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Characterization of Bacteria on aerosols From Dust Events in Dakar, Senegal, West Africa

GEOHEALTH 2020年第6期4卷 e2019GH000216页

作者： Marone, Alioune Kane, Coumba Toure Mbengue, Malick Jenkins, Gregory S. Niang, Demba Ndao Drame, Mamadou Simina Gernand, Jeremy M. Cheikh Anta Diop Univ Lab Appl Microbiol & Ind Engn Ecole Super Polytech ESP Dakar Senegal Epidemiol Surveillance & Training IRESSEF Inst Hlth Res Diamniadio Senegal Penn State Univ Dept Meteorol & Atmospher Sci University Pk PA 16802 USA Univ Cheikh Anta Diop Lab Atmospher Ocean Phys Simeon Fongang Ecole Super Polytech ESP Dakar Senegal Penn State Univ Dept Mineral Engn University Pk PA 16802 USA

We identify bacteria types on collected dust samples in Dakar Senegal, a region that experiences frequent Saharan dust events. We use classical techniques to identify bacteria types from dust samples. Seventy-seven bacteria types are identified from samples collected by spatula and the QuickTake (R) 30 air sampling pump. The dominant groups in the first batch of 51 bacteria (collected via deposition) are Micrococcus (33.33%), Bacillus (13.73%), Kytococcus (11.76%), Pseudomonas (9.80%), and Burkholderia (7.84%) and dominants in the second batch of 26 bacteria (collected with aerosol sampling vacuum pump): Pseudomonas (38.61%), Burkholderia (26.92%), Micrococcus (11.54%), and Brucella spp (7.69%). These bacteria are found in earlier studies from desert sources and can potentially cause respiratory diseases to exposed populations. Future work will use molecular methods is necessary to search for additional pathogens, including viruses on dust aerosols. Plain Language Summary Bacteria on the surfaces of Saharan dust samples collected from 2013-2016 were analyzed using traditional techniques at Dakar, Senegal. The samples were collected using a spatula and the QuickTake (R) 30 air sampling pump. The analysis finds some bacteria that are linked to respiratory disease, including Micrococcus, Burkholderia, and Pseudomonas. We believe that the spatula technique may include bacteria such as Bacillus from soils, which was not present in airborne samples. Additional analysis using genomic techniques will assist in better identifying bacteria and potential pathogens, which can impacts West African populations and are transported downstream over long distances to the Caribbean, Southeastern United States, South America, and Europe.

关键词： Sahara Senegal aerosols bacteria identification respiratory

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Tackling second-hand exposure to tobacco smoke and aerosols of electronic cigarettes: the TackSHS project protocol

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GACETA SANITARIA 2020年第1期34卷 77-82页

作者： Fernandez, Esteve Jose Lopez, Maria Gallus, Silvano Semple, Sean Clancy, Luke Behrakis, Panagiotis Ruprecht, Ario Gorini, Giuseppe Lopez-Nicolas, Angel Radu-Loghin, Cornel Soriano, Joan B. Inst Catala dOncol ICO Lhospitalet De Llobregat Barcelona Spain Inst dInvest Biomed Bellvitge IDIBELL Lhospitalet De Llobregat Barcelona Spain Univ Barcelona Sch Med & Hlth Sci Bellvitge Campus Lhospitalet De Llobregat Barcelona Spain Agencia Salut Publ Barcelona Barcelona Spain CIBER Epidemiol & Salud Publ CIBERESP Madrid Spain Inst dInvest Biomed St Pau IIB St Pau Barcelona Spain Ist Ric Farmacol Mario Negri IRCCS Milan Italy Univ Stirling Inst Social Mkt Stirling Scotland TobaccoFree Res Inst Ireland Dublin Ireland Hellen Canc Soc George D Behrakis Res Lab Athens Greece Fdn IRCCS Ist Nazl Tumori Milan Italy Ist Studio Prevenz & Rete Oncol Florence Italy Univ Politecn Cartagena Cartagena Spain European Network Smoking & Tobacco Prevent Brussels Belgium Hosp Univ La Princesa Resp Dept Madrid Spain

