Branka Miljevic

Biomass burning and biogenic aerosols in northern Australia during the SAFIRED campaign

Publisher: Copernicus GmbH

Date: 23-03-2017

DOI: 10.5194/ACP-17-3945-2017

Abstract: 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 c aign 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 ersity 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 s led 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 %).

Engine performance and emissions from fuels containing nitrogen and sulphur

Publisher: Elsevier BV

Date: 05-2022

DOI: 10.1016/J.ECMX.2022.100179

Quantification of Particle-Bound Organic Radicals in Secondary Organic Aerosol

Publisher: American Chemical Society (ACS)

Date: 10-05-2019

DOI: 10.1021/ACS.EST.9B00825

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

Reactions of sulfoxides with reactive oxygen species to reveal the radical chemistry of pollution-derived particulate matter

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D2CC04024G

Abstract: The radical reactions of dimethylsulfoxide (DMSO) and tetrahydrothiophene-1-oxide (THTO) with reactive oxygen species (ROS) in the presence of a nitroxide radical scavenger have been evaluated both synthetically and in analytical practice.

Characterisation of the impact of open biomass burning on urban air quality in Brisbane, Australia

Publisher: Elsevier BV

Date: 05-2016

DOI: 10.1016/J.ENVINT.2016.02.030

Abstract: Open biomass burning from wildfires and the prescribed burning of forests and farmland is a frequent occurrence in South-East Queensland (SEQ), Australia. This work reports on data collected from 10 to 30 September 2011, which covers the days before (10-14 September), during (15-20 September) and after (21-30 September) a period of biomass burning in SEQ. The aim of this project was to comprehensively quantify the impact of the biomass burning on air quality in Brisbane, the capital city of Queensland. A multi-parameter field measurement c aign was conducted and ambient air quality data from 13 monitoring stations across SEQ were analysed. During the burning period, the average concentrations of all measured pollutants increased (from 20% to 430%) compared to the non-burning period (both before and after burning), except for total xylenes. The average concentration of O3, NO2, SO2, benzene, formaldehyde, PM10, PM2.5 and visibility-reducing particles reached their highest levels for the year, which were up to 10 times higher than annual average levels, while PM10, PM2.5 and SO2 concentrations exceeded the WHO 24-hour guidelines and O3 concentration exceeded the WHO maximum 8-hour average threshold during the burning period. Overall spatial variations showed that all measured pollutants, with the exception of O3, were closer to spatial homogeneity during the burning compared to the non-burning period. In addition to the above, elevated concentrations of three biomass burning organic tracers (levoglucosan, mannosan and galactosan), together with the amount of non-refractory organic particles (PM1) and the average value of f60 (attributed to levoglucosan), reinforce that elevated pollutant concentration levels were due to emissions from open biomass burning events, 70% of which were prescribed burning events. This study, which is the first and most comprehensive of its kind in Australia, provides quantitative evidence of the significant impact of open biomass burning events, especially prescribed burning, on urban air quality. The current results provide a solid platform for more detailed health and modelling investigations in the future.

