75 results on '"Zoran Ristovski"'
Search Results
2. The correlation between diesel soot chemical structure and reactivity
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Zoran Ristovski, Elizabeth Graham, Svetlana Stevanovic, Mohammad Jafari, Branka Miljevic, Richard J. C. Brown, Puneet Verma, and Yi Guo
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Materials science ,Diesel exhaust ,Chemical substance ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Diesel engine ,medicine.disease_cause ,01 natural sciences ,Soot ,0104 chemical sciences ,Diesel fuel ,chemistry ,medicine ,General Materials Science ,Reactivity (chemistry) ,0210 nano-technology ,Carbon ,Oxygenate - Abstract
Four types of fuels blended with diesel in scaling proportion were used in a diesel engine to generate 13 different soot samples. The samples were characterised for their thermal-induced oxidation process with DSC and TGA from which the mass loss during each of three phases and 6 critical temperatures was obtained per sample. With the same samples, soot chemical structure was characterised by Raman, XPS and TEM. This analysis provided information on different carbon chemical structures, O/C ratio on the sample surface, and nanostructure (fringe length and tortuosity). It was observed that generally for oxygenated fuel blends, the soot samples are more reactive, have more O functional groups on the carbon layer edge plane and have smaller polyaromatic layer size than reference diesel soots, while aromatic fuel blends show the opposite trends. However, the trend was not distinctive for all the samples analysed. Nevertheless, the two groups of data are highly correlated which implies that the chemical structure is the underlying reason dominating the soot reactivity. Specifically, the soot samples with more O functional groups and/or C–C bonds on the edge plane, are more reactive, they lose more mass at the lower temperature range and require lower temperature to initiate oxidation.
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- 2020
3. Relationship between Atmospheric PM-Bound Reactive Oxygen Species, Their Half-Lives, and Regulated Pollutants: Investigation and Preliminary Model
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Steven E. Bottle, Hao Wang, Svetlana Stevanovic, Changda Wu, Boguang Wang, Reece Brown, Ziyuan Hu, and Zoran Ristovski
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China ,Ozone ,Atmospheric pollution ,010501 environmental sciences ,01 natural sciences ,Standard deviation ,Atmosphere ,chemistry.chemical_compound ,11. Sustainability ,Environmental Chemistry ,0105 earth and related environmental sciences ,Pollutant ,chemistry.chemical_classification ,Air Pollutants ,Reactive oxygen species ,General Chemistry ,Particulates ,chemistry ,13. Climate action ,Environmental chemistry ,Environmental science ,Environmental Pollutants ,Particulate Matter ,Reactive Oxygen Species ,Environmental Monitoring ,Carbon monoxide - Abstract
The concentration, nature, and persistence of particulate matter (PM)-bound reactive oxygen species (ROS) are of significant interest in understanding how atmospheric pollution affects health. However, the inherent difficulties in their measurement, particularly regarding the so-called "short-lived" ROS, have limited our understanding of their persistence and concentrations in the atmosphere. This paper aims to address this limitation through the analysis of PM-bound ROS measurements from the Particle Into Nitroxide Quencher (PINQ) system at an atmospheric monitoring site in the city of Heshan, Guangdong Province, China. The measured daily average and standard deviation for the measurement period was 0.050 ± 0.017 nmol·m-3. The averaged measured concentration of ROS per mass of PM and standard deviation was 0.0012 ± nmol·mg. The dataset was also correlated with standard pollutants, and a simplified model was constructed to separate the contributions of short-lived (t1/2 = 5 min) and long-lived (t1/2 ∼ infinity) ROS to total concentration using ozone, carbon monoxide, and PM mass. This showed that the short-lived ROS contribute an average of 33% of the daily PM-bound ROS burden over the measurement period, up to 52% of daily average on elevated days, and up to 71% for hourly averages. These results highlight the need for accurate measurements of short-lived ROS and provide the starting point for a general model to predict PM-bound ROS concentrations using widely available standard pollutants for future epidemiological research.
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- 2020
4. Comparison of manual and automatic approaches for characterisation of morphology and nanostructure of soot particles
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Edmund Pickering, Puneet Verma, Zoran Ristovski, Ali Zare, Natascha Savic, and Richard J. C. Brown
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Fluid Flow and Transfer Processes ,Atmospheric Science ,Environmental Engineering ,Nanostructure ,010504 meteorology & atmospheric sciences ,Computer science ,Mechanical Engineering ,Computation ,Fast Fourier transform ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image processing ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Pollution ,Tortuosity ,GeneralLiterature_MISCELLANEOUS ,Soot ,medicine ,Particle analysis ,Soot particles ,Algorithm ,0105 earth and related environmental sciences - Abstract
This study is an attempt to compare the manual and automatic approaches for analysis of the morphology and nanostructure of soot particles. The automated methodology is composed of two parts: soot particle analysis (morphology characterisation) and soot fringe analysis (nanostructure characterisation) such as fringe length, fringe tortuosity and fringe separation distance. In this study the application of Fast Fourier Transform (FFT) is introduced, which omits the manual selection of fringe pairs for measurement of fringe separation distance and aids fast computation. The parameters which effect the performance of automated approach were identified and optimised. The automated approach was applied to analyse images from different fuels. Using the optimised parameters, the performance of the automatic approach was tested against results obtained by the manual approach. The statistical comparison between two approaches showed similar results but with better accuracy for automated approach (lower standard error) and thus validates the functionality of the proposed methodology. The application of FFT in computation of fringe separation distance reduces the computation time and avoids biases of operator in selecting fringe pairs.
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- 2019
5. The cytotoxic, inflammatory and oxidative potential of coconut oil-substituted diesel emissions on bronchial epithelial cells at an air-liquid interface
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Kwun M. Fong, Md. Mostafizur Rahman, Andrew P.W. Banks, Ali Zare, Zoran Ristovski, Ian A. Yang, Svetlana Stevanovic, Rayleen V. Bowman, and Annalicia Vaughan
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Diesel exhaust ,food.ingredient ,Antioxidant ,Cell Survival ,Health, Toxicology and Mutagenesis ,medicine.medical_treatment ,010501 environmental sciences ,Diesel engine ,complex mixtures ,01 natural sciences ,03 Chemical Sciences, 05 Environmental Sciences, 06 Biological Sciences ,Diesel fuel ,food ,medicine ,Humans ,Plant Oils ,Environmental Chemistry ,Food science ,Vehicle Emissions ,0105 earth and related environmental sciences ,Chemistry ,Coconut oil ,technology, industry, and agriculture ,food and beverages ,Epithelial Cells ,General Medicine ,respiratory system ,Particulates ,Pollution ,respiratory tract diseases ,Oxidative Stress ,Vegetable oil ,Biofuel ,Biofuels ,Coconut Oil ,Particulate Matter ,Environmental Sciences ,Gasoline - Abstract
Diesel emissions contain high levels of particulate matter (PM) which can have a severe effect on the airways. Diesel PM can be effectively reduced with the substitution of diesel fuel with a biofuel such as vegetable oil. Unfortunately, very little is known about the cellular effects of these alternative diesel emissions on the airways. The aim of this study was to test whether coconut oil substitution in diesel fuel reduces the adverse effect of diesel emission exposure on human bronchial epithelial cells. Human bronchial epithelial cells were cultured at air-liquid interface for 7 days and exposed to diesel engine emissions from conventional diesel fuel or diesel fuel blended with raw coconut oil at low (10%), moderate (15%) and high (20%) proportions. Cell viability, inflammation, antioxidant production and xenobiotic metabolism were measured. Compared to conventional diesel, low fractional coconut oil substitution (10% and 15%) reduced inflammation and increased antioxidant expression, whereas higher fractional coconut oil (20%) reduced cell viability and increased inflammation. Therefore, cellular responses after exposure to alternative diesel emission are dependent on fuel composition.
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- 2019
6. Quantification of Particle-Bound Organic Radicals in Secondary Organic Aerosol
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Markus Kalberer, Steven J. Campbell, Branka Miljevic, Steven E. Bottle, Zoran Ristovski, and Svetlana Stevanovic
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Aerosols ,chemistry.chemical_classification ,Air Pollutants ,Reactive oxygen species ,Ozonolysis ,Atmosphere ,Radical ,General Chemistry ,010501 environmental sciences ,Particulates ,01 natural sciences ,Aerosol ,Ozone ,Reaction rate constant ,chemistry ,13. Climate action ,Environmental chemistry ,Monoterpenes ,Humans ,Environmental Chemistry ,Particle ,Particulate Matter ,Chemical composition ,0105 earth and related environmental sciences - Abstract
The chemical composition and evolution of secondary organic aerosol (SOA) in the atmosphere represents one of the largest uncertainties in our current understanding of air quality. Despite vast research, the toxicological mechanisms relating to adverse human health effects upon exposure to particulate matter are still poorly understood. Particle-bound reactive oxygen species (ROS) may substantially contribute to observed health effects by influencing aerosol oxidative potential (OP). The role of radicals in both the formation and aging of aerosol, as well as their contribution to aerosol OP, remains highly uncertain. The profluorescent spin trap BPEAnit (9,10-bis(phenylethynyl)anthracenenitroxide), previously utilized to study combustion-generated aerosol, has been applied to provide the first estimate of particle-bound radical concentrations in SOA. We demonstrate that SOA from different atmospherically important VOC precursors have different particle-bound radical concentrations, estimated for the ozonolysis of α-pinene (0.020 ± 0.0050 nmol/μg), limonene (0.0059 ± 0.0010 nmol/μg), and β-caryophyllene (0.0025 ± 0.00080 nmol/μg), highlighting the potential importance of OH-initiated formation of particle-bound organic radicals. Additionally, the lifetime of particle-bound radical species in α-pinene SOA was estimated, and a pseudo-first-order rate constant of k = 7.3 ± 1.7 × 10–3 s–1 was derived, implying a radical lifetime on the order of minutes.
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- 2019
7. Effect of sulphur and vanadium spiked fuels on particle characteristics and engine performance of auxiliary diesel engines
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Zoran Ristovski, Thuy Chu Van, Thomas J. Rainey, Timothy A. Bodisco, Nicholas C. Surawski, Kabir Adewale Suara, Farhad M. Hossain, S.M. Ashrafur Rahman, Joel Alroe, Branka Miljevic, and Richard J. C. Brown
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Materials science ,Common rail ,010504 meteorology & atmospheric sciences ,Particle number ,Health, Toxicology and Mutagenesis ,Analytical chemistry ,Vanadium ,chemistry.chemical_element ,010501 environmental sciences ,Toxicology ,Combustion ,Diesel engine ,01 natural sciences ,Diesel fuel ,Humans ,Gasoline ,Ships ,Vehicle Emissions ,0105 earth and related environmental sciences ,Air Pollutants ,General Medicine ,Pollution ,chemistry ,Particulate Matter ,Sulfur ,Turbocharger - Abstract
Particle emission characteristics and engine performance were investigated from an auxiliary, heavy duty, six-cylinder, turbocharged and after-cooled diesel engine with a common rail injection system using spiked fuels with different combinations of sulphur (S) and vanadium (V) spiking. The effect of fuel S content on both particle number (PN) and mass (PM) was clearly observed in this study. Higher PN and PM were observed for fuels with higher S contents at all engine load conditions. This study also found a correlation between fuel S content and nucleation mode particle number concentration which have more harmful impact on human health than larger particles. The highest PN and PM were observed at partial load conditions. In addition, S in fuel resulted in higher viscosity of spiked fuels, which led to lower engine blow-by. Fuel V content was observed in this study, evidencing that it had no clear effect on engine performance and emissions. Increased engine load also resulted in higher engine blow-by. The lower peak of in-cylinder pressure observed at both pre-mixed and diffusion combustion phases with the spiked fuels may be associated with the lower energy content in the fuel blends compared to diesel fuel.
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- 2018
8. Investigating particles, VOCs, ROS produced from mosquito-repellent incense emissions and implications in SOA formation and human health
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Xinran Zheng, Jianmin Chen, Hongli Wang, Svetlana Stevanovic, Zhiyuan Xiang, Jun Gao, Jing Liu, Lin Wang, Zoran Ristovski, Mingzhou Yu, Lina Wang, and Shengqiang Zhu
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Environmental Engineering ,010504 meteorology & atmospheric sciences ,Particle number ,Chemistry ,Gaseous pollutants ,Geography, Planning and Development ,Building and Construction ,010501 environmental sciences ,Particulates ,01 natural sciences ,Incense ,Aerosol ,Human health ,chemistry.chemical_compound ,Environmental chemistry ,Methanol ,Benzene ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
Mosquito-repellent incense is popular for dispelling mosquitos indoors in Asia, Africa and South America. However, the released large amounts of particulate and gaseous pollutants have a negative effect on human health. We conducted real-time measurements in laboratory chamber to characterize the particulate matter, volatile organic species (VOCs), reactive oxygen species (ROS) released from the Disc and Liquid mosquito-repellent incenses using. And further to evaluate the secondary organic aerosol (SOA) formation potential indoors attributed to the main VOCs species and the health exposure risk. Results show that the disk type produces more particles but less VOCs. The particle number concentration produced by the disc and the liquid types were 130085 part/cm3 and 7963 part/cm3, respectively. The former one concentrated at the size bins below 100 nm, in comparison with the latter one mainly between 100 and 500 nm. Burning disk type produced particles carrying much higher oxidative potential (OP) 0.0430 nmol/mg. The VOCs species produced by the disc and liquid types were mainly VOC to m/z 79(benzene) and VOC to m/z 33(methanol), and the corresponding benzene concentration were 40.7 ppb and 58.6 ppb, respectively, and the methanol concentration was 26.3 ppb and 35.2 ppb, respectively. SOA formation rate related to benzene of liquid type using was larger compared to disk type, which was 0.015 mg/(m3s) and 0.012 mg/(m3s), respectively. The health risk assessment coefficient of the disc and liquid types were 6.2×10−5 and 9.1×10−5, respectively, both exceeding the limit of 1×10−6, indicating mosquito-repellent incenses is harmful to human health.
