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Atmospheric modelling of grass pollen rupturing mechanisms for thunderstorm asthma prediction


Emmerson, KM and Silver, JD and Thatcher, M and Wain, A and Jones, PJ and Dowdy, A and Newbigin, EJ and Picking, BW and Choi, J and Eber, E and Bannister, T, Atmospheric modelling of grass pollen rupturing mechanisms for thunderstorm asthma prediction, PLoS One, 16, (4) pp. 1-21. ISSN 1932-6203 (2021) [Refereed Article]


Copyright Statement

Copyright 2021 Emmerson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

DOI: doi:10.1371/journal.pone.0249488


The world's most severe thunderstorm asthma event occurred in Melbourne, Australia on 21 November 2016, coinciding with the peak of the grass pollen season. The aetiological role of thunderstorms in these events is thought to cause pollen to rupture in high humidity conditions, releasing large numbers of sub-pollen particles (SPPs) with sizes very easily inhaled deep into the lungs. The humidity hypothesis was implemented into a three-dimensional atmospheric model and driven by inputs from three meteorological models. However, the mechanism could not explain how the Melbourne event occurred as relative humidity was very low throughout the atmosphere, and most available grass pollen remained within 40 m of the surface. Our tests showed humidity induced rupturing occurred frequently at other times and would likely lead to recurrent false alarms if used in a predictive capacity. We used the model to investigate a range of other possible pollen rupturing mechanisms which could have produced high concentrations of SPPs in the atmosphere during the storm. The mechanisms studied involve mechanical friction from wind gusts, electrical build up and discharge incurred during conditions of low relative humidity, and lightning strikes. Our results suggest that these mechanisms likely operated in tandem with one another, but the lightning method was the only mechanism to generate a pattern in SPPs following the path of the storm. If humidity induced rupturing cannot explain the 2016 Melbourne event, then new targeted laboratory studies of alternative pollen rupture mechanisms would be of considerable value to help constrain the parameterisation of the pollen rupturing process.

Item Details

Item Type:Refereed Article
Keywords:thunderstorm asthma, pollen rupturing, allergy, grass pollen
Research Division:Health Sciences
Research Group:Public health
Research Field:Public health not elsewhere classified
Objective Division:Environmental Management
Objective Group:Air quality, atmosphere and weather
Objective Field:Atmospheric processes and dynamics
UTAS Author:Jones, PJ (Dr Penelope Jones)
ID Code:144064
Year Published:2021
Web of Science® Times Cited:14
Deposited By:Menzies Institute for Medical Research
Deposited On:2021-04-17
Last Modified:2021-06-25
Downloads:14 View Download Statistics

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