Abstract
Introduction: Residents of Macassar, South Africa, were exposed to sulphur dioxide vapours (SO2) caused by an ignited sulphur stockpile, which produced peak hourly SO2 levels of 20–200 ppm. The aim of this study was to assess the risk factors associated with persistent lower respiratory symptoms (LRS) or asthma six years after acute exposure to high SO2 levels. Methods: A case-control study of residents that presented for a health evaluation six years after the incident was conducted. Survey instruments included a questionnaire, clinical examination and medical record review by an expert panel. A “case” was defined as a resident with persistent LRS/asthma. The Industrial Source Complex Short Term Model (ISCST 3) was used to predict time-averaged hourly SO2 levels. Results: A previous history of pulmonary tuberculosis (PTB) was associated with persistent LRS/asthma (ORudj: 3.49, CI: 1.46–8.35). Cases were more likely to report chest tightness (ORudj: 9.93; CI: 5.15–19.11) at the time of the incident. Peak exposure at hour 15 was associated with persistent LRS/asthma (ORadj: 1.04; CI: 1.01–1.07). Conclusion: LRS/asthma persisted in some individuals six years after acute SO2 exposure. Aside from peak exposures, initial chest tightness and a previous history of PTB were the strong predictors of persistent LRS/asthma.
Highlights
Residents of Macassar, South Africa, were exposed to sulphur dioxide vapours (SO2 ) caused by an ignited sulphur stockpile, which produced peak hourly SO2 levels of20–200 ppm
This was followed by a review of the collected information together with other medical records provided by their doctor by a medical reference panel (MRP) comprising occupational medicine specialists
Discussion of medical dossier by the MRP: A panel of at least 3 experienced occupational medicine specialists reviewed the information obtained from the questionnaire, medical records provided by the individual’s personal doctor and the clinical examination to assess the presence of persistent lower respiratory symptoms (LRS), their relationship to the incident and the need for further investigations
Summary
Residents of Macassar, South Africa, were exposed to sulphur dioxide vapours (SO2 ) caused by an ignited sulphur stockpile, which produced peak hourly SO2 levels of20–200 ppm. The aim of this study was to assess the risk factors associated with persistent lower respiratory symptoms (LRS) or asthma six years after acute exposure to high SO2 levels. A limited number of studies have documented long term respiratory morbidity among individuals that have been acutely exposed to high levels of SO2 following an incident. The most commonly reported adverse respiratory health effects include bronchial hyper-responsiveness (BHR), acute irritant induced asthma (IIA) (commonly referred to as reactive airways dysfunction syndrome—RADS) and chronic obstructive pulmonary disease (COPD) [9,10,11]. Public Health 2019, 16, 438; doi:10.3390/ijerph16030438 www.mdpi.com/journal/ijerph
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