ATMOSPHERIC CHEMISTRY

Species in trace quantities in the atmosphere play significant roles in many processes that directly and indirectly affect the quality of our life.  We are interested in understanding the sources, reactions and effects that these species have.

The described projects are indicative of the work carried out in the Atmospheric Chemistry group.  Research programs are negotiable and areas of interest to potential students will be accommodated if they fall within the general theme of the group’s activities.

Trace Gases and Volatile Organic Compounds

Identifying and quantifying the sources of volatile organic compounds (VOC’s) is important as these compounds are involved in complex chemical and physical transformations that result in effects such as smog formation, changes in the oxidative capacity of the atmosphere and aerosol formation.  Large volumes of VOC’s are emitted from plants (biogenic VOC’s) and from human activities (anthropogenic VOC’s), such as fossil fuel and biomass combustion, evaporation of solvents and fuels and production processes.  Much effort has been put into reducing emissions of anthropogenic VOC’s, yet if the quantity of biogenic VOC’s is significant, then this effort may be misplaced.

VOC’s and other trace species (such as NO, NO₂ and CO) are contributors to poor indoor air quality.  Increasing urbanisation results in an increase in the occupation of well-sealed buildings using recirculated air for climate control, which may lead to a decrease in indoor air quality.  This is a growing concern throughout the world.  Identification of sources of VOC’s and other trace species is a central issue in environmental management.

We have a range of projects concerned with identifying and quantifying VOC’s and their sources.  The techniques incorporate Solid Phase Microextraction with GC and GC/MS analysis, cavity ring-down spectroscopy and Fourier Transform Infrared spectroscopy.

Structure and Composition of Secondary Organic Aerosols

Organic aerosol accounts for a very large fraction of air particulate matter.  It affects the atmosphere and climate through interaction with reactive trace gases, water vapour, clouds, precipitation, and radiation.   It also influences the biosphere and human health through the spread of reproductive materials and micro-organisms, has impacts on respiratory and cardiovascular functions, and is a factor in allergic and infectious disease spread.  While advances have occurred in the science of organic aerosols, much remains to be understood concerning their composition, sources and transformation.   The broad aim of this project is to improve our understanding of Secondary Organic Aerosol (SOA) composition in major Australian airsheds.  In particular, we are concerned with the impact that both plant and motor vehicle emissions of volatile organic compounds (VOCs) have on SOA formation and composition and hence on air quality.  This project will address the follow scientific questions:

• Under photolytic conditions associated with aerosol formation, what are the reaction pathways of VOCs of significance in Australian urban and semi-urban airsheds?
• What is the molecular composition of Secondary Organic Aerosols?
• What is the polymeric composition of Secondary Organic Aerosols?
• What similarities and differences are there between aerosol formation under homogeneous (unseeded) and heterogeneous (seeded) conditions?

Synthesis and Characterisation of Important Peroxyl Nitrate Compounds

The PAN family of compounds play a very important role in atmospheric chemistry because they act as reservoirs of reactive nitrogen NO_X).  While the archetypal compound, peroxyacetyl nitrate, (CH₃C(O)OONO₂) is relatively well characterised, there is little information available concerning the compounds in the family based on this structure.  Good quality infrared spectra are needed for use in identifying and quantifying these species in smog chamber experiments.  A number of compounds have been identified from modelling studies as important targets for synthesis and characterisation.  In this project, we will synthesize as many of these compounds as possible and obtain their infrared spectra.  Characterisation of the product mixture will be achieved through infrared spectroscopy and GC-MS investigations.  Vibrational analysis using computer-based modelling (Gaussian) will be used to aid in spectral identification.  Synthesis will be undertaking using photolytic gas phase reactions, and liquid phase reactions if appropriate to obtain pure samples.  There is the possibility of conducting atmospheric simulation experiments using the CSIRO Energy Technology smog chamber facilities.

Emissions of Greenhouse Gases

The substitution of compressed natural gas (CNG) for diesel fuel in heavy-duty vehicles has potential greenhouse gas benefits due to an expected reduction in CO₂ emissions.   However, even if CO₂ emissions are reduced, the nett global warming potential may be offset by increased emissions of gases with greater global warming potentials (e.g. N₂O and CH₄).  The present work was initially commissioned by the Australian Greenhouse Office as a pilot study to determine N₂O emissions from dual-fuel trucks operated back-to-back on diesel and then in CNG/diesel mode.  Analyses were carried out by using an analyser specific to N₂O (continuous, on-site) and off-line by FTIR spectroscopy of filtered bag samples.  The FTIR spectra are also processed to obtain CO and CH₄ concentrations.

