Medium-Term Increases in Ambient Grass Pollen Between 1994-1999 and 2016-2020 in a Subtropical Climate Zone

Abstract

Grass pollen is the major outdoor trigger of allergic respiratory diseases. Climate change is influencing pollen seasonality in Northern Hemisphere temperate regions, but many aspects of the effects on grass pollen remain unclear. Carbon dioxide and temperature rises could increase the distribution of subtropical grasses, however, medium term shifts in grass pollen in subtropical climates have not yet been analysed. This study investigates changes in grass pollen aerobiology in a subtropical city of Brisbane, Australia, between the two available monitoring periods, 1994-1999 and 2016-2020. Potential drivers of pollen change were examined including weather and satellite-derived vegetation indicators. The magnitude of the seasonal pollen index for grass showed almost a three-fold increase for 2016-2020 over 1994-1999. The number and proportion of high and extreme grass pollen days in the recent period increased compared to earlier monitoring. Statistically significant changes were also identified for distributions of CO2, satellite-derived seasonal vegetation health indices, and daily maximum temperatures, but not for minimum temperatures, daily rainfall, or seasonal fraction of green groundcover. Quarterly grass pollen levels were correlated with corresponding vegetation health indices, and with green groundcover fraction, suggesting that seasonal-scale plant health was higher in the latter period. The magnitude of grass pollen exposure in the subtropical region of Brisbane has increased markedly in the recent past, posing an increased environmental health threat. This study suggests the need for continuous pollen monitoring to track and respond to the possible effects of climate change on grass pollen loads.

Association between grass, tree and weed pollen and asthma health outcomes in Adelaide, South Australia: a time series regression analysis

“…Considering the at times sharp upward trend in pollen concentrations over the study period, it will be necessary to observe pollen in concurrence with ongoing climate change, specifically since the pollen season, as shown in this study, is not confined to spring. Rising CO 2 levels, warming and changing rainfall patterns may increase and shift the flowering seasons in conjunction with increased pollen load, possible changing allergenicity of pollen and potentially increasing the risk to public health year-round 34 37 38. Improved understanding of the spatiotemporal distribution of pollen and its allergenicity is required, with a necessary aim being the establishment of an extensive, standardised aerobiology monitoring programme.…”

“…Improved understanding of the spatiotemporal distribution of pollen and its allergenicity is required, with a necessary aim being the establishment of an extensive, standardised aerobiology monitoring programme. This will improve knowledge of pollen taxa and subspecies across Australia and aid understanding of associated health outcomes, the importance of which has been voiced by other researchers in Australia 34 35 38…”

Sensitization patterns to Poaceae pollen indicates a hierarchy in allergens and a lead of tropical grasses

“…The components of multiplex allergy test ALEX 2 The sex, age, and medical conditions of the patients were also recorded (Table 1). To determine the IgE-reactivity pattern to grass pollen in different age groups, we assessed sensitivity patterns in the following age groups: 0-1 year, 2-3, 4-6, 7-12, 13-18, 19-25, 26-36, 37-44 and 45-60 years.…”

“…The allergenicity of pollen from plants of the Poaceae family is a well‐known and confirmed fact 1,2 . Depending on the climate and regional characteristics, sensitivity to this type of pollen can reach up to 30% 3 .…”

“…The allergenicity of pollen from plants of the Poaceae family is a well‐known and confirmed fact. 1 , 2 Depending on the climate and regional characteristics, sensitivity to this type of pollen can reach up to 30%. 3 Exposure to Poaceae pollen causes symptoms of allergic rhinoconjunctivitis and/or asthma in sensitive individuals, 4 such as thunderstorm asthma in Australia.…”