A new study says air currents in storms trigger asthma attacks - not electrical activity, rain or thunder as thought.
Downward draughts of cold air in the storm sweep up particles such as pollen and concentrate them in a narrow band of air close to the ground, called outflow.
People allergic to pollen and in the path of the outflow inhale air with super-concentrated levels of allergens, triggering an asthma attack.
The theory was advanced by researchers from the University of Sydney, Australia, who published their study in the journal Thorax.
They studied airflow patterns and rates of hospital admissions for asthma during thunderstorms in six Australian towns between 1995 and 1998.
PA