Objective: The TackSHS project aims to comprehensively elucidate the impact that exposure to second-hand smoke (SHS) from cigarettes and second-hand aerosols (SHA) from electronic cigarettes have on the respiratory health of the European population according to socioeconomic characteristics and other determinants. Method: The TackSHS project involves a series of coordinated studies carried out by 11 academic and public health organisations from six European countries. The project will investigate: a) the determinants of SHS and SHA exposure assessed at the individual level (surveys on representative general population samples) and in common environments (environmental sampling in specific settings): b) the overall disease burden, mortality and morbidity attributable to such exposure;and c) its economic impact in terms of direct health care costs. The project will also examine specific acute respiratory health changes in healthy individuals and patients with respiratoly diseases exposed to SHS and SHA. In addition, the project will examine the effectiveness of a novel intervention to reduce SHS exposure in households where smoking is permitted. All these studies are inter-related and involve collaborative coordination among the participant organisations. Conclusion: The comprehensive, integrated approach of the TackSHS project will enable a significant step forward from the current status quo in the understanding of the impact of SHS and SHA exposure on health and provide the basis for health policy recommendations to help European countries to further reduce the harm caused by SHS and SHA exposure. (C) 2019 SESPAS. Published by Elsevier Espana, S.L.U.

关键词： Second-hand smoke Passive smoking Electronic cigarette Electronic nicotine delivery systems aerosols Second-hand aerosols Respiratory health Burden of disease Economic impact

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Impact of Atomizer Age and Flavor on In Vitro Toxicity of aerosols from a Third-Generation Electronic Cigarette against Human Oral Cells

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CHEMICAL RESEARCH IN TOXICOLOGY 2020年第10期33卷 2527-2537页

作者： Urena, Jose F. Ebersol, Lauren A. Silakov, Alexey Elias, Ryan J. Lambert, Joshua D. Penn State Univ Dept Food Sci University Pk PA 16802 USA Penn State Univ Dept Chem University Pk PA 16802 USA Penn State Univ Ctr Mol Toxicol & Carcinogenesis University Pk PA 16802 USA

Electronic cigarettes (ECs) are categorized into generations which differ in terms of design, aerosol production, and customizability. Current and former smokers prefer third-generation devices that satisfy tobacco cravings more effectively than older generations. Recent studies indicate that EC aerosols from first- and second-generation devices contain reactive carbonyls and free radicals and can cause in vitro cytotoxicity. Third-generation ECs have not been adequately studied. Further, previous studies have focused on cells from the respiratory tract, whereas those of the oral cavity, which is exposed to high levels of EC aerosols, have been understudied. We quantified the production of reactive carbonyls and free radicals by a third-generation EC and investigated the induction of cytotoxicity and oxidative stress in normal and cancerous human oral cell lines using a panel of eight commercial EC liquids. We found that EC aerosols produced using a new atomizer contained formaldehyde, acetaldehyde, and acrolein, but did not contain detectable levels of free radicals. We found that EC aerosols generated from only one of the eight liquids tested using a new atomizer induced cytotoxicity against two human oral cells in vitro. Treatment of oral cells with the cytotoxic EC aerosol caused a concomitant increase in intracellular oxidative stress. As atomizer age increased with repeated use of the same atomizer, carbonyl production, radical emissions, and cytotoxicity increased. Overall, our results suggest that thirdgeneration ECs may cause adverse effects in the oral cavity and normal EC use, which involves repeated use of the same atomizer to generate aerosol, may enhance the potential toxic effects of third-generation ECs.

关键词： Liquids aerosols Carbonyls Nicotine Toxicity

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Investigating the relative responses of regional monsoon dynamics to snow darkening and direct radiative effects of dust and carbonaceous aerosols over the Indian subcontinent

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CLIMATE DYNAMICS 2020年第3-4期55卷 1011-1030页

作者： Das, Sushant Giorgi, Filippo Giuliani, Graziano Abdus Salam Int Ctr Theoret Phys Earth Syst Phys Sect Trieste Italy

A large uncertainty exists today in quantifying the absorbing aerosol snow darkening effect (SnoDE) and its relative role compared to the direct radiative effect (DRE), especially at the regional scale. Using a regional climate model over an enlarged South Asia Coordinated Regional Climate Downscaling Experiment (CORDEX) domain, here we isolate these effects and examine their impacts on the dynamics of the Indian pre-monsoon and summer monsoon (ISM) circulation. Our results clearly indicate that the regional dynamics associated with the pre-monsoon and ISM are highly sensitive to both aerosol SnoDE and DRE, with the SnoDE dominating during the pre-monsoon, and the DRE during the ISM. During the pre-monsoon, the deposition of aerosols on the Himalayas and Tibetan Plateau (HTP) reduces the surface albedo, leading to an increase in absorption of solar radiation and accelerated snow melting. The associated increase in surface and tropospheric temperature draws dry air from central Asia towards northern India and along the Himalayan foothills, creating a low-level anti-cyclonic anomaly over eastern India and the Bay of Bengal. This limits the northward propagation of southwest winds and leads to a decrease in precipitation over the central and eastern parts of India during the pre-monsoon and across northern India in the following ISM. Conversely, an increase in precipitation during the ISM is due to the strengthening of southwest winds caused by large-scale convergence over the Arabian Peninsula. The shift of winds from central Asia towards northern India in the SnoDE and towards the Arabian Peninsula in DRE leads to contrasting effects and can possibly modulate the monsoon onset dates. The SnoDE, with a prevailing contribution from dust, leads to an increase in precipitation over the HTP, which is amplified during the ISM when DRE is also considered. Our study provides evidence that both these aerosol effects have substantial impacts on the pre-monsoon and ISM dynamics

