Aerobiological studies based in Galway. A comparison of pollen and spore counts over two seasons of widely differing weather conditions

A comprehensive aerobiological study of the airborne pollen in the Irish environment

Respiratory allergies triggered by pollen allergens represent a significant health concern to the Irish public. Up to now, Ireland has largely refrained from participating in long-term aerobiological studies. Recently, pollen monitoring has commenced in several sampling locations around Ireland. The first results of the pollen monitoring campaigns for Dublin (urban) and Carlow (rural) concerning the period 2017-2019 and 2018-2019, respectively, are presented herein. Additional unpublished pollen data from 1978-1980 and, 2010-2011 were also incorporated in creating the first pollen calendar for Dublin. During the monitoring period over 60 pollen types were identified with an average Annual Pollen Integral (APIn) of 32,217 Pollen × day/m³ for Dublin and 78,411 Pollen × day/m³ for Carlow. The most prevalent pollen types in Dublin were: Poaceae (32%), Urticaceae (29%), Cupressaceae/Taxaceae (11%), Betula (10%), Quercus (4%), Pinus (3%), Fraxinus (2%), Alnus (2%) and Platanus (1%). The predominant pollen types in Carlow were identified as Poaceae (70%), Urticaceae (12%), Betula (10%), Quercus (2%), Fraxinus (1%) and Pinus (1%). These prevalent pollen types increased in annual pollen concentration in both locations from 2018 to 2019 except for Fraxinus. Although higher pollen concentrations were observed for the Carlow (rural) site a greater variety of pollen types were identified for the Dublin (urban) site. The general annual trend in the pollen season began with the release of tree pollen in early spring, followed by the release of grass and herbaceous pollen which dominated the summer months with the annual pollen season coming to an end in October. This behaviour was illustrated for 21 different pollen types in the Dublin pollen calendar. The correlation between ambient pollen concentration and meteorological parameters was also examined and differed greatly depending on the location and study year. A striking feature was a substantial fraction of the recorded pollen sampled in Dublin did not correlate with the prevailing wind directions. However, using non-parametric wind regression, specific source regions could be determined such as Alnus originating from the Southeast, Betula originating from the East and Poaceae originating from the Southwest.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10453-022-09751-w.

First Long-Time Airborne Fungal Spores Study in Dublin, Ireland (1978–1980)

Ambient fungal spores within the atmosphere can contribute to a range of negative human, animal and plant health conditions and diseases. However, trends in fungal spore seasonality, species prevalence, and geographical origin have been significantly understudied in Ireland. Previously unpublished data from the late 1970s have recently been collected and analysed to establish historical fungal spore trends/characteristics for Dublin. Historical spore concentrations were largely dominated by Alternaria, Ascospores, Basidiospores, Botrytis, Cladosporium, Erysiphe and Rusts. The main fungal spore season for Dublin commenced in April with the fructification of Scopulariopsis and Ganoderma. However, the vast majority of other spore types did not reach peak spore release until late summer. The correlation between ambient spore concentration, and meteorological parameters was examined using Multivariable Regression Tree (MRT) analysis. The notable correlations found for fungal spore concentrations tended to involve temperature-based parameters. The use of a non-parametric wind regression was also employed to determine the potential geographical origin of ambient fungal spores. The impact of wind direction, and high windspeed on fungal spores was established, ultimately highlighting the importance of studying and monitoring fungal spores within Ireland, rather than attempting to rely on data from other regions, as most fungal spores collected in Dublin appeared to originate from within the island.

Diversity, Concentration and Dynamics of Culturable Fungal Bioaerosols at Doha, Qatar

