Seasonal distribution of pollen in the atmosphere of Darwin, tropical Australia: Preliminary results

Stevenson, Janelle; Haberle, Simon; Johnston, Fay H.; Bowman, David M. J. S.

doi:10.1080/00173130601178250

Cited by 17 publications

(23 citation statements)

References 23 publications

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“…Multiple peaks within a season may represent different species flowering at various temporal intervals and/or multiple flowering events for the same species in a year. For example, the flowering season of Gamba grass is noted to occur after that of native grasses in NT (Stevenson et al 2007). These variables have not been able to be evaluated on a broader scale as the pollen-monitoring methods used do not differentiate grass pollen to species level nor between C 3 and C 4 types.…”

Section: Discussionmentioning

confidence: 99%

“…Pollen counts were performed and converted to grains per cubic meter of air for sites in (from lowest to highest latitude) Darwin (two sites), Brisbane, Sydney, Canberra (two sites) and Hobart over 2, 5, 8, 4 and 3 fiscal years, respectively (Dass 2010; Erbas et al 2007b; Green et al 2004; Katelaris and Burke 2003; Newnham et al 1995; Newnham 1999; Stevenson et al 2007, Tng et al 2010). Airborne pollen were counted within the expected grass pollen season of 92 days for Melbourne (October–December) over 13 of the 17 seasons, the others being full years, and between 88 and 134 days for the NZ sites (October–April) over one season.…”

Section: Methodsmentioning

confidence: 99%

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Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand

et al. 2015

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand

et al. 2015

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“…Pollen loads were validated against those from the secondary sampler. For the first 12 months of the study, these showed similar temporal distribution and loads of each taxa with the following exceptions: the primary sampler has a more urban location, and has the highest values of Arecaceae (palms) and Casuarina pollen, reflecting the proximity of the sample location to suburban gardens (that commonly feature palms) and the coast (where native Casuarina sp predominates); while the secondary site is in closer proximity to the regional savanna landscape and had slightly higher counts for Poaceae, Cyperaceae, and the native conifer Callitris (Stevenson et al, 2007). Some large Callitris plantations were established on the outskirts of Darwin in the 1960s.…”

Section: Environmental Exposuresmentioning

confidence: 99%

“…Seven taxonomic groups account for 90% of the pollen load. In order of frequency, these are: Myrtaceae (Eucalyptus and Melaleuca trees); Arecaceae (palms); Poaceae (grasses); Callitris (cypress pine); Cyperaceae (sedges); Casuarina (sheoak); and Acacia (wattles), with the remaining 10% composed of approximately 30 different pollen types seen only occasionally and in low numbers (Stevenson et al, 2007). The one major source of outdoor air pollution is vegetation fire smoke during the dry season (Gras et al, 2001).…”

Section: Settingmentioning

confidence: 99%

Pollen Loads and Allergic Rhinitis in Darwin, Australia: A Potential Health Outcome of the Grass-Fire Cycle

2009

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Although the prevalence of asthma and allergic rhinitis has been increasing in tropical regions, little is known about the allergenicity of pollens from tropical plant families or the importance of ongoing environmental changes. We investigated associations between daily average pollen counts of several tropical plant families and sales of medications for the treatment of allergic rhinitis in Darwin, Australia-a tropical setting in which grass abundance has increased due to increased fire frequencies and the introduction of African pasture grasses. Daily pollen counts with detailed identification of plant species were undertaken in conjunction with a weekly survey of flowering plant species from April 2004 to November 2005. Five pharmacies provided daily sales data of selected medications commonly used to treat allergic rhinitis. We used generalized linear modeling to examine outcomes.All analyses accounted for the potential confounding effects of time trends, holidays, respiratory viral illnesses, meteorological conditions, and air pollution. The peak total pollen count was 94 grains/m 3 . Despite the low levels of Poaceae (grass) pollen (maximum daily count, 24 grains/m 3 ), there was a clear association with daily sales of anti-allergic medications greatest at a lag of 1 day. Sales increased by 5% with an interquartile range rise (3 grain/ m 3 ) in Poaceae pollen (5.07%, 95%CI 1.04%, 9.25%). No associations were observed with pollen from other plant families. Although further testing is required, we suggest that an overlooked aspect of the ''grass-fire cycle'' that is degrading many tropical landscapes, could be an increase in the prevalence of allergic rhinitis.

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“…In recent years, several papers have highlighted differences or similarities between pollen counts in the atmospheres of several specific locations in regions with different climates, and relationships between meteorological conditions and atmospheric pollen concentrations (Galán et al 1995;Green et al 2004;Stevenson et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Pollen production in anemophilous species of the Poaceae family in Tetouan (NW Morocco)

et al. 2008

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Total pollen production per inflorescence and per square meter were studied in anemophilous species of the Poaceae family, to determine the relative contribution of each species to the total load of pollen released and to identify the species with the highest potential pollen emission. This was done by calculating the number of pollen grains per flower and per inflorescence and by estimating the density of inflorescences in an area of one square meter. Pollen production per inflorescence varied between 12,000 and 15 million grains, often being higher in the perennial species. Mountainous, grassland, riverside, and littoral areas contributed similarly to the amount of pollen grain production per square meter. Species such as Gaudinia fragilis, Hordeum murinum, Lolium rigidum, and Trisetaria panicea, with high pollen records, were found in all the studied areas. Aerobiological analysis will be undertaken to determine the main pollen season of Poaceae species. The results obtained are of great importance for respiratory health management in this region.

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Seasonal distribution of pollen in the atmosphere of Darwin, tropical Australia: Preliminary results

Cited by 17 publications

References 23 publications

Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand

Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand

Pollen Loads and Allergic Rhinitis in Darwin, Australia: A Potential Health Outcome of the Grass-Fire Cycle

Pollen production in anemophilous species of the Poaceae family in Tetouan (NW Morocco)

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