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- 2018
9. Observations of clouds, aerosols, precipitation, and surface radiation over the Southern Ocean: An overview of CAPRICORN, MARCUS, MICRE and SOCRATES
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Julie Haggerty, Sonia M. Kreidenweis, Greg Roberts, Luke T. Cravigan, Christina S. McCluskey, Alain Protat, Kevin J. Sanchez, Robyn Schofield, Francisco Lang, Yang Wang, Yi Huang, Steve Siems, Martin Schnaiter, Isabel L. McCoy, Kathryn A. Moore, Cory A. Wolff, Junshik Um, Georges Saliba, Paul J. DeMott, Andrew Klekociuk, Adrian McDonald, Lynn M. Russell, Simon P. Alexander, C. H. Twohy, Robert Wood, Mike Harvey, Saisai Ding, Ezra J. T. Levin, Christopher W. Fairall, Robert M. Rauber, Wei Wu, Melita Keywood, Son C.H. Truong, John J. D'Alessandro, Marc Mallet, Darin W. Toohey, Thomas C. J. Hill, Greg M. McFarquhar, Zoran Ristovski, Andrew Gettelman, Jeffrey L. Stith, Bryan Rainwater, Charles G. Bardeen, Christopher S. Bretherton, Roger Marchand, Rachel Atlas, Ruhi S Humphries, Emma Järvinen, Jay Mace, Sonia Lasher-Trapp, Jørgen Jensen, Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, Centre national de recherches météorologiques (CNRM), Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Cloud top ,0207 environmental engineering ,02 engineering and technology ,Atmospheric sciences ,01 natural sciences ,Aerosol ,Troposphere ,Lidar ,13. Climate action ,Radiative transfer ,Cloud condensation nuclei ,Environmental science ,14. Life underwater ,Precipitation ,Shortwave radiation ,020701 environmental engineering ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
Weather and climate models are challenged by uncertainties and biases in simulating Southern Ocean (SO) radiative fluxes that trace to a poor understanding of cloud, aerosol, precipitation, and radiative processes, and their interactions. Projects between 2016 and 2018 used in situ probes, radar, lidar, and other instruments to make comprehensive measurements of thermodynamics, surface radiation, cloud, precipitation, aerosol, cloud condensation nuclei (CCN), and ice nucleating particles over the SO cold waters, and in ubiquitous liquid and mixed-phase clouds common to this pristine environment. Data including soundings were collected from the NSF–NCAR G-V aircraft flying north–south gradients south of Tasmania, at Macquarie Island, and on the R/V Investigator and RSV Aurora Australis. Synergistically these data characterize boundary layer and free troposphere environmental properties, and represent the most comprehensive data of this type available south of the oceanic polar front, in the cold sector of SO cyclones, and across seasons. Results show largely pristine environments with numerous small and few large aerosols above cloud, suggesting new particle formation and limited long-range transport from continents, high variability in CCN and cloud droplet concentrations, and ubiquitous supercooled water in thin, multilayered clouds, often with small-scale generating cells near cloud top. These observations demonstrate how cloud properties depend on aerosols while highlighting the importance of dynamics and turbulence that likely drive heterogeneity of cloud phase. Satellite retrievals confirmed low clouds were responsible for radiation biases. The combination of models and observations is examining how aerosols and meteorology couple to control SO water and energy budgets.
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- 2021
10. Modeling Indoor Particulate Matter and Small Ion Concentration Relationship—A Comparison of a Balance Equation Approach and Data Driven Approach
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Predrag Kolarž, Milena Jovasevic-Stojanovic, Zoran Ristovski, Rastko Jovanović, Milena Davidović, and Miloš D. Davidović
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010504 meteorology & atmospheric sciences ,chemistry.chemical_element ,Radon ,010501 environmental sciences ,01 natural sciences ,lcsh:Technology ,lcsh:Chemistry ,Indoor air quality ,Approximation error ,11. Sustainability ,Linear regression ,General Materials Science ,Statistical physics ,Instrumentation ,Air quality index ,lcsh:QH301-705.5 ,0105 earth and related environmental sciences ,Fluid Flow and Transfer Processes ,particulate matter ,small ions ,Artificial neural networks ,lcsh:T ,Process Chemistry and Technology ,General Engineering ,Statistical model ,radon ,Particulates ,Small ions ,lcsh:QC1-999 ,Computer Science Applications ,chemistry ,lcsh:Biology (General) ,lcsh:QD1-999 ,13. Climate action ,lcsh:TA1-2040 ,Balance equation ,linear regression ,Environmental science ,Particulate matter ,lcsh:Engineering (General). Civil engineering (General) ,artificial neural networks ,lcsh:Physics ,indoor air quality - Abstract
In this work we explore the relationship between particulate matter (PM) and small ion (SI) concentration in a typical indoor elementary school environment. A range of important air quality parameters (radon, PM, SI, temperature, humidity) were measured in two elementary schools located in urban background and suburban area in Belgrade city, Serbia. We focus on an interplay between concentrations of radon, small ions (SI) and particulate matter (PM) and for this purpose, we utilize two approaches. The first approach is based on a balance equation which is used to derive approximate relation between concentration of small ions and particulate matter. The form of the obtained relation suggests physics based linear regression modelling. The second approach is more data driven and utilizes machine learning techniques, and in this approach, we develop a more complex statistical model. This paper attempts to put together these two methods into a practical statistical modelling approach that would be more useful than either approach alone. The artificial neural network model enabled prediction of small ion concentration based on radon and particulate matter measurements. Models achieved median absolute error of about 40 ions/cm3 and explained variance of about 0.7. This could potentially enable more simple measurement campaigns, where a smaller number of parameters would be measured, but still allowing for similar insights. © 2020 by the authors.
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- 2020
11. Soot particle morphology and nanostructure with oxygenated fuels: A comparative study into cold-start and hot-start operation
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Puneet Verma, Chiemeriwo Godday Osuagwu, Richard J. C. Brown, Edmund Pickering, Yi Guo, Svetlana Stevanovic, Ali Zare, Zoran Ristovski, and Mohammad Jafari
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Nanostructure ,Materials science ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,Toxicology ,medicine.disease_cause ,Diesel engine ,complex mixtures ,01 natural sciences ,Microscopy, Electron, Transmission ,Soot ,medicine ,Particle Size ,0105 earth and related environmental sciences ,Vehicle Emissions ,Cold start (automotive) ,Aggregate (composite) ,General Medicine ,Pollution ,Nanostructures ,Fractals ,Chemical engineering ,Transmission electron microscopy ,Radius of gyration ,Particle ,Gasoline - Abstract
This study investigates the morphology and nanostructure of soot particles during cold-start and hot-start engine operation of a diesel engine using oxygenated fuels. The soot samples were analysed using transmission electron microscopy. The oxygen content in the fuel was varied between 0 and 12%. The results showed that the primary particles during cold-start have significantly smaller size when compared to hot-start engine operation. The addition of oxygenated fuels also resulted in smaller sized primary particles. Smaller radius of gyration and higher fractal dimension of soot aggregates during cold-start would mean smaller aggregate size with a more compact structure. Shorter fringes with a higher inter-fringe spacing for cold-start would mean lower graphitisation of soot particles that could be related to higher oxidation reactivity of soot particles.
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- 2020
12. Role of semi-volatile particulate matter in gas-particle partitioning leading to change in oxidative potential
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Svetlana Stevanovic, Zoran Ristovski, Nirmal Kumar Gali, Zhi Ning, and Reece Brown
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Aerosols ,Air Pollutants ,Volatile Organic Compounds ,010504 meteorology & atmospheric sciences ,Particle number ,Chemistry ,Health, Toxicology and Mutagenesis ,Thermal desorption ,General Medicine ,Carbon black ,010501 environmental sciences ,Particulates ,Toxicology ,01 natural sciences ,Pollution ,Aerosol ,Oxidative Stress ,Environmental chemistry ,Particle-size distribution ,Mass concentration (chemistry) ,Particle ,Particulate Matter ,Particle Size ,0105 earth and related environmental sciences ,Environmental Monitoring - Abstract
Atmospheric semi-volatile organic compounds (SVOCs) are complex in their chemical and toxicological characteristics with sources from both primary combustion emissions and secondary oxygenated aerosol formation processes. In this study, thermal desorption of PM2.5 in association with online measurement of reactive oxygen species (ROS) was carried out to study the role of SVOCs in its gas-particle partitioning. The mass concentrations of PM2.5, black carbon (BC) and p-PAHs downstream of a thermodenuder were measured online at different temperature settings (25, 50, 100, and 200 °C) to characterize PM physico-chemical properties. While the mass concentrations of PM2.5 and p-PAHs reduced to ∼34% at 200 °C compared to that in ambient temperature, BC mass concentration has decreased by 30% at the highest temperature. Furthermore, the submicron particle size distribution showed reduced particle number concentration in Aitken mode at 200 °C heating. The ROS, measured by Particle-into-Nitroxide-Quencher, also showed reduction and followed a similar trend with PM measurements, where the total ROS decreased by 12%, 31%, and 53% at 50 °C, 100 °C, and 200 °C, respectively, compared to the ambient sample. When a HEPA filter was included in the upstream of samples, 39% of gas phase ROS reduction was observed at 200 °C. This provided a good estimate of the contribution of SVOCs in ROS production in PM2.5, where decreased SVOCs concentration at 200 °C increased the percentage of particle surface area. This concludes that the surface chemistry of these organic coatings on the particles is important for assessing the health impacts of PM.
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- 2020
13. Assessing the Effect of Reactive Oxygen Species and Volatile Organic Compound Profiles Coming from Certain Types of Chinese Cooking on the Toxicity of Human Bronchial Epithelial Cells
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Lina Wang, Farhad Salimi, Jianmin Chen, Svetlana Stevanovic, Lin Wang, Li Li, Yaqin Gao, Jun Gao, Shengao Jing, Hongli Wang, Zoran Ristovski, Linyuan Zhang, and Xinran Zheng
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food.ingredient ,Rapeseed ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Soybean oil ,food ,medicine ,Environmental Chemistry ,Humans ,Plant Oils ,Volatile organic compound ,Food science ,Cooking ,Carcinogen ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Reactive oxygen species ,Volatile Organic Compounds ,Autoxidation ,Epithelial Cells ,General Chemistry ,chemistry ,Toxicity ,Reactive Oxygen Species ,Oxidative stress - Abstract
The International Agency of Research on Cancer identifies high-temperature frying, which features prominently in Chinese cooking, as producing group 2A carcinogens. This study simultaneously characterized particulate and gaseous-phase cooking emissions, monitored their reactive oxygen species (ROS) concentrations, and evaluated their impact on genetic damage and expression in exposed human bronchial epithelial cells. Five types of edible oil, three kinds of seasonings, and two dishes were assessed. Among tested edible oils, heating of soybean oil released the largest particle number concentration (2.09 × 1013 particles/(g cooking material and oil)·h) and volatile organic compounds (VOCs) emissions (12103.42 μg/(g cooking material and oil)·h). Heating of lard produced the greatest particle mass concentration (0.75 mg/(g cooking material and oil)·h). The main finding was that sunflower and rapeseed oils produced the highest ROS concentrations (80.48 and 71.75 nmol/(g cooking material and oil)·h, respectively). ROS formation most likely occurred during the autoxidation of both polyunsaturated and monounsaturated fatty acids. Among all the tested parameters, only ROS concentrations exhibited consistency with cell viability and showed significant correlations with the expression levels of CYP1A1, HIF-1a, and especially with IL-8 (the marker for oxidative stress within the cell). These findings indicate that ROS concentration is potentially a suitable metric for direct assessment of exposure levels and potential toxicity.
