Volcanic Plumes are Bad for Human Health. The Silent ‘Plumerang’ Could Be Worse

Massive volcanic eruptions may not be frequent, but they are memorable. When Iceland's Eyjafjallajökull erupted in 2010, millions of air travellers were stranded worldwide, while local populations suffered significant respiratory distress.

Now a team of scientists at the University of Leeds has found a second type of volcanic plume (the mixture of particles and gas emitted by an eruption) that may have even greater effects than the primary plume in an eruption, in part because the second plume -- which the team cleverly dubbed a "plumerang" -- descends again after the initial plume has dispersed and local populations have returned to normal activities.

Led by Dr. Evgenia Ilyinskaya, the team of researchers studied plume chemistry from the 2014-2015 lava field eruption at Holuhraun in Iceland. According to the study, this second plume circled back to Icelandic cities and towns after the health warning about the first plume was lifted.

"The return of this second, mature plume, which we referred to as a 'plumerang,' showed that the volcanic sulphur had undergone a gas-to-particle conversion by spending time in the atmosphere," Dr. Ilyinskaya said. "This conversion meant that the sulphur dioxide (SO2) levels of the plumerang were reduced and within the European Commission air quality standards and therefore there were no health advisory messages in place."

"However, our samples showed that the mature plume was instead very rich in fine particles which contained high concentrations of sulphuric acid and trace metals," Dr. Ilyinskaya continued. "The concentrations of these trace metals did not reduce as the plume matured and included heavy metals found in human-made air pollution that are linked to negative health effects."

Dr. Ilyinskaya's team found particles small enough to penetrate deep into the lungs, which could lead to serious health problems such as exacerbating asthma attacks. In fact, researchers estimate that short-term and long-term exposure to these particles will cause more than three million premature deaths globally per year.

"The Holuhraun eruption caused one of the most intense and widespread volcanogenic air pollution events in centuries. It's estimated that the amount of sulphur dioxide released into the atmosphere was roughly two times that of a yearly total of SO2 emissions generated by the European Economic area," co-author, Dr. Anja Schmidt added.

"It gave us a rare opportunity to study volcanism of this style and scale using modern scientific techniques. The data we have gathered will be invaluable to preparing for a potential future event and its impacts on air quality and human health."