Electronic cigarette-generated aldehydes: The contribution of e-liquid
components to their formation and the use of urinary aldehyde metabolites
as biomarkers of exposure
Daniel J. Conklina,b , Mumiye A. Ogunwalec,d , Yizheng Chend, Whitney S. Theisa,b, Michael H. Nantza,c,
Xiao-An Fua,d, Lung-Chi Chena,e, Daniel W. Riggsa,b, Pawel Lorkiewicza,b, Aruni Bhatnagara,b, and
Sanjay Srivastavaa,b
aAmerican Heart Association – Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY, USA; bDiabetes and Obesity Center, University of Louisville, Louisville, KY, USA; cDepartment of Chemistry, University of Louisville, Louisville, KY, USA; dDepartment of Chemical Engineering, University of Louisville, Louisville, KY, USA; eDepartment of Environmental Medicine, New York University, Tuxedo, NY, USA
ABSTRACT
Electronic cigarettes (e-cigarette) have emerged as a popular electronic nicotine delivery system (ENDS) in the last decade. Despite the absence of combustion products and toxins such as carbon monoxide (CO) and tobacco-specific nitrosamines (TSNA), carbonyls including short-chain, toxic aldehydes have been detected in e-cigarette-derived aerosols up to levels found in tobacco smoke. Given the health concerns regarding exposures to toxic aldehydes, understanding both aldehyde generation in e-cigarette and e-cigarette exposure is critical. Thus, we measured aldehydes generated in aerosols derived from propylene glycol
(PG): vegetable glycerin (VG) mixtures and from commercial e-liquids with flavorants using a state-of-the-art carbonyl trap and mass spectrometry. To track e-cigarette exposure in mice, we measured urinary metabolites of 4 aldehydes using ULPC-MS/MS or GC-MS. Aldehyde levels, regardless of abundance (saturated: formaldehyde, acetaldehyde unsaturated: acrolein, crotonaldehyde), were dependent on the PG:VG ratio and the presence of flavorants. The metabolites of 3 aldehydes – formate, acetate, and 3-hydroxypropyl mercapturic acid (3-HPMA; acrolein metabolite) – were increased in urine after e-cigarette aerosol and mainstream cigarette smoke (MCS) exposures, but the crotonaldehyde metabolite (3-hydroxy-1-methylpropylmercapturic acid, HPMMA) was increased only after MCS exposure. Interestingly, exposure to menthol-flavored e-cigarette aerosol increased the levels of urinary 3-HPMA and sum of nicotine exposure (nicotine, cotinine, trans-3 0-hydroxycotinine) relative to exposure to a Classic Tobacco-flavored e-cigarette aerosol. Comparing these findings with aerosols of other ENDS and by measuring aldehyde-derived metabolites in human urine following exposure to e-cigarette aerosols will further our understanding of the relationship between ENDS use, aldehyde exposure, and health risk.
Aerosol size distribution measurement of electronic cigarette emissions
using combined differential mobility and inertial impaction methods:
Smoking machine and puff topography influence
Vladimir B. Mikheeva, Alexander Ivanova, Eric A. Lucasa, Patrick L. Southa, Hendrik O. Colijnb, and
Pamela I. Clarkc
aBattelle Memorial Institute, Columbus, Ohio, USA; bCenter for Electron Microscopy and Analysis, Ohio State University, Columbus, Ohio, USA; cUniversity of Maryland, College Park, Maryland, USA
ABSTRACT
A combination of a real-time high resolution aerosol differential mobility spectrometer (DMS500) and an electrical low pressure impactor (used as a traditional impactor) was applied to simultaneously collect real-time data and analyze particle size by weighing the mass of the aerosol collected on the impactor stages. Nonrefillable fixed-power as well as refillable and power adjustable e-cigarettes (e-cigs) were tested at various puffing flow rates. Two types of smoking machines were used: a smoke cycle simulator that provides instantaneous straight sample delivery to the analyzer and a Human Profile Pump that utilizes two
synchronized pistons and operates by sample pull–push mode. Chemical analysis of the major components of e-liquid (propylene glycol, vegetable glycerol, water, and nicotine) was made using a proton nuclear magnetic resonance method. Limited amounts of samples collected on impactor stages were analyzed by liquid chromatography time-of-flight massspectrometry to find newly formed semi- or low-volatile organic compounds in e-cig aerosol and by transmission electron microscopy to check for the presence of nanoparticles in e-cig emissions. Differential mobility and inertial impaction methods showed comparable particle
size results. Method of aerosol generation (type of the smoking machine) as well as puffing topography affected the e-cig particle size. Newly formed semi- or low-volatile organic compounds as well as metal nanoparticles were found in e-cig aerosol.