This research was conducted to investigate the dynamics of airborne fungi using viable culture collection and in respect to different abiotic variables, including seasonal and intra-diurnal variations. A gravimetric method was used to sample airborne fungal deposition on potato dextrose agar plates on alternate days, for a year between April 2015 to March 2016. From 176 settle plate exposures, a total of 1197 mould and 283 yeast colony-forming units (CFU), 21 genera and 62 species were retrieved. The highest fungal spore count was recorded in February 2016, whereas the lowest count occurred in August 2015. The main constituents of the fungal airspora were attributed to Cladosporium (60.2%), Aspergillus (10.4%), Fusarium (9.4%), Alternaria (8.5%), and Ganoderma spp. (2.3%). Temperature was negatively correlated with total colony count (r = −0.231, p ≤ 0.05) or species richness (r = −0.267, p ≤ 0.001), while wind speed was positively correlated with total colony count (r = 0.484, p ≤ 0.001) or species richness (r = 0.257, p ≤ −0.001). The highest dispersal of fungal spores was obtained at 18:00, whereas the lowest fungal spores release was recorded at 00:00 (midnight). There were no significant differences in species composition and richness of the airborne fungal population between two study sites, the Industrial area and Qatar University Campus. The count of Alternaria spp. and Fusarium spp. were significantly higher at the Industrial area site, which corresponds to a higher CO₂ level than the Qatar University site. This study lays the foundation for future work to assess the implications of such aeromycological data on public health.

Concentrations of airborne pollen grains in Sivrihisar (Eskisehir), Turkey

Pollen grains in the atmosphere of Sivrihisar were studied for a continuous period of 2 years (1 January 2005-31 December 2006) using a Durham sampler. During this period, pollen grains belonging to 41 taxa were recorded, 24 of which belonged to arboreal plants and 17 to non-arboreal. From these, 23,219 were identified in 2005 and 34,154 in 2006. Of the total pollen grains, 90.46% were arboreal, 9.43% non-arboreal, and 0.1% unidentifiable. The majority of the investigated allergic pollen grains were from Pinaceae, Cupressaceae, Fraxinus spp., Cedrus spp., Artemisia spp., Poaceae, Chenopodiaceae/Amaranthaceae, Populus spp., Quercus spp., Urticaceae and Asteraceae, respectively. Pollen concentrations reached their highest levels in May. This information was then established into a calendar form according to the pollens determined in 2005-2006, in terms of annual, monthly and weekly numbers of taxa fall per cm2. A comparison between the results and the meteorological factors revealed a close relationship between pollen concentrations in the air and meteorological conditions. An increase in pollination was also linked to increasing temperatures and the wind. It was therefore concluded that high temperatures and relative humidity were also effective in increasing the number of pollens in the air.

Meteorologic variables in aerobiology

Although prevalent weather helps define climate, individual weather conditions, such as rain, humidity, wind speed and direction, temperature, or amount of sunshine, may have direct and indirect effects on bioaerosols. Effects may be immediate or cumulative. Precipitation and humidity acutely decrease particle air burden, but sufficient preseason moisture is necessary to assure proper growth of flower buds on perennials and trees and growth of annuals in general. Ambient temperature increase is necessary for anthesis in many plants, and cumulative heat above a threshold value has been linked to onset and intensity of pollination in grasses, weeds, and trees. Wind direction only impacts if there is lack of uniformity in the pollen sources that surround sampling sites. Wind speed may factor in re-entrainment of settled particles or may act to scour the air. Thunderstorms provide a unique sum of factors that greatly may increase aeroallergen burden. Dispersal of mold spores is linked intimately to precipitation and humidity. The effects may be opposed diametrically, however, depending on the type of fungi. Certain ascospores and basidiospores require active rainfall for release of spores, whereas other Deuteromycetes are suppressed by precipitation.

A year-round study on functional relationships of airborne fungi with meteorological factors

Air sampling was conducted in Waterloo, Canada throughout 1992. Functional relationships between aeromycota and meteorological factors were analysed. The meteorological factors were, in descending order of importance: mean temperature, minimum temperature, maximum temperature, mean wind speed, relative humidity (RH), rain, maximum wind speed and snow. The most important airborne fungal propagules in descending order were total fungal spores, unidentified Ascomycetes, Cladosporium, Coprinus, unidentified Basidiomycetes, Alternaria and unidentified fungi. Most airborne fungal taxa and highly significant relationship with temperature, but Aspergillus/Penicillium, hyphal fragments were positively associated with wind speed. In comparison with other airborne fungal taxa, Leptosphaeria and unidentified Ascomycetes were more closely correlated with rain and RH during the growing season.