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- 2020
14. Low-cost PM2.5 Sensors: An Assessment of Their Suitability for Various Applications
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Kang Ho Ahn, Adrian Mabon, Phong K. Thai, Benjamin J. Mullins, Akwasi Bonsu Asumadu-Sakyi, Lidia Morawska, Mawutorli Nyaku, Zoran Ristovski, Xiaoting Liu, Jian Gao, Mandana Mazaheri, Yvonne Scorgie, Matthew Dunbabin, Gavin Fisher, and Rohan Jayaratne
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Accuracy and precision ,010504 meteorology & atmospheric sciences ,business.industry ,01 natural sciences ,Pollution ,Air quality monitoring ,Range (aeronautics) ,Environmental Chemistry ,Environmental science ,Process engineering ,business ,Air quality index ,0105 earth and related environmental sciences ,Field conditions - Abstract
Recently, there has been a substantial increase in the availability and use of low-cost particulate matter sensors in a wide range of air quality applications. They carry the promise of revolutionising air quality monitoring, yet considerable reservations exist regarding their performance and capabilities, thus hindering the broader-scale utilization of these devices. In order to address these concerns and assess their feasibility and accuracy for various applications, we evaluated six low-cost PM2.5 sensors (the Sharp GP2Y1010AU0F, Shinyei PPD42NS, Plantower PMS1003, Innociple PSM305, Nova SDS011 and Nova SDL607) in laboratory and field conditions using two combustion aerosols, concrete dust and ambient particles. In assessing the performance of these sensors, we focussed on indicators such as the linearity, accuracy and precision, critically differentiating between these qualities, and employed inter-comparison (the coefficient of determination, R2). In the laboratory, all sensors responded well, with an R2 > 0.91 when the PM2.5 concentration was > 50 µg m–3, as measured by the DustTrak. In particular, the PMS1003 demonstrated good accuracy and precision in both laboratory and ambient conditions. However, some limitations were noted for the tested sensors at lower concentrations. For example, the Sharp and Shinyei sensors showed poor correlations (R2
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- 2020
15. Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols
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Melita Keywood, Alastair G. Williams, Ruhi S Humphries, Paul Selleck, Branka Miljevic, Graham R. Johnson, Scott D. Chambers, Zoran Ristovski, Joel Alroe, and Luke T. Cravigan
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Atmospheric sciences ,Sea spray ,01 natural sciences ,lcsh:QC1-999 ,Aerosol ,Troposphere ,lcsh:Chemistry ,lcsh:QD1-999 ,13. Climate action ,Synoptic scale meteorology ,Environmental science ,Cloud condensation nuclei ,Climate model ,Precipitation ,14. Life underwater ,Air mass ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
Cloud–radiation interactions over the Southern Ocean are not well constrained in climate models, in part due to uncertainties in the sources, concentrations, and cloud-forming potential of aerosol in this region. To date, most studies in this region have reported measurements from fixed terrestrial stations or a limited set of instrumentation and often present findings as broad seasonal or latitudinal trends. Here, we present an extensive set of aerosol and meteorological observations obtained during an austral summer cruise across the full width of the Southern Ocean south of Australia. Three episodes of continental-influenced air masses were identified, including an apparent transition between the Ferrel atmospheric cell and the polar cell at approximately 64∘ S, and accompanied by the highest median cloud condensation nuclei (CCN) concentrations, at 252 cm−3. During the other two episodes, synoptic-scale weather patterns diverted air masses across distances greater than 1000 km from the Australian and Antarctic coastlines, respectively, indicating that a large proportion of the Southern Ocean may be periodically influenced by continental air masses. In all three cases, a highly cloud-active accumulation mode dominated the size distribution, with up to 93 % of the total number concentration activating as CCN. Frequent cyclonic weather conditions were observed at high latitudes and the associated strong wind speeds led to predictions of high concentrations of sea spray aerosol. However, these modelled concentrations were not achieved due to increased aerosol scavenging rates from precipitation and convective transport into the free troposphere, which decoupled the air mass from the sea spray flux at the ocean surface. CCN concentrations were more strongly impacted by high concentrations of large-diameter Aitken mode aerosol in air masses which passed over regions of elevated marine biological productivity, potentially contributing up to 56 % of the cloud condensation nuclei concentration. Weather systems were vital for aerosol growth in biologically influenced air masses and in their absence ultrafine aerosol diameters were less than 30 nm. These results demonstrate that air mass meteorological history must be considered when modelling sea spray concentrations and highlight the potential importance of sub-grid-scale variability when modelling atmospheric conditions in the remote Southern Ocean.
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- 2019
16. Measurements of Oxidative Potential of Particulate Matter at Belgrade Tunnel; Comparison of BPEAnit, DTT and DCFH Assays
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Alena Bartonova, Svetlana Stevanovic, Farhad Salimi, Jasmina Savić, Dragan Manojlović, Zoran Ristovski, Milena Jovasevic-Stojanovic, Maja Jovanović, Reece Brown, and Steven E. Bottle
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Diesel exhaust ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,Analytical chemistry ,Oxidative phosphorylation ,PM2.5 ,010501 environmental sciences ,01 natural sciences ,Dithiothreitol ,Article ,chemistry.chemical_compound ,PM10 ,Particle Size ,0105 earth and related environmental sciences ,Morning ,Total organic carbon ,Anthracenes ,reactive oxygen species ,Air Pollutants ,online and offline OP probes ,Public Health, Environmental and Occupational Health ,Particulates ,Fluoresceins ,Carbon ,Oxidative Stress ,chemistry ,Alkynes ,Late afternoon ,Particulate Matter ,Elemental carbon ,Oxidation-Reduction ,Environmental Monitoring - Abstract
To estimate the oxidative potential (OP) of particulate matter (PM), two commonly used cell-free, molecular probes were applied: dithiothreitol (DTT) and dichloro-dihydro-fluorescein diacetate (DCFH-DA), and their performance was compared with 9,10-bis (phenylethynyl) anthracene-nitroxide (BPEAnit). To the best of our knowledge, this is the first study in which the performance of the DTT and DCFH has been compared with the BPEAnit probe. The average concentrations of PM, organic carbon (OC) and elemental carbon (EC) for fine (PM2.5) and coarse (PM10) particles were determined. The results were 44.8 ± 13.7, 9.8 ± 5.1 and 9.3 ± 4.8 µg·m−3 for PM2.5 and 75.5 ± 25.1, 16.3 ± 8.7 and 11.8 ± 5.3 µg·m−3 for PM10, respectively, for PM, OC and EC. The water-soluble organic carbon (WSOC) fraction accounted for 42 ± 14% and 28 ± 9% of organic carbon in PM2.5 and PM10, respectively. The average volume normalized OP values for the three assays depended on both the sampling periods and the PM fractions. The OPBPEAnit had its peak at 2 p.m.; in the afternoon, it was three times higher compared to the morning and late afternoon values. The DCFH and BPEAnit results were correlated (r = 0.64), while there was no good agreement between the BPEAnit and the DTT (r = 0.14). The total organic content of PM does not necessarily represent oxidative capacity and it shows varying correlation with the OP. With respect to the two PM fractions studied, the OP was mostly associated with smaller particles.
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- 2019
17. Application of a Fluorescent Probe for the Online Measurement of PM-Bound Reactive Oxygen Species in Chamber and Ambient Studies
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Steven E. Bottle, Branka Miljevic, Jun Zhao, Wei Song, Zoran Ristovski, Zachary Brown, Reece Brown, Svetlana Stevanovic, Mingfu Cai, Shengzhen Zhou, and Xinming Wang
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Nitroxide mediated radical polymerization ,Materials science ,010504 meteorology & atmospheric sciences ,Resolution (mass spectrometry) ,aerosol ,Analytical chemistry ,010501 environmental sciences ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,Article ,Analytical Chemistry ,HEPA ,Fluorometer ,oxidative stress ,lcsh:TP1-1185 ,BPEAnit ,Electrical and Electronic Engineering ,Instrumentation ,0105 earth and related environmental sciences ,reactive oxygen species ,profluorescent nitroxide ,particulate matter ,Particulates ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Aerosol ,Particle - Abstract
This manuscript details the application of a profluorescent nitroxide (PFN) for the online quantification of radical concentrations on particulate matter (PM) using an improved Particle Into Nitroxide Quencher (PINQ). A miniature flow-through fluorimeter developed specifically for use with the 9,10-bis(phenylethynyl)anthracene-nitroxide (BPEAnit) probe was integrated into the PINQ, along with automated gas phase corrections through periodic high efficiency particle arrestor (HEPA) filtering. The resulting instrument is capable of unattended sampling and was operated with a minimum time resolution of 2.5 min. Details of the fluorimeter design and examples of data processing are provided, and results from a chamber study of side-stream cigarette smoke and ambient monitoring campaign in Guangzhou, China are presented. Primary cigarette smoke was shown to have both short-lived (t1/2 = 27 min) and long-lived (t1/2 = indefinite) PM-bound reactive oxygen species (ROS) components which had previously only been observed in secondary organic aerosol (SOA).
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- 2019
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18. Engine blow-by with oxygenated fuels: A comparative study into cold and hot start operation
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Nurun Nabi, Richard J. C. Brown, Brett J. Mitchell, Ali Zare, Timothy A. Bodisco, Farhad M. Hossain, and Zoran Ristovski
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Cold start (automotive) ,Biodiesel ,Common rail ,Waste management ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Building and Construction ,010501 environmental sciences ,Diesel engine ,01 natural sciences ,Pollution ,Industrial and Manufacturing Engineering ,Diesel fuel ,General Energy ,Lubricity ,Biofuel ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Electrical and Electronic Engineering ,0105 earth and related environmental sciences ,Civil and Structural Engineering ,Turbocharger - Abstract
T{(NPI), 1999 #117}his research compares the effects of oxygenated fuels on engine blow-by during engine cold and hot start operation using a common rail, turbocharged diesel engine. Diesel, waste cooking biodiesel and a highly oxygenated additive, triacetin, were used to make a range of fuel oxygen contents (0–13.57%). This study investigated engine blow-by and its correlation with indicated, brake and friction power; and blow-by normalised by different parameters. Result showed that neat diesel produces higher blow-by during cold start than the oxygenated fuels. There was a strong correlation between blow-by and indicated power, and the fuel calorific value was identified as a leading factor. To further analyse the results, this study normalised the engine blow-by by power to reveal the other influences on engine blow-by. The result verified the strong influence of power. This study also furthered the analysis by normalising the blow-by data by exhaust flow rate, intake air flow rate and injected fuel flow rate. It was discovered that oxygenated fuels perform better between hot and cold start, when compared to diesel. The blow-by inhibited properties of oxygenated fuels, such as higher lubricity and viscosity may be the cause for better performance of oxygenated fuels during cold start.
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- 2017
19. Biomass burning emissions in north Australia during the early dry season: an overview of the 2014 SAFIRED campaign
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Fabienne Reisen, Marc Mallet, Dean Howard, Clare Paton-Walsh, Leah R. Williams, Marcel van der Schoot, Andelija Milic, Branka Miljevic, Anthony Morrison, Paul Selleck, Zoran Ristovski, Peter F. Nelson, R. W. Gillett, Min Cheng, Stephen R. Wilson, Luke T. Cravigan, Scott D. Chambers, Maximilien Desservettaz, Jason Ward, Sylvester Werczynski, E. Rohan Jayaratne, David W. T. Griffith, Graham Kettlewell, Alastair G. Williams, Suzie B. Molloy, James Harnwell, Grant C. Edwards, Sarah Lawson, V. Holly L. Winton, Joel Alroe, Brad Atkinson, Xianyu Wang, and Melita Keywood
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,chemistry.chemical_element ,Biomass ,Radon ,010501 environmental sciences ,15. Life on land ,Atmospheric sciences ,01 natural sciences ,complex mixtures ,lcsh:QC1-999 ,Aerosol ,Atmosphere ,lcsh:Chemistry ,chemistry ,lcsh:QD1-999 ,13. Climate action ,Greenhouse gas ,Dry season ,Environmental science ,Biomass burning ,Air mass ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
The SAFIRED (Savannah Fires in the Early Dry Season) campaign took place from 29 May until 30 June 2014 at the Australian Tropical Atmospheric Research Station (ATARS) in the Northern Territory, Australia. The purpose of this campaign was to investigate emissions from fires in the early dry season in northern Australia. Measurements were made of biomass burning aerosols, volatile organic compounds, polycyclic aromatic carbons, greenhouse gases, radon, speciated atmospheric mercury and trace metals. Aspects of the biomass burning aerosol emissions investigated included; emission factors of various species, physical and chemical aerosol properties, aerosol aging, micronutrient supply to the ocean, nucleation, and aerosol water uptake. Over the course of the month-long campaign, biomass burning signals were prevalent and emissions from several large single burning events were observed at ATARS.Biomass burning emissions dominated the gas and aerosol concentrations in this region. Dry season fires are extremely frequent and widespread across the northern region of Australia, which suggests that the measured aerosol and gaseous emissions at ATARS are likely representative of signals across the entire region of north Australia. Air mass forward trajectories show that these biomass burning emissions are carried north-west over the Timor Sea and could influence the atmosphere over Indonesia and the tropical atmosphere over the Indian Ocean. Here we present characteristics of the biomass burning observed at the sampling site and provide an overview of the more specific outcomes of the SAFIRED campaign.
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- 2017
20. Reductions in diesel emissions including PM and PN emissions with diesel-biodiesel blends
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Farhad M. Hossain, Zoran Ristovski, Richard J. C. Brown, Ali Zare, and Md. Nurun Nabi
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Biodiesel ,Engineering ,Diesel exhaust ,Common rail ,Waste management ,Renewable Energy, Sustainability and the Environment ,business.industry ,020209 energy ,Strategy and Management ,02 engineering and technology ,010501 environmental sciences ,Particulates ,Diesel engine ,01 natural sciences ,7. Clean energy ,Industrial and Manufacturing Engineering ,Diesel fuel ,13. Climate action ,0202 electrical engineering, electronic engineering, information engineering ,business ,NOx ,0105 earth and related environmental sciences ,General Environmental Science ,Turbocharger - Abstract
The current work is an experimental investigation to examine the influence of biodiesel derived from waste cooking oil on engine performance and exhaust emissions. Experiments were conducted with three biodiesel blends at 20%, 40%, and 60% (by volume). A petroleum diesel fuel was used as a reference fuel. The primary purpose of this study was to observe both particulate matter (PM) and particle number (PN) emissions for the three biodiesel blends. Furthermore, the blow-by emissions of the biodiesel blends were also studied. All measurements were conducted in a six-cylinder turbocharged diesel engine with a high-pressure common rail injection system in compliance with a 13-Mode European Stationary Cycle (ESC).
