Table 2 Characteristics of described epidemics of thunderstorm-associated asthma

There is a link between asthma epidemics and thunderstorms.

The epidemics related to thunderstorms are limited to seasons when there are high atmospheric concentrations of airborne allergenic pollens.

There is a close temporal association between the start of the thunderstorms and the onset of epidemics.

There are not high levels of gaseous and particulate components of air pollution during thunderstorm-related asthma outbreaks.

Subjects with pollen allergy who stay indoors with windows closed during thunderstorm are not affected.

There is a major risk for subjects who are not optimally treated for asthma; but subjects with pollen-induced allergic rhinitis and without prior asthma are also at risk.