Measurement report: Understanding the seasonal cycle of Southern Ocean aerosols

Publisher: Copernicus GmbH

Date: 29-03-2023

DOI: 10.5194/ACP-23-3749-2023

Abstract: Abstract. The remoteness and extreme conditions of the Southern Ocean and Antarctic region have meant that observations in this region are rare, and typically restricted to summertime during research or resupply voyages. Observations of aerosols outside of the summer season are typically limited to long-term stations, such as Kennaook / Cape Grim (KCG 40.7∘ S, 144.7∘ E), which is situated in the northern latitudes of the Southern Ocean, and Antarctic research stations, such as the Japanese operated Syowa (SYO 69.0∘ S, 39.6∘ E). Measurements in the midlatitudes of the Southern Ocean are important, particularly in light of recent observations that highlighted the latitudinal gradient that exists across the region in summertime. Here we present 2 years (March 2016–March 2018) of observations from Macquarie Island (MQI 54.5∘ S, 159.0∘ E) of aerosol (condensation nuclei larger than 10 nm, CN10) and cloud condensation nuclei (CCN at various supersaturations) concentrations. This important multi-year data set is characterised, and its features are compared with the long-term data sets from KCG and SYO together with those from recent, regionally relevant voyages. CN10 concentrations were the highest at KCG by a factor of ∼50 % across all non-winter seasons compared to the other two stations, which were similar (summer medians of 530, 426 and 468 cm−3 at KCG, MQI and SYO, respectively). In wintertime, seasonal minima at KCG and MQI were similar (142 and 152 cm−3, respectively), with SYO being distinctly lower (87 cm−3), likely the result of the reduction in sea spray aerosol generation due to the sea ice ocean cover around the site. CN10 seasonal maxima were observed at the stations at different times of year, with KCG and MQI exhibiting January maxima and SYO having a distinct February high. Comparison of CCN0.5 data between KCG and MQI showed similar overall trends with summertime maxima and wintertime minima however, KCG exhibited slightly (∼10 %) higher concentrations in summer (medians of 158 and 145 cm−3, respectively), whereas KCG showed ∼40 % lower concentrations than MQI in winter (medians of 57 and 92 cm−3, respectively). Spatial and temporal trends in the data were analysed further by contrasting data to coincident observations that occurred aboard several voyages of the RSV Aurora Australis and the RV Investigator. Results from this study are important for validating and improving our models and highlight the heterogeneity of this pristine region and the need for further long-term observations that capture the seasonal cycles.

The Use of a Nitroxide Probe in DMSO to Capture Free Radicals in Particulate Pollution

Publisher: Wiley

Date: 11-09-2012

DOI: 10.1002/EJOC.201200903

Oxidative Potential of Logwood and Pellet Burning Particles Assessed by a Novel Profluorescent Nitroxide Probe

Publisher: American Chemical Society (ACS)

Date: 04-08-2010

DOI: 10.1021/ES100963Y

Abstract: This study reports the potential toxicological impact of particles produced during biomass combustion by an automatic pellet boiler and a traditional logwood stove under various combustion conditions using a novel profluorescent nitroxide probe, BPEAnit. This probe is weakly fluorescent but yields strong fluorescence emission upon radical trapping or redox activity. S les were collected by bubbling aerosol through an impinger containing BPEAnit solution, followed by fluorescence measurement. The fluorescence of BPEAnit was measured for particles produced during various combustion phases: at the beginning of burning (cold start), stable combustion after refilling with the fuel (warm start), and poor burning conditions. For particles produced by the logwood stove under cold-start conditions, significantly higher amounts of reactive species per unit of particulate mass were observed compared to emissions produced during a warm start. In addition, s ling of logwood burning emissions after passing through a thermodenuder at 250 degrees C resulted in an 80-100% reduction of the fluorescence signal of the BPEAnit probe, indicating that the majority of reactive species were semivolatile. Moreover, the amount of reactive species showed a strong correlation with the amount of particulate organic material. This indicates the importance of semivolatile organics in particle-related toxicity. Particle emissions from the pellet boiler, although of similar mass concentration, were not observed to lead to an increase in fluorescence signal during any of the combustion phases.

Application of Multicriteria Decision Making Methods to Compression Ignition Engine Efficiency and Gaseous, Particulate, and Greenhouse Gas Emissions

Publisher: American Chemical Society (ACS)

Date: 08-02-2013

DOI: 10.1021/ES3035208

Abstract: Compression ignition (CI) engine design is subject to many constraints, which present a multicriteria optimization problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient but must also deliver low gaseous, particulate, and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming is minimized. Consequently, this study undertakes a multicriteria analysis, which seeks to identify alternative fuels, injection technologies, and combustion strategies that could potentially satisfy these CI engine design constraints. Three data sets are analyzed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of (1) an ethanol fumigation system, (2) alternative fuels (20% biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and (3) various biodiesel fuels made from 3 feedstocks (i.e., soy, tallow, and canola) tested at several blend percentages (20-100%) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20% by energy) at moderate load, high percentage soy blends (60-100%), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem. Further research is, however, required to reduce reactive oxygen species (ROS) emissions with alternative fuels and to deliver technologies that do not significantly reduce the median diameter of particle emissions.

