Spatial and Temporal Variations in SO2 and PM2.5 Levels Around Kīlauea Volcano, Hawai'i During 2007–2018

Abstract

Among the hazards posed by volcanoes are the emissions of gases and particles that can affect air quality and damage agriculture and infrastructure. A recent intense episode of volcanic degassing associated with severe impacts on air quality accompanied the 2018 lower East Rift Zone (LERZ) eruption of Kīlauea volcano, Hawai'i. This resulted in a major increase in gas emission rates with respect to usual emission values for this volcano, along with a shift in the source of the dominant plume to a populated area on the lower flank of the volcano. This led to reduced air quality in downwind communities. We analyse open-access data from the permanent air quality monitoring networks operated by the Hawai'i Department of Health (HDOH) and National Park Service (NPS), and report on measurements of atmospheric sulfur dioxide (SO 2) between 2007 and 2018 and PM 2.5 (aerosol particulate matter with diameter <2.5 µm) between 2010 and 2018. Additional air quality data were collected through a community-operated network of low-cost PM 2.5 sensors during the 2018 LERZ eruption. From 2007 to 2018 the two most significant escalations in Kīlauea's volcanic emissions were: the summit eruption that began in 2008 (Kīlauea emissions averaged 5-6 kt/day SO 2 from 2008 until summit activity decreased in May 2018) and the LERZ eruption in 2018 when SO 2 emission rates reached a monthly average of 200 kt/day during June. In this paper we focus on characterizing the airborne pollutants arising from the 2018 LERZ eruption and the spatial distribution and severity of volcanic air pollution events across the Island of Hawai'i. The LERZ eruption caused the most frequent and severe exceedances of the Environmental Protection Agency (EPA) PM 2.5 air quality threshold (35 µg/m 3 as a daily average) in Hawai'i in the period 2010-2018. In Kona, for example, the maximum 24-h-mean mass concentration of PM 2.5 was recorded as 59 µg/m 3 on the twenty-ninth of May 2018, which was one of eight recorded exceedances of the EPA air quality threshold during the 2018 LERZ eruption, where there had been no exceedances in the previous 8 years as measured by the Whitty et al. Kīlauea-PM 2.5 and SO 2 Concentrations HDOH and NPS networks. SO 2 air pollution during the LERZ eruption was most severe in communities in the south and west of the island, as measured by selected HDOH and NPS stations in this study, with a maximum 24-h-mean mass concentration of 728 µg/m 3 recorded in Ocean View (100 km west of the LERZ emission source) in May 2018. Data from the low-cost sensor network correlated well with data from the HDOH PM 2.5 instruments, confirming that these low-cost sensors provide a robust means to augment reference-grade instrument networks.

Reconstructing Magma Storage Depths for the 2018 Kı̄lauean Eruption From Melt Inclusion CO2 Contents: The Importance of Vapor Bubbles

“…The 2018 lower East Rift Zone (LERZ) eruption was the largest and most destructive in the last 200 years of activity at Kı̄lauea Volcano, Hawai’i (Neal et al., 2019), accompanied by the highest co‐eruptive fluxes of SO 2 ever measured at Kı̄lauea (up to 200 kt a day; Kern et al., 2020; Whitty et al., 2020), and very high lava effusion rates (100–300 m 3 /s; Neal et al., 2019; Patrick, Dietterich et al., 2019). Before the onset of this new eruptive episode in May 2018, Kı̄lauea had been erupting near‐continuously for 35 years on the middle East Rift Zone (ERZ) at Puʻu ʻŌʻō cone and surrounding vents, located approximately ∼20 km east of Kı̄lauea’s summit (1983–2018), and ∼24‐km uprift of the 2018 eruption site (Figure 1b).…”

Chalcophile elements track the fate of sulfur at Kīlauea Volcano, Hawai’i

“…For example, during the last 35 years, the near-continuous effusion of lava at Kīlauea Volcano, Hawaii has released globally significant amounts of S to the lower troposphere, culminating in fluxes of >50,000 t/day SO 2 during the lower East Rift Zone eruption in 2018 (Neal et al, 2019). These emissions have serious implications for regional air quality, respiratory health and agricultural productivity across the island (Longo et al, 2010;Nelson and Sewake, 2008;Tam et al, 2016;Whitty et al, 2020).…”

The 2019 Raikoke volcanic eruption: Part 1 Dispersion model simulations and satellite retrievals of volcanic sulfur dioxide

“…Observations are vital in determining the skill of the dispersion models. While in situ observations are available for several well-studied volcanoes (e.g., Pfeffer et al, 2018;Sahyoun et al, 2019;Whitty et al, 2020), they are only available for a limited number of locations. In recent decades, many high-resolution remote-sensing measurements have become available, providing a great data source on activity at even the most remote volcanoes across the globe.…”