Rotapollen Sampler: An affordable, portable, and programmable rotorod-style device for measuring airborne pollen concentrations

We present designs for a rotorod-style device for sampling airborne pollen and other particulates >10 µm. This device is affordable ($118 USD for the first individual sampler with an incremental cost of $48 for the 10th sampler built) and collects data very similar to commercial pollen measurement devices (that cost $1300-$6000 per sampler). The design is portable, battery operated, programmable, and includes retracting sampling rods to prevent passive sampling between periods of active sampling and can include a rain shield to allow deployment in inclement weather. The main sampler is 135 × 75 × 93 mm and weighs 185 g, allowing for easy deployment on portable tripods at breathing height. As with other rotorod-style devices, active sampling time during normal pollen concentrations is limited to 1 h, but this sampling activity can be distributed across periods ranging up to several days; the timing of sampling is programmable through a simple and easily modifiable Arduino script. This validated sampler (r > 0.99 compared to a commercial rotorod-style device) is field tested and results have been published in several peer-reviewed publications. The Rotapollen Sampler is well suited for investigations of airborne pollen concentrations, and especially for sampling campaigns that simultaneously collect measurements in multiple locations, such as those that seek to understand spatial heterogeneity in airborne pollen concentrations.