A new oxidation flow reactor for the measurements of secondary aerosol formation: Characterisation and a case study

Publisher: Elsevier BV

Date: 09-2023

DOI: 10.1016/J.ATMOSENV.2023.119886

The ambient aerosol characterization during the prescribed bushfire season in Brisbane 2013

Publisher: Elsevier BV

Date: 08-2016

DOI: 10.1016/J.SCITOTENV.2016.04.036

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 s ling 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 s ling site.

Sea spray aerosol in the Great Barrier Reef and the presence of non-volatile organics

Publisher: American Geophysical Union (AGU)

Date: 22-06-2016

DOI: 10.1002/2016JD024966

A review of biomass burning: Emissions and impacts on air quality, health and climate in China

Publisher: Elsevier BV

Date: 02-2017

DOI: 10.1016/J.SCITOTENV.2016.11.025

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.

The correlation between diesel soot chemical structure and reactivity

Publisher: Elsevier BV

Date: 05-2020

DOI: 10.1016/J.CARBON.2020.01.061

Atmospheric concentrations and sources of black carbon over tropical Australian waters

Publisher: Elsevier BV

Date: 2023

DOI: 10.1016/J.SCITOTENV.2022.159143

Abstract: Black carbon (BC) aerosols significantly contribute to radiative budgets globally, however their actual contributions remain poorly constrained in many under-s led ocean regions. The tropical waters north of Australia are a part of the Indo-Pacific warm pool, regarded as a heat engine of global climate, and are in proximity to large terrestrial sources of BC aerosols such as fossil fuel emissions, and biomass burning emissions from northern Australia. Despite this, measurements of marine aerosols, especially BC remain elusive, leading to large uncertainties and discrepancies in current chemistry-climate models for this region. Here, we report the first comprehensive measurements of aerosol properties collected over the tropical warm pool in Australian waters during a voyage in late 2019. The non-marine related aerosol emissions observed in the Arafura Sea region were more intense than in the Timor Sea marine region, as the Arafura Sea was subject to greater continental outflows. The median equivalent BC (eBC) concentration in the Arafura Sea (0.66 μg m

Physicochemical Characterization of Particulate Emissions from a Compression Ignition Engine Employing Two Injection Technologies and Three Fuels

Publisher: American Chemical Society (ACS)

Date: 31-05-2011

DOI: 10.1021/ES200388F

Abstract: Alternative fuels and injection technologies are a necessary component of particulate emission reduction strategies for compression ignition engines. Consequently, this study undertakes a physicochemical characterization of diesel particulate matter (DPM) for engines equipped with alternative injection technologies (direct injection and common rail) and alternative fuels (ultra low sulfur diesel, a 20% biodiesel blend, and a synthetic diesel). Particle physical properties were addressed by measuring particle number size distributions, and particle chemical properties were addressed by measuring polycyclic aromatic hydrocarbons (PAHs) and reactive oxygen species (ROS). Particle volatility was determined by passing the polydisperse size distribution through a thermodenuder set to 300 °C. The results from this study, conducted over a four point test cycle, showed that both fuel type and injection technology have an impact on particle emissions, but injection technology was the more important factor. Significant particle number emission (54%-84%) reductions were achieved at half load operation (1% increase-43% decrease at full load) with the common rail injection system however, the particles had a significantly higher PAH fraction (by a factor of 2 to 4) and ROS concentrations (by a factor of 6 to 16) both expressed on a test-cycle averaged basis. The results of this study have significant implications for the health effects of DPM emissions from both direct injection and common rail engines utilizing various alternative fuels.

Concentration and oxidative potential of on-road particle emissions and their relationship with traffic composition: Relevance to exposure assessment

Publisher: Elsevier BV

Date: 11-2012

DOI: 10.1016/J.ATMOSENV.2012.05.039

Light absorption properties of black and brown carbon during the prescribed burning season at an urban background site in Brisbane, Australia

Publisher: Elsevier BV

Date: 11-2023

DOI: 10.1016/J.ATMOSENV.2023.120072

Inorganic Salt Interference on CO₂⁺ in Aerodyne AMS and ACSM Organic Aerosol Composition Studies

Publisher: American Chemical Society (ACS)

