[1816]
Liu, X., G. L. Huey, R. J. Yokelson, V. Selimovic, I. J. Simpson, M. Müller, J. L. Jimenez, P. Campuzano-Jost, A. J. Beyersdorf, D. R. Blake, et al.,
"Airborne measurements of western U.S. wildfire emissions: Comparison with prescribed burning and air quality implications",
Journal of Geophysical Research: Atmospheres, vol. 122, pp. 6108–6129, jun, 2017.
Link:
https://doi.org/10.1002/2016JD026315
<p>Wildfires emit significant amounts of pollutants that degrade air quality. Plumes from three wildfires in the western U.S. were measured from aircraft during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) and the Biomass Burning Observation Project (BBOP), both in summer 2013. This study reports an extensive set of emission factors (EFs) for over 80 gases and 5 components of submicron particulate matter (PM1) from these temperate wildfires. These include rarely, or never before, measured oxygenated volatile organic compounds and multifunctional organic nitrates. The observed EFs are compared with previous measurements of temperate wildfires, boreal forest fires, and temperate prescribed fires. The wildfires emitted high amounts of PM1 (with organic aerosol (OA) dominating the mass) with an average EF that is more than 2 times the EFs for prescribed fires. The measured EFs were used to estimate the annual wildfire emissions of carbon monoxide, nitrogen oxides, total nonmethane organic compounds, and PM1 from 11 western U.S. states. The estimated gas emissions are generally comparable with the 2011 National Emissions Inventory (NEI). However, our PM1 emission estimate (1530 ± 570 Gg yr−1) is over 3 times that of the NEI PM2.5 estimate and is also higher than the PM2.5 emitted from all other sources in these states in the NEI. This study indicates that the source of OA from biomass burning in the western states is significantly underestimated. In addition, our results indicate that prescribed burning may be an effective method to reduce fine particle emissions.</p>
[1814]
Lin, B., Y. Huangfu, N. Lima, B. Jobson, M. Kirk, P. O'Keeffe, S. Pressley, V. Walden, B. Lamb, and D. Cook,
"Analyzing the Relationship between Human Behavior and Indoor Air Quality",
Journal of Sensor and Actuator Networks, vol. 6, pp. 13, aug, 2017.
Link:
http://www.mdpi.com/2224-2708/6/3/13
<p>In the coming decades, as we experience global population growth and global aging issues, there will be corresponding concerns about the quality of the air we experience inside and outside buildings. Because we can anticipate that there will be behavioral changes that accompany population growth and aging, we examine the relationship between home occupant behavior and indoor air quality. To do this, we collect both sensor-based behavior data and chemical indoor air quality measurements in smart home environments. We introduce a novel machine learning-based approach to quantify the correlation between smart home features and chemical measurements of air quality, and evaluate the approach using two smart homes. The findings may help us understand the types of behavior that measurably impact indoor air quality. This information could help us plan for the future by developing an automated building system that would be used as part of a smart city.</p>
[1833]
Müller, M., P. Eichler, B. D'Anna, W. Tan, and A. Wisthaler,
"Direct Sampling and Analysis of Atmospheric Particulate Organic Matter by Proton-Transfer-Reaction Mass Spectrometry",
Analytical Chemistry, sep, 2017.
Link:
http://pubs.acs.org/doi/10.1021/acs.analchem.7b02582
<p>We report on a new method for analyzing atmospheric submicrometer particulate organic matter which combines direct particle sampling and volatilization with online chemical ionization mass spectrometric analysis. Technically, the method relies on the combined use of a CHARON (“Chemical Analysis of Aerosol Online”) particle inlet and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS). Laboratory studies on target analytes showed that the ionization conditions in the PTR-ToF-MS lead to extensive fragmentation of levoglucosan and cis-pinonic acid, while protonated oleic acid and 5α-cholestane molecules remain intact. Potential problems and biases in quantitative and qualitative analyses are discussed. Side-by-side atmospheric comparison measurements of total particulate organic mass and levoglucosan with an aerosol mass spectrometer (AMS) were in good agreement. Complex and clearly distinct organic mass spectra were obtained from atmospheric measurements in three European cities (Lyon, Valencia, Innsbruck). Data visualization in reduced-parameter frameworks (e.g., oxidation state of carbon vs carbon number) revealed that the CHARON-PTR-ToF-MS technique adds significant analytical capabilities for characterizing particulate organic carbon in the Earth’s atmosphere. Positive matrix factorization (PMF) was used for apportioning sources of atmospheric particles in late fall in Innsbruck. The m/z signatures of known source marker compounds (levoglucosan and resin acids, polycyclic aromatic hydrocarbons, nicotine) in the mass spectra were used to assign PMF factors to biomass burning, traffic, and smoking emission sources.</p>
[1824]
Eichler, P., M. Müller, C. Rohmann, B. Stengel, J. Orasche, R. Zimmermann, and A. Wisthaler,
"Lubricating Oil as a Major Constituent of Ship Exhaust Particles",
Environmental Science {&} Technology Letters, vol. 4, pp. 54–58, jan, 2017.
