Development of a novel real-time pollen-sorting counter using species-specific pollen autofluorescence

We developed a novel flow particle analyzer that automatically classifies airborne pollen grains. The design of the particle counter (model KP-1000) is based on that of a flow cytometer, applied to the measurement of airborne particles. The counter classifies pollen species by simultaneously detecting both scattered light and the characteristic fluorescence excited by ultraviolet light in the flow cell. We observed airborne pollen using KP-1000 pollen counters and Durham samplers to compare their performance at three study sites in Japan during the spring pollen season. The pollen counter followed the variation in pollen concentrations, and its daily pollen counts were significantly correlated with the results of the Durham sampling method at all study sites. Although the counter over- or under-counted 2 target pollen species (Cryptomeria japonica and Chamaecyparis obtusa) when they coexisted, a data correction based on the Durham sampling results improved the accuracy of pollen classification of the counter. Our results indicate that the new pollen counter has a strong potential for counting and identifying airborne pollen grains in real time, and it requires further improvement, field trials, and tests with other common airborne pollen grains.