关键词： aerosols Snow darkening effect Direct radiative effect Dynamics RegCM4

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Formation of Diacetyl and Other α-Dicarbonyl Compounds during the Generation of E-Vapor Product aerosols

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ACS OMEGA 2020年第28期5卷 17565-17575页

作者： Melvin, Matt S. Avery, Karen C. Ballentine, Regina M. Flora, Jason W. Gardner, William Karles, Georgios D. Pithawalla, Yezdi B. Smith, Donna C. Ehman, Kimberly D. Wagner, Karl A. Altria Client Serv LLC Ctr Res & Technol Richmond VA 23219 USA

Exposure to diacetyl (DA) has been linked to the respiratory condition bronchiolitis obliterans. Previous research has demonstrated that DA and other alpha-dicarbonyl compounds can be detected in both the e-liquids and aerosols of e-vapor products (EVPs). While some EVP manufacturers may add these compounds as flavor ingredients, the primary objective of this work was to determine the potential for the formation of alpha-dicarbonyl compounds during the generation of aerosols from EVPs where no DA or other alpha-dicarbonyl compounds are added to the e-liquid. A novel ultraperformance liquid chromatography-mass spectrometry-based analytical method for the determination of DA, acetyl propionyl, glyoxal, and methylglyoxal was developed and validated. Next, eight commercially available cig-a-like-type EVPs were evaluated for alpha-dicarbonyl formation. Increased levels of alpha-dicarbonyls were observed in the aerosols of all evaluated EVPs compared to their respective e-liquids. Mechanistic studies were conducted using a model microwave reaction system to identify key reaction precursors for DA generated from propylene glycol (PG) and carbon-13-labeled glycerin (GLY). These studies, along with the corresponding retrosynthetic analysis, resulted in the proposed formation pathway where hydroxyacetone is generated from PG and/or GLY. Hydroxyacetone then participates in an aldol condensation with formaldehyde where formaldehyde can also be generated from PG and/or GLY;the resultant product then dehydrates to form DA. This proposed pathway was further investigated through in situ synthetic organic experiments within the model microwave reaction system. This work establishes that DA is formed in the aerosol generation process of the EVPs tested though at levels below toxicological concern.

关键词： Aldehydes Electromagnetic radiation aerosols Chemical reactions Aldol reactions

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Wildfire-Smoke aerosols Lead to Increased Light Use Efficiency Among Agricultural and Restored Wetland Land Uses in California's Central Valley

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JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 2020年第2期125卷 e2019JG005380-e2019JG005380页

作者： Hemes, Kyle S. Verfaillie, Joseph Baldocchi, Dennis D. Univ Calif Berkeley Dept Environm Sci Policy & Management Ecosyst Sci Div Berkeley CA 94720 USA Stanford Univ Stanford Woods Inst Environm Stanford CA 94305 USA

There are few observational studies measuring the ecosystem-scale productivity effects of changes in incident diffuse photosynthetically active radiation (PAR(diffuse)), especially related to wildfire smoke. Climate change-induced increases to the duration and intensity of fire conditions have made smoke a common occurrence across western North America, with largely unquantified ecosystem feedbacks. Under equivalent amounts of radiation, increased atmospheric particulate matter could lead to a boost in productivity as scattering redistributes photons throughout multilayer canopies. In this work, we leverage a meso-network of eddy covariance measurement sites across a unique array of managed and restored C-3 and C-4 canopy types to understand how recent wildfire smoke affected ecosystem productivity during the summer of 2018, an especially smoky year in the agriculturally productive Central Valley. We find that diffuse PAR(diffuse) increased by more than a third compared to the previous growing season, while total PAR was only slightly diminished. These conditions caused nearly a doubling of light use efficiency over the range of diffuse fraction observed, with the highest sensitivity to diffuse fraction exhibited by corn and alfalfa crops. We utilized an empirical model to assess the trade-off between enhanced diffuse fraction and reduced total PAR. Under mean radiation conditions, daily integrated gross ecosystem productivity increased by 1.2-4.2% compared to the previous growing season. Finally, we explore the potential negative effect of heightened ozone, a copollutant often associated with wildfire. In addition to the effects of wildfire smoke, the results of this natural experiment can help validate future predictions of aerosol-productivity feedbacks. Plain Language Summary Exacerbated by climate change, wildfire smoke is becoming a more common occurrence, especially across western North America. While we know that wildfire smoke has negative health impacts fo

