Characterising the Organics and Aerosol Loading of Australia, COALA

January 30th, 2020

COALA is a broad project designed to study the emissions and atmospheric chemistry of Australian biogenic compounds (gases emitted by plants) in pristine conditions and their interactions with man-made pollution. Previous modelling of biogenic emissions in Australia has demonstrated that emissions measured from eucalypts in the northern hemisphere do not represent the ambient measurements made in Australia. The aims of COALA are to make measurements of individual biogenic compounds from adult eucalypt trees in their native environment and to study how these species impact on urban air quality. COALA’s science aims have been endorsed by the International Commission on Atmospheric Chemistry and Global Pollution (iCACGP).

An intensive experiment is being held from January through March, 2020 based in the national parks just south of Sydney. The site is enclosed by many eucalypt species including the scribbly gum and is ~40 km from Wollongong and ~80 km from Sydney.


Personnel from many Australian and international research institutes have joined COALA. Here members of CSIRO’s ACC group help to set up the AirBox. Kathryn and Ruhi help set up the air inlets on the roof, whilst Melita sets up the Aerosol Chemical Speciation Monitor.

Georgia Tech brought their Proton Transfer Reaction Mass Spectrometer to COALA, which can identify individual biogenic compounds at very high time resolution. These measurements will complement the tube samples being taken by the University of Wollongong on behalf of Alex Guenther from the University of California, Irvine (USA).

Kirsti Ashworth from the University of Lancaster (UK) has sent chambers designed to capture emissions of soil NOx and biogenic gases. Staff from CSIRO and the University of Wollongong will take measurements daily, and in some occasions, hourly to capture the diurnal cycle in emissions. Kirsti points out that this collaboration represents her group’s first measurements anywhere in the southern hemisphere!

Malcolm Possell from the University of Sydney is using small branch enclosures to measure the flux of biogenic compounds directly from the leaves of the trees around the Park.


Due to unprecedented bushfire activity in the summer season 2019/2020, we expect some of the COALA measurements to be impacted by smoke. We’re using the opportunity to evaluate CSIRO’s smoke forecasting system AQFx with measurements made on site (including CSIRO’s SMOG small sensor boxes, pictured above), and against four other models of varying spatial resolution (systems operated by NSW Department of Planning, Industry and Environment, the European Centre for Medium range Weather Forecasting, the National Center for Atmospheric Research, USA and the GEOS-Chem model).