Bioaerosol capture is largely biased towards ground sampling, often utilising expensive equipment which is not a viable option for many researchers due to funding limitations. For research requiring atmospheric sampling at significant altitudes i.e., ~1000m above ground level, often planes, helicopters or balloons have been utilised, which are also acquired at a high price. Additionally, it is common for a building roof to be used as a proxy for “high” samples. Having relatively low-cost equipment which can be portable as well as affordable is a more desirable and worthwhile option. This is where we believe that drones can be significant tools in bioaerosol research, especially for fungal spore capture.

Creating sampling methods which utilise drones would allow researchers to explore areas that are difficult to reach i.e., above tree canopies or potentially up to 500metres above ground level. Drones can fly into and within spaces that previously commonly used atmospheric samplers are simply too big to manoeuvre in. Three different sampling methods utilising a drone were tested and compared, methods include using 1) 47mm glass fiber filters placed beneath the propellers, 2) the application of glycerol (impaction medium) to the propellers to capture floating fungal spores and lastly 3) an automated pump system utilising a readily available low-cost pump in combination with an Arduino (open-source electronic hardware).

Using a preowned DJI Phantom 3 Standard drone, Poweregg X (waterproof drone) and a DJI Phantom 4 Pro V2.0, we conducted numerous 10-minute flights in various locations within Kakuma forest, Kanazawa University campus, including below and above the forest canopy, a coastal region as well as upon a building roof, and have explored and compared the collection efficiencies of each proposed sampling method. In addition, sampling efficiency comparisons have been made between the use of a standard conventional sampling pump (Sibata MINIPUMP MP-Sigma500NII) and a drone at the same height above ground, ranging from 8metres to 35.8metres. Furthermore, for the first time, we show how bioaerosol sampling with a drone can be achieved during rain. Results indicate that the automated system is the most efficient sampling method for fungal spores and can be comparable to the conventional sampling pump. Overall, we have provided and compared three low-cost methods of fungal spore collection that can be used whilst exploiting the various attributes and mechanisms of a drone.