Â A report in the July/August 2002 edition of the Canadian Respiratory Journal by Calgary researchers A. Wardman, D. Stefani and J. Macdonald, titled œThunderstorm-associated asthma or shortness of breath epidemic: A Canadian case report suggests a possible explanation for a sudden increase of asthma-related hospital and doctor visits following a July thunderstorm in Calgary.
Following the storm, 157 people sought care for asthma symptoms whereas on average, 17 people seek care for asthma symptoms over a 48 hour period in Calgary. The authors reviewed data from the Calgary Health Region and from air quality measurements before, during and after the storm. The data suggested that a stagnant air mass before the storm allowed many bioaerosols such as pollen and spores to settle. The thunderstorm brought a sudden onset of high winds which triggered a rapid release of pollen and spores into the atmosphere. The spike in bioaerosol levels was probably responsible for the epidemic of asthma symptoms.
The abstract of the paper is available from theÂ Canadian Respiratory Journal.