We examined the reliability of measurements from a single Burkard volumetric trap to represent the distribution of airborne concentrations of spores of Alternaria and pollen across two towns in rural Australia. Each town was sampled with three traps, sited 2.0 to 4.9 km apart, simultaneously. Substantial intra-class correlation coefficients (ICC) were observed between all three sites (ICC~0.52, 95% CI 0.30-0.71 to 0.76, 95% CI 0.61-0.87) when counts of pollen and Alternaria spores were relatively high. The correlation was poor when counts were low. Highly variable distributions of cypress pollen were found to be location dependent. We further compared two central lengthwise microscopic traverses of Burkard trap samples collected daily over one year. Correlation was strong for Alternaria spores (ICC~0.95, 95% CI 0.94-0.96), grass pollen (ICC~0.94, 95% CI 0.91-0.96) and total non-grass pollen (ICC~0.91, 95% CI 0.89-0.93). We conclude that a single central traverse of a Burkard trap sample collected at one location provides an acceptable measure of the concentrations of spores of Alternaria and grass pollen across the two rural towns when counts are relatively high. The measure is less reliable when counts are low.

• fungi: assessment, sampling and analysis