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(BIVN) – The Kῑlauea volcano is not erupting and the alert level of the USGS volcano is at NORMAL.
As scientists and affiliates of the USGS Hawaiian Volcano Observatory wrote it in the week Volcano watch article, it's the perfect time to do some research.
The end of the 2018 eruption of Kīlauea last September is accompanied by a significant decrease in the amount of sulfur dioxide (SO2) emitted by the volcano. This led to a beautiful and clear sky of the island of Hawaii, particularly visible on the west side, where the volcanic pollution known as vog has been collected chronically in recent years.
At the peak of the LERZ (Low Rift Zone) eruption in 2018, when volcanic emissions and pollution were much higher, a team of university researchers worked with the Hawcanian Observatory. Volcano of the US Geological Survey and the State Department of Health of Hawaii to study the intense volcanic air pollution generated by the eruption.
The researchers, British scientists from the Universities of Leeds, Cambridge and Oxford, took samples of volcanic particles and gases at the level of the LERZ 8 crack, the ocean inlet and various sites located downwind (Leilani Estates, Orchidland Estates, Volcano, Phala, Ocean View and Captain Cook). To determine the nature and composition of the volcanic pollution, samples were collected by pumping air through filters, soil and air, using drones.
The tiny particles captured on the filters were then analyzed in the laboratory for chemical composition and analyzed using a powerful scanning electron microscope (SEM) to determine the composition of the individual particles. Other instruments have determined the number or weight of particles of different sizes, associated with different health impacts during studies on human-caused pollution. Samples were analyzed for pH (acidity); major components, including sulphate, fluoride and chloride; and trace metals, such as lead and arsenic.
These analyzes targeted chemical species known to be present in volcanic plumes. The Kīlauea plume consists mainly of water vapor, carbon dioxide, sulfur dioxide (SO2) and entrained air, as well as smaller amounts of other gases, including hydrogen chloride and hydrogen fluoride. SO2 reacts in the atmosphere over time to form tiny acidic and neutral sulphate particles, which are a major component of volcanic pollution in Hawaii. Small amounts of toxic metals have also been found in volcanic plumes emitted by Kīlauea air vents.
The gas and particle sampling campaign of the summer of 2018 was the first effort to examine how trace elements, such as metals, change over time in the Kīlauea plume. It was found that the quantity of these elements was very variable but was not only predicted by the distance between the plume and the vent. Most of the particles (99%) were less than 2.5 microns in diameter, small enough to penetrate deep into the lungs.
The results of the study also corroborate the previous observations concerning the chemical conversion of SO2 gas into particles. Areas far away from the gas source, such as along the Kona coast on Hawaii Island, had high particle concentrations, as much of the SO2 had converted to particles as it moved to wearing. Ambient air quality standards for SO2 gas and particulates were exceeded at various locations on the island during the three months of the LERZ eruption.
Unlike last summer, the current lull in Külauea offers an excellent opportunity to study the quality of the ambient air. This can help us distinguish between anthropogenic pollution, such as the escape of traffic, and volcanic pollution. Although controlling emissions from a volcano is not a practical proposition, understanding the contribution of man-made pollution, which can be controlled, is important on an island whose population is increasing.
To address the characterization of anthropogenic pollution, the same research team plans to return this summer to sample the background air without the volcanic contribution, using the same equipment and the same sampling sites. Snapshots "before" and "after" will help isolate the chemical fingerprint of volcanic particles. This will improve our understanding of the potential effects of volcanic plumes on health, the environment and ecosystems.
The eruptive events of 2018 have reshaped the land and life of many inhabitants of the lower Puna district on Hawaii Island. The end of the eruption allows us all, across the island, to breathe better, both literally and figuratively, and to better understand the chemistry and impacts of Kīlauea's volcanic plume.
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