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- 2017
21. Particle exposure level and potential health risks of domestic Chinese cooking
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Bowen Du, Lin Wang, Zoran Ristovski, Svetlana Stevanovic, Jun Gao, Jie Chen, and Lina Wang
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Vital capacity ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Waste management ,business.industry ,Geography, Planning and Development ,Building and Construction ,Urine ,010501 environmental sciences ,01 natural sciences ,law.invention ,Toxicology ,Exposure level ,Blood pressure ,law ,Exhaled nitric oxide ,Ventilation (architecture) ,Medicine ,Respiratory system ,business ,Lung function ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
Cooking oil fumes (COF) contain massive particulate matter. Chronic exposure to cooking oil fumes constitutes a health hazard. This study aims to measure the COF exposure level during a typical Chinese domestic cooking process and evaluate whether a short-term exposure at this level entails deleterious cardiopulmonary, inflammatory health effects and oxidative stress. 6 young healthy students were recruited to conduct a contrast experiment in a kitchen chamber. Every participant cooked successively three typical Chinese dishes twice a day for two consecutive days, during which the particle mass and number concentration in the breathing zone were monitored. A slot around the pan supplied air at varied rates during cooking, resulting in altered exposure dose. Before the experiment and after their cooking, the levels of biomarkers were measured including 8 biomarkers for lung function, fractional exhaled nitric oxide for respiratory inflammation, blood pressure for cardiovascular risks and three biomarkers in urine for oxidative stress. PM2.5 concentration and particle number concentration in 0.02–6.25 μm were 10.97 ± 9.53 mg/m3 and 23.12 ± 18.27 103/cm3 in the breathing zone under normal ventilation condition and might triple under poor ventilation. Health measurements showed that forced vital capacity and vital capacity declined significantly after the fourth cooking process. Peak expiratory flow rose significantly after the third cooking. Meanwhile, forced expiratory flows at 25% of the vital capacity also increased significantly after both the third and fourth cooking. However, a single short-term exposure to COF of around 20 min does not explicitly entail significant health risks.
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- 2017
22. In-cylinder pressure reconstruction by engine acoustic emission
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Puneet Verma, Pietro Borghesani, Richard J. C. Brown, Ali Zare, Zoran Ristovski, Mohammad Jafari, and Timothy A. Bodisco
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0209 industrial biotechnology ,Signal processing ,Crank ,Materials science ,Mechanical Engineering ,Acoustics ,Aerospace Engineering ,02 engineering and technology ,01 natural sciences ,Pressure sensor ,Computer Science Applications ,symbols.namesake ,020901 industrial engineering & automation ,Internal combustion engine ,Mean effective pressure ,Acoustic emission ,Control and Systems Engineering ,0103 physical sciences ,Signal Processing ,Cepstrum ,symbols ,Hilbert transform ,010301 acoustics ,Civil and Structural Engineering - Abstract
The importance of the in-cylinder pressure transducer has been proven in revealing the information about combustion and exhaust pollution formation, as well as for its capability to classify knock. Due to their high price, they are not used commercially for engine health monitoring, which is of significant importance. Hence, this study will investigate the reconstruction of the in-cylinder pressure trace using a structure-borne acoustic emission (AE) sensor, which are relatively low cost sensors. As shown in the literature, AE indicators show a strong correlation with in-cylinder pressure parameters in both time and crank angle domain. In this study, to avoid the effect of engine speed fluctuations, the reconstruction is done in the crank angle domain by means of the Hilbert transform of AE. Complex cepstrum signal processing analysis with a feed-forward neural network is used to generate a reconstruction regime. Furthermore, the reconstructed signals are used to determine some of the important in-cylinder parameters such as peak pressure (PP), peak pressure timing (PPT), indicated mean effective pressure (IMEP) and pressure rise rate. Results showed that the combination of cepstrum analysis with neural network is capable of reconstructing pressure using AE, regardless of engine load, speed and fuel type. The reconstructed pressure can be used to reliably determine PP and PPT. IMEP can be estimated as well in a reasonable range.
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- 2021
23. Role of Chinese cooking emissions on ambient air quality and human health
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Hongli Wang, Lina Wang, Jun Gao, Farhad Salimi, Zoran Ristovski, Li Li, Zhiyuan Xiang, and Svetlana Stevanovic
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China ,Environmental Engineering ,Peat ,010504 meteorology & atmospheric sciences ,Taiwan ,010501 environmental sciences ,Combustion ,01 natural sciences ,Human health ,Air Pollution ,Humans ,Environmental Chemistry ,Coal ,Cooking ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Pollutant ,Volatilisation ,Waste management ,business.industry ,Chemistry ,Pollution ,Ambient air ,Air Pollution, Indoor ,Stove ,Hong Kong ,Particulate Matter ,business ,Environmental Monitoring - Abstract
Chinese-style cooking often involves volatilization of oils which can potentially produce a large number of pollutants, which have adverse impact on environment and human health. Therefore, we have reviewed 75 published studies associated with research topic among Mainland China, Hong Kong and Taiwan, involving studies on the roles of food ingredients and oil type, cooking style impacting on generated pollutants, and human health. The highest concentration occurred including: 1) when peat, wood, and raw coal were used in stoves; 2) olive oil was adopted; 3) cooking with high temperatures; and 4) without cleaning technology. We conclude that PM concentrations for cooking emissions were between 0.14 and 24.46mg/cm3. VOC concentrations varied from 0.35 to 3.41mg/m3. Barbeque produced the greatest mass concentrations compared to Sichuan cuisine, canteen and other restaurants. The PAHs concentration emitted from the exhaust stacks, dining area and kitchen ranged from 0.0175μg/m3 to 83μg/m3. The largest amount of gaseous pollutants emitted was recorded during incomplete combustion of fuel or when a low combustion efficiency (CO2/ (CO+CO2)
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- 2017
24. Emission factors of trace gases and particles from tropical savanna fires in Australia
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Marcel V. Vanderschoot, Grant C. Edwards, Zoran Ristovski, Marc Mallet, Dean Howard, Brad Atkinson, Maximilien Desservettaz, Jason Ward, Clare Paton-Walsh, Melita Keywood, Andelija Milic, David W. T. Griffith, Graham Kettlewell, and Branka Miljevic
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Smoke ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Atmospheric sciences ,complex mixtures ,01 natural sciences ,Trace gas ,Aerosol ,Tropical savanna climate ,chemistry.chemical_compound ,Geophysics ,chemistry ,Space and Planetary Science ,Greenhouse gas ,parasitic diseases ,Dry season ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Ecosystem ,Sulfate ,0105 earth and related environmental sciences - Abstract
Savanna fires contribute significantly to global aerosol loading and hence to the earth's radiative budget. Modelling of the climatic impact of these aerosols is made difficult due to a lack of knowledge of their size distribution. Australia is the third largest source of global carbon emissions from biomass burning, with emissions dominated by tropical savanna fires. Despite this, only a few previous studies have reported emission factors of trace gases from this important ecosystem and there are no previous published emission factors for the aerosol properties reported here for Australian savanna fires. In June 2014, the SAFIRED campaign (Savanna Fires in the Early Dry season) took place in the northern territory of Australia, with the purpose of investigating emissions and aging of aerosols from Australian savanna fires. This paper presents observed enhancement ratios and inferred emission factors of trace gases (CO2, CO, CH4, N2O and gaseous elemental mercury), particles over different size modes (Aitken and accumulation) and speciated aerosols components (organics, sulfate, nitrate, ammonium and chloride). Nine smoke events were identified from the data using large enhancements in CO and/or aerosol data to indicate biomass burning event. The results reported in this paper include the first emission factors for Aitken and accumulation mode aerosols from savanna fires, providing useful size information to enable better modelling of the climatic impact of this important source of global aerosols.
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- 2017
25. Oxidative potential of gas phase combustion emissions - An underestimated and potentially harmful component of air pollution from combustion processes
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Farzaneh Hedayat, Zoran Ristovski, Xiaolin Wang, Annalicia Vaughan, Ali Zare, Hongxia Wang, Steven E. Bottle, Svetlana Stevanovic, Richard J. C. Brown, Mahmudur Rahman, Farhad Salimi, Ian A. Yang, Reece Brown, and Zehui Zhang
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Atmospheric Science ,Biodiesel ,Diesel exhaust ,010504 meteorology & atmospheric sciences ,Chemistry ,010501 environmental sciences ,Particulates ,Diesel engine ,Combustion ,7. Clean energy ,01 natural sciences ,Aerosol ,Diesel fuel ,13. Climate action ,Phase (matter) ,Environmental chemistry ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Highlights • Gas phase emissions can be potentially as hazardous as the particle phase ones. • Gas phase diesel exhaust has a stronger inflammation effect on human lung cells. • Fuel oxygen content is negatively correlated to the gas phase OP. • Total VOC content is not correlated to the gas phase OP. • Idling produces emissions with the highest OP in the gas phase. Abstract The oxidative potential (OP) of the gas phase is an important and neglected aspect of environmental toxicity. Whilst prolonged exposure to particulate matter (PM) associated reactive oxygen species (ROS) have been shown to lead to negative health effects, the potential for compounds in gas phase to cause similar effects is yet to be understood. In this study we describe: the significance of the gas phase OP generated through vehicle emissions; discuss the origin and evolution of species contributing to measured OP; and report on the impact of gas phase OP on human lung cells. The model aerosol for this study was exhaust emitted from a Euro III Common-rail diesel engine fuelled with different blends of diesel and biodiesel. The gas phase of these emissions was found to be potentially as hazardous as the particle phase. Fuel oxygen content was found to negatively correlate with the gas phase OP, and positively correlate with particle phase OP. This signifies a complex interaction between reactive species present in gas and particle phase. Furthermore, this interaction has an overarching effect on the OP of both particle and gas phase, and therefore the toxicity of combustion emissions.
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- 2017
26. Composition, size and cloud condensation nuclei activity of biomass burning aerosol from northern Australian savannah fires
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Jason Ward, Paul Selleck, Branka Miljevic, Marc Mallet, Leah R. Williams, Zoran Ristovski, Luke T. Cravigan, Melita Keywood, Andelija Milic, and Joel Alroe
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Smoke ,Atmospheric Science ,Supersaturation ,Daytime ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Atmospheric sciences ,01 natural sciences ,complex mixtures ,lcsh:QC1-999 ,Aerosol ,lcsh:Chemistry ,Volume (thermodynamics) ,lcsh:QD1-999 ,13. Climate action ,Climatology ,Dry season ,Cloud albedo ,Cloud condensation nuclei ,Environmental science ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
The vast majority of Australia's fires occur in the tropical north of the continent during the dry season. These fires are a significant source of aerosol and cloud condensation nuclei (CCN) in the region, providing a unique opportunity to investigate the biomass burning aerosol (BBA) in the absence of other sources. CCN concentrations at 0.5 % supersaturation and aerosol size and chemical properties were measured at the Australian Tropical Atmospheric Research Station (ATARS) during June 2014. CCN concentrations reached over 104 cm−3 when frequent and close fires were burning – up to 45 times higher than periods with no fires. Both the size distribution and composition of BBA appeared to significantly influence CCN concentrations. A distinct diurnal trend in the proportion of BBA activating to cloud droplets was observed, with an activation ratio of 40 ± 20 % during the night and 60 ± 20 % during the day. BBA was, on average, less hygroscopic during the night (κ = 0. 04 ± 0.03) than during the day (κ = 0.07 ± 0.05), with a maximum typically observed just before midday. Size-resolved composition of BBA showed that organics comprised a constant 90 % of the aerosol volume for aerodynamic diameters between 100 and 200 nm. While this suggests that the photochemical oxidation of organics led to an increase in the hygroscopic growth and an increase in daytime activation ratios, it does not explain the decrease in hygroscopicity after midday. Modelled CCN concentrations assuming typical continental hygroscopicities produced very large overestimations of up to 200 %. Smaller, but still significant, overpredictions up to ∼ 100 % were observed using aerosol mass spectrometer (AMS)- and hygroscopicity tandem differential mobility analyser (H-TDMA)-derived hygroscopicities as well as campaign night and day averages. The largest estimations in every case occurred during the night, when the small variations in very weakly hygroscopic species corresponded to large variations in the activation diameters. Trade winds carry the smoke generated from these fires over the Timor Sea, where aerosol–cloud interactions are likely to be sensitive to changes in CCN concentrations, perturbing cloud albedo and lifetime. Dry season fires in northern Australia are therefore potentially very important in cloud processes in this region.
