The Surprising Link Between Thunderstorms And Asthma
As severe weather events become more common, public health systems will face a challenge in treating respiratory illnesses.
BY ANUPAM B. JENA AND CHRISTOPHER M. WORSHAM
THIS SUMMER WAS defined by record-breaking heat and dramatic storms across the U.S. Injuries and delays in medical care brought on by flooding, power outages and dangerous road conditions are among the more conspicuous health effects of storms, but they can also lead to a less obvious health problem: asthma. In 2016, the city of Melbourne, Australia, experienced an alarming mass asthma event immediately following a thunderstorm. In the 30 hours following the storm, area hospitals saw 3,365 more medical visits for breathing problems than would be expected based on the average for the previous three years, an increase of 672%. At the peak of the crisis, calls for ambulances were coming in once every 4.5 seconds. The city’s emergency and healthcare systems were overwhelmed, resulting in 10 deaths and spurring new programs to prepare for future episodes of “thunderstorm asthma.”
What happened? It’s hard to know for certain, but studies of over a dozen documented dramatic thunderstorm-related asthma events in the past several decades—mostly in Australia, Europe and the Middle East—show that the most dramatic breakouts tend to occur when pollen counts are high. One prevailing theory holds that storm winds sweep pollen from plants on the ground into the sky, where the humidity can break it into smaller particles that are more easily inhaled deep into the lungs. As these particles spread, people who are allergic to pollen breathe them in, triggering inflammation and tightening of the airways—an asthma attack.
To investigate the relationship between thunderstorms and respiratory illness, we took a big-data approach. Working with economist Eric Zou of the University of Michigan and others, we reviewed the records of millions of recorded lightning strikes in the U.S. from 1999 to 2012 and correlated them with health data from over 46 million Medicare recipients age 65 or older. In a study published in JAMA Internal Medicine in 2020, we found that emergency visits for respiratory illnesses increased around the time of thunderstorms, particularly among people with asthma and chronic obstructive pulmonary disorder (COPD), both reactive airway diseases. All told, we estimated that 52,000 additional respiratory visits occurred nationwide in the several days surrounding major storms during the 13-year study period. There was no storm-related increase in emergency visits for several other medical conditions, suggesting that the storms had specifically respiratory effects.
Unlike in Melbourne, however, we found that emergency visits increased most on the days before a thunderstorm, rather than during or after it. This may be best explained by weather patterns that will be familiar to anyone who got pummeled by thunderstorms this summer.
In the days and hours leading up to a storm, ground temperatures rise and humid air stagnates on the ground, leading to a rise in pollutant levels, such as the fine particulate matter known as PM2.5, consisting of small smoke particles from industrial and vehicle emissions. A build-up of pollutants in stagnant air is a known trigger of breathing problems in people with asthma and COPD. When the humid air eventually rises and a thunderstorm begins, temperatures drop, causing air quality to improve as the storm subsides. Dramatic outbreaks of thunderstorm asthma like the one in Melbourne are much rarer by comparison and may be caused by increased pollen exposure during or after a thunderstorm.
In a future of rising global temperatures, where thunderstorms and severe weather events are expected to become more frequent, people with asthma, COPD or pollen allergies should be prepared for possible breathing problems. Keep prescribed inhalers on
hand and heed any public health warnings to stay inside as temperatures rise or air quality deteriorates. Staying inside during a storm may help avoid environmental triggers.
This is just one example of how climate change will make today’s public health problems worse. During periods of severe weather, even small increases in heat-related illness, heart and lung disease, infectious diseases and mental health problems could add up, causing a “perfect storm” that could overwhelm health systems. Climate change will require preparations in nearly every aspect of modern life, from managing rising sea-levels to ensuring a strong national defense. Our research suggests that shoring up our healthcare system is a key part of protecting our essential infrastructure.
ILLUSTRATION BY JAN BUCHCZIL; GETTY IMAGES
Anupam B. Jena and Christopher M. Worsham are researchers at Harvard Medical School and the authors of “Random Acts of Medicine: The Hidden Forces That Sway Doctors, Impact Patients and Shape Our Health.”
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. This story is dated to the American invasion, not the Anglo-Afghan Wars.
