Wind Tunnel Comparison of the Collection Efficiency of Three Hirst-Type Volumetric Sampler Drum Coatings

A large number of sites worldwide measure airborne pollen and fungal spore concentrations using a Hirst-type volumetric impaction sampler. In Europe anumber of adhesive drum coatings are routinely used. The drum coating routinely used in the UK, V/P,consisting of 90% petroleum Jelly (Vaseline)/10%paraffin wax, has not previously been compared with other coatings, for fungal spores or pollens. The collection efficiency of different coatings was compared in a wind tunnel, at IACR-Rothamsted. Spores of different species were released and trapped in identical miniature suction traps which reproduce the aerodynamic features of a full size Hirst-type spore trap. The trapping surfaces were coated in one of three commonly used drum coatings: (1) V/P; (2) SiliconeFluid; (3) Glycerol Jelly. These are all used in Europe and both V/P and Glycerol Jelly are used the UK.
Four spore types, Lycopodium clavatum (moss);Alternaria alternata; Botrytis cinerea;and Calvatia excipuliformis, which represent the size range of spores most frequently found in the air, were used. With the exception of B cinerea, the numbers of spores collected on Glycerol Jelly were significantly smaller than on the other two coatings. For all spore types, the numbers caught on the V/P andSilicone Fluid were not significantly different.