Exposure to low levels of hydrogen sulphide and its impact on chronic obstructive pulmonary disease and lung function in the geothermal area of Mt. Amiata in Italy: The cross-sectional InVETTA study

by Giorgia Stoppa, Daniela Nuvolone, Davide Petri, Letizia Centi, Francesca Nisticò, Emanuele Crocetti, Fabio Barbone, Fabio Voller

The geothermal power plants for electricity production currently active in Italy are all located in Mt. Amiata area in the Tuscany region. A cross-sectional survey was conducted in the framework of the regional project “InVETTA—Biomonitoring Survey and Epidemiological Evaluations for the Protection of Health in the Amiata Territories”, using objective measures of lung function to investigate the role of hydrogen sulphide (H₂S) in affecting the respiratory health of the population living in this area.

2018 adults aged 18–70 were enrolled during 2017–2019. Home and workplace addresses of participants were geocoded. Dispersion modelling was used to evaluate the spatial variability of exposure to H₂S from the geothermal power plants’ emissions. We estimated average long-term historical exposure to H₂S and more recent exposure indicators. Chronic Obstructive Pulmonary Disease (COPD) was defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Multivariable logistic regressions were performed to investigate associations between outcome and exposure.

Our findings did not showed any evidence of an association between increasing H₂S exposure and lung function impairments. Some risk reductions were observed: a -32.8% (p = 0.003) for FEV1<80% and a -51.7% (p = 0.001) risk decrease for FVC<80% were associated with interquartile increase (13.8 μg/m³) of H₂S levels.

Our study provides no evidence that chronic exposure to low levels of H₂S is associated with decrements in pulmonary function, suggesting that ambient H₂S exposure may benefit lung function.