Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand
Although grass pollen is widely regarded as the major outdoor aeroallergen source in Australia and New Zealand (NZ), no assemblage of airborne pollen data for the region has been previously compiled. Grass pollen count data collected at 14 urban sites in Australia and NZ over periods ranging from 1 to 17 years were acquired, assembled and compared, revealing considerable spatiotemporal variability. Although direct comparison between these data is problematic due to methodological differences between monitoring sites, the following patterns are apparent. Grass pollen seasons tended to have more than one peak from tropics to latitudes of 37°S and single peaks at sites south of this latitude. A longer grass pollen season was therefore found at sites below 37°S, driven by later seasonal end dates for grass growth and flowering. Daily pollen counts increased with latitude; subtropical regions had seasons of both high intensity and long duration. At higher latitude sites, the single springtime grass pollen peak is potentially due to a cooler growing season and a predominance of pollen from C3 grasses. The multiple peaks at lower latitude sites may be due to a warmer season and the predominance of pollen from C4 grasses. Prevalence and duration of seasonal allergies may reflect the differing pollen seasons across Australia and NZ. It must be emphasized that these findings are tentative due to limitations in the available data, reinforcing the need to implement standardized pollen-monitoring methods across Australasia. Furthermore, spatiotemporal differences in grass pollen counts indicate that local, current, standardized pollen monitoring would assist with the management of pollen allergen exposure for patients at risk of allergic rhinitis and asthma.
KeywordsAerobiology Latitude Grass pollen Plant distribution Australia New Zealand
The Australian Aerobiology Working Group was supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS), Terrestrial Ecosystem Research Network (TERN). Merck Sharp and Dohme provided additional independent untied co-sponsorship for the Working Group. The authors wish to thank Associate Professor Alison Specht, Program Manager, and the staff of ACEAS, TERN for assistance in organizing the Workshops of the Working Group “Understanding Australian aerobiology to monitor environmental change and human allergenic exposure”, North Stradbroke Island, Australia (March and November, 2013). We thank Doctors Diana Bass and Geoffrey Morgan for provision of their published pollen count data from Sydney. Alison Jaggard has been assisted by the New South Wales Government through its Environmental Trust (project reference number 2011/RD/0049). The findings and the conclusions in this report are those of the authors and do not necessarily represent the views of the US National Institute for Occupational Safety and Health. The authors also acknowledge the contributions a diverse group of people made to this study through counting pollen and maintaining the pollen records that we consolidated and analyzed. Finally, the authors wish to thank Associate Professor Jeroen Buters (Germany), Associate Professor Frank Murray (Australia), and Dr Michel Thibaudon (France) for their contributions to the working group.
JMD’s institute has received collaborative research funds from Stallergenes, consultancy fees, Honoraria payments from Stallergenes and Glaxo Smith Kline for presentations at Australian Society for Clinical Immunology and Allergy Education Meetings. JMD is an inventor on a patent granted in Australia and further applications for improving diagnosis and treatment of subtropical grass pollen allergy.
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