Brett James Green

Measuring environmental fungal exposure

Airborne fungi are ubiquitous in the environment and human exposure is inevitable. Such fungi differ greatly in their taxonomic, physical, ecological, behavioral, and pathogenic characteristics. Many strategies have evolved to sample, identify and interpret fungal exposure and their choice is determined by the hypotheses involved. While fungi can be sampled directly from surfaces, results do not generally reflect human exposure. For this reason, airborne spores are commonly sampled, by either filtration or impaction, using volumetric air samplers. Identification is commonly performed by either culture on nutrient medium or light microscopy using morphological criteria, although new techniques using DNA probes or characteristic antigens or toxins continue to be developed. Interpretation of such exposure data is both complex and contentious, but while there are numerous recommendations there is no consensus on exposure thresholds. A better understanding of the complex pathogenic roles of fungi and susceptibilities of their hosts will enable refinement of techniques for sampling and interpretation.

Airborne Pinus pollen in the atmosphere of Brisbane, Australia and relationships with meteorological parameters

Relationships between weather parameters andairborne pollen loads of Pinus inBrisbane, Australia have been investigated overthe five-year period, June 1994–May 1999.Pinus pollen accounts for 4.5% of the annualairborne pollen load in Brisbane where thePinus season is confined to the winter months,July–early September. During the samplingperiod loads of 11–>100 grains m3 wererecorded on 24 days and 1–10 grains m3 on204 days. The onset and peak dates wereconsistent across each season, whereas the enddates varied. The onset of the Pinuspollen season coincided with the coolestaverage monthly temperatures (< 22°C),lowest rainfall (< 7mm), and four weeks afterdaily minimum temperatures fell to 5–9°Cin late autumn. Correlations obtained betweendaily airborne Pinus pollen counts andtemperature/rainfall parameters show thatdensities of airborne Pinus pollen arenegatively correlated with maximum temperature(p < 0.0001), minimum temperature (p < 0.0001)and rainfall (p < 0.05) during the mainpollination period. The mean duration of eachpollen season was 52 days; longer seasons wereshown to be directly related to lower averageseasonal maximum temperatures (r2 = 0.85,p = 0.025). These results signify that maximumand minimum temperatures are the majorparameters that influence the onset andduration of the Pinus pollen season inthe environs of Brisbane. Respiratory allergyis an important health issue in Brisbane,Australia, but it remains unknown whether ornot airborne Pinus pollen is acontributing factor.