Wind tunnel comparison of the collection efficiency ofthree Hirst-type volumetric sampler drum coatings

Abstract

A large number of sites worldwide measure airbornepollen and fungal spore concentrations using aHirst-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 withother coatings, for fungal spores or pollens. Thecollection efficiency of different coatings wascompared in a wind tunnel, at IACR-Rothamsted. Sporesof different species were released and trapped inidentical miniature suction traps which reproduce theaerodynamic features of a full size Hirst-type sporetrap. The trapping surfaces were coated in one ofthree commonly used drum coatings: (1) V/P; (2) SiliconeFluid; (3) Glycerol Jelly. These are all used in Europeand 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 thesize range of spores most frequently found in the air,were used. With the exception of B cinerea, thenumbers of spores collected on Glycerol Jelly weresignificantly smaller than on the other two coatings.For all spore types, the numbers caught on the V/P andSilicone Fluid were not significantly different.