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- 2017
27. Biomass burning and biogenic aerosols in northern Australia during the SAFIRED campaign
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Paul Selleck, Sarah Lawson, Marc Mallet, Maximilien Desservettaz, Jason Ward, Branka Miljevic, Luke T. Cravigan, Joel Alroe, Zoran Ristovski, Clare Paton-Walsh, Leah R. Williams, Andelija Milic, and Melita Keywood
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Atmospheric Science ,Ozone ,010504 meteorology & atmospheric sciences ,Tropics ,15. Life on land ,010501 environmental sciences ,Particulates ,respiratory system ,Atmospheric sciences ,01 natural sciences ,complex mixtures ,lcsh:QC1-999 ,Aerosol ,lcsh:Chemistry ,chemistry.chemical_compound ,chemistry ,lcsh:QD1-999 ,13. Climate action ,Northern australia ,Dry season ,Environmental science ,Biomass burning ,Air mass ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
There is a lack of knowledge of how biomass burning aerosols in the tropics age, including those in the fire-prone Northern Territory in Australia. This paper reports chemical characterization of fresh and aged aerosols monitored during the 1-month-long SAFIRED (Savannah Fires in the Early Dry Season) field study, with an emphasis on the chemical signature and aging of organic aerosols. The campaign took place in June 2014 during the early dry season when the surface measurement site, the Australian Tropical Atmospheric Research Station (ATARS), located in the Northern Territory, was heavily influenced by thousands of wild and prescribed bushfires. ATARS was equipped with a wide suite of instrumentation for gaseous and aerosol characterization. A compact time-of-flight aerosol mass spectrometer was deployed to monitor aerosol chemical composition. Approximately 90 % of submicron non-refractory mass was composed of organic material. Ozone enhancement in biomass burning plumes indicated increased air mass photochemistry. The diversity in biomass burning emissions was illustrated through variability in chemical signature (e.g. wide range in f44, from 0.06 to 0.18) for five intense fire events. The background particulate loading was characterized using positive matrix factorization (PMF). A PMF-resolved BBOA (biomass burning organic aerosol) factor comprised 24 % of the submicron non-refractory organic aerosol mass, confirming the significance of fire sources. A dominant PMF factor, OOA (oxygenated organic aerosol), made up 47 % of the sampled aerosol, illustrating the importance of aerosol aging in the Northern Territory. Biogenic isoprene-derived organic aerosol factor was the third significant fraction of the background aerosol (28 %).
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- 2017
28. A review of biomass burning: Emissions and impacts on air quality, health and climate in China
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Andelija Milic, Shuxiao Wang, Hongbo Fu, Mohammad S. Islam, YuanTong Gu, Gavin Pereira, Aijun Ding, Yun Fat Lam, Zoran Ristovski, Branka Miljevic, Jiming Hao, Xin Huang, Phong K. Thai, Lidia Morawska, Hai Guo, Hefeng Zhang, Jianmin Chen, Chunlin Li, Umesh Chandra Dumka, and Congrong He
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China ,medicine.medical_specialty ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Climate ,Air pollution ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Fires ,Emission ,Environmental protection ,Air Pollution ,medicine ,Environmental Chemistry ,Biomass ,Biomass burning ,Waste Management and Disposal ,Air quality index ,Environmental planning ,0105 earth and related environmental sciences ,Air Pollutants ,Public health ,Environmental Exposure ,Pollution ,Systematic review ,Work (electrical) ,Health ,Air quality ,Environmental science ,Particulate Matter ,Environmental Monitoring - Abstract
Biomass burning (BB) is a significant air pollution source, with global, regional and local impacts on air quality, public health and climate. Worldwide an extensive range of studies has been conducted on almost all the aspects of BB, including its specific types, on quantification of emissions and on assessing its various impacts. China is one of the countries where the significance of BB has been recognized, and a lot of research efforts devoted to investigate it, however, so far no systematic reviews were conducted to synthesize the information which has been emerging. Therefore the aim of this work was to comprehensively review most of the studies published on this topic in China, including literature concerning field measurements, laboratory studies and the impacts of BB indoors and outdoors in China. In addition, this review provides insights into the role of wildfire and anthropogenic BB on air quality and health globally. Further, we attempted to provide a basis for formulation of policies and regulations by policy makers in China.
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- 2017
29. Nocturnal new particle formation events in urban environments
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Mahmudur Rahman, Farhad Salimi, Lidia Morawska, Samuel Clifford, and Zoran Ristovski
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Atmospheric Science ,Daytime ,010504 meteorology & atmospheric sciences ,Particle number ,Meteorology ,010501 environmental sciences ,Nocturnal ,Atmospheric sciences ,01 natural sciences ,lcsh:QC1-999 ,lcsh:Chemistry ,lcsh:QD1-999 ,11. Sustainability ,Environmental science ,Trajectory analysis ,Daylight ,Urban environment ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
Few studies have investigated nocturnal new particle formation (NPF) events, and none of them were conducted in urban environments. Nocturnal NPF can potentially be a significant source of particles in urban areas, and studying them would improve our understanding of nucleation mechanisms. To address this, our study was conducted in an urban environment to investigate the physical characteristics of NPF events, with a particular focus on nocturnal events and the differences between them and the daytime NPF events. Particle number size distribution (PNSD) was measured for 2 weeks at each of 25 sites across an urban environment. A new method was proposed to automatically categorise NPF events based on growth rate (GR) in order to remove the bias related to the manual procedure. Out of 219 observed events, 118 and 101 were categorised into class I and II respectively and 73 happened during the nighttime which included more than 30 % of the events. GR and condensation sink (CS) were calculated and a slight negative relationship between GR and CS was observed. Nocturnal events displayed higher GRs compared to daylight ones which were on average about 10 %. Back trajectory analysis was also conducted to estimate the locations of the sources of daylight and nocturnal precursors. While the precursors related to daylight events originated from different locations with no particular pattern, back-trajectory analysis showed many air masses associated with nocturnal NPF events were transported from over the ocean. Overall, nocturnal NPF events were found to be a significant source of particles in the studied environment with different physical characteristics and/or sources compared to daylight events.
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- 2017
30. Sea spray aerosol organic enrichment, water uptake and surface tension effects
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Luke T. Cravigan, Marc Mallet, Greg Olsen, Timothy J. Burrell, David D. Cohen, Lynn M. Russell, Mike Harvey, Petri Vaattovaara, Ed Stelcer, Zoran Ristovski, Robin L. Modini, Karl A. Safi, and Cliff S. Law
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Atmospheric Science ,food.ingredient ,010504 meteorology & atmospheric sciences ,Sea salt ,010501 environmental sciences ,Sea spray ,Algal bloom ,01 natural sciences ,lcsh:QC1-999 ,Aerosol ,lcsh:Chemistry ,food ,lcsh:QD1-999 ,13. Climate action ,Environmental chemistry ,Phytoplankton ,Environmental science ,Cloud condensation nuclei ,Seawater ,Relative humidity ,14. Life underwater ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
The aerosol-driven radiative effects on marine low-level cloud represent a large uncertainty in climate simulations, in particular over the Southern Ocean, which is also an important region for sea spray aerosol production. Observations of sea spray aerosol organic enrichment and the resulting impact on water uptake over the remote Southern Hemisphere are scarce, and therefore the region is under-represented in existing parameterisations. The Surface Ocean Aerosol Production (SOAP) voyage was a 23 d voyage which sampled three phytoplankton blooms in the highly productive water of the Chatham Rise, east of New Zealand. In this study we examined the enrichment of organics to nascent sea spray aerosol and the modifications to sea spray aerosol water uptake using in situ chamber measurements of seawater samples taken during the SOAP voyage. Primary marine organics contributed up to 23 % of the sea spray mass for particles with diameter less than approximately 1 µm and up to 79 % of the particle volume for 50 nm diameter sea spray. The composition of the submicron organic fraction was consistent throughout the voyage and was largely composed of a polysaccharide-like component, characterised by very low alkane-to-hydroxyl-concentration ratios of approximately 0.1–0.2. The enrichment of organics was compared to the output from the chlorophyll-a-based sea spray aerosol parameterisation suggested by Gantt et al. (2011) and the OCEANFILMS (Organic Compounds from Ecosystems to Aerosols: Natural Films and Interfaces via Langmuir Molecular Surfactants) models. OCEANFILMS improved on the representation of the organic fraction predicted using chlorophyll a, in particular when the co-adsorption of polysaccharides was included; however, the model still under-predicted the proportion of polysaccharides by an average of 33 %. Nascent 50 nm diameter sea spray aerosol hygroscopic growth factors measured at 90 % relative humidity averaged 1.93±0.08 and did not decrease with increasing sea spray aerosol organic fractions. The observed hygroscopicity was greater than expected from the assumption of full solubility, particularly during the most productive phytoplankton bloom (B1), during which organic fractions were greater than approximately 0.4. The water uptake behaviour observed in this study is consistent with that observed for other measurements of phytoplankton blooms and can be partially attributed to the presence of sea salt hydrates, which lowers the sea spray aerosol hygroscopicity when the organic enrichment is low. The inclusion of surface tension effects only marginally improved the modelled hygroscopicity, and a significant discrepancy between the observed and modelled hygroscopicity at high organic volume fractions remained. The findings from the SOAP voyage highlight the influence of biologically sourced organics on sea spray aerosol composition; these data improve the capacity to parameterise sea spray aerosol organic enrichment and water uptake.
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- 2019
31. Experimental Investigation of Diesel Engine Performance, Combustion and Emissions Using a Novel Series of Dioctyl Phthalate (DOP) Biofuels Derived from Microalgae
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Md. Mostafizur Rahman, Farhad M. Hossain, Thuy Chu Van, S.M. Ashrafur Rahman, Timothy A. Bodisco, Kabir Adewale Suara, Thomas J. Rainey, Richard J. C. Brown, Nurun Nabi, Saiful Bari, Zoran Ristovski, Hossain, Farhad M, Nabi, Md Nurun, Rahman, Md Mostafizur, Bari, Saiful, Van, Thuy Chu, Rahman, SM Ashrafur, Rainey, Thomas J, Bodisco, Timothy A, Suara, Kabir, Ristovski, Zoran, and Brown, Richard J
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PN ,Control and Optimization ,Materials science ,PM ,020209 energy ,Energy Engineering and Power Technology ,NOx ,02 engineering and technology ,010501 environmental sciences ,Combustion ,Diesel engine ,lcsh:Technology ,01 natural sciences ,Diesel fuel ,0202 electrical engineering, electronic engineering, information engineering ,DOP ,Thrust specific fuel consumption ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,0105 earth and related environmental sciences ,Biodiesel ,lcsh:T ,Renewable Energy, Sustainability and the Environment ,microalgae ,biofuels ,engine performance ,Mean effective pressure ,Chemical engineering ,Biofuel ,Energy (miscellaneous) - Abstract
Physico-chemical properties of microalgae biodiesel depend on the microalgae species and oil extraction method. Dioctyl phthalate (DOP) is a clear, colourless and viscous liquid as a plasticizer. It is used in the processing of polyvinyl chloride (PVC) resin and polymers. A new potential biofuel, hydrothermally liquefied microalgae bio-oil can contain nearly 11% (by mass) of DOP. This study investigated the feasibility of using up to 20% DOP blended in 80% diesel fuel (v/v) in an existing diesel engine, and assessed the performance and exhaust emissions. Despite reasonable differences in density, viscosity, surface tension, and boiling point, blends of DOP and diesel fuel were found to be entirely miscible and no separation was observed at any stage during prolonged miscibility tests. The engine test study found a slight decrease in peak cylinder pressure, brake, and indicated mean effective pressure, indicated power, brake power, and indicated and brake thermal efficiency with DOP blended fuels, where the specific fuel consumption increased. This is due to the presence of 16.4% oxygen in neat DOP, responsible for the relatively lower heating value, compared to that of diesel. The emission tests revealed a slight increase in nitrogen oxides (NOx) and carbon monoxide (CO) emissions from DOP blended fuels. However, particulate matter (PM) emissions were lower from DOP blended fuels, although some inconsistency in particle number (PN) was present among different engine loads. Refereed/Peer-reviewed
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- 2019
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32. Comprehensive aerosol and gas data set from the Sydney Particle Study
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Paul Selleck, Jack B Simmons, Zoran Ristovski, Rosemary Fedele, Min Cheng, Ian E. Galbally, Alan D. Griffiths, Martin Cope, Jennifer Powell, David D. Cohen, Scott D. Chambers, Elise-Andree Guerette, Kathryn M. Emmerson, Suzie B. Molloy, Suzanne Crumeyrolle, Sarah Lawson, James Harnwell, Robert Gillett, Ruhi S Humphries, Erin Dunne, Branka Miljevic, Fabienne Reisen, Jason Ward, Melita Keywood, Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
- Subjects
lcsh:GE1-350 ,Continuous measurement ,010504 meteorology & atmospheric sciences ,Airshed ,Meteorology ,lcsh:QE1-996.5 ,010501 environmental sciences ,Particulates ,01 natural sciences ,Aerosol ,lcsh:Geology ,Data set ,[SDU]Sciences of the Universe [physics] ,General Earth and Planetary Sciences ,Environmental science ,Particle ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,Metadata record - Abstract
The Sydney Particle Study involved the comprehensive measurement of meteorology, particles and gases at a location in western Sydney during February/March 2011 and April/May 2012. The aim of this study was to increase scientific knowledge of the processes leading to particle formation and transformations in Sydney. In this paper we describe the methods used to collect and analyse particle and gaseous samples, as well as the methods employed for the continuous measurement of particle concentrations, particle microphysical properties and gaseous concentrations. This paper also provides a description of the data collected and is a meta data record for the data sets published in Keywood et al. (2016a) https://doi.org/10.4225/08/57903B83D6A5D and Keywood et al. (2016b) https://doi.org/10.4225/08/5791B5528BD63.