Experimental and modeling assessment of a novel automotive cabin PM2.5
removal system
Joshua D. Vande Heya , Hannah Sonderfelda , Antoine P. R. Jeanjeana , Rikesh Panchala,b ,
Roland J. Leigha , Mark A. Allenc, Mark Dawsonc, and Paul S. Monksb
aDepartment of Physics and Astronomy, Earth Observation Science Group, University of Leicester, Leicester, UK; bDepartment of Chemistry, University of Leicester, Leicester, UK; cResearch and Advanced Engineering Division, Jaguar Land Rover, Coventry, UK
ABSTRACT
Poor air quality inside vehicles and its impact on human health is an issue requiring attention, with drivers and passengers facing levels of air pollution potentially greater than streetside outdoor air. This paper assesses the potential effectiveness of a car cabin filtration system to remove fine particulate matter PM2.5 and improve air quality for car passengers. The study was conducted as a practical evaluation coupled to a model implementation. First, the effectiveness of PM2.5 filter material was investigated in a chamber experiment under a range of environmental and loading conditions using a realistic automotive auxiliary scrubber.
Second, implementation of such a system was evaluated in a full air flow 3D computational fluid dynamical model configured for a realistic cabin and ventilation system, and related to the chamber results through a simple decay model. Additionally, performance of low-cost dust sensors was evaluated as potential cabin monitoring devices. The experiment and modeling support the feasibility of a robust system which could be integrated into automotive designs in a straightforward manner. Results suggest that an auxiliary scrubber in the rear of the cabin alone would provide suboptimal performance, but that by incorporating a PM2.5 filter into the main air handling system, cabin PM2.5 concentrations could be reduced from 100 mg m 3 to less than 25 mg m 3 in 100 s and to 5 mg m 3 in 250 s. A health impact assessment for hypothetical occupational driver populations using such technology long term showed considerable reductions in indicative PM2.5 attributable mortality.
Physical and chemical characterization of aerosol in fresh and aged
emissions from open combustion of biomass fuels
Chiranjivi Bhattarai, Vera Samburova, Deep Sengupta, Michealene Iaukea-Lum, Adam C. Watts,
Hans Moosmuller, and Andrey Y. Khlystov€
Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, USA
ABSTRACT
Biomass burning (BB) emissions and their atmospheric oxidation products can contribute significantly to direct aerosol radiative forcing of climate. Limited knowledge of BB organic aerosol chemical and optical properties leads to large uncertainties in climate models. In this article, we describe the experimental setup and the main findings of a laboratory BB study aimed at comprehensive optical, physical, and chemical characterization of fresh and aged BB emissions. An oxidation flow reactor
(OFR) was used to mimic atmospheric oxidation processes. The OFR was characterized in terms of OH production rate, particle transmission efficiency, and characteristic lifetimes of condensible compounds. Emission factors (EFs) of main air pollutants (particulate matter, organic carbon [OC], elemental carbon [EC], carbon monoxide [CO], and nitrogen oxides [NOx]) were determined for five globally and regionally important biomass fuels: Siberian (Russia), Florida (USA), and Malaysian peats; mixed conifer and aspen fuel from Fishlake National Forest, Utah, USA; and mixed grass and brush fuel representative of the Great Basin, Nevada, USA. Measured fuel-based EFs for OC ranged from 0.85 ± 0.24 to 6.56 ± 1.40 mg g 1 . Measured EFs for EC ranged from 0.02 ± 0.01 to 0.16 ± 0.01 mg g 1 . The ratio of organic mass to total carbon mass for fresh emissions from these fuels ranged from 1.04 ± 0.04 to 1.34 ± 0.24. The effect of OFR aging on aerosol optical properties, size distribution, and concentration is also discussed.