Date: 14-09-2016

DOI: 10.1021/ACS.EST.6B01035

Abstract: Aerodyne aerosol mass spectrometer (AMS) and Aerodyne aerosol chemical speciation monitor (ACSM) mass spectra are widely used to quantify organic aerosol (OA) elemental composition, oxidation state, and major environmental sources. The OA CO

Performance and gaseous and particle emissions from a liquefied petroleum gas (LPG) fumigated compression ignition engine

Publisher: Elsevier BV

Date: 10-2014

DOI: 10.1016/J.FUEL.2014.04.093

Multivariate analysis of performance and emission parameters in a diesel engine using biodiesel and oxygenated additive

Publisher: Elsevier BV

Date: 12-2019

DOI: 10.1016/J.ENCONMAN.2019.112183

Critical Analysis of High Particle Number Emissions from Accelerating Compressed Natural Gas Buses

Publisher: American Chemical Society (ACS)

Date: 15-05-2010

DOI: 10.1021/ES1003186

Abstract: Compressed natural gas (CNG) engines are thought to be less harmful to the environment than conventional diesel engines, especially in terms of particle emissions. Although, this is true with respect to particulate matter (PM) emissions, results of particle number (PN) emission comparisons have been inconclusive. In this study, results of on-road and dynamometer studies of buses were used to derive several important conclusions. We show that, although PN emissions from CNG buses are significantly lower than from diesel buses at low engine power, they become comparable at high power. For diesel buses, PN emissions are not significantly different between acceleration and operation at steady maximum power. However, the corresponding PN emissions from CNG buses when accelerating are an order of magnitude greater than when operating at steady maximum power. During acceleration under heavy load, PN emissions from CNG buses are an order of magnitude higher than from diesel buses. The particles emitted from CNG buses are too small to contribute to PM(10) emissions or contribute to a reduction of visibility and may consist of semivolatile nanoparticles.

Determining the link between hygroscopicity and composition for semi-volatile aerosol species

Publisher: Copernicus GmbH

Date: 24-07-2018

DOI: 10.5194/AMT-11-4361-2018

Abstract: Abstract. Internally and externally mixed aerosols present significant challenges in assessing the hygroscopicity of each aerosol component. This study presents a new s ling 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 erse 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.

Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols

Publisher: Copernicus GmbH

Date: 10-07-2020

DOI: 10.5194/ACP-20-8047-2020

Abstract: 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 erted 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.

Particle emissions, volatility, and toxicity from an ethanol fumigated compression ignition engine

Publisher: American Chemical Society (ACS)

Date: 08-12-2010

DOI: 10.1021/ES9021377

Abstract: Particle emissions, volatility, and the concentration of reactive oxygen species (ROS) were investigated for a pre-Euro I compression ignition engine to study the potential health impacts of employing ethanol fumigation technology. Engine testing was performed in two separate experimental c aigns with most testing performed at intermediate speed with four different load settings and various ethanol substitutions. A scanning mobility particle sizer (SMPS) was used to determine particle size distributions, a volatilization tandem differential mobility analyzer (V-TDMA) was used to explore particle volatility, and a new profluorescent nitroxide probe, BPEAnit, was used to investigate the potential toxicity of particles. The greatest particulate mass reduction was achieved with ethanol fumigation at full load, which contributed to the formation of a nucleation mode. Ethanol fumigation increased the volatility of particles by coating the particles with organic material or by making extra organic material available as an external mixture. In addition, the particle-related ROS concentrations increased with ethanol fumigation and were associated with the formation of a nucleation mode. The smaller particles, the increased volatility, and the increase in potential particle toxicity with ethanol fumigation may provide a substantial barrier for the uptake of fumigation technology using ethanol as a supplementary fuel.

Effect of sulphur and vanadium spiked fuels on particle characteristics and engine performance of auxiliary diesel engines

Publisher: Elsevier BV

Date: 12-2018

DOI: 10.1016/J.ENVPOL.2018.08.055

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.

