Airborne grass pollen is a major outdoor aeroallergen, triggering conditions such as hayfever, allergic conjunctivitis and asthma in many people. By international comparisons, Australia has a high rate of allergic illness, and most if not all of this burden of allergy is preventable with appropriate treatment. Grass pollen is also understood to be an ingredient in episodes of 'thunderstorm asthma' (a sudden surge in community-level asthma during or immediately after a thunderstorm) in Australia. In response to the major thunderstorm asthma incident in Melbourne in 2016, a warning service has been developed by a consortium of Federal and State government agencies and Australian universities. Part of the thunderstorm asthma forecasting service is a model for airborne grass pollen concentrations across Victoria. The grass pollen modelling method has thus far shown reasonable skill in Victoria, however by its nature it will not generalise across Australia.

In this work, we will present the progress towards generalising the methodology used for the Victorian case to the whole of Australia. Factors considered include current and recent surface weather, remotely-sensed vegetation indices, and maps of the distributions of major grass taxa. The work is built on grass pollen data collected in five Australian States and Territories, and across a wide range of climates and ecotypes.