Evaluation of Second-Hand Exposure to Electronic Cigarette Vaping under a Real Scenario: Measurements of Ultrafine Particle Number Concentration and Size Distribution and Comparison with Traditional Tobacco Smoke

The present study aims to evaluate the impact of e-cig second-hand aerosol on indoor air quality in terms of ultrafine particles (UFPs) and potential inhalation exposure levels of passive bystanders. E-cig second-hand aerosol characteristics in terms of UFPs number concentration and size distribution exhaled by two volunteers vaping 15 different e-liquids inside a 49 m3 room and comparison with tobacco smoke are discussed. High temporal resolution measurements were performed under natural ventilation conditions to simulate a realistic exposure scenario. Results showed a systematic increase in UFPs number concentration (part cm-3) related to a 20-min vaping session (from 6.56 X 103 to 4.01 X 104 part cm-3) although this was one up to two order of magnitude lower than that produced by one tobacco cigarette consumption (from 1.12 X 105 to 1.46 X 105 part cm-3). E-cig second-hand aerosol size distribution exhibits a bimodal behavior with modes at 10.8 and 29.4 nm in contrast with the unimodal typical size distribution of tobacco smoke with peak mode at 100 nm. In the size range 6-26 nm particles concentration in e-cig second-hand aerosol were from 2-(Dp = 25.5 nm) to 3800-fold (Dp = 9.31 nm) higher than in tobacco smoke highlighting that particles exhaled by users and potentially inhaled by bystanders are nano-sized with high penetration capacity into human airways.The present study aims to evaluate the impact of e-cig second-hand aerosol on indoor air quality in terms of ultrafine particles (UFPs) and potential inhalation exposure levels of passive bystanders. E-cig second-hand aerosol characteristics in terms of UFPs number concentration and size distribution exhaled by two volunteers vaping 15 different e-liquids inside a 49 m(3) room and comparison with tobacco smoke are discussed. High temporal resolution measurements were performed under natural ventilation conditions to simulate a realistic exposure scenario. Results showed a systematic increase in UFPs number concentration (part cm(-3)) related to a 20-min vaping session (from 6.56 x 10(3) to 4.01 x 10(4) part cm(-3)), although this was one up to two order of magnitude lower than that produced by one tobacco cigarette consumption (from 1.12 x 10(5) to 1.46 x 10(5) part cm(-3)). E-cig second-hand aerosol size distribution exhibits a bimodal behavior with modes at 10.8 and 29.4 nm in contrast with the unimodal typical size distribution of tobacco smoke with peak mode at 100 nm. In the size range 6-26 nm, particles concentration in e-cig second-hand aerosol were from 2- (Dp = 25.5 nm) to 3800-fold (Dp = 9.31 nm) higher than in tobacco smoke highlighting that particles exhaled by users and potentially inhaled by bystanders are nano-sized with high penetration capacity into human airways

Monitoring of alcohol-based hand rubs in SARS-CoV-2 prevention by HS-GC/MS and electrochemical biosensor: A survey of commercial samples

Alcohol-based hand rubs (ABHRs) have found large diffusion during the Severe Acute Respiratory Syndrome Coronavirus 2, SARS-CoV-2, thus becoming the most widespread means for hand hygiene. Whereby, it is fundamental to assess the alignment of commercial ABHRs to the indications provided by the principal health agencies regarding alcohol content and possible impurities. In this work, a novel improvement of previous existent methods for the determination of alcohol content in such products was reported. In particular, two alternative sensitive and reproducible methods, such as an electrochemical screen-printed based enzymatic (alcohol oxidase) biosensor and a Headspace Gas Chromatography coupled with Mass Spectrometry (HS-GC/MS) were proposed. The electrochemical device represents a rapid, low-cost and accurate fraud screening method for alcohol-based hand rubs. The second technique confirms, identifies and simultaneously determines ethyl alcohol, isopropyl alcohol, n-propyl alcohol and methyl alcohol, improving their extraction through acidification in the sample pre-treatment step. The developed specific HS-GC/MS method was in-house validated according to ISO/IEC 17025 requirements. Analytical parameters such as limit of detection (LoD 0.13%v/v - 0.17%v/v), limit of quantification (LoQ 0.44% v/v - 0.57% v/v), inter-day repeatability (RSDR 2.1–10.7%) and recovery (80–110%) were assessed. The relative expanded uncertainties range (between 0.1%v/v and 3.4%v/v) for all the analytes were evaluated. Results obtained using the different analytical approaches were compared and indicated that the two data sets were comparable (median; HS-GC/MS, 56%v/v; electrochemical biosensor, 62%v/v) and were not statistically different (one-way ANOVA test; p = 0.062). In addition, a good correlation (95%) was found. This study noticed that only 39% of the tested hand sanitiser products had the recommended average alcohol content, thus highlighting the need for analytical controls on this type of products