Aerobiological studies based in Derby. I. A simplified automatic volumetric spore trap.

A simplified version of the Hirst automatic volumetric spore trap has been developed in Derby for aerobiological studies. In comparative trials, the number of spores retained by the Morrow Brown trap were similar in the case of larger spores such as Alternaria (102%), rather higher in the case of grass pollen (136%) and considerably higher (166--201%) for very small spores such as Sporobolomyces and Tilletiopsis. Impaction efficiency has been improved by using a narrower slit. The trap designed in Derby is simple to produce and presents advantages in design over the Hirst version.