Acute exacerbations of asthma associated with “vog” exposure at Kilauea Volcano, Hawai`i

Emissions of sulfur dioxide gas (SO₂) and sulfuric acid aerosol called “vog” have been venting for over 25 years on Kilauea Volcano's east rift. Alarmingly, in 2008 a new eruption vent opened at the summit increasing SO₂ emissions up to 3,000 – 5,000 metric tonnes per day (tpd), in contrast to previous average emissions of 1,700 tpd. This retrospective cohort study estimated the incidence rate and relative risk of diagnosed exacerbations of asthma in exposed and unexposed communities on the island over a 5-year period. Case records of clinic and emergency room visits by local residents were reviewed for evidence of clinical presentation and diagnostic accuracy. Relative risk (RR) estimates for exacerbations of asthma were standardized for age and gender, revealing an 87% elevated risk [RR = 1.87 (95% CI = 1.50-2.33)] in exposed communities prior to the summit eruption (2004-2007), and a doubling of risk [RR = 2.90 (95% CI = 2.13-3.96)] with the relatively higher volcanic emissions (2008-2009). Moreover, disease burden on the exposed communities increased 3-fold (+71 visits per 1,000 residents/per year) with the increased volcanic activity. This ongoing study is the first to demonstrate that communities continuously exposed to vog have a higher risk and disease burden of acute exacerbations of asthma. Therefore, a community-level assessment of asthma management practices and continued investigations are recommended.