Emissions of Organic Compounds in Natural Product Chemistry

Vegetation emits significant quantities of Volatile Organic Compounds.  These emissions may be correlated with internal chemistry of the plants, and give clues on such things as the presence of useful compounds, stage of plant development and the maturation state of fruit.  The relatively new technique of Solid-Phase Microextraction (SPME) offers a route to convenient in situ sampling.  SPME combines in one-step sampling and preconcentration, prior to GC or GC-MS analysis.  Our research activity aims at developing methods of in situ SPME-GC analysis, and to develop a database of VOC emissions from Australian native vegetation.

Photo-oxidation of VOC’s from Australian Vegetation

Oxidation of compounds emitted by plants occurs through a series of cyclic chain reactions, initiated principally by the hydroxyl radical, OH.  Hydroxyl radicals are produced photolytically, hence the process is generally one of photo-oxidation. Products from this photo-oxidation are involved in a number of important atmospheric processes, including secondary organic aerosol (SOA) formation.  There has been very little exploration of the photo-oxidation reactions of VOC’s emitted in quantity by Australian vegetation, for instance, those of eucalyptol (1,8-cineole).   In this project, compounds of interest will be photo-oxidized under controlled conditions using the Indoor Smog Chamber at CSIRO Lucas heights and analysed via GC- and LC-MS after derivatisation.

Signals and Pollination in Deceptive Orchids and Plants

(with A/Prof Marie Herberstein and Dr Michelle Leishman, Department of Biological Sciences)

Orchids are famous for their unusual deceptive pollination systems, and Australia is a global hotspot for orchid deception. If you are seeking a project involving charismatic study species, independent fieldwork, and broadly-applicable lab skills, this interdisciplinary project may suit you.

'Food-deceptive' orchids do not provide a nectar reward for their pollinators. Instead, they are thought to attract pollinators by mimicking the colours and scents of other flowers. We are interested in the evolution of this mimicry, and in assessing the colour and scent signals without the biases of human perception.

Fieldwork will be required in Sydney and NSW to monitor native orchid pollination rates, collect pollinating insects, and collect flowers from orchids and other plants. Floral colours will be analysed by spectrometry in the Department of Biological Sciences. Floral scents will be analysed by gas chromatography and gas-chromatography-mass spectrometry in the Department of Chemistry & Biomolecular Sciences.

We are seeking a student with a background in evolutionary biology and/or chemistry. We will teach you all the field and lab techniques, and we can develop the project according to your strengths and interests.

Your own car would be an advantage for fieldwork, but it is not essential. The project is well-funded, permits have been applied for, and we are ready to go with the right person. Furthermore, you'll be joining dynamic labs that combine innovative science with great peer-support. Visit our web pages and feel free to contact us for more information.

See also the web pages of Mariella and Michelle

“The foundation of every state is the education of its youth” – Diogenes

The Pedagogy of Laboratory-Based Teaching and Learning

Laboratory-based teaching and learning is generally, but not universally, accepted as a fundamental element in science education.  While our understanding of teaching and learning processes has advanced through education research, the application of this knowledge to the laboratory has lagged behind.  We are interested in addressing a number of general educational questions relating to laboratory-based teaching and learning, such as what are the purposes of teaching in laboratories, what strategies are available for teaching in laboratories and how are they related to the purposes and how might we assess the outcomes of laboratory instruction?

Of particular interest is identifying how generic skills and graduate attributes may be developed in the laboratory context.  Laboratory work provides ample opportunities for students to cultivate skills such as collecting, analysing and organising information, communicating ideas and information, planning and organising activities, working alone and in teams, using mathematical ideas and techniques, solving problems and using technology.

The Advancing Chemistry by Enhancing Learning in the Laboratory (ACELL) Project

The Advancing Chemistry by Enhancing Learning in the Laboratory (ACELL) project was established in 2004 to improve Australian chemistry laboratory education. This project pools the resources of over 30 universities from Australia and New Zealand to establish a protocol for developing and assuring the quality of laboratory teaching experiments.  This protocol is based on research-led teaching and has resulted in the creation of an Educational Template for ensuring that contributions to the project have a b student focus.  ACELL has a relationship with the Australian Journal of Education in Chemistry for dissemination of research results.  Any experiment that passes the two-tiered referee process is automatically accepted for publication in the journal.  The ACELL database (www.acell.org) is open to the public.

