AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Online, Mobile Measurements of the Chemical Composition of Volcanic Smog ("vog")
Eben Cross, ZARA L'HEUREUX, Lisa Wallace, Anna Kelly, Kelly Daumit, Philip Croteau, John Jayne, Douglas Worsnop, Jesse Kroll, MIT
Abstract Number: 651 Working Group: Aerosol Chemistry
Abstract Volcanic smog (“vog”) is a major air quality issue in volcanically active areas of the world. Vog is primarily composed of water vapor, sulfur dioxide gas (SO2) and particulate sulfate (SO4). The atmospheric chemistry of vog is characterized in large part by oxidation of SO2 to SO4. Once formed in the atmosphere, the acidic sulfate aerosol is neutralized by ammonia (NH3) resulting in partial-to-fully oxidized sulfate species ranging from sulfuric acid to ammonium sulfate. The phase of the sulfur (gas phase vs. particle phase) and the acidity of the particulate sulfate has a direct influence on the human health and ecosystem impacts of the vog.
Here we describe a recent study aimed at characterizing the evolving composition of vog from Kilauea, an active volcano on the island of Hawai‘i (the Big Island). Measurements were made in January 2012 by a team of fourteen undergraduates, as part of MIT’s Traveling Research Environmental Experiences (TREX) program. A mobile platform instrumented with a suite of real-time aerosol and gas phase monitors was used to intercept and sample vog at multiple locations downwind of the volcano. Instruments included a Teledyne SO2 monitor and an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) for the measurement of particle mass and composition. To our knowledge these measurements represent the first real-time measurement of the composition of volcanic aerosol. This presentation will provide a summary of the results obtained during the 2-week field project, with a focus on sulfate mass loadings, sulfur oxidation rates, and extent of neutralization within the vog. Inter-comparisons between results obtained from the mobile platform and co-located air quality monitoring sites will also be discussed.