Characterising diurnal & synoptic timescale changes in urban air quality using Radon-222
Loading...
Date
2020-05-01
Journal Title
Journal ISSN
Volume Title
Publisher
Europenan Geosciences Union
Abstract
Urban air quality is strongly influenced by the atmosphere’s ability to disperse primary emissions and opportunities for secondary pollution formation. In mid- to high-latitude regions that experience enduring winter snow cover or soil freezing, regional subsidence and stagnation associated with persistent anti-cyclonic conditions such as the “Siberian High” can lead to “cold pool” or “persistent inversion” events. These events can result in life-threatening pollution episodes that last for weeks. While often associated with complex topography [1,2], persistent inversion events can also influence the air quality of urban centres in flat, inland regions [3]. This presentation will describe a recently-developed radon-based technique for identifying and characterising synoptic-timescale persistent inversion events, which is proving to be a simple and economical alternative to contemporary meteorological approaches that require regular sonde profiles [1]. Furthermore, key assumptions of the radon-based technique to characterise diurnaltimescale changes in the atmospheric mixing state described by Chambers et al. [4] are violated during persistent inversion conditions. Here we demonstrate how atmospheric class-typing, through successive application of radon-based techniques for identifying synoptic- and diurnaltimescale changes in the atmospheric mixing state, improves understanding of atmospheric controls on urban air quality in non-summer months across the full diurnal cycle. This knowledge translates directly to statistically-robust techniques for assessing public exposure to pollution, and for evaluating the efficacy of pollution mitigation measures. Lastly, we show how atmospheric class-typing can be used to enhance the evaluation of chemical transport models. © Author(s) 2020
Description
Keywords
Daily variations, Radon 222, Urban areas, Air quality, Atmospheres, Emission, Pollution, Temperature inversions
Citation
Chambers, S., Kikaj, D., Podstawczyńska, A., Williams, A., Crawford, J., & Griffiths, A. (2020) Characterising diurnal & synoptic timescale changes in urban air quality using Radon-222. Paper presented at the EGU General Assembly 2020 Online, 4-8 May 2020. Retrieved from: https://doi.org/10.5194/egusphere-egu2020-1506