Incidence of airborne fungi in Isfahan, Iran

During the one-year period of this study, 288 samples were taken and 954 fungal colonies were isolated from the air of Isfahan, Iran. Among the fungi isolated, Cladosporium, yeasts, Penicillium, Aspergillus and Alternaria were the most frequent isolates respectively. This study showed that environmental factors affect the number and types of airborne fungi, opportunistic fungi, in Isfahan. Sampling location was an important factor: there were more fungal colony counts in the centre and populated locations of the city than in the less populated and rural areas. Regarding collection time, the most colony counts were obtained from samples collected at mid-day and the least in the morning. This study indicated that the incidence of airborne fungi with clinical significance had a direct relationship with the variation of environmental conditions. The results of the present study contribute towards a better understanding of the pattern of occurrence of airborne fungi, and may be useful for allergists, clinicians and epidemiologists.

Evidence for cross-reactive allergens among basidiomycetes: immunoprint-inhibition studies

Allergenic cross-reactivity among six basidiomycete species (Calvatia cyathiformis, Coprinus quadrifidus, Psilocybe cubensis, Pleurotus ostreatus, Ganoderma meredithae, and Pisolithus tinctorius) was determined by immunoprint inhibition. Extensive cross-reactivity was demonstrated among Coprinus quadrifidus, Psilocybe cubensis, and Pleurotus ostreatus of the order Agaricales, and Calvatia cyathiformis of the order Lycoperdales. However, G. meredithae (order Aphyllophorales) and Pisolithus tinctorius (order Sclerodermatales) did not demonstrate significant cross-reactivity with the other basidiomycete species. Generally, the two most potent inhibitors were Psilocybe cubensis and Pleurotus ostreatus. Inhibitory dose-response curves of a major allergenic band (isoelectric point, 9.3) were obtained by densitometry. Significant cross-reactivity was demonstrated for the 9.3 band among the species of the order Agaricales and with Calvatia cyathiformis. The most potent inhibitors were again Psilocybe cubensis and Pleurotus ostreatus. Thus, there is substantial allergenic cross-reactivity among the species of the order Agaricales tested and with Calvatia cyathiformis but not between these four species and G. meredithae or Pisolithus tinctorius. These studies support earlier RAST-inhibition observations of shared allergenic epitopes among basidiomycetes, especially epitopes within the Agaricales. The presence of shared epitopes suggests the possibility of devising a panel of skin test reagents representative of a large group of basidiomycetes.

Immunoprint analysis of Calvatia cyathiformis allergens. I. Reactivity with individual sera

Basidiomycete allergens have received scant attention to date, compared to allergens from deuteromycetes. This is true even though in previous studies, 32% of atopic patients with respiratory allergies were skin test reactive to basidiospore extracts. Since sufficient quantities of Calvatia cyathiformis spores were available, their allergens were sequentially fractionated by gel filtration (GF) and hydrophobic interaction chromatography (HIC). Unfractionated extract (crude), GF, and HIC fractions were electrofocused in polyacrylamide gel (pH 3.5 to 9.5) and immunoprinted onto CNBr-activated nitrocellulose (0.2 microns) filters. Sera from 19 skin prick test positive and 10 negative subjects, with comparable total IgE levels, were used to screen individual strips of each blot. Blots were reacted with 125I-labeled anti-IgE and analyzed by autoradiography. IgE from 79%, 89%, and 89% of the positive sera bound to crude extract, GF, and HIC, respectively; IgE from none of the negative sera bound to crude extract. A series of bands (pH 3.6 to 4.6) reacted with 63%, one band (pH 6.6) reacted with 68%, and one band (pH 9.3) reacted with 63% of the sera tested. These studies demonstrate at least three important groups of allergens in C. cyathiformis spores. This characterization allows assignment of initial C. cyathiformis allergen designations and development of a purification protocol.

A study on airborne allergenic pollen content of the atmosphere of Naples

In this paper we describe the results of volumetric sampling of the airborne allergenic pollen content of the Naples atmosphere. These studies have been carried out continuously since 1 May 1979 until 31 December 1981 utilizing a Burkard volumetric spore trap. We found that the most important allergenic pollen in Naples air is Parietaria, with a very long-lasting period of pollination occurring from March to November. After Parietaria, Gramineae play an allergenic role frequently in association with the pollen of Olea, which is the most important pollen of all the trees in this area. In the summer/autumn seasons we observed in this area the pollination of mugwort (the unique plant of the Compositae) which was found to be of allergenic importance in Naples.