Volatile Organic Compounds in Patients’ Breath during Conversation

Abstract

Purpose: The protracted coronavirus disease (COVID-19) pandemic has caused an unprecedented global health, social, economic, and psychological crisis. COVID-19 is transmitted via droplets, which include volatile organic compounds (VOCs) emitted by COVID-19 carriers. As a result, medical healthcare workers interacting with COVID-19 patients are at a high risk of infection. In this study, we measured the concentration of total VOCs (TVOCs) in the droplets of patients during conversations. Methods: Thirty patients aged 20–88 years were enrolled in this study. The amounts of VOCs, formaldehyde (HCHO), and carbon dioxide (CO2) as surrogate parameters for the patient’s droplets were measured at a distance of 1 m from the patients under the following conditions: 1) no conversation with a mask on, 2) conversation with a mask on, 3) conversation without a mask on, and 4) no conversation without a mask on. Results: The average concentrations of TVOCs (mg/m3), HCHO (mg/m3), and CO2 (ppm) were all the lowest before the masked conversation (1.79 ± 1.72, 0.25 ± 0.25, 1193 ± 516), increased during the masked conversation (1.99 ± 1.87, 0.29 ± 0.24, 1288 ± 555), were the highest during the unmasked conversation (3.10 ± 1.86, 0.45 ± 0.28, 1705 ± 729), and decreased to baseline after the unmasked conversation (1.89 ± 1.88, 0.26 ± 0.27, 1191 ± 518, respectively). Variations in TVOC and HCHO concentrations were positively correlated with patient age (TVOC: r = 0.42, p = 0.019 and HCHO: r = 0.47, p = 0.008). Conclusion: Wearing a mask reduced the VOC concentrations measured during conversations more than when a mask was not worn. Therefore, wearing a mask can reduce the emission of airborne droplet-derived VOCs and thereby reduce the risk of transmission of unknown patient-derived infections. Clinical Trial Registration no: The Clinical Trial Registration no: (UMIN000039595)