Influence of biodiesel fuel composition on the morphology and microstructure of particles emitted from diesel engines

Publisher: Elsevier BV

Date: 08-2016

DOI: 10.1016/J.CARBON.2016.03.061

Observations on the formation, growth and chemical composition of aerosols in an urban environment

Publisher: American Chemical Society (ACS)

Date: 05-06-2014

DOI: 10.1021/ES5019509

Abstract: The charge and chemical composition of ambient particles in an urban environment were determined using a neutral particle and air ion spectrometer and an aerodyne compact time-of-flight aerosol mass spectrometer. Particle formation and growth events were observed on 20 of the 36 days of s ling, with eight of these events classified as strong. During these events, peaks in the concentration of intermediate and large ions were followed by peaks in the concentration of ammonium and sulfate, which were not observed in the organic fraction. Comparison of days with and without particle formation events revealed that ammonium and sulfate were the dominant species on particle formation days while high concentrations of biomass burning OA inhibited particle growth. Analyses of the degree of particle neutralization lead us to conclude that an excess of ammonium enabled particle formation and growth. In addition, the large ion concentration increased sharply during particle growth, suggesting that during nucleation the neutral gaseous species ammonia and sulfuric acid react to form ammonium and sulfate ions. Overall, we conclude that the mechanism of particle formation and growth involved ammonia and sulfuric acid, with limited input from organics.

The application of profluorescent nitroxides to detect reactive oxygen species derived from combustion-generated particulate matter: Cigarette smoke – A case study

Publisher: Elsevier BV

Date: 06-2010

DOI: 10.1016/J.ATMOSENV.2010.02.043

Characterisation of a Commercially Available Thermodenuder and Diffusion Drier for Ultrafine Particles Losses

Publisher: Taiwan Association for Aerosol Research

Date: 2015

DOI: 10.4209/AAQR.2013.12.0355

Biomass burning emissions in north Australia during the early dry season: an overview of the 2014 SAFIRED campaign

Publisher: Copernicus GmbH

Date: 17-11-2017

DOI: 10.5194/ACP-17-13681-2017

Abstract: Abstract. The SAFIRED (Savannah Fires in the Early Dry Season) c aign 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 c aign 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 c aign, 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 s ling site and provide an overview of the more specific outcomes of the SAFIRED c aign.

Physicochemical Characterization of Particulate Emissions from a Compression Ignition Engine: The Influence of Biodiesel Feedstock

Publisher: American Chemical Society (ACS)

Date: 15-11-2011

DOI: 10.1021/ES2018797

Abstract: This study undertook a physicochemical characterization of particle emissions from a single compression ignition engine operated at one test mode with 3 biodiesel fuels made from 3 different feedstocks (i.e., soy, tallow, and canola) at 4 different blend percentages (20%, 40%, 60%, and 80%) to gain insights into their particle-related health effects. Particle physical properties were inferred by measuring particle number size distributions both with and without heating within a thermodenuder (TD) and also by measuring particulate matter (PM) emission factors with an aerodynamic diameter less than 10 μm (PM(10)). The chemical properties of particulates were investigated by measuring particle and vapor phase Polycyclic Aromatic Hydrocarbons (PAHs) and also Reactive Oxygen Species (ROS) concentrations. The particle number size distributions showed strong dependency on feedstock and blend percentage with some fuel types showing increased particle number emissions, while others showed particle number reductions. In addition, the median particle diameter decreased as the blend percentage was increased. Particle and vapor phase PAHs were generally reduced with biodiesel, with the results being relatively independent of the blend percentage. The ROS concentrations increased monotonically with biodiesel blend percentage but did not exhibit strong feedstock variability. Furthermore, the ROS concentrations correlated quite well with the organic volume percentage of particles - a quantity which increased with increasing blend percentage. At higher blend percentages, the particle surface area was significantly reduced, but the particles were internally mixed with a greater organic volume percentage (containing ROS) which has implications for using surface area as a regulatory metric for diesel particulate matter (DPM) emissions.

To Sonicate or Not to Sonicate PM Filters: Reactive Oxygen Species Generation Upon Ultrasonic Irradiation

Publisher: Informa UK Limited

Date: 20-11-2014

DOI: 10.1080/02786826.2014.981330

On the efficiency of impingers with fritted nozzle tip for collection of ultrafine particles

Publisher: Elsevier BV

Date: 02-2009

DOI: 10.1016/J.ATMOSENV.2008.12.001

An Overview of Small Unmanned Aerial Vehicles for Air Quality Measurements: Present Applications and Future Prospectives

Publisher: MDPI AG

Date: 12-07-2016

DOI: 10.3390/S16071072

Application of a Fluorescent Probe for the Online Measurement of PM-Bound Reactive Oxygen Species in Chamber and Ambient Studies

Publisher: MDPI AG

Date: 21-10-2019

DOI: 10.3390/S19204564

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 s ling and was operated with a minimum time resolution of 2.5 min. Details of the fluorimeter design and ex les of data processing are provided, and results from a chamber study of side-stream cigarette smoke and ambient monitoring c aign 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).