Link:
http://pubs.acs.org/doi/abs/10.1021/acs.estlett.6b00488
<p>A proton-transfer-reaction time-of-flight mass spectrometer combined with the novel CHARON (“chemical analysis of aerosol online”) aerosol inlet was used for characterization of submicrometer particulate organic matter in ship engine exhaust. Particles were sampled from diluted and cooled exhaust of a marine test bench engine that was operated on residual heavy fuel oil (HFO) and low-sulfur distillate marine gas oil (MGO), respectively. In both fuel operation modes, exhaust particle mass spectra were dominated by polycycloalkanes in the C20-to-C39 range, which are typical main constituents of lubricating oils. Exhaust particle mass spectra were closely reproduced when the engine’s lubricant oil was directly measured in aerosolized form. We report emission profiles of lubricant oil hydrocarbons as a function of their volatility and as a function of their carbon atom number. Total emissions of lubricant oil amounted to 183 and 74 mg kW–1 h–1 for HFO and MGO combustion, respectively. These values resemble typical oil loss rates of marine four-stroke trunk piston engines in which most of the lubricant is known to be lost through the combustion chamber and the tailpipe. We conclude that marine trunk piston engines are generally prone to high emissions of particles mainly composed of unburned lubricating oil.</p>
[1770]
Hatch, L. E., R. J. Yokelson, C. E. Stockwell, P. R. Veres, I. J. Simpson, D. R. Blake, J. J. Orlando, and K. C. Barsanti,
"Multi-instrument comparison and compilation of non-methane organic gas emissions from biomass burning and implications for smoke-derived secondary organic aerosol precursors",
Atmospheric Chemistry and Physics, vol. 17, pp. 1471–1489, Jan, 2017.
Link:
http://dx.doi.org/10.5194/acp-17-1471-2017
<p>Multiple trace-gas instruments were deployed during the fourth Fire Lab at Missoula Experiment (FLAME-4), including the first application of proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) and comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC-TOFMS) for laboratory biomass burning (BB) measurements. Open-path Fourier transform infrared spectroscopy (OP-FTIR) was also deployed, as well as whole-air sampling (WAS) with one-dimensional gas chromatography–mass spectrometry (GC-MS) analysis. This combination of instruments provided an unprecedented level of detection and chemical speciation. The chemical composition and emission factors (EFs) determined by these four analytical techniques were compared for four representative fuels. The results demonstrate that the instruments are highly complementary, with each covering some unique and important ranges of compositional space, thus demonstrating the need for multi-instrument approaches to adequately characterize BB smoke emissions. Emission factors for overlapping compounds generally compared within experimental uncertainty, despite some outliers, including monoterpenes. Data from all measurements were synthesized into a single EF database that includes over 500 non-methane organic gases (NMOGs) to provide a comprehensive picture of speciated, gaseous BB emissions. The identified compounds were assessed as a function of volatility; 6–11 % of the total NMOG EF was associated with intermediate-volatility organic compounds (IVOCs). These atmospherically relevant compounds historically have been unresolved in BB smoke measurements and thus are largely missing from emission inventories. Additionally, the identified compounds were screened for published secondary organic aerosol (SOA) yields. Of the total reactive carbon (defined as EF scaled by the OH rate constant and carbon number of each compound) in the BB emissions, 55–77 % was associated with compounds for which SOA yields are unknown or understudied. The best candidates for future smog chamber experiments were identified based on the relative abundance and ubiquity of the understudied compounds, and they included furfural, 2-methyl furan, 2-furan methanol, and 1,3-cyclopentadiene. Laboratory study of these compounds will facilitate future modeling efforts.</p>
[1840]
Güntner, A.. T., N.. A. Sievi, S.. J. Theodore, T.. Gulich, M.. Kohler, and S.. E. Pratsinis,
"Noninvasive Body Fat Burn Monitoring from Exhaled Acetone with Si-doped {WO}3-sensing Nanoparticles",
Analytical Chemistry, vol. 89, pp. 10578–10584, sep, 2017.
