Study Identifies Link Between Asthma Attacks & Thunderstorms

It’s not true, it turns out, that thunderstorms clear the air. Quite the contrary. In a study on thunderstorms and asthma, researchers recently found a surprising relationship between the two that could have a significant public health impact.

The study was done in the southeastern US, an area where thunderstorms and asthma are both highly prevalent. Researchers from the University of Georgia and Emory University compared a database of more than 10 million emergency room visits in 41 hospitals in 20 Atlanta-area counties between 1993 and 2004 with thunderstorm data taken from an Atlanta airport. The researchers found an overall increase of 3% in asthma-related visits to ERs over the 11-year period.


  • ER visits due to asthma increased following thunderstorms with rain, but not following thunderstorms without rain.
  • Asthma visits also correlated with intermediate or high thunderstorm wind gusts.

Though this study did not examine case histories, previous research has found that even people without a previous history of asthma sought medical attention for asthma symptoms after thunderstorms.


For greater insight into the connection, I contacted the study’s lead author, Andrew Grundstein, PhD, a climatologist at the University of Georgia. He said, “There are a number of hypotheses relating to rainfall, wind speeds and lightning to explain the relationship between thunderstorms and asthma attacks, but no definitive explanation at this point.” The most popular theory is that rain ruptures pollen grains, releasing allergens, which are then spread by wind gusts.

Dr. Grundstein told me that in other countries, including the UK and Australia, the thunderstorm-asthma link has long been reported in medical journal literature. One study noted a five- to tenfold increase in patients seeking medical attention in locations in the United Kingdom. In fact, following a thunderstorm in June 1994, emergency departments in London reported running out of medication, nebulizers and mouthpieces for peak flow meters. “Not all thunderstorms lead to epidemics,” said Dr. Grundstein. Further study is needed to identify the particular thunderstorm ingredients that boost asthma rates — however, the London event provides a dramatic example of the public health implications when one does occur, he said.

What to do? If you know you are at risk — typically if you have pollen allergies and asthma — Dr. Grundstein advises staying indoors during and for a few hours after a storm. He also suggests asking your doctor about measures to control your asthma, noting that previous research shows that those taking medications to control their asthma and who were indoors tended to have fewer problems.