Original ResearchCardiorespiratory health effects associated with sulphurous volcanic air pollution
Introduction
Eruption at Kilauea Volcano has persisted since 1983 on the Island of Hawaii, United States. The volcanic emissions are primarily composed of water vapour, sulphur dioxide (SO2) gas (averaging 1600 metric ton/day),1 and fine sulphates, principally sulphuric acid aerosol (mean diameter ⩽0.3 μm).2 Unlike explosive volcanic eruptions that send particulates and gases into the stratosphere, Kilauea's effusive eruption emits gases and aerosols into the lower troposphere where humans reside; thus, long-standing effusive eruptions may create an environment detrimental to health. The purpose of this investigation was to evaluate the health status of adults chronically exposed to Kilauea's air pollution.
Human health effects from sulphurous air pollutants can occur. SO2 is an irritant that affects changes in the mechanical functioning of the upper airways, resulting in bronchoconstriction or increased pulmonary resistance.3, 4 In healthy, non-asthmatic adults, dose–response relationships exist at various thresholds for different exposure durations and activity levels.3, 4, 5 Several population subgroups are sensitive to SO2 at lower concentrations: asthmatics; children and adolescents; respiratory- and cardiac-compromised individuals; and healthy but SO2-sensitive individuals.4, 5, 6, 7 Some paediatric asthmatics can show effects at even lower levels of SO2 than identified previously.8, 9 Public health concentrations for SO2 that consider these sensitive population subgroups are the World Health Organization's (WHO) guideline10 and the minimal risk level (MRL).11
Fine sulphates are ocular and respiratory irritants that can have a negative effect on both sensitive and general populations by inducing respiratory tract irritation and altering lung defences, including airway reactivity, alveolar particle clearance and mucociliary transport.4, 12 No threshold has been identified10 but current evidence suggests that secondary sulphates sized ⩽2.5 μm, at ambient levels from 4 to 7 μg/m3, have little adverse impact on public health.13
An estimated 500 million people live near the world's 600 active volcanoes.14 These volcanoes degass pollutants continuously during eruption and in states of quiescence between eruptions.15 Health may be affected adversely from continual emissions of SO2, carbon dioxide, radon and/or hydrogen sulphide.14, 16, 17, 18 At Kilauea, studies have focused on acute health effects associated with the eruption, identifying increased hospital visits for respiratory conditions19, 20, 21 and respiratory effects in known paediatric asthmatics.22 A recent study, however, found the highest prevalence of paediatric asthma in Hawaiian communities with the lowest exposure to volcanic pollution, suggesting other causal factors.23
Section snippets
Design
Kilauea's ongoing eruption provided a natural laboratory for investigating chronic, adverse health effects from sulphurous air pollution in a non-mixed air polluted environment. An environmental–epidemiological, cross-sectional design was used to measure the prevalence of cardiorespiratory signs, self-reported symptoms and diagnosed diseases in exposed groups and an unexposed reference group. Groups were identified based on exposure status without prior knowledge of disease status.
Summary of previous exposure assessment
To assess
Characteristics of the participants
Table 1 describes characteristics of the 335 participants. All groups had nearly equal distributions for gender, occupational dust exposure and medication usage, and no statistical difference in current smoking prevalence. The unexposed group was younger and had a higher mean BMI than the exposed groups. Distributions of birth place, residency and education were similar between the SO2-exposed and the unexposed group. The sulphate-exposed group was primarily White, more educated, had a lower
Discussion
This study revealed significant associations between exposure to long-standing volcanogenic sulphurous air pollution and cardiorespiratory health effects. The relevance of the study, its limitations, major findings and the implications for clinical practice are discussed below.
Acknowledgements
The authors wish to thank: international health specialist Dr. Chunhuei Chi; air physicist Dr. Raymond Chuan; IAVCEI volcanologists Dr. Anita Grunder and Dr. Anthony Longo; toxicologist Dr. Cathy Neumann; Big Island pulmonologist Dr. Benjamin Ono; Dr. Jennifer Orme-Zavaletta (EPA); Dr. Jackie Paulson, RN; the Hawaiian Volcano Observatory; and the Kau Hospital physicians.
Ethical approval
Institutional Review Board Approval of Oregon State University.
Funding
None declared.
Competing interests
None
References (47)
Toxicology of sulfur oxides
- et al.
Health hazards and disaster potential of ground gas emissions at Furnas volcano, Sao Miguel, Azores
J Volcanol Geotherm Res
(1999) - et al.
Emergency department visits and ‘vog’-related air quality in Hilo, Hawaii
Environ Res
(2004) - et al.
The impact of volcanic gases from Miyake Island on the chemical constituents in precipitation in the Tokyo metropolitan area
Sci Total Environ
(2005) Respiratory reflexes
- et al.
Effects of volcanic air pollution on health
Lancet
(2001) Effects of cigarette smoke and air pollutants on the lower respiratory tract
- et al.
Twenty years of continuous gas release at Kilauea: effusive lessons in a volatile time
EOS
(2002) - Chuan R. Characteristics of ‘VOG’ from Kilauea volcano, Hawaii. In: Andres JR, editor. Volcano–atmosphere interactions....
- World Health Organization. Sulfur oxides and suspended particulate matter. Environmental health criteria 8. Geneva:...
Health effects of ambient air pollution: how safe is the air we breathe?
Air pollution and health in urban areas
Rev Environ Health
Evaluating the health risk from secondary sulfates in Eastern North American regional ambient air particular matter
Inhal Toxicol
Hazards of volcanic gases
Preliminary studies of acid and gas contamination at Poas Volcano, Costa Rica. Environmental geochemistry and health with special reference to developing countries
Geol Soc Spec Publication
Volcanic emissions and health
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