CSIRO, Bureau of Meteorology and British scientists are spending summer studying the ‘self-cleansing’ ability of the atmosphere. They are participating in a major international project called the Southern Ocean Atmospheric Photochemistry Experiment, based in north-western Tasmania.
Air contains naturally occurring chemicals called hydroxyl radicals that react with, and destroy, a range of pollutants and natural compounds.
‘If levels of hydroxyl radicals are changing, one consequence may be increasing concentrations of ozone gas in the lower atmosphere,’ says Professor Stuart Penkett, from the School of Environmental Sciences at the University of East Anglia in the UK. Professor Penkett is a project leader for the experiment.
Ozone near the ground is both a greenhouse gas and an irritant that attacks the throat and lungs and irritates the eyes.
‘A change in ozone and hydroxyl radical concentrations in the lower atmosphere would certainly affect stability of the world’s climate,’ says Professor Penkett.
‘Our Experiment is giving us a present-day baseline in the cleanest air present in the atmosphere against which we can check future changes. We will also use our results as a comparison for similar studies in the more polluted northern hemisphere,’ says Professor Penkett.
The Southern Ocean Atmospheric Photochemistry Experiment is taking place now because sunlight is most intense at this time of the year. The sun’s energy plays a vital role in driving many of the chemical reactions in the atmosphere.
The Experiment involves measurements from the Cape Grim Baseline Air Pollution Station in Tasmania, from research aircraft and from the CSIRO research vessel "Southern Surveyor"Leeds University, Leicester University and the University of East Anglia are working with CSIRO and Bureau of Meteorology scientists on the Experiment.
There will also be measurement flights by a small pilotless aircraft. The ‘aerosonde’ will fly as high as three kilometres, collecting data on atmospheric pressure, temperature, relative humidity and wind speed. These data will be used in conjunction with observations from the Cape Grim station of both atmospheric chemistry and meteorology.
The Experiment involves approximately 50 scientists and engineers, PhD students and technical staff from CSIRO Atmospheric Research and CSIRO Marine Research, from the Bureau of Meteorology, and from the three British universities who are funded by the UK Natural Environment Research Council.
The Southern Ocean Atmospheric Photochemistry Experiment is one of the largest and most comprehensive studies ever conducted into the chemistry of the lower atmosphere. It is part of a major international effort being made to understand more about the chemistry of our atmosphere and its impact on climate.
The Experiment will continue until 21 February, 1999.
Broadcast quality footage of the Cape Grim Baseline Air Pollution Station, and the "Southern Surveyor" research vessel is available on request.
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