关键词： wildfire carbon flux aerosols smoke light use efficiency ecosystem productivity

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Induction of Oxidative DNA Damage and Epithelial Mesenchymal Transitions in Small Airway Epithelial Cells Exposed to Cosmetic aerosols

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TOXICOLOGICAL SCIENCES 2020年第1期177卷 248-262页

作者： Pearce, Kaitlin M. Okon, Imoh Watson-Wright, Christa Georgia State Univ Sch Publ Hlth Div Environm Hlth Atlanta GA 30302 USA Georgia State Univ Ctr Mol & Translat Med Atlanta GA 30302 USA

Engineered metal nanoparticles (ENPs) are frequently incorporated into aerosolized consumer products, known as nanoenabled products (NEPs). Concern for consumer pulmonary exposures grows as NEPs produce high concentrations of chemically modified ENPs. A significant knowledge gap still exists surrounding NEP aerosol respiratory effects as previous research focuses on pristine/unmodified ENPs. Our research evaluated metal-containing aerosols emitted from nano-enabled cosmetics and their induction of oxidative stress and DNA damage, which may contribute to epithelial mesenchymal transitions (EMT) within primary human small airway epithelial cells. We utilized an automated NEP generation system to monitor and gravimetrically collect aerosols from two aerosolized cosmetic lines. Aerosol monitoring data were inputted into modeling software to determine potential inhaled dose and in vitro concentrations. Toxicological profiles of aerosols and comparable pristine ENPs (TiO2 and Fe2O3) were used to assess reactive oxygen species and oxidative stress by fluorescent-based assays. Single-stranded DNA (ssDNA) damage and 8-oxoguanine were detected using the CometChip assay after 24-h exposure. Western blots were conducted after 21-day exposure to evaluate modulation of EMT markers. Results indicated aerosols possessed primarily ultrafine particles largely depositing in tracheobronchial lung regions. Significant increases in oxidative stress, ssDNA damage, and 8-oxoguanine were detected post-exposure to aerosols versus pristine ENPs. Western blots revealed statistically significant decreases in E-cadherin and increases in vimentin, fascin, and CD44 for two aerosols, indicating EMT. This work suggests certain prolonged NEP inhalation exposures cause oxidative DNA damage, which may play a role in cellular changes associated with reduced respiratory function and should be of concern.

关键词： aerosols nano-enabled products oxidative stress genotoxicity epithelial mesenchymal transition exposure modeling

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Optical and Chemical Analysis of Absorption Enhancement by Mixed Carbonaceous aerosols in the 2019 Woodbury, AZ, Fire Plume

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2020年第15期125卷 e2020JD032399-e2020JD032399页

作者： Lee, James E. Dubey, Manvendra K. Aiken, Allison C. Chylek, Petr Carrico, Christian M. Los Alamos Natl Lab Earth & Environm Sci Los Alamos NM 87545 USA New Mexico Inst Min & Technol Dept Civil & Environm Engn Socorro NM 87801 USA

Wildfires emit mixtures of light-absorbing aerosols (including black and brown carbon, BC and BrC, respectively) and more purely scattering organic aerosol (OA). BC, BrC, and OA interactions are complex and dynamic and evolve with aging in the atmosphere resulting in large uncertainties in their radiative forcing. We report microphysical, optical, and chemical measurements of multiple plumes from the Woodbury Fire (AZ, USA) observed at Los Alamos, NM, after 11-18 hr of atmospheric transit. This includes periods where the plumes exhibited little entrainment as well as periods that had become more dilute after mixing with background aerosol. Aerosol mass absorption cross sections (MAC) were enhanced by a factor of 1.5-2.2 greater than bare BC at 870 nm, suggesting lensing by nonabsorbing coatings following a core-shell morphology. Larger MAC enhancement factors of 1.9-5.1 at 450 nm are greater than core-shell morphology can explain and are attributed to BrC. MAC of OA (MAC(Org)) at 450 nm was largest in intact portions of the plumes (peak value bounded between 0.6 and 0.9 m(2)/g [Org]) and decreased with plume dilution. We report a strong correlation between MAC(Org) (450 nm) with the f(C2H4O2) (a tracer for levoglucosan-like species) of coatings and of bulk OA indicating that BrC in the Woodbury Fire was coemitted with levoglucosan, a primary aerosol. f(C2H4O2) and MAC(Org)(450 nm) are shown to vary between the edge and the core of plumes, demonstrating enhanced oxidation of OA and BrC bleaching near plume edges. Our process-level finding can inform parameterizations of mixed BC, BrC, and OA properties for wildfire plumes in climate models. Plain Language Summary Wildfires generate particles that can cool or warm climate regionally. Organic particles in the atmosphere typically cool climate by redirecting incoming light away from the Earth. Conversely, soot particles absorb light and can cause warming. Additionally, a specific type of organic particle called brown ca