Engine performance and emissions of high nitrogen-containing fuels

Publisher: Elsevier BV

Date: 03-2020

DOI: 10.1016/J.FUEL.2019.116805

Restructuring of carbonaceous particles upon exposure to organic and water vapours

Publisher: Elsevier BV

Date: 05-2012

DOI: 10.1016/J.JAEROSCI.2011.12.005

Review-evaluating the molecular assays for measuring the oxidative potential of particulate matter

Publisher: National Library of Serbia

Date: 2015

DOI: 10.2298/CICEQ140228031H

Abstract: Several cell-free assays are currently used to quantify and detect the Reactive Oxygen Species (ROS). All of them have certain limitations, do not provide direct comparison of results and, to date, none of these assays have been acknowledged as the most suitable acellular assay and none has yet been adopted for investigation of potential PM toxicity. These assays include DTT, ascorbic acid, DCFHDA and PFN assays which have been used in measurements of the particles generated from various combustion sources such as diesel engine, wood smoke (or biomass burning) and cigarette smoke, as well as for outdoor measurements. All the probes use different units for expressing redox properties of PM. Also, their reactivity is being triggered by different types of ROS. This limits the direct comparison of the results that are reporting the toxicity of the same aerosol type measured with various probes. This study is evaluating and comparing the various assays in order to develop deeper understanding of their capabilities, selectivity as well as improve understanding of the underlying chemical mechanisms.

Influence of oxygenated organic aerosols (OOAs) on the oxidative potential of diesel and biodiesel particulate matter

Publisher: American Chemical Society (ACS)

Date: 26-06-2013

DOI: 10.1021/ES4007433

Abstract: Generally, the magnitude of pollutant emissions from diesel engines running on biodiesel fuel is ultimately coupled to the structure of the fuel's constituent molecules. Previous studies demonstrated the relationship between the organic fraction of particulate matter (PM) and its oxidative potential. Herein, emissions from a diesel engine running on different biofuels were analyzed in more detail to explore the role that different organic fractions play in the measured oxidative potential. In this work, a more detailed chemical analysis of biofuel PM was undertaken using a compact time of flight aerosol mass spectrometer (c-ToF AMS). This enabled a better identification of the different organic fractions that contribute to the overall measured oxidative potentials. The concentration of reactive oxygen species (ROS) was measured using a profluorescent nitroxide molecular probe 9-(1,1,3,3-tetramethylisoindolin-2-yloxyl-5-ethynyl)-10-(phenylethynyl)anthracene (BPEAnit). Therefore, the oxidative potential of the PM, measured through the ROS content, although proportional to the total organic content in certain cases, shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS. This highlights the importance of knowing the surface chemistry of particles for assessing their health impacts. It also sheds light onto new aspects of particulate emissions that should be taken into account when establishing relevant metrics for assessing health implications of replacing diesel with alternative fuels.

The contribution of coral-reef-derived dimethyl sulfide to aerosol burden over the Great Barrier Reef

Publisher: Copernicus GmbH

Date: 22-02-2022

DOI: 10.5194/ACP-22-2419-2022

Abstract: Abstract. Coral reefs have been found to produce the sulfur compound dimethyl sulfide (DMS), a climatically relevant aerosol precursor predominantly associated with phytoplankton. Until recently, the role of coral-reef-derived DMS within the climate system had not been quantified. A study preceding the present work found that DMS produced by corals had negligible long-term climatic forcing at the global–regional scale. However, at sub-daily timescales more typically associated with aerosol and cloud formation, the influence of coral-reef-derived DMS on local aerosol radiative effects remains unquantified. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) has been used in this work to study the role of coral-reef-derived DMS at sub-daily timescales for the first time. WRF-Chem was run to coincide with an October 2016 field c aign over the Great Barrier Reef, Queensland, Australia, against which the model was evaluated. After updating and scaling the DMS surface water climatology, the model reproduced DMS and sulfur concentrations well. The inclusion of coral-reef-derived DMS resulted in no significant change in sulfate aerosol mass or total aerosol number. Subsequently, no direct or indirect aerosol effects were detected. The results suggest that the co-location of the Great Barrier Reef with significant anthropogenic aerosol sources along the Queensland coast prevents coral-reef-derived aerosol from having a modulating influence on local aerosol burdens in the current climate.

