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Research plans in air chemistry |
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Team
Derek Bowden
Peter Brimblecombe
Simon Clegg
Carlota Grossi
Young Hun Yoon
Area of research
Studies of gas-solid, gas-liquid, and solid-liquid partition involving
atmospheric aerosols and cloud droplets. This is relevant to understanding
- the behaviour of trace compounds and their removal from the atmosphere,
- the physical state and chemical behaviour of aerosol populations.
Current and past work
For more than two decades we have been studying the thermodynamics of gas dissolution into aqueous solutions. Much of our attention has focussed on predicting activity coefficients in concentrated electrolytes containing the salts and acids found in aqueous aerosols. Increasingly we have becom interested in containing organic compounds (including surfactants) relevant to the atmosphere (e.g. oxalic acid, humic acid). We have also been concerned with measuring and estimating Henry's law constants of organic acids in order to obtain a better understanding of their gas/(aerosol, cloud) partitioning.
Future plans
Our research has both modelling and experimental components, which we will maintain and develop in a complementary way. Over the next few years we will make laboratory based measurements in concentrated solutions using electrodynamic balances. We continue to look at the presence and chemistry of large organic molecules (such as humic acid) and surfactants in the atmosphere. In the indoor environment we have begun to study the interactions of gases with a range of surface materials, both from the perspective of the removal of the gases from air and damage to indoor materials.
The research will be developed along the following lines:
MODELLING/THEORY
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How effectively can the vapour pressures of organic
compounds, and their activity coefficients in mixtures, be
predicted from molecular structure and other fundamental
properties?
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Development of methods of combining different thermodynamic
models of liquid phases (e.g., of electrolytes, and of
non-electrolytes) in a self consistent way.
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Can the thermodynamic properties of aqueous electrolyte
mixtures be calculated from the physics of ensembles of
ions and water molecules, and so enable predictions to be
made for systems for which no experimental data are
available?
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Practical construction of models of aerosol formation,
including organic compounds, by extending our existing
models (e.g., AIM).
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Use of these models in the development/testing/validation
of atmospheric codes used for air pollution modelling both
for research and by regulatory agencies.
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The use of thermodynamics to describe the uptake of compounds such as HONO and nictoine on typical indoor surfaces.
EXPERIMENTS
- Use of the electrodynamic balance to determine relative
humidity/size relationships of soluble particles at extreme
concentrations.
- Use of the electrodynamic balance to study solid/liquid/gas
partitioning of organic compounds in aerosol particles.
- Experiments and measurements on the chemistry of polycarboxylic acids and surfactants in atmospheric aerosols to understand their role in aerosols.