Table 3 The evidence about thunderstorm-related epidemics of rhinitis and asthma exacerbations

1) The occurrence of epidemics is closely linked to thunderstorm.

2) The thunderstorm-related epidemics are limited to late spring and summer when there are high levels of airborne pollen grains.

3) There is a close temporal association between the arrival of the thunderstorm, a major rise in the concentration of pollen grains and the onset of epidemics.

4) Subjects with pollen allergy, who stay indoors with window closed during thunderstorm, are not involved.

5) There are not high levels of gaseous and particulate components of air pollution during outbreaks.

6) There is a major risk for subjects who are not under anti-asthma correct treatment.