Application of profluorescent nitroxides for measurements of oxidative capacity of combustion generated particles

Publisher: National Library of Serbia

Date: 2012

DOI: 10.2298/CICEQ120113113S

Abstract: Oxidative stress caused by generation of free radicals and related reactive oxygen species (ROS) at the sites of deposition has been proposed as a mechanism for many of the adverse health outcomes associated with exposure to particulate matter (PM). Recently, a new profluorescent nitroxide molecular probe (BPEAnit) developed at QUT was applied in an entirely novel, rapid and non-cell based assay for assessing the oxidative potential of particles (i.e. potential of particles to induce oxidative stress). The technique was applied on particles produced by several combustion sources, namely cigarette smoke, diesel exhaust and wood smoke. One of the main findings from the initial studies undertaken at QUT was that the oxidative potential per PM mass significantly varies for different combustion sources as well as the type of fuel used and combustion conditions. However, possibly the most important finding from our studies was that there was a strong correlation between the organic fraction of particles and the oxidative potential measured by the PFN assay, which clearly highlights the importance of organic species in particle-induced toxicity.

Composition, size and cloud condensation nuclei activity of biomass burning aerosol from northern Australian savannah fires

Publisher: Copernicus GmbH

Date: 14-03-2017

DOI: 10.5194/ACP-17-3605-2017

Abstract: 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 c aign 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.

Untangling the influence of Antarctic and Southern Ocean life on clouds

Publisher: University of California Press

Date: 2023

DOI: 10.1525/ELEMENTA.2022.00130

Abstract: Polar environments are among the fastest changing regions on the planet. It is a crucial time to make significant improvements in our understanding of how ocean and ice biogeochemical processes are linked with the atmosphere. This is especially true over Antarctica and the Southern Ocean where observations are severely limited and the environment is far from anthropogenic influences. In this commentary, we outline major gaps in our knowledge, emerging research priorities, and upcoming opportunities and needs. We then give an overview of the large-scale measurement c aigns planned across Antarctica and the Southern Ocean in the next 5 years that will address the key issues. Until we do this, climate models will likely continue to exhibit biases in the simulated energy balance over this delicate region. Addressing these issues will require an international and interdisciplinary approach which we hope to foster and facilitate with ongoing community activities and collaborations.

Comprehensive aerosol and gas data set from the Sydney Particle Study

Publisher: Copernicus GmbH

Date: 02-12-2019

DOI: 10.5194/ESSD-11-1883-2019

Abstract: 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 understanding of particle formation and transformations in the Sydney airshed. In this paper we describe the methods used to collect and analyse particle and gaseous s les, 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 metadata record for the data sets published in Keywood et al. (2016a, 0.4225/08/57903B83D6A5D) and Keywood et al. (2016b, 0.4225/08/5791B5528BD63).

Influence of oxygen content of the certain types of biodiesels on particulate oxidative potential

Publisher: Elsevier BV

Date: 03-2016

DOI: 10.1016/J.SCITOTENV.2015.12.036

Abstract: Oxidative potential (OP) is related to the organic phase, specifically to its oxygenated organic fraction (OOA). Furthermore, the oxygen content of fuel molecules has significant influence on particulate OP. Thus, this study aimed to explore the actual dependency of the OOA and ROS to the oxygen content of the fuel. In order to reach the goal, different biodiesels blends, with various ranges of oxygen content have been employed. The compact time of flight aerosol mass spectrometer (c-ToF AMS) enabled better identification of OOA. ROS monitored by using two assays: DTT and BPEA-nit. Despite emitting lower mass, both assays agreed that oxygen content of a biodiesel is directly correlated with its OOA, and highly related to its OP. Hence, the more oxygen included in the considered biodiesels, the higher the OP of PM emissions. This highlights the importance of taking oxygen content into account while assessing emissions from new fuel types, which is relevant from a health effects standpoint.

