Asthma and allergies can occur together, and substances that trigger common allergies may also cause asthma symptoms. This is called allergic asthma.
Rain often helps people with allergies or allergic asthma by bringing pollen to the ground. But a new study says that's not necessarily the case with thunderstorms, which may actually trigger asthma outbreaks.
The study was published recently in the Journal of Applied Meteorology and Climatology.
For example, a 2016 thunderstorm asthma outbreak in Australia occurred when high grass pollen concentrations were dispersed by strong winds. This resulted in multiple deaths and a surge of people seeking medical help for breathing problems.
According to a recent report by the Global Initiative for Asthma (GINA), South Africa has the world’s fourth highest asthma death rate among five to 35 year olds.
Strong winds spread pollen
The authors of the new study explained that rainfall and high humidity rupture pollen particles. Thunderstorm electrical activity further fragments the particles. And strong winds can spread pollen ahead of the storm. A combination of several of these factors can lead to asthma outbreaks.
"Thunderstorm asthma is a very complex phenomenon and involves interactions of allergens like grass pollens, thunderstorms and susceptible groups of people," said study lead author Andrew Grundstein. He is a professor of geography at the University of Georgia.
"Our study may help anticipate significant thunderstorms by employing a technique that helps identify wind magnitudes commonly associated with thunderstorm asthma outbreaks," Grundstein said in a university news release.
Cross-referencing several forecast modelling tools can help the public and emergency service providers be better prepared for thunderstorm asthma outbreaks, the researchers suggested.
According to the Western Cape Government Department of Health there is undoubted evidence of a significant increase in the number of people who have asthma among all races in South Africa over the past 25 years.
Study co-author Marshall Shepherd is a professor of geography and atmospheric sciences at the University of Georgia. He said, "While this study does not yet provide the capability of predicting thunderstorm asthma outbreaks, our methodology may provide a key piece to the puzzle for alerting public health officials about what storms may trigger an episode and which ones may not."
Who gets asthma? (Prevalence)
Pleasant and unpleasant asthma triggers
A third of asthma patients may be misdiagnosed