关键词： wildfire aerosols brown carbon black carbon absorption enhancement chemistry

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Experimental investigation of aerosols removal efficiency through self-priming venturi scrubber

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NUCLEAR ENGINEERING AND TECHNOLOGY 2020年第10期52卷 2230-2237页

作者： Ali, Suhail Waheed, Khalid Qureshi, Kamran Irfan, Naseem Ahmed, Masroor Siddique, Waseem Farooq, Amjad PIEAS Dept Nucl Engn Islamabad Pakistan PIEAS Dept Mech Engn Islamabad Pakistan

Self-priming venturi scrubber is one of the most effective devices used to collect aerosols and soluble gas pollutants from gaseous stream during severe accident in a nuclear power plant. The present study focuses on investigation of dust particle removal efficiency of the venturi scrubber both experimentally and theoretically. Venturi scrubber captures the dust particles in tiny water droplets flowing into it. Inertial impaction is the main mechanism of particles collection in venturi scrubber. The water injected into venturi throat is in the form of jets through multiple holes present at venturi throat. In this study, aerosols removal efficiency of self-priming venturi scrubber was experimentally measured for different operating conditions. Alumina (Al2O3) particles with 0.4-mu m diameter and 3950 kg/m(3) density were treated as aerosols. Removal efficiency was calculated for different gas flow rates i.e. 3-6 m(3)/h and liquid flow rates i.e. 0.009-0.025 m(3)/h. Experimental results depict that aerosols removal efficiency increases with the increase in throat velocity and liquid head. While at lower air flow rate of 3 m(3)/h, removal efficiency decreases with the increase in liquid head. A theoretical model of venturi scrubber was also employed and experimental results were compared with mathematical model. Experimental results are found to be in good agreement with theoretical results. (c) 2020 Korean Nuclear Society, Published by Elsevier Korea LLC. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： aerosols Self-priming venturi scrubber Filtered containment venting system Particulate removal

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New Multiphase Chemical Processes Influencing Atmospheric aerosols, Air Quality, and Climate in the Anthropocene

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ACCOUNTS OF CHEMICAL RESEARCH 2020年第10期53卷 2034-2043页

作者： Su, Hang Cheng, Yafang Poeschl, Ulrich Max Planck Inst Chem D-55128 Mainz Germany

Atmospheric aerosols and fine particulate matter (PM2.5) are strongly affecting human health and climate in the Anthropocene, that is, in the current era of globally pervasive and rapidly increasing human influence on planet Earth. Poor air quality associated with high aerosol concentrations is among the leading health risks worldwide, causing millions of attributable excess deaths and years of life lost every year. Besides their health impact, aerosols are also influencing climate through interactions with clouds and solar radiation with an estimated negative total effective radiative forcing that may compensate about half of the positive radiative forcing of carbon dioxide but exhibits a much larger uncertainty. Heterogeneous and multiphase chemical reactions on the surface and in the bulk of solid, semisolid, and liquid aerosol particles have been recognized to influence aerosol formation and transformation and thus their environmental effects. However, atmospheric multiphase chemistry is not well understood because of its intrinsic complexity of dealing with the matter in multiple phases and the difficulties of distinguishing its effect from that of gas phase reactions. Recently, research on atmospheric multiphase chemistry received a boost from the growing interest in understanding severe haze formation of very high PM2.5 concentrations in polluted megacities and densely populated regions. State-of-the-art models suggest that the gas phase reactions, however, are not capturing the high concentrations and rapid increase of PM2.5 observed during haze events, suggesting a gap in our understanding of the chemical mechanisms of aerosol formation. These haze events are characterized by high concentrations of aerosol particles and high humidity, especially favoring multiphase chemistry. In this Account, we review recent advances that we have made, as well as current challenges and future perspectives for research on multiphase chemical processes involved in atmospheri

关键词： Anions aerosols Chemical reactions Phase transitions Gases

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