Link:
http://pubs.acs.org/doi/abs/10.1021/acs.analchem.7b02843
<p>Obesity is a global health threat on the rise, and its prevalence continues to grow. Yet suitable biomedical sensors to monitor body fat burn rates in situ, to guide physical activity or dietary interventions toward efficient weight loss, are missing. Here, we introduce a compact and inexpensive breath acetone sensor based on Si-doped WO3 nanoparticles that can accurately follow body fat burn rates in real time. We tested this sensor on 20 volunteers during exercise and rest and measured their individual breath acetone concentrations in good agreement with benchtop proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS). During exercise, this sensor reveals clearly the onset and progression of increasing breath acetone levels that indicate intensified body fat metabolism, as validated by parallel venous blood β-hydroxybutyrate (BOHB) measurements. Most importantly, we found that the body fat metabolism was especially pronounced for most volunteers during fasting for 3 h after exercise, with strong variation between subjects, and this was displayed correctly by the sensor in real-time. As a result, this simple breath acetone sensor enables easily applicable and hand-held body fat burn monitoring for personalized and immediate feedback on workout effectiveness that can guide dieting as well.</p>
[1839]
Doran, S., A. Romano, and G. B. Hanna,
"Optimization of sampling parameters for standardized exhaled breath sampling",
Journal of Breath Research, sep, 2017.
Link:
http://iopscience.iop.org/article/10.1088/1752-7163/aa8a46/meta
The lack of standardization of breath sampling is a major contributing factor to the poor repeatability of results and hence represents a barrier to the adoption of breath tests in clinical practice. On-line and bag breath sampling have advantages but do not suit multicentre clinical studies whereas storage and robust transport are essential for the conduct of wide-scale studies. Several devices have been developed to control sampling parameters and to concentrate volatile organic compounds (VOCs) onto thermal desorption (TD) tubes and subsequently transport those tubes for laboratory analysis. We conducted three experiments to investigate (i) the fraction of breath sampled (whole vs. lower expiratory exhaled breath); (ii) breath sample volume (125, 250, 500 and 1000ml) and (iii) breath sample flow rate (400, 200, 100 and 50 ml/min). The target VOCs were acetone and potential volatile biomarkers for oesophago-gastric cancer belonging to the aldehyde, fatty acids and phenol chemical classes. We also examined the collection execution time and the impact of environmental contamination. The experiments showed that the use of exhaled breath-sampling devices requires the selection of optimum sampling parameters. The increase in sample volume has improved the levels of VOCs detected. However, the influence of the fraction of exhaled breath and the flow rate depends on the target VOCs measured. The concentration of potential volatile biomarkers for oesophago-gastric cancer was not significantly different between the whole and lower airway exhaled breath. While the recovery of phenols and acetone from TD tubes was lower when breath sampling was performed at a higher flow rate, other VOCs were not affected. A dedicated 'clean air supply' overcomes the contamination from ambient air, but the breath collection device itself can be a source of contaminants. In clinical studies using VOCs to diagnose gastro-oesophageal cancer, the optimum parameters are 500mls sample volume of whole breath with a flow rate of 200ml/min.
[1834]
Yuan, B., A. R. Koss, C. Warneke, M. Coggon, K. Sekimoto, and J. A. de Gouw,
"Proton-Transfer-Reaction Mass Spectrometry: Applications in Atmospheric Sciences",
Chemical Reviews, oct, 2017.