Flow rate-independent electrical aerosol sensor
A. Rostedt and J. Keskinen
Aerosol Physics, Laboratory of Physics, Tampere University of Technology, Tampere, Finland
ABSTRACT
A new diffusion charging-based aerosol instrument design is presented, intended to be a starting point for a low-cost particle concentration sensor. The aim in the design is to minimize instrument response dependence on the sample flow rate. The operation principle, response functions of the components, and performance of a prototype instrument are reported. Based on the performance evaluation, the instrument response remained constant within ±15% over a wide sample flow rate range of 3 to 10 lpm. While in the design some sensitivity is sacrificed to minimize flow rate dependency, the detection limit is still sufficient
for a practical sensor application.
Performance characteristics of air intake pleated panel filters for internal
combustion engines in a two-stage configuration
Tadeusz Dziubak
Department of Mechanical Engineering, Military University of Technology, Warsaw, Poland
ABSTRACT
Previous numerical studies that have used computational fluid dynamics (CFD) and experimental software to address the effects of the geometric parameters of pleats on the pressure drop and air flow rate through a fibrous filter are analyzed. The analysis establishes that using a test dust with gradually smaller particle sizes (10, 5, and 1 µm) results in a more intense increase in the filter pressure drop, thus decreasing the service life of the filter. The benefits of using a multicyclone as the first stage of air filtration are discussed. Selecting the air filter by determining the active surface of the filter medium Ac based on the allowable filtration rate is not sufficient; to select the filter medium of a motor vehicle air filter, the dust mass retained per unit of filtration area (mass loading of dust km) must be known for a specific allowable pressure drop Dpfdop. New methods and conditions for determining the mass loading of dust km for filter paper and non-woven fabric in single-stage and two-stage filtration systems are presented. The characteristics of the separation efficiency and filtration performance as well as the pressure drop of a filter set comprising a single cyclone and a filter element with a specific filter medium surface are determined. The effects of the particle size distribution of the dust in the air downstream of the cyclone on the mass loading of dust km of the filter paper and non-woven fabric in a two-stage filtration system are presented. The mileage of a truck fitted with a single-stage or two-stage filtration system in a “multicyclone–panel filter” configuration is estimated based on the calculated mass loading of dust km of the filter paper and non-woven fabric.
Experimental study of oil particle emission rate and size distribution
during milling
Fei Wanga,b, Zhenhai Lia, Peng Wangb, and Ruiyan Zhanga
aSchool of Mechanical Engineering, Tongji University, Shanghai, China; bSchool of Environment and Architecture, University of
Shanghai for Science and Technology, Shanghai, China
ABSTRACT
Metalworking fluids (MWFs) used in milling generate oil particles through impaction, action of centrifugal forces and evaporation/condensation mechanisms. The oil particles suspended in the factory atmosphere can affect the health of the labor force. In order to study the emission properties of these oil particles, this work investigates the oil particle emission rate and size distribution during milling using an environmental chamber method. Two commonly used operating modes for MWFs were selected, the minimum quantity lubrication (MQL) mode (40 ml/h) and the cooling mode (1 m3/h). The cooling mode without cutting was studied separately for comparison with the cooling mode with cutting. The results show that the oil particle emission rate in milling ranges from 7.2 to 641 mg/h, and the size distribution ranges from 0.265 to 12.5 mm. Evaporation/condensation is the main mechanism in the MQL mode. The majority of oil particles formed by evaporation/condensation are in the range of 0.265 to 1.8 mm. As the tool rotation speed increases, the particle emission rate increases, while the mass mean diameter (MMD) and the sauter mean diameter (SMD) decrease. Oil particles are mainly generated by the action of centrifugal force in the cooling mode, and mainly distributed in the range of 1.8 to 12.5 mm. The particle emission rate increases with the tool rotation speed, and the particle MMD and SMD increase with the tool rotation speed only in the cooling mode without cutting. The particle emission rate ranging from 1.8 to 12.5 mm, as well as PM5 and PM10, are a polynomial function of the square of tool rotation speed during the cooling mode. The coefficient of determination (R2) is above 0.99.