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- 2019
33. An Overview of the Influence of Biodiesel, Alcohols, and Various Oxygenated Additives on the Particulate Matter Emissions from Diesel Engines
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Puneet Verma, Svetlana Stevanovic, Ali Zare, Gaurav Dwivedi, Richard J. C. Brown, Morgan Davidson, Zoran Ristovski, Thomas J. Rainey, and Thuy Chu Van
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Pollution ,Alcohol fuel ,Control and Optimization ,PM ,020209 energy ,media_common.quotation_subject ,Energy Engineering and Power Technology ,alternative fuel ,biodiesel ,02 engineering and technology ,010501 environmental sciences ,Combustion ,01 natural sciences ,lcsh:Technology ,Diesel fuel ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Gasoline ,Engineering (miscellaneous) ,0105 earth and related environmental sciences ,media_common ,particulate matter ,Biodiesel ,Diesel particulate filter ,Waste management ,Renewable Energy, Sustainability and the Environment ,lcsh:T ,Particulates ,health effect ,Environmental science ,Energy (miscellaneous) - Abstract
Rising pollution levels resulting from vehicular emissions and the depletion of petroleum-based fuels have left mankind in pursuit of alternatives. There are stringent regulations around the world to control the particulate matter (PM) emissions from internal combustion engines. To this end, researchers have been exploring different measures to reduce PM emissions such as using modern combustion techniques, after-treatment systems such as diesel particulate filter (DPF) and gasoline particulate filter (GPF), and alternative fuels. Alternative fuels such as biodiesel (derived from edible, nonedible, and waste resources), alcohol fuels (ethanol, n-butanol, and n-pentanol), and fuel additives have been investigated over the last decade. PM characterization and toxicity analysis is still growing as researchers are developing methodologies to reduce particle emissions using various approaches such as fuel modification and after-treatment devices. To address these aspects, this review paper studies the PM characteristics, health issues, PM physical and chemical properties, and the effect of alternative fuels such as biodiesel, alcohol fuels, and oxygenated additives on PM emissions from diesel engines. In addition, the correlation between physical and chemical properties of alternate fuels and the characteristics of PM emissions is explored.
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- 2019
34. Comparison of light absorption and oxidative potential of biodiesel/diesel and chemicals/diesel blends soot particles
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Yi Guo, Zoran Ristovski, Jiali Zhu, Jing Shang, Svetlana Stevanovic, Yu Kuang, and Jiaqi Chai
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Environmental Engineering ,010504 meteorology & atmospheric sciences ,chemistry.chemical_element ,010501 environmental sciences ,medicine.disease_cause ,Combustion ,01 natural sciences ,Diesel fuel ,Soot ,Bioenergy ,medicine ,Environmental Chemistry ,Absorption (electromagnetic radiation) ,0105 earth and related environmental sciences ,General Environmental Science ,Vehicle Emissions ,Biodiesel ,Air Pollutants ,Chemistry ,General Medicine ,Biofuel ,Environmental chemistry ,Biofuels ,Particulate Matter ,Carbon - Abstract
Soot particles, mainly coming from fuel combustion, affect climate forcing through absorbing light and also result in adverse human health outcomes. Though biodiesel or additives blending with diesel was considered environmentally friendly, the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear. The water-soluble organic carbon (WSOC) content, surface chemical structure, light absorption and oxidative potential (OPDTT) of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer, X-ray photoelectron spectrometer, ultraviolet–visible spectrophotometry and dithiothreitol (DTT) assay. The differences and correlations between soot properties were statistically analyzed. Chemicals/diesel blends soot owned significantly higher WSOC content, ratio of mass absorbing efficiency (MAE) in 250 and 365 nm (E2/E3), OPDTT, and higher surface carbonyl content. Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond (Ar_C–O) content, and higher MAE365. The individual comparison of biodiesel/diesel blends showed 20% coconut biodiesel blend owned the lowest WSOC, E2/E3 and OPDTT, while highest Ar_C–O and MAE365, representing strongest absorbing properties. Association analysis showed OPDTT was significantly positively correlated with WSOC. Further, the evident negative correlation between MAE365 and OPDTT was observed. Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential, whereas absorption of light was higher, which have far reaching consequences on climate forcing. Therefore, it is important to evaluate the balance point between light-absorbing properties and oxidative potential, under the wide use of biodiesel.
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- 2019
35. Effect of cold start on engine performance and emissions from diesel engines using IMO-Compliant distillate fuels
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Nicholas C. Surawski, Ali Zare, Thomas J. Rainey, Zoran Ristovski, Mohammad Jafari, Puneet Verma, Kabir Adewale Suara, Thuy Chu Van, Timothy A. Bodisco, Svetlana Stevanovic, and Richard J. C. Brown
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Common rail ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,Toxicology ,Combustion ,01 natural sciences ,Diesel fuel ,Cylinder block ,Ships ,0105 earth and related environmental sciences ,Vehicle Emissions ,Cold start (automotive) ,Air Pollutants ,Carbon Monoxide ,Waste management ,Temperature ,General Medicine ,Pollution ,Coolant ,Cold Temperature ,Environmental science ,Nitrogen Oxides ,Particulate Matter ,Engine control unit ,Automobiles ,Gasoline ,Sulfur ,Turbocharger - Abstract
Emissions from ships at berth are small compared to the total ship emissions; however, they are one of the main contributors to pollutants in the air of densely-populated areas, consequently heavily affecting public health. This is due to auxiliary marine engines being used to generate electric power and steam for heating and providing services. The present study has been conducted on an engine representative of a marine auxiliary, which was a heavy duty, six-cylinder, turbocharged and after-cooled engine with a high pressure common rail injection system. Engine performance and emission characterisations during cold start are the focus of this paper, since cold start is significantly influential. Three tested fuels were used, including the reference diesel and two IMO (International Maritime Organization) compliant spiked fuels. The research engine was operated at a constant speed and 25% load condition after 12 h cooled soak. Results show that during cold start, significant heat generated from combustion is used to heat the engine block, coolant and lubricant. During the first minute, compared to the second minute, emissions of particle number (PN), carbon monoxide (CO), particulate matter (PM), and nitrogen oxides (NO x) were approximately 10, 4, 2 and 1.5 times higher, respectively. The engine control unit (ECU) plays a vital role in reducing engine emissions by changing the engine injection strategy based on the engine coolant temperature. IMO-compliant fuels, which were higher viscosity fuels associated with high sulphur content, resulted in an engine emission increase during cold start. It should be taken into account that auxiliary marine diesel engines, working at partial load conditions during cold start, contribute considerably to emissions in coastal areas. It demonstrates a need to implement practical measures, such as engine pre-heating, to obtain both environmental and public health advantages in coastal areas.
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- 2019
36. Characterization of aerosols over the Great Barrier Reef: The influence of transported continental sources
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S. Fiddes, Xiaowen Shu, Jason Ward, Clare Paton-Walsh, Robert G. Ryan, Tianshu Zhang, Zhenyi Chen, Zoran Ristovski, Claire Louise Vincent, Melita Keywood, Travis A Naylor, Peter Rayner, Cheng Liu, Robyn Schofield, Joel Alroe, and Ruhi S Humphries
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Pollution ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,010501 environmental sciences ,Atmospheric sciences ,01 natural sciences ,Meteorology ,Sea breeze ,Environmental Chemistry ,Mass concentration (chemistry) ,14. Life underwater ,Waste Management and Disposal ,Weather ,0105 earth and related environmental sciences ,media_common ,Aerosols ,geography ,Air Pollutants ,geography.geographical_feature_category ,Coral Reefs ,Australia ,Coral reef ,Models, Theoretical ,Aerosol ,Boundary layer ,Lidar ,13. Climate action ,Weather Research and Forecasting Model ,Environmental science ,Environmental Monitoring - Abstract
The rapid environmental changes in Australia prompt a more thorough investigation of the influence of transportation, local emissions, and optical–chemical properties on aerosol production across the region. A month-long intensive measurement campaign was conducted during spring 2016 at Mission Beach, a remote coastal site west of the Great Barrier Reef (GBR) on the north-east coast of Australia. One aerosol pollution episode was investigated in early October. This event was governed by meteorological conditions and characterized by the increase in black carbon (BC) mass concentration (averaged value of 0.35 ± 0.20 μg m−3). Under the influence of the continental transportation, a new layer of nucleation-mode aerosols with an initial size diameter of 20 nm was observed and aerosol number concentrations reached the peak of 6733 cm−3 at a diameter of 29 nm. The averaged aerosol extinction coefficient at the height of 2 km was 150 Mm−1, with a small depolarized ratio (3.5–5%). Simultaneously, the boundary layer height presented a fall–rise trend in the presence of these enhanced aerosol concentrations and became stable in a later stage of the episode. We did not observe clear boundary layer height diurnal variations from the LiDAR observations or from the Weather Research and Forecasting (WRF) model outputs, except in an earlier stage of the aerosol episode for the former. Although the sea breeze may have been responsible for these particles, on the balance of available data, we suggest that the aerosol properties at the GBR surface during this period are more likely influenced by regional transportation of continental sources, including biomass-burning aerosols.
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- 2019
37. Characterization of the particle emission from a ship operating at sea using an unmanned aerial vehicle
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L. Felipe Gonzalez, Tommaso Francesco Villa, Lidia Morawska, Reece Brown, E. Rohan Jayaratne, and Zoran Ristovski
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Particle number ,Meteorology ,lcsh:TA715-787 ,lcsh:Earthwork. Foundations ,Ranging ,010501 environmental sciences ,01 natural sciences ,Aerosol ,Plume ,lcsh:Environmental engineering ,Altitude ,Particle emission ,Fuel efficiency ,Particle ,Environmental science ,lcsh:TA170-171 ,0105 earth and related environmental sciences - Abstract
This research demonstrates the use of an unmanned aerial vehicle (UAV) to characterize the gaseous (CO2) and particle (10–500 nm) emissions of a ship at sea. The field study was part of the research voyage “The Great Barrier Reef as a significant source of climatically relevant aerosol particles” on board the RV Investigator around the Australian Great Barrier Reef. Measurements of the RV Investigator exhaust plume were carried out while the ship was operating at sea, at a steady engine load of 30 %. The UAV system was flown autonomously using several different programmed paths. These incorporated different altitudes and distances behind the ship in order to investigate the optimal position to capture the ship plume. Five flights were performed, providing a total of 27 horizontal transects perpendicular to the ship exhaust plume. Results show that the most appropriate altitude and distance to effectively capture the plume was 25 m a.s.l. and 20 m downwind. Particle number emission factors (EFPNs) were calculated in terms of number of particles emitted (no.) per weight of fuel consumed (kgfuel). Fuel consumption was calculated using the simultaneous measurements of plume CO2 concentration. The calculated EFPN was 7.6±1.4×1015no. kgfuel-1 which is in line with those reported in the literature for ship emissions ranging from 0.2 to 6.2×1016 no. kgfuel-1. This UAV system successfully assessed ship emissions to derive EFPN under real world conditions. This is significant as it provides a novel, relatively inexpensive and accessible way to assess ship EFPN at sea.