Link:
http://pubs.acs.org/doi/10.1021/acs.chemrev.7b00325
<p>Proton-transfer-reaction mass spectrometry (PTR-MS) has been widely used to study the emissions, distributions, and chemical evolution of volatile organic compounds (VOCs) in the atmosphere. The applications of PTR-MS have greatly promoted understanding of VOC sources and their roles in air-quality issues. In the past two decades, many new mass spectrometric techniques have been applied in PTR-MS instruments, and the performance of PTR-MS has improved significantly. This Review summarizes these developments and recent applications of PTR-MS in the atmospheric sciences. We discuss the latest instrument development and characterization work on PTR-MS instruments, including the use of time-of-flight mass analyzers and new types of ion guiding interfaces. Here we review what has been learned about the specificity of different product ion signals for important atmospheric VOCs. We present some of the recent highlights of VOC research using PTR-MS including new observations in urban air, biomass-burning plumes, forested regions, oil and natural gas production regions, agricultural facilities, the marine environment, laboratory studies, and indoor air. Finally, we will summarize some further instrument developments that are aimed at improving the sensitivity and specificity of PTR-MS and extending its use to other applications in atmospheric sciences, e.g., aerosol measurements and OH reactivity measurements.</p>
[1817]
Materić, D., M. Lanza, P. Sulzer, J. Herbig, D. Bruhn, V. Gauci, N. Mason, and C. Turner,
"Selective reagent ion-time of flight-mass spectrometry study of six common monoterpenes",
International Journal of Mass Spectrometry, jun, 2017.
Link:
http://www.sciencedirect.com/science/article/pii/S1387380617303044?via%3Dihub
<p>One of the most common volatile organic compounds (VOCs) group is monoterpenes. Monoterpenes share the molecular formula C10H16, they are usually cyclic and have a pleasant smell. The most common monoterpenes are limonene (present in citrus fruits) and α-pinene (present in conifers’ resin). Different monoterpenes have different chemical, biological and ecological properties thus it is experimentally very important to be able to differentiate between them in real time. Real time instruments such as Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS), offer a real time solution for monoterpene measurement but at the cost of selectivity resulting in all monoterpenes being seen at the same m/z. In this work we used Selective Reagent Ion-Time of Flight-Mass Spectrometry (SRI/PTR-ToF-MS) in order to explore the differences in ion branching when different ionizations (H3O+, NO+ and O2+) and different drift tube reduced field energies (E/N) were used. We report a comprehensive ion library with many unique features, characteristic for individual monoterpenes.</p>
[1823]
Chandra, B.P.., V. Sinha, H. Hakkim, and B. Sinha,
"Storage stability studies and field application of low cost glass flasks for analyses of thirteen ambient {VOCs} using proton transfer reaction mass spectrometry",
International Journal of Mass Spectrometry, vol. 419, pp. 11–19, aug, 2017.
Link:
http://www.sciencedirect.com/science/article/pii/S138738061730043X?via%3Dihub
<p>Ambient volatile organic compounds play a key role in atmospheric chemistry and air pollution studies due to their chemical reactivity and in several instances high toxicity. Quantification of ambient whole air samples which contain reactive and short-lived VOCs such as acetaldehyde, isoprene, dimethylsulphide and trimethylbenzenes at ppt-ppb concentrations is analytically challenging and generally accomplished using online proton transfer reaction mass spectrometry. Deployment of online instrumentation is still not feasible in several regions of the world due to practical constraints (power, safety issues). Consequently there is paucity of VOC data in vast regions of the world. We present here, the validation and application of a novel method for ambient VOC speciation and emission factor studies using low cost (<100 USD) whole air glass flask samplers and offline proton transfer reaction mass spectrometry that can help reduce the paucity of VOC datasets. Experiments to assess the stability during storage of thirteen VOCs, many of which are very reactive, showed that acetaldehyde, acetonitrile, acetone, dimethylsulphide, methyl vinyl and methyl ethyl ketones, benzene, xylenes, trimethylbenzenes and monoterpenes can be quantified reproducibly within the respective precision error (e.g. 40% at 100ppt α-pinene and 3% at 13 ppb acetaldehyde) between collection and storage (at >95% confidence), for samples analyzed within 10 days of collection. For toluene and isoprene, similar results were obtained until day 9 and 1, respectively and at confidence >70%, over the 10 day period. A storage artefact was observed for methanol resulting in higher analytical uncertainty of upto 40%. We applied the method for measuring toluene/benzene emission ratios and aromatic VOCs in traffic plumes, and determining VOC emission factors (gVOC/kg fuel) from an agricultural wheat straw fire in India. The results of this study demonstrate that use of the low cost glass flask samplers described herein can significantly improve acquisition of spatially and temporally resolved datasets for atmospheric chemistry and air quality studies at sites where online deployment of instruments remains unfeasible.</p>
[1818]
Schallhart, S., P. Rantala, M. K. Kajos, J. Aalto, I. Mammarella, T. M. Ruuskanen, and M. Kulmala,
"Temporal variation of {VOC} fluxes measured with {PTR}-{TOF} above a boreal forest",
Atmospheric Chemistry and Physics Discussions, pp. 1–29, jun, 2017.
