Passive exposure to e-cigarette emissions: irritation symptoms, severity and duration

Background: The current study, part of the EU H2020 funded TackSHS project, aimed to test the hypothesis that passive exposure to e-cigarette emissions provokes systemic symptoms and to determine their severity and timing. Methods: 30 nonsmokers, 18-35 years old, BMI< 30, with no significant medical history, no medications, normal physical examination and spirometry, were passively exposed in a 35m3 room, during a 30-minute Control (no passive smoking) and Experimental (standardized e-cigarette smoking by a human smoker) session. PM2.5 concentrations were 0.027 mg/m3and 3.3 mg/m3 during the Control and Experimental sessions, respectively. Participants completed an irritation questionnaire, grading symptom severity at T0(pre-exposure), T15 (midway), T30 (exposure endpoint) and T60 (30-minute post-exposure) in both sessions. The questionnaire showed internal consistency (Cronbach's α> 0.70). Scores 1-5 were generated for the environmental, ocular, nasal, airway and general complaints by adding symptoms per system. Analysis was performed using Wilcoxon-signed rank sum test and Spearman correlation (p< 0.05). Results: The most frequent and intense symptoms reported were mild eye burning, nasal and airway dryness. Ocular irritation score gradually increased from T0reaching a significant increase by T30 (p=0.034). Nasal score increased significantly from T0 to T15 (p=0.008) and remained significantly higher at T30. Airway irritation score increased significantly from T0 to T15 (p=0.004) and furthermore from T15 to T30 (p=0.018). All symptoms returned to T0 scores by T60 (p> 0.05). The increased scores for ocular, nasal and airway complaints were positively correlated with increased environmental scores at T15and T30. General complaint scores showed a tendency to increase at T30that was positively correlated with increased environmental scores at T30. Conclusions: Short-term exposure of nonsmokers to e-cigarette emissions resulted in mild ocular, nasal and airway symptoms that persisted up to 30 minutes and were positively correlated with environmental indices. Further research is needed to investigate long-term health implications.