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- 2019
38. In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches
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Dušan B. Topalović, Miloš D. Davidović, Zoran Ristovski, Alena Bartonova, Milena Jovasevic-Stojanovic, and Maja Jovanović
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Artificial neural network ,Atmospheric Science ,Multilinear map ,010504 meteorology & atmospheric sciences ,Air pollution monitoring ,Computer science ,010501 environmental sciences ,Residual ,computer.software_genre ,01 natural sciences ,Bayesian multivariate linear regression ,11. Sustainability ,Linear regression ,Calibration ,Low-cost sensors ,0105 earth and related environmental sciences ,General Environmental Science ,Univariate ,13. Climate action ,Data quality ,Data mining ,computer ,Multivariate linear regression - Abstract
The current compliance networks of automatic air-quality monitoring stations in large urban environments are not sufficient to provide spatial and temporal measurement resolution for realistic assessment of personal exposure to pollutants. Small low-cost sensor platforms with greater mobility and expected lower maintenance costs, are increasingly being used as a supplement to compliance monitoring stations. However, low-cost sensor platforms usually provide data with uncertain precision. To improve the precision, these sensor platforms require in-field calibration. Our paper aims to demonstrate that data from each individual sensor system can be corrected using that sensor system's own data to achieve much improved data quality compared to a reference. However, in this procedure, there are practical difficulties such as individual sensor outputs from the multi-sensor system not being sufficiently available due to malfunctions for instance. We explore how this can be dealt with. In our opinion, this is a novel approach, of practical importance both to users and manufacturers. We present a detailed comparative analysis of Linear Regression (univariate), Multivariate Linear Regression and Artificial Neural Networks used with a specific aim of calibrating field-deployed low-cost CO and O3 sensors. For Artificial Neural Network models, the performance of three common training algorithms was compared (Levenberg-Marquardt, Resilient back-propagation and Conjugate Gradient Powell-Beale algorithm). Data for this study were obtained from two campaigns conducted with 25 multi-sensor AQMESH v.3.5 platforms used within the activities of the CITI-SENSE project. The platforms were co-located to reference gas monitors at the Automatic Monitoring Station Stari Grad, in Belgrade, Serbia. This paper demonstrates that Multivariate Linear Regression and Artificial Neural Network calibration models can improve the output signal. This improvement can be measured by changes in the median and interquartile ranges of statistical parameters used for model evaluation. Artificial Neural Networks showed the best results compared to Linear Regression and Multivariate Linear Regression models. The best predictors for CO, in addition to CO low-cost sensor data, were PM2.5 and NO2, while for O3, in addition to O3 low-cost sensor data, the most suitable input predictors were NO and aH. Based on residual error analysis, we have shown that for CO and O3, a certain range of concentrations exists in which calibrated values differ by less than 10% from the reference method results. In addition, it was noted that for all models, CO sensors consistently showed lower variability between platforms compared to O3 sensors. © 2019 Elsevier Ltd
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- 2019
39. The effect of diesel emission exposure on primary human bronchial epithelial cells from a COPD cohort: N-acetylcysteine as a potential protective intervention
- Author
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Ian A. Yang, Rayleen V. Bowman, Annalicia Vaughan, Kwun M. Fong, Mohammad Jafari, Svetlana Stevanovic, Md. Mostafizur Rahman, and Zoran Ristovski
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Cell ,Inflammation ,010501 environmental sciences ,Pharmacology ,medicine.disease_cause ,Toxicology ,01 natural sciences ,Biochemistry ,Antioxidants ,Acetylcysteine ,03 Chemical Sciences, 05 Environmental Sciences, 06 Biological Sciences ,03 medical and health sciences ,Pulmonary Disease, Chronic Obstructive ,0302 clinical medicine ,Interferon ,medicine ,Humans ,030212 general & internal medicine ,Viability assay ,0105 earth and related environmental sciences ,General Environmental Science ,Vehicle Emissions ,MHC class II ,COPD ,biology ,business.industry ,Epithelial Cells ,respiratory system ,medicine.disease ,respiratory tract diseases ,medicine.anatomical_structure ,biology.protein ,Particulate Matter ,medicine.symptom ,business ,Oxidative stress ,medicine.drug - Abstract
INTRODUCTION: Chronic obstructive pulmonary disease (COPD) will be the third leading cause of death world-wide by 2020. Prolonged exposure to particulate matter is associated with COPD progression and mortality. Diesel emissions are a major contributor to particulate matter pollution. In this study we test a therapeutic antioxidant, N-acetylcysteine (NAC), for its ability to protect bronchial epithelial cells (pHBECs) from patients with COPD from adverse effects of diesel emission exposure. METHODS: pHBECs from patients with or without COPD were cultured at air-liquid interface (ALI). Cells were exposed to diesel emissions for 30 min with or without 3-h post-exposure treatment with 5 mM N-acetylcysteine (NAC). Filtered laboratory air was tested as a negative control. Cell responses (cell viability, inflammation and oxidative stress) and gene expression profiles for intracellular and immune signaling were assessed. RESULTS: Diesel emissions exposure increased IL-8 secretion and production, antioxidant production, and cytochrome P450 1a1 (CYP1a1) mRNA expression and suppressed superoxide dismutase-1 (SOD1) mRNA expression in bronchial epithelial cells from COPD patients. Treatment with N-acetyl cysteine attenuated the suppression of SOD1. Nanostring gene expression profiling of the filtered air controls showed COPD epithelial cells have increased expression of MHC class II and an interferon signaling profile. CONCLUSIONS: This study indicates that bronchial epithelial cells from COPD patients may be vulnerable to diesel emission exposure due to reduced antioxidant capacity, and elevated CYP1a1 mRNA expression. NAC did not appear to offer protection. Future research will be needed to explore other means of recovering oxidant capacity in COPD airways.
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- 2018
40. Elevated levels of glyoxal and methylglyoxal at a remote mountain site in southern China: Prompt in-situ formation combined with strong regional transport
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Hao Wang, Min Shao, Daocheng Gong, Zoran Ristovski, Yuanhang Zhang, Youjing Lin, Boguang Wang, Duohong Chen, Chunqian He, Yaozhou Ding, Gengchen Wu, Shaojun Lv, Shaw Chen Liu, Lei Zhou, and Hang Ding
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In situ ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,Methylglyoxal ,010501 environmental sciences ,01 natural sciences ,Pollution ,Atmosphere ,chemistry.chemical_compound ,Speciation ,Prevailing winds ,chemistry ,Southern china ,Atmospheric chemistry ,Environmental chemistry ,Environmental Chemistry ,Glyoxal ,Environmental science ,Waste Management and Disposal ,0105 earth and related environmental sciences ,media_common - Abstract
The dicarbonyls glyoxal (Gly) and methylglyoxal (Mgly) are key tracers for the oxidation of volatile organic compounds (VOCs) in the atmosphere, but their atmospheric chemistry in remote forest environments is not well understood. A study was carried out during Jul. 31–Nov. 5 of 2016 at the summit of Mt. Tianjing (1690 m.a.s.l.), a remote mountaintop site in southern China, to measure the levels of Gly and Mgly and explore their sources and fate. During the study period, the average mixing ratios of Gly and Mgly were 509 ± 31 pptv and 340 ± 32 pptv, respectively, with the Gly/Mgly ratios averaging 1.8 ± 0.2. Both the dicarbonyl concentrations and the Gly/Mgly ratios were significantly higher than those observed in other background sites. Production yield calculations and meteorological data analysis indicate that high levels of Gly and Mgly observed at the study site were largely a combined result of rapid in-situ formation and regional transport by prevailing winds. On average, in-situ formation from precursors is estimated to account for 67% of the observed Mgly and about 9% of the observed Gly. There were significant changes in Gly and Mgly mixing ratios among different time periods when air masses from different source regions dominated, indicating contribution of regional transport to the observed dicarbonyl mixing ratios at the study site. Biogenic emissions in eastern China and anthropogenic emissions in the Pearl River Delta region were the two main sources responsible for the dicarbonyls observed at the site during most of the sampling period, but large-scale biomass burning in central China was also important in the late autumn, as supported by a backward trajectory analysis of fire spot data and the identification of biomass burning tracers. This study provides insights into the background atmospheric chemistry and the impact of biogenic and anthropogenic sources on the dicarbonyls speciation.
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- 2018
41. An instrument for the rapid quantification of PM oxidative potential: the Particle Into Nitroxide Quencher (PINQ)
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Svetlana Stevanovic, Zoran Ristovski, Reece Brown, and Steven E. Bottle
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Nitroxide mediated radical polymerization ,Chromatography ,010504 meteorology & atmospheric sciences ,Chemistry ,Particle ,Time resolution ,010501 environmental sciences ,Particulates ,01 natural sciences ,0105 earth and related environmental sciences ,Collection methods ,Aerosol - Abstract
Presence or generation of reactive oxygen species (ROS) on/by particulate matter (PM) have been implicated in PM-induced health effects. Methodologies to quantify ROS concentrations vary widely both in detection and collection methods. However, there is currently an increasing emphasis on rapid collection and measurement due to observations of short half-live ROS. To address this problem, this manuscript details the design and characterization of a novel instrument named the Particle Into Nitroxide Quencher (PINQ). This instrument combines the BPEAnit ROS assay in conjunction with a purpose-built aerosol collection device, the insoluble aerosol collector (IAC). The IAC continuously collects PM regardless of size or chemistry directly into a liquid sample with a collection efficiency of 0.98 and a low cut-off size of < 20 nm. The sampling time resolution of the PINQ is one minute, with a limit of detection (LOD) of 0.08 nmol m−3 in equivalent BPEAnit-Me concentration per volume of air. This high sample time resolution and sensitivity is achieved due a combination of the highly concentrated IAC liquid sample and the rapid reaction and stability of the BPEAnit probe.
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- 2018
42. Determining the link between hygroscopicity and composition for semi-volatile aerosol species
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Chiemeriwo Godday Osuagwu, Branka Miljevic, Joel Alroe, Luke T. Cravigan, Graham R. Johnson, Marc Mallet, and Zoran Ristovski
- Subjects
Atmospheric Science ,Ammonium sulfate ,010504 meteorology & atmospheric sciences ,lcsh:TA715-787 ,lcsh:Earthwork. Foundations ,Sulfuric acid ,010501 environmental sciences ,respiratory system ,Mass spectrometry ,Sea spray ,01 natural sciences ,complex mixtures ,Aerosol ,lcsh:Environmental engineering ,chemistry.chemical_compound ,chemistry ,Environmental chemistry ,Environmental science ,Cloud condensation nuclei ,Organic component ,lcsh:TA170-171 ,Volatility (chemistry) ,0105 earth and related environmental sciences - Abstract
Internally and externally mixed aerosols present significant challenges in assessing the hygroscopicity of each aerosol component. This study presents a new sampling technique which uses differences in volatility to separate mixtures and directly examine their respective composition and hygroscopic contribution. A shared thermodenuder and unheated bypass line are continuously cycled between an aerosol mass spectrometer and a volatility and hygroscopicity tandem differential mobility analyser, allowing real-time comparative analysis of heated and unheated aerosol properties. Measurements have been taken of both chamber-generated secondary organic aerosol and coastal marine aerosol at Cape Grim, Australia, to investigate system performance under diverse conditions. Despite rapidly changing aerosol properties and the need to restrict analysis to a narrow size range, the former experiment separated the hygroscopic influences of ammonium sulfate and two distinct organic components with similar oxygen to carbon ratios but different volatilities. Analysis of the marine aerosol revealed an external mixture of non-sea-salt sulfates and sea spray aerosol, which likely shared similar volatile fractions composed of sulfuric acid and a non-hygroscopic organic component.
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- 2018
43. The diurnal characteristics of PM-bound ROS and its influencing factors at urban ambient and roadside environments
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Peter Brimblecombe, Nirmal Kumar Gali, Svetlana Stevanovic, Zoran Ristovski, Reece Brown, and Zhi Ning
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Chemistry ,Cardiovascular health ,Urban background ,Environmental chemistry ,010501 environmental sciences ,Particulates ,01 natural sciences ,0105 earth and related environmental sciences ,Gas phase - Abstract
The airborne particulate matter (PM) is known to cause adverse pulmonary and cardiovascular health effects. This study investigated the diurnal characteristics of PM induced PM-bound ROS from real time measurements in typical roadside and urban background sites in Hong Kong, and identified potential influencing factors to its variation in atmosphere. A nitroxide probe (BPEAnit) was employed in the real-time measurement of separate PM and gas phase induced reactive oxygen species (ROS) with a Particle-into-Liquid-Sampler. Measurements were carried in 2 h intervals over a 24 h period, and repeated for 6 days at each site. The total ROS (particle + gas phase) measurements resulted in multiple peaks at 08:00, 16:00 and 20:00 h time periods at background site, compared to non-intermittent decrease/increase trends at roadside. The total ROS generation was noted significantly higher by 50–100% (n = 6 p < .05) at roadside compared to the background site. While the contribution of PM2.5- and gas phase-induced ROS to the total ROS was on average 48 ± 8% and 52 ± 8% across 24 h at background site, the ratio of gas phase-induced ROS increased to 79 ± 4% and that of particle phase decreased to 21 ± 4% at roadside site. The total ROS well correlated with black carbon (BC) and particle-bound PAHs (p-PAHs), which are 4–8 fold and 10–20 fold higher at roadside than background. The ratio of p-PAHs/BC was high at roadside during peak hours compared to late nights suggesting fresh PM may have induced more total ROS generation compared to aged aerosols using this specific ROS probe.
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- 2020
44. Synthesize of magnetite Mg-Fe mixed metal oxide nanocatalyst by urea-nitrate combustion method with optimal fuel ratio for reduction of emissions in diesel engines
- Author
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Mohammad Hossein Abbaspour-Fard, Hamed Nayebzadeh, Mohammad Jafari, Thuy Chu Van, Mohammad Tabasizadeh, Nasrin Sabet Sarvestani, Zoran Ristovski, and Richard J. C. Brown
- Subjects
Materials science ,Mechanical Engineering ,Metals and Alloys ,Oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Combustion ,Diesel engine ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Crystallinity ,Diesel fuel ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Mechanics of Materials ,Materials Chemistry ,Thermal stability ,0210 nano-technology ,Stoichiometry - Abstract
In the present study, Mg0.25Fe2.75O4 nanocatalyst for reduction of emissions in diesel engine was fabricated via urea-nitrate combustion method. The effect of urea concentrations as fuel on its structural characteristics and Oxygen Storage Capacity (OSC) was thoroughly investigated. The results of various characterization analyses showed that fuel ratio significantly affects crystallinity, textural, size and morphology of particles, and thermal stability of nanocatalyst. These are mainly due to increase in combustion temperature and duration. The Mg0.25Fe2.75O4 fabricated at fuel ratio of 2.5 times of stoichiometric ratio exhibited the lowest weight loss/high crystallinity (less than 1 wt %) and lowest lattice parameter (8.346 A) which are related to well diffusion of Mg cations into ferric oxide as host. The Raman and FTIR analyses showed the existence of strong peaks correspond to formation of tetrahedral and octahedral sublattices and also the formation of spinel structure of MgFe2O4. The reduction in crystalline size, obtained with higher amount of fuel, resulted in a higher surface area (23.6 m2/g), higher pore volume (0.0950 cc/g) and proper particle size distribution (25–35 nm). These cause a better catalytic activity. Moreover, the enhanced OSC (8661 μmol H2/g) along with shifting the reduction peaks to lower temperatures, as major attributes in relation to catalytic technologies, confirmed the strong effect of fuel ratio of 2.5 on fabrication process of Mg0.25Fe2.75O4. Finally, the highest reduction in HC (33%), CO (14-17%), PM1.0 (16%), and CO2 (12%) achieved, using the optimum sample-mixed diesel fuel at 90 ppm.