An inter-comparison of black-carbon-related instruments in a laboratory
study of biomass burning aerosol
Antonios Tasogloua,b , R. Subramanianc, and Spyros N. Pandisa,d,e
aDepartment of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; bRJ Lee Group, Inc, Monroeville, Pennsylvania, USA; cDepartment of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; dDepartment of Chemical Engineering, University of Patras, Patras, Greece; eInstitute of Chemical Engineering Sciences (ICE-HT), FORTH, Patras, Greece
ABSTRACT
Black carbon (BC)-containing particles are the most strongly light absorbing aerosols in the atmosphere. Measurements of BC are challenging because of its semi-empirical definition based on physical properties and not chemical structure, the complex and continuously changing morphology of the corresponding particles, and the effects of other particulate components on its absorption. In this study, we compare six available commercial continuous instruments measuring BC using biomass burning aerosol. The comparison involves a Soot Particle Aerosol Mass Spectrometer (SP-AMS), a Single-Particle Soot Photometer (SP2), an aethalometer, a Multiangle Absorption Photometer (MAAP), and a blue and a green photoacoustic extinctiometer (PAX). An SP-AMS collection efficiency equal to 0.35 was measured for this aerosol system. The corrected SP-AMS BC mass measurements agreed within 6% with the SP2 refractory BC mass values. Two regimes of behavior were identified for the
optical instruments corresponding to high and low organic/BC ratio. The mass absorption cross-sections (MAC) measured varied from 26% to two times the instrument default values depending on the instrument and the regime. The presence of high organic aerosol concentration in this system can lead to overestimation of the BC mass by the optical instruments by as much as a factor of 2.7. In general, the discrepancy among the BC measurements increased as the organic carbon content of the BC-containing particles increased.
Characterization of a high-resolution supercritical differential mobility
analyzer at reduced flow rates
Runlong Caia,b, Michel Attouib,c, Jingkun Jianga, Frans Korhonenb, Jiming Haoa, Tuukka Pet€aj€ab,d, and
Juha Kangasluomab,e
aState Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, ; bInstitute for Atmospheric and Earth System Research/Physics Faculty of Science, University of Helsinki, Helsinki, Finland; cLISA, UMR CNRS 7583, University Paris-Diderot, University Paris Est-Creteil, IPSL, Paris, France; dSchool of Atmospheric Sciences, Nanjing University, Nanjing, China; eAerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
ABSTRACT
Classifying sub-3 nm particles effectively with relatively high penetration efficiencies and sizing resolutions is important for atmospheric new particle formation studies. A high-resolution supercritical differential mobility analyzer (half-mini DMA) was recently improved to classify aerosols at a sheath flow rate less than 100 L/min. In this study, we characterized the transfer functions, the penetration efficiencies, and the sizing resolution of the new half-mini DMA at the aerosol flow rate of 2.5–10 L/min and the sheath flow rate of 25–250 L/min using tetra-alkyl ammonium ions and tungsten oxide particles. The transfer functions of the new half-mini DMA at an aerosol flow rate lower than 5 L/min and a sheath flow rate lower than 150 L/min agree well with predictions using a theoretical diffusing transfer function. The penetration efficiencies can be approximated using an empirical formula. When classifying 1.48 nm molecular ions at an aerosol-to-sheath flow ratio of 5/50 L/min, the penetration
efficiency, the sizing resolution, and the multiplicative broadening factor of the new half-mini DMA are 0.18, 6.8, and 1.11, respectively. Compared to other sub-3 nm DMAs applied in atmospheric measurements (e.g. the mini-cyDMA, the TSI DMA 3086, the TSI nanoDMA 3085, and the Grimm S-DMA), the new half-mini DMA characterized in this study is able to classify particles at higher aerosol and sheath flow rates, leading to a higher sizing resolution at the same aerosol-to-sheath flow ratio.
Accordingly, the new half-mini DMA can reduce the uncertainties in atmospheric new particle formation measurement if coupled with an aerosol detector that could work at the corresponding high aerosol flow rate.