Mathematics in Chemistry Education

Anecdotal evidence suggests that the many science students are finding the mathematical aspects of their courses to be difficult and therefore a barrier to their studies.  We are interested in determining if anecdotal evidence can be supported by research, in discovering why this position has come about, and developing approaches to achieve the desired learning outcomes for our graduates, which includes the ability to use mathematical tools in a confident and competent manner.

Maths Anxiety in Chemistry Students

Maths anxiety is described in a number of ways, but the common themes are that a sufferer feels, to greater or lesser extent, panic, helplessness, paralysis, and mental disorganization.  This may mean that the student stops him- or herself from starting on a task, even if capable of doing it.  Students may be caught in a cycle of maths avoidance when, in the past, the student has suffered a bad experience relating to maths.  The student then avoids mathematical tasks, resulting in poor mathematical preparation.  This then leads to more negative maths experiences, reinforcing negative perceptions, and hence completing the cycle.  In the milder form of this behaviour, simple reassurance and guidance may be sufficient to break the cycle.  In the ber form, this will result in a true lack of mathematical preparation and a fear of doing anything about it.  The protocol for dealing with students suffering from maths anxiety should be different from that for those students simply lacking adequate mathematical skills, but without anxiety. For this reason it is necessary to measure the extent of maths anxiety amongst the student cohort, and develop mechanisms for identifying these people early in their studies, so that appropriate support for them can be provided.

Chemical Misconceptions and Constructivism

“Constructivism” refers to the theory that the process of learning is not one of simple acceptance and remembrance of facts, but one where the learner must incorporate them into an already constructed world-view.  If that world-view can not be modified to fit the new knowledge, then the knowledge is not retained.  In other words, the learner must construct meaning for the knowledge for it to be preserved.   It is therefore necessary for teachers to understand the ways in which students incorporate knowledge into their “world-views”.  Students bring with them many preconceptions and/or misconceptions.  These form the scaffolding on which students build all subsequent knowledge, unless they are distinguished, confronted and replaced or reconstructed in line with modern scientific thinking. Preconceptions in chemistry are extremely persistent. There is typically a rapid evolution in fundamental ideas about chemistry between the ages of 6 and 12, but only very slow change thereafter, in spite of intensive instruction in chemistry. These misconceptions are likely to still be present in tertiary level students, right through to those studying for their Ph.D.’s.  It is important that teachers are aware of the range of preconceptions and misconceptions that students bring with them, and put in place appropriate teaching methods that adequately address these issues.

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Senior Lecturer

Stephen White

Summer Vaction Project (2006)
Passive NO_X Sampling

CBMS207 - Physical and Environmental Chemistry I

Environmental issues are of foremost concern in the world today. The environment depends on complex interactions of chemical and physical processes. In this unit these processes will be explored through the study of the underlying principles that govern the properties and behaviour of chemical systems. Physical chemistry permeates all of modern chemistry and many adjoining areas such as biomolecular sciences, materials science and, of course, environmental science. Using environmental chemistry examples and contexts, we will explore the “what”, “why” and “how fast” of chemistry: Structure, Energy, and Rate. These topics will be examined in terms of the origin, transport and fate of chemicals in the biosphere, atmosphere, hydrosphere and lithosphere.

CBMS307 - Physical and Environmental Chemistry II

This unit explores the underlying principles that govern the properties and behaviour of chemical processes. Using environmental chemistry examples and contexts, we will explore the “what”, “why” and “how fast” of chemistry: Structure, Energy, and Rate. The theoretical foundations of these topics are respectively, quantum mechanics, thermodynamics and equilibrium statistical mechanics, and chemical kinetics. There is an emphasis of the chemistry of global climate change, ozone depletion, dispersal and transformation of chemicals in the environment, equilibrium and non-equilibrium processes in the World’s oceans and other environmentally relevant topics. Measurement and modelling of these systems will be described and practiced.

CBMS302 - Chemistry Capstone

This unit provides an opportunity to take an overview of your studies in your Major, and a focus on how what you have learnt equips you for your next step, whether this is to further study, or into the workforce. We will examine the latest advances in chemistry, such as in Green Chemistry, molecular recognition and drug design through guest lectures from leading researchers.  We will look at the idea of the “ethical chemist”, and through workshops with industry employers and recruiters we will get you ready to apply for positions in industry and academia. An important part of the course will be a self-directed laboratory investigation into a topic of current interest, such as biodiesel synthesis and characterisation, development of novel materials, and new synthesis methods. You will plan and carry out the investigation, and report on the outcomes. You will have the opportunity to use sophisticated research instruments and to refine your laboratory skills.

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