An older vog plume has less sulfur dioxide and more particulate matter, resulting in reduced impacts to property, such as corroding ranch fences, Massachusetts Institute of Technology students said Thursday.
As sulfur dioxide has time to spread and move across land, it reacts with water vapor and other elements to create sulfate, a less corrosive substance, said MIT student Jessica Parker.
According to data from the students’ study conducted over the past week, the amount of sulfate, a particulate, composed about two percent of a vog plume near Kilauea crater and increased to about 20 percent near Pahala.
That means less of an impact on plants and property, such as ranch fences, she said.
“It doesn’t corrode as quickly as battery acid,” she said of the difference between sulfur dioxide and sulfate, which she compared to the acidity of drip coffee.
“When ammonia neutralizes it, (the sulfur dioxide) becomes less acidic and acid is what contributes to corrosion of fences.”
Even though it may be neutralized, the amount of particulate in the air is still a health concern, she said.
Vog, volcanic smog, is associated with coughing, asthma, and respiratory illness, among other issues.
“They are still particulates in the air, which don’t make lungs very happy, Parker said. “It’s a trade-off.”
Several dozen people attended the presentation by more than a dozen MIT undergraduate students held at the Kaloko-Honokohau National Historical Park in North Kona.
The event was part of the ReefTalk series hosted by the University of Hawaii’s Sea Grant program.
The students from MIT’s Department of Civil and Environmental Engineering discussed their recent measurements of the chemical composition of volcanic smog during the two-hour presentation, “Chasing the Plume: Air and Ground-based Vog Characterization.” The information will be made available in a peer-reviewed journal.
The students spent about a week on the Big Island as part of an annual MIT class, “Traveling Research Environmental Experiences,” which is aimed at providing undergraduates with hands-on experience in environmental fieldwork.
The class has visited Hawaii Island twice and has focused on measuring two of the most noxious components of vog: sulfur dioxide and particulate matter.
To do this, both ground-based instruments and sensors onboard an unmanned aerial vehicle were used to capture the data.
During the week, the group set out to answer a multitude of questions including what comprises vog, how a vog plume evolves over time and distance and how the intensity of vog varies by location.
For more information about the project and to read blogs posted by the students, visit cee.mit.edu/blogs/trex-2013.