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- 2020
45. The ambient aerosol characterization during the prescribed bushfire season in Brisbane 2013
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Andelija Milic, Marc Mallet, André S. H. Prévôt, Branka Miljevic, Zoran Ristovski, Joel Alroe, and Francesco Canonaco
- Subjects
Environmental Engineering ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,01 natural sciences ,Fires ,chemistry.chemical_compound ,Air Pollution ,Environmental Chemistry ,Sulfate ,Biomass burning ,Waste Management and Disposal ,Chemical composition ,Air quality index ,0105 earth and related environmental sciences ,Central business district ,Aerosols ,Air Pollutants ,Pollution ,Aerosol ,chemistry ,13. Climate action ,Environmental chemistry ,Environmental science ,Aerosol mass spectrometry ,Queensland ,Environmental Monitoring - Abstract
Prescribed burnings are conducted in Queensland each year from August until November aiming to decrease the impact of bushfire hazards and maintain the health of vegetation. This study reports chemical characteristics of the ambient aerosol, with a focus on source apportionment of the organic aerosol (OA) fraction, during the prescribed biomass burning (BB) season in Brisbane 2013. All measurements were conducted within the International Laboratory for Air Quality and Health (ILAQH) located in Brisbane's Central Business District. Chemical composition, degree of ageing and the influence of BB emission on the air quality of central Brisbane were characterized using a compact Time of Flight Aerosol Mass Spectrometer (cToF-AMS). AMS loadings were dominated by OA (64%), followed by, sulfate (17%), ammonium (14%) and nitrates (5%). Source apportionment was applied on the AMS OA mass spectra via the multilinear engine solver (ME-2) implementation within the recently developed Source Finder (SoFi) interface. Six factors were extracted including hydrocarbon-like OA (HOA), cooking-related OA (COA), biomass burning OA (BBOA), low-volatility oxygenated OA (LV-OOA), semivolatile oxygenated OA (SV-OOA), and nitrogen-enriched OA (NOA). The aerosol fraction that was attributed to BB factor was 9%, on average over the sampling period. The high proportion of oxygenated OA (72%), typically representing aged emissions, could possess a fraction of oxygenated species transfored from BB components on their way to the sampling site.
- Published
- 2016
46. Influence of biodiesel fuel composition on the morphology and microstructure of particles emitted from diesel engines
- Author
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Mahmudur Rahman, Branka Miljevic, Jamie Riches, Natascha Savic, Zoran Ristovski, Nunzio Motta, Harald Saathoff, Thomas Leisner, Bharati Gupta, and Karl-Heinz Naumann
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Biodiesel ,Materials science ,020209 energy ,02 engineering and technology ,General Chemistry ,010501 environmental sciences ,medicine.disease_cause ,Diesel engine ,01 natural sciences ,Soot ,Algae fuel ,Diesel fuel ,Chemical engineering ,Biofuel ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,Particle ,General Materials Science ,Particle size ,0105 earth and related environmental sciences - Abstract
This study investigates the morphology, microstructure and surface composition of Diesel engine exhaust particles. The state of agglomeration, the primary particle size and the fractal dimension of exhaust particles from petroleum Diesel (petrodiesel) and biodiesel blends from microalgae, cotton seed and waste cooking oil were investigated by means of high resolution transmission electron microscopy. With primary particle diameters between 12-19 nm, biodiesel blend primary particles are found to be smaller than petrodiesel ones (21±2 nm). Also it was found that soot agglomerates from biodiesels are more compact and spherical, as their fractal dimensions are higher, e.g. 2.2±0.1 for 50% algae biodiesel compared to 1.7±0.1 for petrodiesel. In addition, analysis of the chemical composition by means of x-ray photoelectron spectroscopy revealed an up to a factor of two increased oxygen content on the primary particle surface for biodiesel. The length, curvature and distance of graphene layers were measured showing a greater structural disorder for biodiesel with shorter fringes of higher tortuosity. This change in carbon chemistry may reflect the higher oxygen content of biofuels. Overall, it seems that the oxygen content in the fuels is the underlying reason for the observed morphological change in the resulting soot particles.
- Published
- 2016
47. Sea spray aerosol in the Great Barrier Reef and the presence of nonvolatile organics
- Author
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Zoran Ristovski, Luke T. Cravigan, Graham B Jones, Elisabeth Deschaseaux, Branka Miljevic, Petri Vaattovaara, Marc Mallet, and Hilton B. Swan
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Atmospheric Science ,geography ,food.ingredient ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Sea salt ,Coral reef ,010501 environmental sciences ,Atmospheric sciences ,Sea spray ,01 natural sciences ,Aerosol ,Geophysics ,food ,13. Climate action ,Space and Planetary Science ,Phytoplankton ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Cloud condensation nuclei ,Seawater ,14. Life underwater ,Sea salt aerosol ,0105 earth and related environmental sciences - Abstract
Sea spray aerosol (SSA) particles produced from the ocean surface in regions of biological activity can vary greatly in size, number and composition and in their influence on cloud formation. Algal species such as phytoplankton can alter the SSA composition. Numerous studies have investigated nascent SSA properties, but all of these have focused on aerosol particles produced by seawater from non-coral related phytoplankton and in coastal regions. Bubble chamber experiments were performed with seawater samples taken from the reef flat around Heron Island in the Great Barrier Reef during winter 2011. Here we show that the SSA from these samples was comprised of an internal mixture of varying fractions of sea salt, semi-volatile organics as well as non-volatile (below 550°C) organics. A relatively constant volume fraction of semi-volatile organics of 10%-13% was observed while non-volatile organic volume fractions varied from 29%-49% for 60 nm SSA. SSA organic fractions were estimated to reduce the activation ratios of SSA to cloud condensation nuclei by up to 14% when compared with artificial sea salt. Additionally, a sea salt calibration was applied so that a compact Time-of-Flight Aerosol Mass Spectrometer could be used to quantify the contribution of sea salt to sub-micron SSA, which yielded organic volume fractions of 3%-6%. Overall, these results indicate a high fraction of organics associated with wintertime Aitken mode SSA generated from Great Barrier Reef seawater. Further work is required to fully distinguish any differences coral reefs have on SSA composition when compared to open oceans.
- Published
- 2016
48. Dimethyl sulfide and other biogenic volatile organic compound emissions from branching coral and reef seawater: potential sources of secondary aerosol over the Great Barrier Reef
- Author
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Robert W. Crough, Petri Vaattovaara, Bradley D. Eyre, Elisabeth Deschaseaux, Zoran Ristovski, Branka Miljevic, Graham B Jones, and Hilton B. Swan
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Coral ,010501 environmental sciences ,01 natural sciences ,Acropora aspera ,chemistry.chemical_compound ,Environmental Chemistry ,Dimethyl disulfide ,14. Life underwater ,Reef ,Isoprene ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,biology ,fungi ,technology, industry, and agriculture ,Coral reef ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Oceanography ,chemistry ,13. Climate action ,Environmental chemistry ,population characteristics ,Dimethyl sulfide ,Seawater ,geographic locations ,Geology - Abstract
Volatile organic compounds (VOCs) in the headspace of bubble chambers containing branches of live coral in filtered reef seawater were analysed using gas chromatography with mass spectrometry (GC-MS). When the coral released mucus it was a source of dimethyl sulfide (DMS) and isoprene; however, these VOCs were not emitted to the chamber headspace from mucus-free coral. This finding, which suggests that coral is an intermittent source of DMS and isoprene, was supported by the observation of occasional large pulses of atmospheric DMS (DMSa) over Heron Island reef on the southern Great Barrier Reef (GBR), Australia, in the austral winter. The highest DMSa pulse (320 ppt) was three orders of magnitude less than the DMS mixing ratio (460 ppb) measured in the headspace of a dynamically purged bubble chamber containing a mucus-coated branch of Acropora aspera indicating that coral reefs can be strong point sources of DMSa. Static headspace GC-MS analysis of coral fragments identified mainly DMS and seven other minor reduced sulfur compounds including dimethyl disulfide, methyl mercaptan, and carbon disulfide, while coral reef seawater was an indicated source of methylene chloride, acetone, and methyl ethyl ketone. The VOCs emitted by coral and reef seawater are capable of producing new atmospheric particles < 15 nm diameter as observed at Heron Island reef. DMS and isoprene are known to play a role in low-level cloud formation, so aerosol precursors such as these could influence regional climate through a sea surface temperature regulation mechanism hypothesized to operate over the GBR.
- Published
- 2016
49. Engine Performance and Emissions Analysis in a Cold, Intermediate and Hot Start Diesel Engine
- Author
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Ali Zare, Richard J. C. Brown, Priyanka Arora, Svetlana Stevanovic, Faisal Lodi, Zoran Ristovski, Timothy A. Bodisco, and Mohammad Jafari
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HC ,020209 energy ,intermediate start ,FMEP ,NOx ,02 engineering and technology ,010501 environmental sciences ,Diesel engine ,lcsh:Technology ,01 natural sciences ,BMEP ,lcsh:Chemistry ,Brake specific fuel consumption ,Animal science ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,lcsh:QH301-705.5 ,Instrumentation ,0105 earth and related environmental sciences ,Fluid Flow and Transfer Processes ,Cold start (automotive) ,lcsh:T ,Hot start ,Process Chemistry and Technology ,BSFC ,General Engineering ,IMEP ,lcsh:QC1-999 ,Computer Science Applications ,Coolant ,engine performance ,lcsh:Biology (General) ,lcsh:QD1-999 ,Mean effective pressure ,lcsh:TA1-2040 ,Coolant temperature ,Environmental science ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:Physics ,diesel engine cold start ,engine stop/start - Abstract
Presented in this paper is an in-depth analysis of the impact of engine start during various stages of engine warm up (cold, intermediate, and hot start stages) on the performance and emissions of a heavy-duty diesel engine. The experiments were performed at constant engine speeds of 1500 and 2000 rpm on a custom designed drive cycle. The intermediate start stage was found to be longer than the cold start stage. The oil warm up lagged the coolant warm up by approximately 10 °, C. During the cold start stage, as the coolant temperature increased from ~25 to 60 °, C, the brake specific fuel consumption (BSFC) decreased by approximately 2% to 10%. In the intermediate start stage, as the coolant temperature reached 70 °, C and the injection retarded, the indicated mean effective pressure (IMEP) and the brake mean effective pressure (BMEP) decreased by approximately 2% to 3%, while the friction mean effective pressure (FMEP) decreased by approximately 60%. In this stage, the NOx emissions decreased by approximately 25% to 45%, while the HC emissions increased by approximately 12% to 18%. The normalised FMEP showed that higher energy losses at lower loads were most likely contributing to the heating of the lubricating oil.
- Published
- 2020
50. Diurnal profiles of particle-bound ROS of PM2.5 in urban environment of Hong Kong and their association with PM2.5, black carbon, ozone and PAHs
- Author
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Zoran Ristovski, Luke T. Cravigan, Zhi Ning, Steven E. Bottle, Farhad Salimi, Svetlana Stevanovic, Reece Brown, Nirmal Kumar Gali, and Peter Brimblecombe
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Pollutant ,Atmospheric Science ,Ozone ,010504 meteorology & atmospheric sciences ,Particle number ,Air pollution ,Particle (ecology) ,010501 environmental sciences ,Particulates ,medicine.disease_cause ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,13. Climate action ,Urban background ,Environmental chemistry ,11. Sustainability ,medicine ,Environmental science ,Urban environment ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Air pollution exposure is associated with a range of adverse health effects, including cardiovascular and respiratory diseases. Particle-bound ROS has been recognised as one of the prevailing parameters to indicate the toxic potential of airborne particulate matter (PM). The temporal variability of particle-bound ROS is a very important metric crucial for the improvement of public health and risk assessment policies. To our knowledge this is the first study aiming to investigate diurnal ROS profiles in both the particle and gas phase and associate them with diurnal variations of important pollutants. For that purpose, we have successfully applied a new instrument to continuously monitor diurnal ROS profiles at two locations in Hong Kong: a busy roadside and an urban background. Data was collected over both the working week and during weekends. We have observed a high correlation between particle-bound ROS and lower concentrations of black carbon (BC) at the roadside during the working week. These associations were less significant over the weekend and at all times with ozone. Our results suggest that most of the particle-bound ROS from both the particle and the gas phase arises from fresh emission sources directly from the traffic. A very interesting observation came out as a result of this study where measured ROS concentration was decreasing with the rise of ozone in conjunction with particle number, suggesting potential role of ROS in particle growth and aging.
- Published
- 2019
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