Time-Resolved Characterization of Primary Emissions from Residential Wood Combustion Appliances

Publisher: American Chemical Society (ACS)

Date: 04-10-2012

DOI: 10.1021/ES301654W

Abstract: Primary emissions from a log wood burner and a pellet boiler were characterized by online measurements of the organic aerosol (OA) using a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and of black carbon (BC). The OA and BC concentrations measured during the burning cycle of the log wood burner, batch wise fueled with wood logs, were highly variable and generally dominated by BC. The emissions of the pellet burner had, besides inorganic material, a high fraction of OA and a minor contribution of BC. However, during artificially induced poor burning BC was the dominating species with ∼80% of the measured mass. The elemental O:C ratio of the OA was generally found in the range of 0.2-0.5 during the startup phase or after reloading of the log wood burner. During the burnout or smoldering phase, O:C ratios increased up to 1.6-1.7, which is similar to the ratios found for the pellet boiler during stable burning conditions and higher than the O:C ratios observed for highly aged ambient OA. The organic emissions of both burners have a very similar H:C ratio at a given O:C ratio and therefore fall on the same line in the Van Krevelen diagram.

Respiratory health effects of diesel particulate matter

Publisher: Wiley

Date: 24-01-2012

DOI: 10.1111/J.1440-1843.2011.02109.X

Abstract: Particulate matter (PM) emissions involve a complex mixture of solid and liquid particles suspended in a gas, where it is noted that PM emissions from diesel engines are a major contributor to the ambient air pollution problem. While epidemiological studies have shown a link between increased ambient PM emissions and respiratory morbidity and mortality, studies of this design are not able to identify the PM constituents responsible for driving adverse respiratory health effects. This review explores in detail the physico-chemical properties of diesel PM (DPM) and identifies the constituents of this pollution source that are responsible for the development of respiratory disease. In particular, this review shows that the DPM surface area and adsorbed organic compounds play a significant role in manifesting chemical and cellular processes that if sustained can lead to the development of adverse respiratory health effects. The mechanisms of injury involved included inflammation, innate and acquired immunity, and oxidative stress. Understanding the mechanisms of lung injury from DPM will enhance efforts to protect at-risk in iduals from the harmful respiratory effects of air pollutants.

E-cigarettes induce toxicity comparable to tobacco cigarettes in airway epithelium from patients with COPD

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.TIV.2021.105204

Emission factors of trace gases and particles from tropical savanna fires in Australia

Publisher: American Geophysical Union (AGU)

Date: 10-06-2017

DOI: 10.1002/2016JD025925

Emissions of Selected Semivolatile Organic Chemicals from Forest and Savannah Fires

Publisher: American Chemical Society (ACS)

Date: 18-01-2016

DOI: 10.1021/ACS.EST.6B03503

Abstract: The emission factors (EFs) for a broad range of semivolatile organic chemicals (SVOCs) from subtropical eucalypt forest and tropical savannah fires were determined for the first time from in situ investigations. Significantly higher (t test, P < 0.01) EFs (μg kg

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

Publisher: Springer Science and Business Media LLC

Date: 22-01-2016

DOI: 10.1007/S10874-016-9327-7

Queensland University Of Technology

Location: Australia

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Discovery Projects - Grant ID: DP120100126

Start Date: 06-2012

End Date: 12-2015

Amount: $390,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP180100516

Start Date: 12-2019

End Date: 12-2023

Amount: $889,797.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE150100048

Start Date: 09-2015

End Date: 12-2016

Amount: $630,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE220100103

Start Date: 07-2022

End Date: 12-2023

Amount: $328,389.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE230100008

Start Date: 2023

End Date: 12-2023

Amount: $831,200.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP210103284

Start Date: 07-2021

End Date: 12-2024

Amount: $351,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP180102632

Start Date: 02-2018

End Date: 06-2022

Amount: $354,636.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP150101649

Start Date: 05-2015

End Date: 12-2017

Amount: $263,500.00

Funder: Australian Research Council