Sampling pollens

Although early microscopists established the presence of pollens in the air in the 18th century, airborne pollens were not sampled until the end of the 19th century. For many years, the sedimentation slide was the commonest method of assessing airborne pollen concentrations but later, samplers originally developed for sampling airborne bacteria and fungal spores were utilised. In particular, the Hirst automatic volumetric spore trap, which was based on a cascade impactor but additionally allowed collection of the sample onto a moving slide, became the commonest method of pollen sampling. This allowed much more accurate assessments of pollen concentration than had previously been possible and more detailed studies of diurnal and seasonal periodicities. This article evaluates different pollen sampling methods and recently developed techniques for collecting pollen antigens for immunoassay and DNA amplification.