An eruption of Mauna Loa may contribute to local air quality issues, depending on the size and location of the eruption.
However, negative health symptoms generally occur at gas concentrations well above current levels. Currently, the smell of volcanic gas (sulfur dioxide and hydrogen sulfide) can be detected near Kīlauea's gas-emitting vents, particularly when the trade winds are absent. Volcanic activity in Hawaii creates the potential for airborne health hazards to residents and visitors. What health effects are associated with vog? Vog Fact Sheets Hawai‘i Interagency Vog Dashboard.ģ.Current Air Quality Conditions Hawai‘i Interagency Vog Dashboard.Online tool to forecast vog from The Vog Measurement and Prediction Project.The near-vent volcanic plume has had little time to disperse and dilute before reaching downwind communities tens of km or miles. Eruptions of other Hawaiian volcanoes will create vog impact dependent on the altitude and location of the eruptive vent.Ĭommunities in the path of SO 2 emissions, particularly those nearest the source vent, can be subjected to a very acrid haze that contains both SO 2 gas and acidic particles. When trade winds are absent, most often during winter months, East Hawai‘i Island, the entire Island of Hawai‘i, or the even the entire State of Hawaii can be affected by vog. This layer of the atmosphere increases in temperature with altitude, inhibiting the rise of cooler, vog-laden air. Most vog generated by Kīlauea stays below 6,000–8,000 feet above sea level, the usual height of the trade wind inversion. Under trade wind conditions, vog travels around the southern part of the island, and along the Kona coast, where it becomes trapped by daytime onshore and nighttime offshore sea breezes. When Kīlauea is erupting (as was the case from 1983–2018), areas to the southwest of the volcano are most frequently affected by vog. From May through September, the trade winds blow 80–95 percent of the time. The main wind direction in the Hawaiian Islands is from the northeast (trade winds). Vog concentrations are primarily dependent on the amount of SO 2 emitted from a volcano, the distance downwind, and the wind direction and speed on a given day. The flank of Hualālai is visible at right. The summit of Mauna Loa (left) rises above the vog layer on the leeward side of the Island of Hawai‘i in November 2012. What controls vog on the Island of Hawai‘i? Vog: A Volcanic Hazard USGS Hawaiian Volcano Observatory "Volcano Watch" article originally written in May 1996, and still relevant today.Ģ.Volcanic air pollution hazards in Hawaii.What is vog? Hawai‘i Interagency Vog Information Dashboard.Closer to the volcano, vog contains both aerosols and unreacted SO 2 gas.
In areas far (tens to hundreds of km or miles) from active vents, aerosols are the main component of vog. The exact composition of vog depends on how much time the volcanic plume has had to react in the atmosphere. Aerosols are created when SO 2 and other volcanic gases combine in the atmosphere and interact chemically with oxygen, moisture, dust, and sunlight over minutes to days. Vog is a hazy mixture of SO 2 gas and aerosols (tiny particles or droplets) which are primarily sulfuric acid and other sulfate (SO 4) compounds. What is "vog"? How is it related to SO 2 emissions? Photos taken in 2010. (Public domain.) 1. HVO observation tower and building can be seen near the center in each photo.
Side-by-side comparison of the northwest wall of Kīlauea Caldera on a clear day (left) and a day with thick vog (right).
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