Page 102 - Volcano and Geothermal Tourism

Geotourism and Public Safety in Volcanic Environments 79

unconsciousness in 1–10 min and may result in low concentrations, H S can irritate eyes and act as
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seizures followed by death (Manning et al, 1981; a depressant. At higher concentrations, H S can
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Ikeda et al, 1989; Stupfel and Le Guern, 1989; cause upper respiratory irritation and pulmonary
Hansell and Oppenheimer, 2004; Cantrell and edema (USGS, 2009a). Hydrogen sulphide is
Young, 2009). Exposure to CO in volcanic areas known to have resulted in tourist fatalities in
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is generally the result of exposure to CO clouds various parts of Japan and at the geothermal field
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or CO accumulations in low-lying topographic in Rotorua, New Zealand. Moreover, it is calculated
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areas where the denser CO concentrations that exposure to 500ppm of H S for 30 minutes
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accumulate below the air (Beaubien et al, 2003; can result in headache, dizziness, an unsteady gait
Hansell and Oppenheimer, 2004). Such exposure and diarrhoea (USGS, 2009a). It can also be
often occurs near preferential pathways such as followed by the development of bronchitis and
faults and fractures along which concentrations bronchopneumonia (USGS, 2009a). Acute
of CO are able to migrate towards the surface exposures to >700ppm of H S can result in
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(Hansell and Oppenheimer, 2004). Hence, the unconsciousness within a matter of minutes and
threat from CO is most acute in locations such eventual death from H S poisoning (Beaubien
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as health spas/thermal springs, near surface areas, et al, 2003; Costigan, 2003; Hansell and
poorly vented vacation homes or hotels in high Oppenheimer, 2004).
seepage areas, or poorly ventilated vacation
homes or hotels with ground-floor bedrooms, Sulphur dioxide
basement suites and wooden or cracked floors Following water and carbon dioxide, SO is one of
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that permit high seepage (Baxter et al, 1999; the more common gases in volcanic emissions and
Dibben and Chester, 1999). Small children may is a hazard to humans as a gas or a sulphate aerosol
be particularly vulnerable because of their limited (International Volcanic Health Hazard Network,
height and near surface patterns of play (Dibben 2009). SO is irritating to the eyes, throat and
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and Chester, 1999). Likewise, those sleeping or respiratory tract and induces coughing, burning of
lying near the floor may be vulnerable (Dibben the eyes and difficulty breathing (International
and Chester, 1999). CO related deaths in volcanic Volcanic Health Hazard Network, 2009). While
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environments have been well documented. these reactions are considered relatively short-
However, literature documenting CO concerns term effects, tourists with pre-existing asthmatic
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directly effecting tourists have only been conditions can be sensitive to SO at low
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identified for tourists visiting Vulcano, a popular concentrations and suffer more severe consequences
volcanic island off Sicily, tourists owning vacation (Baxter et al, 1999; Hansell and Oppenheimer,
homes in the Azores, tourists visiting Hawai‘i 2004). In fact, SO is known to have played a
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Volcanoes National Park and tourists visiting significant role in the death of several tourists at
Mammoth Mountain, a dormant volcano and Aso, Japan, and in Hawai‘i Volcanoes National
popular recreation destination in the United Park. In these situations, half of the fatalities
States (Baxter et al, 1990; Sorey et al, 1998; involved asthmatic tourists (Heggie, 2005;
Baxter et al, 1999; Dibben and Chester, 1999; International Volcanic Health Hazard Network,
Heggie and Heggie, 2004; Heggie, 2005; Cantrell 2009). The World Health Organization (WHO)
and Young, 2009). air quality guidelines have set a maximum exposure
limit for SO at 175 ppb for ten minutes and
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Hydrogen sulphide 44ppb over a single day (World Health
In addition to CO , hydrogen sulphide (H S) is Organization, 2000). In contrast, the USGS
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historically associated with volcanic emissions and Volcanic Hazards Program notes that a
degassing events. Hydrogen sulphide is a colourless concentration of 6–12ppm of SO can result in
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gas with a sewer or rotten egg smell that is the immediate irritation of the nose and throat,
primarily found in destinations with high 20ppm can cause immediate eye irritation and
geothermal activity (Hansell and Oppenheimer, 10,000ppm will irritate moist skin within minutes
2004; USGS Volcano Hazards Program, 2009a). At (USGS, 2009a).

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