Link:
https://www.atmos-chem-phys-discuss.net/acp-2017-394/
<p>Between April and June 2013 fluxes of volatile organic compounds (VOCs) were measured in a Scots pine and Norway spruce forest using the eddy covariance (EC) method with a proton transfer reaction time of flight (PTR-TOF) mass spectrometer. The observations were performed above a boreal forest at the SMEAR II site in Southern Finland. We found a total of 25 different compounds with exchange and investigated their seasonal variations from spring to summer. The majority of the net VOC flux was comprised of methanol, monoterpenes, acetone and butene. The VOC emissions followed a seasonal trend, the released amount increased from spring to summer. Only a three compounds were emitted in April while in June emissions of some 19 VOCs were observed. During the measurements in April, the emissions were dominated by butene, while in May and June methanol was the most emitted compound. The main source of methanol is likely the growth of new biomass. During a 21-day period in June, the net VOC flux was 2.3 nmol m−2 s−1. This is on the lower end of PTR-TOF flux measurements from other ecosystems, which range from 2 to 10 nmol m−2 s−1. The EC flux results were compared with surface layer profile measurements, an indirect method using a proton transfer reaction quadrupole mass spectrometer, which is permanently installed at the SMEAR II site was used. For most of the compounds the fluxes, measured with the two different methods, agreed well.</p>
[1820]
Ghude, S. D., G.. S. Bhat, T. Prabhakaran, R.. K. Jenamani, D.. M. Chate, P.. D. Safai, A.. K. Karipot, M.. Konwar, P. Pithani, V.. Sinha, et al.,
"Winter Fog Experiment Over the Indo-Gangetic Plains of India",
Current Science, vol. 112, pp. 767, feb, 2017.
Link:
http://www.indiaenvironmentportal.org.in/files/file/winter%20fog%20Indo%20Gangetic%20plain.pdf
<p>The objectives of the Winter Fog Experiment (WIFEX) over the Indo-Gangetic Plains of India are to develop better now-casting and forecasting of winter fog on various time- and spatial scales. Maximum fog occurrence over northwest India is about 48 days (visibility < 1000 m) per year, and it occurs mostly during the December-February time-period. The physical and chemical characteristics of fog, meteorological factors responsible for its genesis, sustenance, intensity and dissipation are poorly understood. Improved understanding on the above aspects is required to develop reliable forecasting models and observational techniques for accurate prediction of the fog events. Extensive sets of comprehensive groundbased instrumentation were deployed at the Indira Gandhi International Airport, New Delhi. Major in situ sensors were deployed to measure surface micrometeorological conditions, radiation balance, turbulence, thermodynamical structure of the surface layer, fog droplet and aerosol microphysics, aerosol optical properties, and aerosol and fog water chemistry to describe the complete environmental conditions under which fog develops. In addition, Weather Forecasting Model coupled with chemistry is planned for fog prediction at a spatial resolution of 2 km. The present study provides an introductory overview of the winter fog field campaign with its unique instrumentation. Winter Fog Experiment Over the Indo-Gangetic Plains of India (PDF Download Available). Available from: https://www.researchgate.net/publication/314118438_Winter_Fog_Experiment_Over_the_Indo-Gangetic_Plains_of_India [accessed Aug 9, 2017].</p>