Harvard researchers wanted to see if increases in emergency department visits for respiratory illnesses among older adults happened in the days surrounding thunderstorms because vulnerable groups and those with common chronic respiratory disease may be able to take steps to prevent worsening. The study in JAMA Internal Medicine found thunderstorms are linked with an average of 3,700 emergency department visits annually in the U.S. among seniors with respiratory illnesses, including asthma and chronic obstructive pulmonary disease (COPD). They collected the data from 1999 through 2012 in more than 3,000 counties and looked at emergency department visits due to respiratory conditions in older patient populations in the days before and after thunderstorms. They found an uptick of ER visits of those with asthma and COPD on the day before thunderstorms. You can find the full study here.