Attack of the Vog: Natural Air Pollution Has Residents of Hawaii All Choked Up
Monastersky, Richard, Science News
Jeff Sutton wrinkles his nose at the acrid fumes drifting across his desk. It's 9:45 a.m., a time when the office air typically transports the scent of bad coffee or perhaps the faint aroma of jelly donuts. But today the hallways reek unmistakably of sulfur.
As a geochemist with the U.S. Geological Survey, Sutton has the equipment to analyze the odor. He and colleague Tamar Elias pull out a sulfur dioxide detector tube and take a quick reading of 600 parts per billion. Moving outside to the parking lot, they measure 1,000 parts per billion, a value almost as high as the sulfur dioxide concentrations associated with the deadly London fog in December 1952, which claimed 4,000 lives.
You might expect air pollution this bad in Manhattan or Mexico City. But the USGS researchers work in a sparsely populated national park on the island of Hawaii, far from anything even remotely resembling a smokestack. Their tropical neighborhood has no coal-burning power plants, no paper mills, no steel smelters, no traffic-laden superhighways. Just a small tourist town and an industrious volcano named Kilauea.
Unlike better-known volcanoes, which explode for a few days and then take an extended vacation, Kilauea has worked almost nonstop since 1986, producing a slow but steady supply of lava. As a by- product, the natural factory also emits about 1,000 tons of sulfur dioxide gas each day, making it one of the biggest sources of air pollution on the island. The sulfur compounds have proved so persistent in some spots that residents even invented a name for the problem -- vog, for volcanic smog.
Nine years ago, during the early stages of the eruption, residents viewed vog as a nuisance that would disappear when Kilauea shut down. But the ongoing eruption has outlasted everyone's expectations. And in increasing numbers, Hawaiians are indicting Kilauea's chemical cloud as a real threat.
"We're realizing that the gases emitted by the volcano when it is in continuous eruption can cause health problems, can harm agriculture, and can have economic effects. It's a real concern," claims David A. Clague, scientist-in-charge at the USGS Hawaiian Volcano Observatory at Kilauea.
But others say vog has become a scapegoat -- an easy excuse for people's myriad physical complaints. "The latest studies show that there haven't been any significant health effects from vog," argues Katherine Hendricks of Hawaii's Department of Health in Honolulu.
The vog question mirrors in many ways the debate over other potential health hazards, such as exposure to second-hand tobacco smoke or pesticides in food. But the Hawaiian issue breaks all molds because the pollution in this case comes from nature itself, which pays no attention to regulatory laws or federal air quality standards.
To trace the origins of vog, Sutton and Elias strap on gas masks and strike northeast across the floor of Kilauea's summit crater. Hiking across the black lava flows, they reach a mound bedecked with yellow crystals glistening in the sunlight. The crystals contain sulfur compounds that precipitated out of gas plumes exhaled by the volcano. Elias inserts a tube into one productive fumarole and collects a sample of the noxious fumes for later analysis.
The principal gas escaping from Kilauea is carbon dioxide, which dissipates in the air. Sulfur dioxide, the next most abundant gas, doesn't behave as nicely. On relatively calm days, when no wind clears the air, sulfur dioxide can accumulate in the vicinity, giving a full dose to employees of the national park and the USGS volcano observatory, which sits on the rim of Kilauea. Exposure to such high doses can cause breathing difficulties, although concentrations typically do not remain so high for long. For instance, the lethal London fog persisted for days, whereas the extreme pollution at Kilauea usually lasts only for minutes or hours.
Sulfur dioxide afflicts only the immediate volcanic neighborhood because the gas oxidizes before it can drift far from Kilauea. …