If you have outdoor workers who are susceptible to asthma attacks, you may be interested in this recently published research by UGA scientist Andrew Grundstein.  Dr. Grundstein points out that usually rain is linked to lower pollen and dust amounts and reduced asthma symptoms.  However, in his research he found that thunderstorms often have the opposite effect and can make asthma worse.  The strong updrafts in thunderstorms can carry small particles long distances and can also cause pollen grains to rupture and produce even smaller particles that can be inhaled deep into lungs, making asthma symptoms a bigger problem.  You can read the story here.