on urban pollutant concentrations. While bulk radon gradients are ideal for this purpose, since the vertical differencing substantially removes contributions from processes on timescales greater than diurnal, more commonly radon measurements are available only at a single height. Here we explain why single-height, near-surface (<20 m agl) radon observations should not be used quantitatively as an indicator of atmospheric stability without prior conditioning of the time series to remove contributions from larger-scale “non-local” (including fetch-related) processes. We outline a simple technique to obtain an approximation of the diurnal radon gradient signal from a single-height measurement time series, and use it to derive a 4-category classification scheme for atmospheric stability on a “whole night” basis. We then apply this stability classification scheme to selected climatological and pollution observations, and compare the results with stability classifications performed using the Pasquil-Gifford “turbulence” and “radiation” schemes. Lastly, we apply the radon-based classification scheme to nocturnal mixing height estimates calculated from the diurnal radon accumulation time series, and provide insight to the range of nocturnal mixing depths expected for each of the stability classes.
Description
Keywords
Radon, Radon 222, Urban areas, Pollution, Turbulence, Air pollution, Ecological concentration
Citation
Chambers, S. D., Williams, A. G., Crawford, J., & Griffiths, A. (2015). A radon-only technique for quantifying the effects of atmospheric stability on air pollution concentrations. Paper presented at the International Symposium of Environmental Quality and Pollution Control, at Fusion Technology Centre, Hanyang University, Seoul Korea, 21 January 2015.