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Rationale: Ambrosia (ragweed), a member of the Asteraceae family, is very allergenic and its pollen is clinically important because its immunogenic components can exacerbate airway allergic diseases. Investigators have demonstrated that ragweed flourishes more in urban than rural areas because of the increase levels of atmospheric CO2. From the recent weather reports of unusually high temperatures in Florida, we hypothesized that anemophilous ragweed pollen will increase significantly in 2023. Methods: A 7-day Burkard volumetric sampler on the roof of a 5-story dormitory at Edward Waters University in Jacksonville Florida collected daily pollen from December 2020 to August 2023. However, the spore trap was inoperable during the late spring of 2022 through the summer of 2022. Pollen samples were analyzed as specified by the NAB of the AAAAI. Results: Previously, we observed only moderate (>10<50 grains /m3) levels of Ambrosia pollen during the late Spring and Summer of 2021. In 2023, high levels were observed as the difference between the median Ambrosia pollen concentrations from the 2021 and 2023 seasons was statistically significant (p<0.001) and estimated to be 4.32 (95% CI 2.16 to 6.48). Conclusions: The significant increase in concentration of Ambrosia pollen grains from moderate in 2021 to high in 2023 are important aerobiological data to assist the allergists for the treatment of patients with pollinosis especially from the vulnerable urban communities. The unusually high temperatures in 2023 may be partially responsible for the observed significant increase in pollen concentration levels in Jacksonville Florida.
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Airborne sub-pollen particles from rupturing giant ragweed pollen
Abstract Ragweed pollen is a prevalent allergen in late summer and autumn, worsening seasonal allergic rhinitis and asthma symptoms. In the atmosphere, pollen can osmotically rupture to produce sub-pollen particles (SPP). Because of their smaller size, SPP can penetrate deeper into the respiratory tract than intact pollen grains and may trigger severe cases of asthma. Here we characterize airborne SPP forming from rupturing giant ragweed ( Ambrosia trifida ) pollen for the first time, using scanning electron microscopy and single-particle fluorescence spectroscopy. SPP ranged in diameter from 20 nm to 6.5 μm. Most SPP are capable of penetrating into the lower respiratory tract, with 82% of SPP < 1.0 μm, and are potential cloud condensation nuclei, with 50% of SPP < 0.20 μm. To support predictions of the health and environmental effects of SPP, we have developed a quantitative method to estimate the number of SPP generated per pollen grain ( $${n}_{\mathrm{f}}$$ n f ) based upon the principle of mass conservation. We estimate that one giant ragweed pollen grain generates 1400 SPP across the observed size range. The new measurements and method presented herein support more accurate predictions of SPP occurrence, concentration, and air quality impacts that can help to reduce the health burden of allergic airway diseases. Graphic abstract Rupturing ragweed pollen releasing cellular components (right), viewed by an inverted light microscope.
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- Award ID(s):
- 1906091
- PAR ID:
- 10314309
- Date Published:
- Journal Name:
- Aerobiologia
- Volume:
- 37
- Issue:
- 3
- ISSN:
- 0393-5965
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s10453-021-09702-x
